Directory of automotive words

DICTIONARY OF AUTOMOTIVE TERMS
(A - E)
A:
Abbreviation or symbol for absolute temperature, absorption coefficient,
acceleration, adenine, ampere, amplitude, angular acceleration, area,
attenuation coefficient, fine-structure constant, helium nucleus, Helmhotz
free energy, magnetic vector potential, relative atomic mass, a
stereoisomer of a sugar, substitution on a carbon atom next to one common
to two condensed aromatic nuclei, substitution on the carbon atom next to
the hetero-atom in ahetero-cyclic compound, and substitution on the
carbon atom of a chain next to the functional group.
A-2 tire:
A term used for tire sizes 16.00 and larger in nominal cross section. Also
called earthmover or off-the-road tire.
AA:
Abbreviation for "Automobile Association" a term used in Great Britain.
aa:
A term of Hawaiian origin for lava flows with a rough, jagged surface.
AAA:
Acronym for "American Automobile Association" or "Alberta Automobile
Association."
AABM:
Acronym for "Association of American Battery Manufacturers, Inc."
AAE:
Acronym for "Association of Automotive Employers" (Poland).

AAIA:
Acronym for "Automotive Aftermarket Industry Association".
AALA:
Acronym for "American Automobile Labelling Act."
aalenian:
The oldest stage of the Middle-Jurassic.
AAM:
Acronym for "Alliance of Automobile Manufacturers".
AAP:
Acronym for "auxiliary acceleration pump".
A arm:
See A-arm
A-arm:
A suspension linkage formed in the shape of
an "A" or "V" found commonly on the front
suspension. The sides of the two legs of the
A-arm are connected to the chassis by rubber
bushings and the peak of the A-arm is
attached to the wheel assembly. In this way,
the wheel can freely move up and down.
Sometimes there is an upper A-arm, a lower
A-arm, or both upper and lower A-arms. The
British call it a "wishbone."
Also see
double wishbone
A-arm suspension:
See double wishbone
AAS:

Acronym for "air aspirator system".
abacus:
[1] The uppermost part of a column capital or
pilaster, on which the architrave rests.
[2] A bead frame. Used as an arithmetic
calculating aid.
abampere:
A unit of electric current in the CGS electromagnetic system of units. One
abampere equals 10A.
abamurus:
A supporting wall or buttress, built to add strength to another wall.
abandonment:
A voluntary surrender of legal rights or title to a mining claim.
abatjour:
An opening to admit light and generally to deflect it downwards; a
skylight.
abaxial:
Rays of light which do not coincide with the optical axis of a lens system.
ABC:
[1] Acronym for "aerial bunched conductors"
[2] Acronym for "automatic beam control".
ABDC:
Acronym for after bottom dead center. A term used in timing the relation
of the spark and the crankshaft.
Abel flashpoint apparatus:

A petroleum-testing apparatus for determining the flash-point.
Abelian group:
A group in which the group operation is commutative. It is important in
the study of rings and vector spaces.
aberration:
[1] An apparent change of position of a heavenly body, due to the speed of
light having a finite ratio to the relative velocity of the source and the
observer.
[2] In an image-forming system, e.g., an optical or electronic lens, failure
to produce a true image, e.g., a point object as a point image. Geometrical
aberrations include spherical aberration, coma, astigmatism, curvature of
the field, and distortion.
See chromatic aberration
abhesive:
A substance which prevents two materials sticking together, e.g., Teflon®
on frying pans.
ability:
See
climbing ability
cold cranking ability
ABL:
Acronym for "atmospheric boundary layer" panel.
ablation:
[1] Any one of the processes by which snow and ice are lost from a glacier,
mainly by melting and evaporation (sublimation).
[2] Removal of surface layers of a meteorite and tektites during flight.
ablative polymer:
A material which degrades controllably in an aggressive environment,
especially on re-entry space-craft. Extreme temperatures are reached on
heat shield, so it is protected with ablation shield made of e.g., silicone
polymer. The same principle is used in intumescent paints for fire

resistance.
Abney law:
A rule stating that if a spectral color is desaturated by the addition of white
light, and if its wave length is less than 570 nm, its hue then moves
towards the red end of the spectrum, while if the wavelength is more than
570 nm its hue moves towards the blue.
Abney level:
Hand-held instrument in which angles of steep sights are measured while
simultaneously viewing a spirit-level bubble.
Abney mounting:
A form of mounting for a concave diffraction grating, in which the eye-
piece (or photographic plate holder) is fixed at the center of curvature of
the grating and the slit can move around the circumference of the Rowland
circle, to bring different orders of spectrum into view.
abnormal glow discharge:
A discharge carrying current in excess of that which is required to cover
the cathode completely with visible radiation.
abnormal reflection:
Reflection from the ionosphere of a radio wave whose frequency is greater
than the critical frequency.
aboard:
See lighter aboard ship
aboard ship:
See lighter aboard ship
A-bomb:
See atomic bomb
A bone:

Nickname for a Ford Model "A".
abort:
To terminate a vehicle's flight either by failure or deliberate action to
prevent dangerous consequences; if manned, a predetermined sequence of
events is followed to ensure the safety of the crew.
ABPV:
Acronym for "air bypass valve".
abradant:
A substance, usually in powdered form, used for grinding.
Also see
abrasive
abrade:
To scratch or tear away two surfaces in contact by relative motion.
Abram's law:
A rule that the ratio of water to cement for chemical action to impart
strength to concrete is 0.85:1.
abrasion:
[1] Wearing or rubbing away some surface because of friction.
[2] Mechanical wearing away of rocks by rubbing during movement.
abrasion hardness:
Resistance to abrasive wear, under specified conditions, of metal or
mineral.
abrasive:
A hard grit used for sanding or grinding. It is usually in powdered form,
used for the removal of material by scratching and grinding, e.g., silicon
carbide powder (carborundum).
Also see
bonded abrasive

coated abrasive
non-woven abrasive
abrasive blast cleaning:
A method for preparing steel for painting whereby abrasive particles, e.g.,
copper slag, are projected under pressure through a nozzle. Very effective
in removing rust and mill scale, leaving an anchor pattern (a pattern of
minute projections) on the substrate affording good paint adhesion.
abrasive cleaner:
A cleanser with some hard grit used to remove the grime and oils from a
surface.
abrasive disc:
A circular plate (often made of plastic with hard grit
embedded into it) used for grinding or sanding.
abrasive paper:
Sandpaper (a paper upon which sand or hard grit has been glued) used for
sanding or grinding.
abrasive wear:
A mechanism of wear due to the presence in one or both surfaces of hard
particles (e.g., carbide in steels), or to hard particles trapped between them.
A/B roll editing:
Video editing using two source players (A and B) enabling dubbing from
both. Necessary if scenes are to be superimposed.
A/B roll printing:
A method of film printing with alternate scenes assembled in two rolls,
each having black spacing equivalent in length to the omitted scene;
double printing from the two allows the inclusion of fade and dissolve
effects and avoids visible splice marks between scenes in 16 mm printing.

ABS:
[1] Acronym for "anti-lock brakes. The acronym ABS comes from the
German anti blockier system.
[2] Acronym for "acylonitrile-butadiene-styrene."
Also see
copolymer
abscissa:
For rectilineal axes of coordinates, the distance of a point from the axis of
ordinates measured in a direction parallel to the axis of abscissae, which is
usually horizontal. The sign convention is that measurements to the right
from the axis of ordinates are positive, measurements to the left negative.
absolute:
A conic (a quadric in three dimensions) formed by the assemblage of the
points at infinity on a line (in general two points). Its form determines the
metrical properties of the geometrical system being operated. Thus in
Euclidean geometry, the absolute is the degenerate conic comprising the
line at infinity taken twice, while in non-Euclidean geometry, the absolute
is either a real conic (hyperbolic geometry) or an imaginary conic (elliptic
geometry).
Also see
manifold absolute pressure sensor
POA suction throttling valve
absolute address:
A computer code designation of a specific memory location as determined
by the hardware.
absolute age:
The geological age of a fossil, mineral, rock or event, generally given in
years.
absolute ampere:
The standard MKS unit of electric current; replaced the international
ampere in 1948.

absolute ceiling:
The height at which the rate of climb of an aircraft, in standard
atmosphere, would be zero; the maximum height attainable under standard
conditions.
absolute electrometer:
A high-grade attracted-disk electrometer in which an absolute
measurement of potential can be made by weighing the attraction between
two charged disks against gravity.
absolute filter:
A filter which removes most particulate matter from gases.
absolute humidity:
The mass (actual amount) of water vapor present in a unit of volume of
moist air.
absolute instrument:
An instrument which measures a quantity directly in absolute units,
without the necessity for previous calibration.
absolute permeability:
See permeability
absolute pressure:
Pressure measured from a starting point of zero in perfect vacuum. When
measured by the absolute pressure scale, atmospheric pressure is 14.7 psi
or 29.92 inches of mercury (in-Hg).
Also see
manifold absolute pressure sensor
absolute pressure sensor:
See manifold absolute pressure sensor
barometric absolute pressure sensor
absolute reaction rate:
The reaction rate determined from statistical thermodynamics; uses the
assumption of the theory of absolute reaction rates that the rate of a

chemical reaction is governed by the rate of crossing an energy barrier or
of forming an activated complex.
absolute temperature:
Temperature measured with respect to absolute zero, i.e., the zero of the
kelvin thermodynamic scale of temperature, a scale which cannot take
negative values.
absolute temperature scale:
Also called the absolute scale temperature as measured on a scale in
which the hypothetical lowest limit of physical temperature is assigned the
value zero. The Kelvin scale is an example of the absolute temperature
scale.
absolute units:
Units derived directly from the fundamental units of a system and not
based on arbitrary numerical definitions. The differences between absolute
and international units were small; both are now superseded by the
definitions of SI units.
absolute wavemeter:
A wavemeter in which the frequency of the injected radio-frequency signal
is by calculation of physical properties (circuit elements or dimensions) of
a resonant circuit line or cavity.
absolute weight:
The weight (or mass) of a body in a vacuum.
absolute zero:
The point at which there is a total absence of heat, minus 459.67°F
(-273.15°C).
absorbance:
[1] The logarithm of the ratio of the intensity of light incident on a sample
to that transmitted by it. It is usually directly proportional to the
concentration of the absorbing substance in a solution.

[2] The capacity of materials such as textile fibers and paper to absorb
liquids.
absorbed dose:
Quantity of energy imparted by ionizing radiation to a unit mass of
biological tissue. Unit is the gray.
absorbent:
Substance with the ability to take up or absorb another substance.
absorber:
Any material which converts energy of radiation or particles into another
form, generally heat. Energy transmitted is not absorbed. Scattered energy
is often classed with absorbed energy.
Also see
air shock absorber
arc absorber
adjustable shock
absorbers
damper
direct-acting shock
absorber
double-tube shock
absorber
friction shock
absorber
gas shock absorber
impact absorber
lever-type shock
absorber
monotube shock
absorber
self-levelling shock
absorber
shock absorber
single-tube shock
absorber.
telescopic shock
absorber
UV absorber
absorber rod:
See control rod
absorber tower:
See shock absorber tower
absorbing:
See energy absorbing steering column
energy absorbing bumper
absorbing bumper:
See energy absorbing bumper
absorbing material:
Any medium used for absorbing energy from radiation of any type.

absorbing steering:
absorbing steering column:
absorptance:
A measure of the ability of a body to absorb radiation; the ratio of the
radiant flux absorbed by the body to that incident on the body.
absorption:
The use of reagents to remove unwanted antibodies or antigens from a
mixture.
Also see
acoustic absorption
air absorption
atmospheric absorption
sound absorption
absorption band:
A dark gap in the continuous spectrum of white light transmitted by a
substance which exhibits selective absorption.
absorption capacitor:
A capacitor connected across a spark gap to damp the discharge.
absorption coefficient:
[1] The volume of gas, measured at stp, dissolved by unit volume of a
liquid under normal pressure (i.e., one atmosphere).
[2] The fraction of the energy which is absorbed.
[3] The reduction of amplitude, for a beam of radiation or other wave
system incident on a discontinuity in the medium through which it is
propagated, or in the path along which it is transmitted.
[4] In a medium, the natural logarithm of the ratio of incident and
emergent energy or amplitude for a beam of radiation passing through unit
thickness of a medium.
Also see
acoustic absorption coefficient

absorption discontinuity:
See absorption edge
absorption dynamometer:
A dynamometer which absorbs and dissipates the power which it
measures, e.g., the ordinary rope brake and the Froude hydraulic brake.
absorption edge:
The wavelength at which there is an abrupt discontinuity in the intensity of
an absorption spectrum for electromagnetic waves, giving the appearance
of a sharp edge in its photograph. The transition is due to one particular
energy-dissipating process.
absorption factor:
See acoustic absorption factor
absorption hygrometer:
An instrument by which the quantity of water vapor in air may be
measured.
absorption inductor:
See interphase transformer
absorption lines:
Dark lines in a continuous spectrum caused by absorption by a gaseous
element. The positions (i.e., wavelengths) of the dark absorption lines are
identical to those of the bright lines given by the same element in
emission.
absorption nebula:
See dark nebula
absorption plant:
Plant where oils are removed from natural gas by absorption in suitable
oil.
absorption refrigerator:

[1] A plant in which ammonia is continuously evaporated from an aqueous
solution under pressure, condensed, allowed to evaporate, and then
reabsorbed.
[2] A refrigerator which creates low temperatures by using the cooling
effect formed when a refrigerant is absorbed by chemical substance.
absorption spectrum:
The system of absorption bands or lines seen when a selectively absorbing
substance is placed between a source of white light and a spectroscope.
absorption wavemeter:
A wavemeter which depends on a resonance absorption in a tuned circuit,
constructed with very stable inductance and capacitance.
absorptive power:
See absorptance
absorptivity:
See absorptance
ABS override button:
A button or switch which disengages the automatic anti-lock braking
system so that the driver can operate the brakes himself.
ABS relay valve:
An electrically controlled valve which modulates the air pressure in the
ABS.
abundance:
See relative abundance
frequency
abundance ratio:
For a naturally occurring element, the proportion or percentage of one
isotope to the total.
abundant number:

A natural number for which the sum of the proper factors is greater than
the number itself, e.g., 18 is abundant since 1+2+3+6+9>18. Compare
deficient number and perfect number.
abut:
The action of two gear teeth making contact.
abutment:
[1] A part which stops the motion of another part from proceeding any
farther.
[2] A cement raised shoulder secured to the side of the road to prevent a
vehicle from going over the edge.
[3] The contact made between opposing teeth of two gears.
abutment load:
In stopping or other deep-level excavation, weight transferred to the
adjacent solid rock by unsupported roof.
abutting edge:
The side or edge of a panel which joins another panel.
abutting joint:
a timber joint whose plane is at right angles to the fibers, the fibers of both
joining pieces being in the same straight line.
ABV:
Acronym for "air bypass valve".
abyssal:
term describing the ocean floor environment between ca4000 and 6000 m.
abyssal deposits:
Pelagic marine sediments, accumulating in depths of more than 2000 m
including, with increasing depth, calcareous oozes, siliceous oozes and red
clay (500 m).

abyssal plain:
a flat region of the deep ocean floor with a slope of less than 1:1000.
abyssopelagic:
relating to the open waters of the abyssal zone.
A/C:
[1] An abbreviation for air conditioning or air conditioner.
[2] An abbreviation for "across corners" which indicates the distance on a
nut (for instance) from one corner to the opposite corner rather than the
distance from one flat surface (A/F) to the opposite (which would be the
size of wrench needed to install or remove the nut). The purpose of the
A/C dimension is to know how large a hole might be needed to insert a
recessed nut.
AC:
[1] A vehicle brand of which the 1925-48 models are classic cars.
[2] Acronym for "alternating current."
[3] Acronym for "air conditioning" or "air conditioner."
[4] Symbol for actinium
[5] The transformation temperature on heating of the phase changes of iron
or steel, subscripts indicating the designated change, e.g., Ac1 is the
eutectoid (723°C) and Ac3 the ferrite/austenite phase boundary.
AC-3:
Trade name for the digital audio coding used in 35 mm motion picture film
to provide six-channel surround sound. It uses data blocks recorded
optically between the perforations, leaving room for a conventional
soundtrack. It is also suitable for multi-channel TV audio, as well as video
software and home cinema.
AC Ace:
A vehicle brand of which the 1954-61 Ace models are
milestone cars.

AC Aceca:
(pronounced ah-SEEK-uh) A vehicle
brand of which the 1955-61 Aceca
models are milestone cars.
acanthite:
An ore of silver, Ag2S, crystallizing in the monoclinic system.
ACAP:
Acronym for "Associação do comércio automovóvel de Portugal".
ac balancer:
An arrangement of transformers or reactors used to equalize the voltages
between the wires of a multiple-wire system. Also called static balancer.
ac bias:
A high-frequency signal applied to a magnetic tape recording head along
with the signal to be recorded. This stabilizes magnetic saturation and
improves frequency response, at the same time reducing noise and
distortion. The bias signal frequency has to be many times the highest
recording frequency.
AC Buckland:
A vehicle brand of which the 1949
Buckland Open Tourer is a milestone
car.
ac-boundary layer:
See stokes layer
acc:

Abbreviation for "accessories."
ACC:
[1] Acronym for "Automatic Cruise Control."
[2] A term found on a cruise control switch which indicates the direction
the switch needs to be moved to increase the speed (accelerate) of the
vehicle.
ACCC:
Acronym for "air conditioner clutch compressor" signal.
accelerate:
[1] To increase the speed of a vehicle. Opposite of decelerate.
[2] To accelerate an adhesive is to speed up a chemical reaction or a curing
process. For example, you can speed up the drying time of an adhesive or
sealer by increasing the temperature. Also, by adding a chemical curing
agent, or accelerator, to a base compound.
accelerated aging test:
A stability test for cables using twice normal working voltage. It is
claimed this give quick results that correlate with service records.
accelerated fatigue test:
Test which applies a cyclic loading schedule, which can be of varying
frequency and/or amplitude, to a machine or component simulating its
loading in service, but at a higher rate, to determine its safe fatigue life
before it is reached in service.
accelerate-stop distance:
The total distance, under specified conditions, in which an aircraft can be
brought to rest after accelerating to critical speed for an engine failure at
take-off.
accelerating chain:
The section of an electron beam tube or system, e.g., cathode-ray tube or
electron microscope, in which electrons are accelerated by voltages on
accelerating electrodes. Also used in particle accelerators.

accelerating electrode:
An electrode in a thermionic valve or cathode-ray tube maintained at a
high positive potential with respect to the electron source. It accelerates
electrons in their flight to the anode but does not collect a high proportion
of them.
accelerating machine:
See accelerator
accelerating potential:
The potential applied to an electrode to accelerate electrons from a
cathode.
accelerating-well ports:
These ports prevent momentary leanness during the period that occurs
between the opening of the air valve and the actual discharge of fuel from
the secondary nozzles.
acceleration:
The rate of change of velocity or speed. Velocity is steady and is measured
in distance per time (e.g., feet per second, miles per hour, kilometers per
hour). Acceleration keeps increasing and is measured in velocity per time
(e.g., feet (or meters) per second per second or feet (or meters) per second
squared). It is a vector quantity and has both magnitude and direction.
Also see
angular acceleration
lateral acceleration
sluggish acceleration
yaw acceleration
acceleration due to gravity:
(g) Acceleration with which a body would fall freely under the action of
gravity in a vacuum. This varies according to the distance from the Earth's
center, but the internationally adopted value is 9.80665ms-2
.
Also see
Helmert's formula
acceleration enrichment:

The action of increasing the fuel/air mixture during acceleration in order to
improve the vehicle's speed and its smooth response.
acceleration error:
The error in an airborne magnetic compass due to maneuvering; caused by
the vertical component of the Earth's magnetic field when the center of
gravity of the magnetic element is displaced from normal.
acceleration pump:
See auxiliary acceleration pump
acceleration slip regulation:
(ASR) The Bosch term for traction control.
acceleration stress:
The influence of acceleration (or deceleration) on certain physiological
parameters of the human body. Man can withstand transverse accelerations
better than longitudinal ones, which have a profound effect on the
cardiovascular system. The degree of tolerance also depends on the
magnitude and duration of the acceleration.
acceleration tolerance:
The maximum acceleration force that a person can withstand before
"blacking out" or otherwise losing control.
accelerator:
[1] In automobiles, this is the
"gas pedal" which is attached
by linkage to the throttle in
the carburetor or to the fuel
injection system. It regulates
the amount of fuel which is
sent to the engine. In
motorcycles, the accelerator is
located on the right-hand twist
grip or an actuating lever.
[2] A device, similar to a
catapult, but generally

mounted below deck level, for
assisting the acceleration of
aircraft flying off aircraft
carriers. Land versions have
been tried experimentally.
[3] A chemical which is added
to something to make a
process happen more quickly.
For example, a chemical may
be added to paint to cause it to
dry faster. The opposite is
"retarder." A material added to
an adhesive to speed up its
cure or to chemically convert
the whole mass to a solid.
Accelerators differ from
catalysts in that they are a part
of the chemical reaction and
lose their chemical identity as
a result.
[4] A substance which
increases the efficient action
of an enzyme
[5] Any substance increasing
the speed of the vulcanization
process of rubber. The
principal types are aldehyde
derivatives of Schiff's bases:
butyraladehyde-butylidene-
aniline, di-orthotolyl-
guanidine, diphenyl-
guanidine, benzthiazyl
disulphide, tetramethyl-
thiuran disulphide and zinc
dimethyl-dithiocarbamate.
[6] A special circuit board
which is placed within a
computer to speed up some
aspect of its operation.
[7] Machine used to
accelerate charged particles to
very high energies such as
betatron, cyclotron, linear

accelerator, synchrocyclotron,
and synchrotron.
[8] A chemical used to
increase the rate of
development, e.g., sodium
carbonate or borax
[9] Any muscle or nerve
which increases rate of action.
Also see
depress the accelerator
ease up on the accelerator
step on the accelerator
take foot off the accelerator
accelerator board:
A circuit board plugged into a computer motherboard to increase the
operating speed of a computer.
accelerator interlock:
A connection between the gas pedal and the automatic transmission.
accelerator pedal:
The accelerator, gas pedal, or throttle pedal.
accelerator pump:
A small cylinder and piston usually located inside the carburetor that
sprays an extra amount of fuel into the engine during acceleration. It
improves acceleration by giving more boost and reducing a momentary lag
in power. It is actuated by depressing the pedal.
accelerometer:
[1] A transducer used to provide a signal proportional to the rate of
acceleration of a vibrating or other body, usually employing the
piezoelectric principle.
[2] An instrument which measures the amount of acceleration in a specific
direction.
Also see
impact accelerometer
vertical-gust recorder

acceptable quality level:
(AQL) A manufactured good that may not be perfect but does reach a
level of shape, size, and performance, etc. that will make it work and last
as long as the manufacturer expects.
acceptance angle:
The solid angle within which all incident light reaches the photocathode of
a phototube.
acceptance test:
An examination of a part or its assembly to determine if it meets a
prescribed standard.
acceptor:
[1] The reactant in an induced reaction whose rate of reaction with a third
substance is increased by the presence of the inductor.
[2] The atom which accepts electrons in a co-ordinate bond.
[3] Impurity atoms introduced in small quantities into a crystaline
semiconductor and having a lower valency than the semiconductor, from
which they attract electrons. In this way holes are produced, which
effectively become positive charge carriers; the phenomenon is known as
p-type conductivity.
Also see
donor
impurity
acceptor level:
See energy levels
access:
A way of reaching something that is usually hidden or covered.
Also see
access panel
Access Cab:
A type of pickup truck (by Toyota) which as a second row of seating; but
unlike a crew cab (which has four full size doors) it has a "half-door" that
can be opened only after the main door is opened. The seating is usually a

little more cramped than in a crew cab. Also called club Cab, extended
Cab, king Cab, xtracab, supercab, or cab Plus
access charge:
A financial charge for access to a computer or telecommunications
network.
access eye:
A screwed plug provided in soil, waste and drain pipes at bends and
junctions, to clear a stoppage.
access hole:
An opening through which you can reach something. It is usually covered
with a panel.
accessible hermetic:
Assembly of motor and compressor inside a single bolted housing unit.
accessories:
Items and packages of equipment which are beyond the standard
equipment supplied in a new vehicle.
accessory:
See accessories
accessory gearbox:
A gearbox, driven remotely from an aero-engine, on which aircraft
accessories, e.g., hydraulic pump and electrical generator, are mounted.
accessory minerals:
Minerals which occur in small, often minute, amounts in igneous rocks;
their presence or absence makes no difference to classification and
nomenclature.
accessory package:

A set of features or appointments which may be ordered at extra cost on a
new vehicle.
accessory plates:
Quartz-wedge, gypsum plate and mica plate. Used with petrological
microscope to help determine the optical character of a mineral as an aid in
its examination.
accessory shoe:
A mounting bracket on the body of a camera to which separate units such
as a flash or range-finder may be fitted.
access panel:
The cover which conceals the engine on a mid-engine vehicle. Also called
engine cover.
Also see
hood
access time:
The time interval between the instant at which data are called from
memory and the instant at which the data can be used. It can vary from
microseconds with fast store to minutes with magnetic tape.
access to store:
Entry or extraction of data from a memory location. The method and speed
of access depends on the type of memory.
Also see
backing store
fast store
random access memory
serial access memory
accident:
See car accident
accident damage:
The destruction caused to a vehicle's bodywork when it is involved in an
accident.

ac circuit:
A circuit which passes alternating current as opposed to direct current,
e.g., it may have a capacitor in series, which blocks direct current.
ac commutator motor:
An ac motor which embodies a commutator as an essential part of its
construction.
Also see
ac series motor
compensated induction motor
repulsion motor
Schrage motor
Accord:
A model of automobile manufactured by
Honda
.
Click for books on Honda
Accord
accordion:
The method of folding a leaflet or insert so that it opens out and closes in a
zig-zag fashion. The British term is concertina fold.
accretion:
[1] The process in which a celestial body, particularly an evolved star in a
binary system, is enlarged by the accumulation of extraneous matter
falling in under gravity
[2] The process of enlargement of a continent by the tectonic coalescences
of exotic crustal fragments.
accretion disc:
The disc of material at the edge of a black hole, which has been attracted
from a neighboring star and which emits X-rays as its inner edge
disappears into the gravitational field of the hole.

accumulation point:
A mathematical term which says that of a set of points, one such that every
neighborhood of it includes at least one point of the set.
accumulator:
[1] A storage battery for an electric car.
[2] A pressurized container for an automatic leveling suspension system.
[3] A part of the hydraulic system which is charged by the fluid pump,
absorbs fluctuating fluid delivery, stores fluid at pressure, and can provide
a rapid flow of fluid under pressure.
[4] A vessel that stores hydraulic fluid under pressure.
[5] A storage tank which receives liquid refrigerant from evaporator and
prevents it from flowing into the suction line before vaporizing.
[6] A refrigerant storage device used on General Motors and Ford systems
that receives vapor and liquid refrigerant from the evaporator. The
accumulator, which contains "desiccant," performs a function similar to
that of a receiver-drier: it separates liquid from the vapor, retains the liquid
and releases the vapor to the compressor. Always located on the low side
of the system.
[7] A special storage register associated with the arithmetic logic unit, used
for holding the results of a computation or data transfer
Also see
accumulator piston
fuel accumulator
hydraulic accumulator
pressure accumulator
accumulator battery:
A storage battery (i.e., the main battery in your vehicle).
accumulator box:
A vessel usually made of plastic which contains the plates and electrolyte
of an accumulator.
accumulator drier:
A device which is part of the air conditioning system. It is made up of a
tank, filter, drying agent, and a vapor return tube. It is usually found on the

evaporator outlet. It stores the excess refrigerant and removes the moisture
from the refrigerant (thus the name "drier").
Also see
receiver drier
accumulator grid:
The lead grid which forms one of the plates of a lead-acid accumulator
having pasted plates.
accumulator piston:
A unit found in the automatic transmission to assist the servo to apply the
brake band quickly and smoothly.
accumulator system:
In an automatic transmission, it includes a hydraulic accumulator piston
which is controlled by a valve.
accumulator traction:
See battery traction
accumulator valve:
A device which operates the hydraulic accumulator piston in an automatic
transmission.
accumulator vehicle:
See battery traction
AC current sine wave:
Wave form of single frequency alternating current; wave whose
displacement is sine of angle proportional to time or distance.
Ace:
An American trucker's colloquial term for someone with a class "A"
licence.
Also see
AC Ace

ACEA:
Acronym for "Association des Constructeurs européens dAutomobiles"
(i.e., European Automakers Association).
Aceca:
See AC Aceca
acet-:
Prefix from the Latin acetum meaning vinegar.
acetate film:
Film with its photographic emulsion coated on a base of cellulose
triacetate, of low flammability.
aceto-:
Prefix from the Latin acetum meaning vinegar.
acetylene:
[1] Ethyne HC≡CH. A colorless, poisonous gas, owing its disagreeable
odor to impurities; soluble in ethanol, in acetone (25 times its volume at
standard temperature and pressure) and in water. Boiling point -84°C,
relative density 0.91. Prepared by the action of water on calcium carbide
and catalytically from naphtha.
[2] A gas composed of two parts of carbon and two parts of hydrogen.
When burned in an atmosphere of oxygen, it produces one of the highest
flame temperatures obtainable for welding.
[3] Also used for illuminating, acetic acid synthesis and for manufacturing
derivatives
Also see
oxygen acetylene cutting
acetylene bottle:
See acetylene cylinder
acetylene cutting:
See oxygen acetylene cutting

acetylene cylinder:
A specially built container
manufactured according to
I.C.C. Standards. Used to store
and ship acetylene. Also called
acetylene tank or acetylene
bottle
acetylene hose:
A flexible medium used to carry gases from regulators to the torch. It is
made of fabric and rubber.
acetylene regulator:
An automatic valve used to reduce acetylene cylinder pressures to torch
pressures and to keep the pressures constant.
acetylene tank:
acetylene cylinder.
acetyl group:
Ethanoyl group CH3CO-. The radical of acetic acid.
aceval:
Abbreviation for air combat evaluation.

AC generator:
[1] An electromagnetic generator for
producing alternating emf and delivering ac to
an outside circuit.
[2] A generator produces direct current (DC)
while an alternator produces alternating
current (AC). Because alternators were
introduced to automobile electrical systems
after generators had been in use for some time,
some people referred to the new alternator as
"AC generator."
ache:
See head ache rack
ache rack:
See head ache rack
achromatic lens:
A lens designed to minimize chromatic aberration. The simplest form
consists of two component lenses, one convergent, the other divergent,
made of glasses having different dispersive powers, the ratio of their focal
lengths being equal to the ratio of the dispersive powers.
achromatic prism:
An optical prism with a minimum of dispersion but a maximum of
deviation.
achromatic sensation:
A visual perception of grey. Represented by the equal energy point on a
chromaticity diagram.
achromatic stimulus:
Stimulus which produces an achromatic sensation.
acid:
Also see
battery acid
chromic acid

oxalic acid
acid brittleness:
The brittleness developed in steel in pickling bath, through evolution of
hydrogen.
acid condition in system:
Condition in which refrigerant or oil in system is mixed with fluids that
are acid in nature.
acid cure:
In extraction of uranium from its ores, lowering of gangue carbonates by
puddling with sulphuric acid before leach treatment.
acid deposition:
Acid compounds emitted into the atmosphere which then return to the
surface either in the form in which they were discharged or as new
compounds formed by reaction in the atmosphere. Includes dry deposition,
usually of sulphur and nitrogen oxides near the source, and wet deposition
which follows when acids are washed from the atmosphere by
precipitation (i.e., acid rain and occult deposition.
acid drift:
The process by which ores, pulps, and products become acidic through
pick-up of atmospheric oxygen through standing.
acid dyes:
Dyes which have their color associated with the negative ion or radical.
acid egg:
A pump for sulphuric acid, of simple and durable construction, with few
moving parts. The acid is run into a pressure vessel, usually egg-shaped,
from which it can be forcibly expelled by compressed air.
acid fixer:
Fixing solution (hypo) with the addition of an acid (sodium bisulphite or
potassium metabisulphite) to prevent staining.

acidizing:
Improving the flow of oil from a limestone formation by pumping acid
into it.
acid mine water:
Water containing sulphuric acid as a result of the breakdown of the
sulphide minerals in rocks. Acid mine water causes corrosion of mining
equipment, and may contaminate water supplies into which it drains.
acid process:
[1] A steel-making process in which the furnace is lined with a siliceous
refractory, and for which iron low in phosphorous is required, as this
element is not removed.
[2] Any pulp digestion process utilizing an acid regent, e.g., a bisulphite
liquor with some free sulphur dioxide.
acid rain:
[1] When the smoke created by factories and vehicle exhausts is taken by
the wind and joined with rain clouds, the mixture is often acidic. As a
result the rain that falls to the ground (and even on your car) may damage
whatever it strikes.
[2] A form of wet deposition in which acid molecules or particles in the
atmosphere are returned to the surface having been washed out by rain or
snow as it falls. The unnatural acidity (pH 3-5.5) is caused mainly by the
oxides of sulphur and nitrogen from the burning of coal and oil.
acid refractory:
See silica
acid resist foils:
Blocking foils for use in etching metal. The foil is stamped on to paper and
the excess foil blocked on to the metal rule or other object which is then
exposed to an acidic etching fluid such as ferric chloride.
acid rock:

An igneous rock with more than 63% quartz.
acid slag:
Furnace slag in which silica and alumina exceed lime and magnesia.
acid smut:
See acid soot
acid soot:
A pollutant, consisting of particles of carbon bound together by water
containing sulphuric acid, formed as a by-product of the incomplete
combustion of carbon-based fuel. Also called acid smut.
acid steel:
Steel made by an acid process.
acid stop:
Weak acid photography processing solution used immediately after the
developer to halt its chemical activity and neutralize it before fixing.
AC Ignition System:
See continuous AC Ignition System
Ackermann:
See Ackermann steering

Ackermann steering:
[1] A double-pivoting steering system where
the outer ends of the steering arms are bent
slightly inward so that when the vehicle is
making a turn, the inside wheel will turn more
sharply than the outer wheel. This is done to
compensate for the greater distance the outside
wheel must travel. Notice 20 degrees on left
wheel and 30 degrees on right wheel
[2] Arrangement whereby a line extended from
the track-arms, when the wheels are set
straight ahead, should meet on the chassis
centerline at 2/3 of the wheelbase from the
front, allowing the inner stub-axle to move
through a greater angle than the outer.
Ackermann angle:
The toe-out or toe-in of a vehicle with Ackermann steering when the
wheels are positioned straight ahead.
Ackermann axle:
In a vehicle with Ackermann steering (at the front of the vehicle), it is a
non-rotating axle that is steerable and has two pivot points (one on each
end of the axle) with vertical kingpins.
acknowledgement signal:
A signal transmitted along a circuit from B to A when triggered by a signal
from A to B.
A-class insulation:
Insulating material which will withstand temperatures up to 105°C.
ACL BI-MET:
Acronym for "air cleaner bi-metal sensor".
ACL DV:
Acronym for "air cleaner duct and valve vacuum" motor.

ACM:
Abbreviation for Association for Computing Machinery, a US professional
association.
ac magnet:
Electromagnet excited by alternating current having normally a laminated
magnetic circuit.
Also see
shaded pole
acme screw-thread:
A thread having a profile angle of 29° and a flat crest and root, used for
example for lathe lead screw for easy engagement by a split nut.
acmite:
A variety of aegirine; also used for the NaFe+3
Si2 O6 end-member.
ac motor:
An electric motor which operates from a single or polyphase alternating
current supply.
Also see
capacitor motor
induction motor
synchronous motor
acnode:
See double point
acoustic absorption:
Transfer of energy into thermal energy when sound is incident at an
interface.
acoustic absorption coefficient:
The ratio of the acoustic energy absorbed by a surface to that which is
incident on the surface. For an open window this can be 1.00, for painted
plaster 0.02. The value varies with the frequency of the incident sounds,
e.g., for 2 cm glass fiber it is 0.04 at 125 Hz, 0.80 at 4000 Hz. Also called
acoustic absorption factor.

acoustic absorption factor:
The ratio of the acoustic energy absorbed by a surface to that which is
incident on the surface. For an open window this can be 1.00, for painted
plaster 0.02. The value varies with the frequency of the incident sounds,
e.g., for 2 cm glass fiber it is 0.04 at 125 Hz, 0.80 at 4000 Hz. Also called
acoustic absorption coefficient.
acoustical inertia:
The quantity M, where ωM is the part of the acoustical reactance which
corresponds to the inductance of an electrical reactance: ω is the pulstance,
given by 2πf is the frequency in hertz. Also called acoustical mass.
acoustical mass:
The quantity M, where ωM is the part of the acoustical reactance which
corresponds to the inductance of an electrical reactance: ω is the pulstance,
given by 2πf is the frequency in hertz. Also called acoustical inertia.
acoustical stiffness:
For an enclosure of volume V, the quantity given by S-pc³/V, where c is
velocity of propagation of sound and p is density. It is assumed that the
dimensions of the enclosure are small compared with the sound
wavelength and that the walls around the volume do not deflect.
acoustic amplifier:
An amplifier of mechanical vibrations.
acoustic branch:
A branch of the dispersion curve (frequency ω against wavenumber q) for
crystal lattice vibrations for which ω is proportional to q for small q. For a
crystal containing n atoms per unit cell, the dispersion curve has 3n
branches of which three are acoustic branches. The branches are
characterized by different patterns of movement of the atoms.
Also see
optic branch
acoustic center:

The effective source point of the spherically divergent wave system
observed at distinct points in the radiation field of an acoustic transducer.
acoustic compliance:
The reciprocal of the acoustic stiffness.
acoustic construction:
Building construction which aims at the control of transmission of sound,
or of mechanical vibration giving rise to sound, particularly unwanted
noises. The parts of the structure are separated by air-spaces or acoustic
absorbing material and can be decoupled by the interposing of springs.
acoustic coupler:
A device which enables a digital signal to be transmitted over the
telephone network using an ordinary telephone handset.
acoustic delay line:
A device, magnetostrictive or piezoelectric, e.g., a quartz bar or plate of
suitable geometry, which reflects an injected sound pulse many times
within the body.
acoustic distortion:
Distortion in sound-reproducing systems.
acoustic emission:
Non-destructive testing method of investigating deformation and failure
processes in materials by the signals generated when the elastic waves
released by them are detected at the materials' surfaces.
acoustic feedback:
Instability or oscillation in a second reproduction system caused by the
microphone or pick-up receiving vibrations from the loudspeaker.
acoustic filter:
Filter which uses tubes and resonating boxes in shunt and series as
reactance elements, providing frequency cut-offs in acoustic wave

transmission, as in an electric wave filter.
acoustic grating:
A diffraction grating for production of directive sound. Spacings are much
larger than in optical gratings due to the longer wavelength of sound
waves. Both transmission and reflection grating are used.
acoustic impedance:
the complex ratio of sound pressure on surface to sound flux through
surface, having imaginary (reactance) and real (resistance) components,
respectively. Unit is the acoustic ohm.
acoustic interferometer:
Instrument in which measurements are made by study of interference
pattern set up by two sound or ultrasonic waves generated at the same
source.
acoustic lens:
A system of slats or disks to spread or converge sound waves.
acoustic microscope:
Microscope based on acoustic waves (longitudinal compressions and
rarefactions of density) at microwave frequencies the interaction of an
acoustic wave with a material is sensitive to its elastic properties. Images
can be created by modulating a display with the intensity received by a
detector/specimen system scanned synchronously (ultrasonic imaging).
Coupling between electrical signals and acoustic vibrations exploits the
piezoelectric effect.
acoustic model:
A scale model of a room (e.g., concert hall) or structure which is used to
measure qualities important for architectural acoustics and noise control
(e.g., sound distribution). The scale is typically between 1:10 and 1:20. In
order to adjust the wavelength, the frequency has to be increased by a
factor of 10-20.
acoustic ohm:

Unit of acoustic resistance, reactance, and impedance, equal to 105
Pasm-3
.
acoustic perspective:
The quality of depth and localization inherent in a pair of ears, which is
destroyed in a single channel for sound reproduction. It is transferable with
two microphones and two telephone ear-receivers with matched channels,
and more adequately realized with three microphones and three radiating
receivers with three matched channels.
acoustic plaster:
Rough or flocculent plaster which has good acoustic absorbing properties
and which can be used for covering walls. Added to the mix is fine
aluminum, which evolves gas on contact with water and so aerates the
mass. These tiny holes lower the acoustic impedance and so reduce the
reflection of incidence sound waves.
acoustic pressure:
See sound pressure
acoustic radiator:
Device to generate and radiate sound. The more common radiators are (1)
vibrating elastic systems (membrane, string, vocal cord) which cause a
fluctuating pressure in the surrounding medium; (2) electrically driven
membranes and plates (loudspeaker, sonar transducer); (3) vortices in
turbulent fluid flow.
acoustic ratio:
The ratio between the directly radiated sound intensity from a source, at
the ear of a listener (or a microphone), and the intensity of the reverberant
sound in the enclosure. The ratio depends on the distance from the source,
the polar distribution of the radiated sound power, and the period of
reverberation of the enclosure.
acoustic reactance:
See acoustic impedance
acoustic resistance:
See acoustic impedance

acoustic resonance:
Enhancement of response to an acoustic pressure of a frequency equal or
close to the eigenfrequency of the responding system. When a system is at
resonance, the imaginary part of its impedance is zero. Prominent in
Helmholtz resonators, organ, and other pipes and vibrating strings.
acoustics:
[1] The science of sound waves including production and propagation
properties.
[2] The characteristics of a room which determine the quality of sound
transmission inside.
Also see
architectural acoustics
atmospheric acoustics
acoustic saturation:
The aural effectiveness of a source of sound amid other sounds; it is low
for a violin, but high for a triangle. The relative saturation of instruments
indicates the number required in an auditorium of given acoustic
properties.
acoustic scattering:
Irregular and multi-directional reflection and diffraction of sound waves
produced by multiple reflecting surfaces the dimensions of which are
small compared to the wavelength; or by certain discontinuities in the
medium through which the wave is propagated.
acoustic spectrometer:
An instrument designed to analyze a complex sound signal into its
wavelength components and measure their frequencies and relative
intensities.
Also see
real-time analyzer
acoustic spectrum:
Graph showing frequency distribution of sound energy emitted by source.
acoustic streaming:

Generation of constant flows by a strong sound wave. Acoustic streaming
is a non-linear effect. It is responsible for the motion of the light particles
(lycopodium spores) in a Kundt's tube.
Also see
quartz wind
acoustic survey:
Determination of the porosity of a rock by measuring the time required for
a sonic impulse to travel through a given distance.
acoustic suspension:
Sealed-cabinet system of loudspeakers in which the main restoring force
of the diaphragm is provided by the acoustic stiffness of the enclosed air.
acoustic telescope:
An array of microphones. The signals of the microphones are added with
certain phase-delays so as to generate desired directions.
Also see
directional microphone
acoustic tile:
A tile made of soft, sound-absorbing substance.
acousto-optic modulator:
A telecommunication device in which acoustic waves in an optical
medium from a grating used to diffract an optical signal and thus
effectively turn it on or off.
acquisition fee:
A charge for processing a lease and is probably not negotiable. On a
shorter term lease, the acquisition fee can have a large impact on the cost
of the lease.
ACR:
Abbreviation for approach control radar.
acro-:

Prefix from Greek akros (ακρος), topmost, farthest, terminal.
Acrobat:
Trade name for a computer application which converts text, line drawings,
and half-tones into a stream of alphanumeric text while retaining the
format of the original. Such a page description file (PDF) is an extension
of the Adobe PostScript language and can be read by any type of
computer.
acronical rising:
The rising of a star at nightfall.
acronical setting:
The setting of a star at nightfall.
acronychal:
British term for "acronical".
across corners:
(A/C) The distance on a nut (for instance) from one corner to the opposite
corner rather than the distance from one flat surface (A/F) to the opposite
(which would be the size of wrench needed to install or remove the nut).
The purpose of the A/C dimension is to know how large a hole might be
needed to insert a recessed nut.
across flats:
(A/F) The distance on a nut (for instance) from one flat surface to the
opposite flat surface, i.e., this is the size of the wrench needed to install or
remove the nut.
Also see
across corners.
acroterium:
A base or mounting on the apex and/or extremities of a pediment, for the
support of an ornamental figure or statuary.

ACR tubing:
Tubing used in air conditioners and refrigerators. The ends are sealed to
keep tubing clean and dry.
acrux:
A bright white supergiant star in the constellation Crux. A visual binary
consisting of two spectroscopic binary components. Distance 80 pc. Also
called Alpha Crucis.
acrylate:
A polymer used to strengthen rubber (e.g., ethyl acrylate).
acrylic:
A term relating to a type of paint made by polymerizing acrylonitrile.
acrylic fibers:
Continuous filaments or, more fibers from linear polymers which are
synthesized from several monomers containing at least 85% by weight of
acrylonitrile.
acrylic finish:
A final coating of paint which uses acrylic paint, often where the pigment
and an acrylic paint are mixed together.
Also see
two-pack paint.
acrylic paint:
A type of paint made by polymerizing acrylonitrile.
acrylic resin:
A thermoplastic synthetic polymer made by polymerizing an acrylic
derivative such as acrylonitrile, acrylic acid, ethyl acrylate, and
methacrylate. It is used for adhesives, protective coatings, and paint
finishes.
ACS:

[1] Abbreviation for active control system
[2] Abbreviation for attitude control system
[3] Abbreviation for air conditioning system .
ac series motor:
A series motor which operates from an ac supply with laminated field
construction and usually a compensating winding.
AC Shelby Cobra:
A vehicle brand of which the 1962-67 Shelby Cobra models
are milestone cars.
ACT:
[1] Acronym for "air charge temperature."
[2] Acronym for active control technology.
Also see
active control system
act:
See Motor Vehicle Safety Act
acting:
See double-acting
dual-acting
single-acting
actinic radiation:
Ultraviolet waves, which have enhanced biological effect by inducing
chemical change; basis of the science of photochemistry.
actinic rays:
Electromagnetic waves of wavelength that can cause a latent image,
potentially able to be developed, in a photographic emulsion. They include
an extension at each end of the visible spectrum and X-rays.
actino-:

Prefix from Greek aktis (ακτις).
actinolite:
A monoclinic calcium magnesium iron member of the amphibole group,
green in color and usually showing an elongated or needle-like habit;
occurs in metamorphic and altered basic igneous rocks.
action:
[1] The performance of a scene to be recorded on camera
[2] The film record of this performance as picture only, separate from the
sound record
[3] The time integral of kinetic energy (E) of a conservative dynamic
system undergoing a change, given by this formula:
Also see
capillary action
caster action
mist action
oscillating action
parallel action locking pliers
reciprocating action
action brakes:
See servo action brakes
action locking:
See parallel action locking pliers
action locking pliers:
See parallel action locking pliers
activate:
To change an adhesive film from a dry or inactive state to a useful, sticky
state.
activated:
See cable activated
activated alumina:

Chemical which is a form of aluminum oxide. it is used as a drier or
desiccant.
activated carbon:
[1] A highly porous carbon which is able to absorb gases and fluids. It is
usually found in small pellets so that the surface area is greater than a large
chunk of it. Also it has a number of pores on each pellet to increase the
surface area more. Thus the greater surface area means greater ability to
absorb. Used to clean air. Also called activated charcoal.
[2] Carbon obtained from vegetable matter by carbonization in the absence
of air, preferably in a vacuum. Activated carbon has the property of
absorbing large quantities of gasses. Important for gas masks, adsorption
of solvent vapors, clarifying of liquids, and in medicine.
activated carbon canister:
An automotive filter in which activated carbon has been placed so that gas
tank fuel vapors, which have accumulated when the vehicle is not running,
are trapped in the filter. When the engine is running, hot air is forced into
the filter and push out the vapors into the engine. In this way, pollution is
reduced and conservation of the fuel is maintained. Also called activated
charcoal trap or charcoal canister.
activated cathode:
Emitter in thermionic devices comprising a filament of basic tungsten
metal, alloyed with thorium, which is brought to the surface by process of
activation, such as heating without electric field.
activated charcoal:
Charcoal treated with acid to increase its adsorptive power
Also see
activated carbon
charcoal
activated charcoal trap:
See activated carbon canister
activated sintering:
Sintering of a compact in the presence of a gaseous reactant. Also called
reaction sintering.

activating agent:
See activator
activation:
[1] Alteration of the surface of a metal to a chemically active state.
Compare passivation
[2] Induction of radioactivity in otherwise non-radioactive atoms, e.g., in a
cyclotron or reactor.
activation cross-section:
The effective cross-sectional area of a target nucleus undergoing
bombardment by e.g., neutrons for radioactivation analysis. Measured in
barns.
Also see
cross-section
activator:
[1] A substance which is used to speed up the process of curing a tire.
[2] Surface-active chemical used in a flotation process to increase the
attraction to a specific mineral in an aqueous pulp of collector ions from
the ambient liquid and increase in aerophilic quality. Also called activating
agent.
active array:
An antenna array in which the individual elements are separately excited
by integrated circuit or transistor amplifiers.
active braking time:
The length of time (excluding the driver's reaction time) a vehicle takes to
come to a complete stop after the brakes are applied.
active component:
The component of the vector representing an alternating quantity which is
in phase with some reference vector; e.g., the active component of the
current, commonly called the active current.
Also see

active current
active voltage
active volt-amperes
active control:
Modern technique of noise or vibration control using one or more sources
that generate signals with the aim of making the resulting total signal
smaller. Used for example for the control of low-frequency airborne noise
and vibration of machinery.
Also see
antisound
active control system:
(ACS) An advanced automatic flight control system designed to provide
several special features, for example activation of flight control surfaces to
minimize gust loads and bending stresses in the wing by detection and
response to normal accelerations, provision of stability to a naturally
unstable aircraft and implementation of pilot maneuver demands. All these
characteristics improve aircraft behavior and performance, but the active
control system demands extensive integration between aerodynamics,
structure, and electronic system design to achieve these advantages with
reliability and safety.
active current:
The component of a vector representing the ac in a circuit which is in
phase with the voltage of the circuit. The product of this and the voltage
gives power.
active device:
A component capable of controlling voltages or currents, to produce gain
or switching action in a circuit, valves, diodes, and transistors, and
integrated circuits are all classed as active devices or components.
active electrode:
The electrode of an electrical precipitator which is kept at a high potential.
Also called discharge electrode..
active filter:

A filter which combines amplification with conventional passive filter
components (capacitance, inductance, resistance) to enhance fixed or
tunable passband or rejection characteristics.
active galaxy:
A galaxy which emits unusually large amounts of radiation from a
compact central source, such as Seyfert galaxy, N galaxy, quasar, or BL
Lac object.
active homing:
A guidance system where the missile contains the transmitter for
illuminating the target and the receiver for the reflected energy.
active lattice:
The regular pattern of arrangement of fissionable and non-fissionable
materials in the core of a lattice reactor.
active lines:
Lines which are effective in establishing a picture.
active material:
In a storage battery, peroxide of lead (brown) in positive plates and
metallic lead (gray) in negative plates upon which sulphuric acid acts.
active materials:
[1] General term for essential materials required for the functioning of a
device, e.g., iron or copper in a relay or machine, electrode materials in a
primary or secondary cell, emitting surface material in a valve, or
photocell, phosphorescent and fluorescent material forming a
phosphorescent and fluorescent material forming a phosphor in a cathode-
ray tube, or that on the signal plate of a TV camera.
[2] Term applied to all types of radioactive isotopes.
active noise control system:
See anti-noise system
active power:

The time average over one cycle of the instantaneous input powers at the
points of entry of a polyphase circuit.
Also see
active volt-amperes
active safety:
The opposite of passive safety. Passive safety involves seat belts, airbags,
bumpers, etc. so that in the event of an accident the passengers are
protected. Active safety involves factors which will assist the driver in
avoiding an accident. They include brakes, steering, handling response,
acceleration, etc.
active satellite:
A satellite equipped for sending out probing signals and receiving returned
information. A passive satellite receives information only on the state of
the target.
active sun:
The Sun during periods of intense sunspot activity.
active suspension:
While conventional suspension uses springs and shock absorbers to isolate
the vehicle from the bouncing movement of the wheels when it contacts
rough roads, active suspension uses power actuators which are controlled
by a computer. These actuators place the wheels of the vehicle in the best
position to accommodate rough roads as well as compensate for different
load levels.
active transducer:
Any transducer in which the applied power controls or modulates locally
supplied power, which becomes the transmitted signal, as in a modulator, a
radio transmitter or a carbon microphone.
active voltage:
The component of a vector representing the voltage which is in phase with
the current in a circuit.

active volt-amperes:
The product of the active voltage and the amperes in a circuit, or of the
active current (amperes) and the voltage of the circuit; equal to the power
in watts. Also called active power.
activities:
See Kaizen Activities
activity:
[1] The magnitude of the oscillations of a piezoelectric crystal relative to
the exciting voltage
[2] The rate at which transformations occur in a radionuclide. Unit is the
becquerel
Also see
catalytic activity
low temperature activity
specific activity
activity factor:
See blade activity factor
ac transformer:
an electromagnetic device which alters the voltage and current of an ac
supply in inverse ratio to one another. It has no moving parts and is very
efficient.
ACTS:
Acronym for "air charge temperature sensor".
actual cash value:
(ACV) The amount of money a dealer has invested in the purchase of a
used vehicle and any additional costs to repair the unit in order to get it
ready for resale.
actual throat:
A welding term which describes the distance from the face of a weld to the
root of the weld.

actuate:
The action of bringing a part or assembly into operation.
actuating lever:
A triggering device used to bring a part or assembly into operation.
actuating switch:
A triggering device used to bring a part or assembly into operation.
actuation:
See variable valve actuation
actuator:
[1] A Device which controls or operates another device.
[2] The portion of a regulating valve which converts mechanical fluid,
thermal energy, or electrical energy into mechanical motion to open or
close the valve seats
Also see
hydraulic actuators
actuator arm:
An arm connecting the diaphragm to the contact breaker platform in an
advance mechanism. Also called diaphragm link..
Acura:
A vehicle brand from the Honda manufacturers
.
Click for books on Acura
acutance:
Objective formulation of the sharpness of a photographic image, expressed
as where .
"N" is the number of increments between "A" and "B", DB-DA is the
average gradient of density curve, and ΔD/Δx is the maximum gradient
curve.

ACV:
[1] Acronym for "actual cash value."
[2] Acronym for "air control valve"
[3] Acronym for air cushion vehicle (i.e., hovercraft).
ad:
See classified ad
A-D:
Analogue-to-digital, referring to the conversion of signals.
adamantine:
See lustre
adaptation layer:
See ATM adaptation layer
adapter:
[1] A device used to connect two different types or sizes of electrical
terminals
[2] An arrangement for using types of photographic material in a camera
different from that for which it was designed; e.g., filmpack in a plate
camera, or a smaller plate than normal
[3] A device for the interchange of lenses between different types of
camera
[4] A connector which links two items usually of dissimilar structure or
size. (Also spelled "adaptor")
Also see
bit adapter
bit adapter
caliper mounting bracket
carburetor adapter
engine adapter
increasing adapter
ratchet adapter
reducing adapter
transmission adapter
wheel adapter.

adaptive array:
A radar antenna (either a phased array or an active array) whose gain,
directivity and side lobes can be adjusted automatically to optimize the
radar's performance under specific operating conditions.
adaptive control:
The ability of a control unit to adapt its closed-loop operation to changing
operating conditions -- such as engine wear, fuel quality or altitude -- to
maintain proper air-fuel mixture control, ignition timing or idle rpm. Also
referred to as self-learning.
adaptive differential pulse code modulation:
A form of differential pulse code modulation in which the basic step size is
varied continually to suit the rate of change of the signal. A further
refinement is to transmit only differences from a continually adjusted
prediction of the signal. These measures greatly reduce the required
bandwidth.
adaptive radiation:
Evolutionary diversification of species from a common ancestral stock,
filling available ecological niches. Also called divergent adaptation.
adaptor carburetor:
A device attached to a gasoline carburetor which permits an internal
combustion engine to run either on gas or liquefied petroleum gas (LP
gas).
adapter plate:
A plate which is placed between two different parts in order to link them.
(Also spelled "adaptor plate")
Also see
transfer plate
Adcock antenna:
A directional antenna consisting of pairs of vertical wires, spaced by one
half wavelength or less, and fed in phase opposition; a figure-of-eight
radiation pattern results, and arrays of Adcock antennas can be used for
direction-finding.

ADD:
Acronym for "airstream direction detector" which is used for aircraft stall
protection.
add-drop multiplexer:
Equipment used to add data originating from a particular source or group
of sources to a synchronous digital hierarchy data stream, or conversely to
extract data destined for a particular source or group of sources.
addendum:
[1] The radial distance between the major and pitch cylinders of an
external thread.
[2] The radial distance between the minor and pitch cylinders of an
internal thread the height from the pitch circle to the tip of the tooth on a
gearwheel.
addition agent:
A substance added to the electrolyte in an electro deposition process in
order to improve the character of the deposit formed. The agent does not
take part in the main electrochemical reaction.
additive:
A substance (liquid or powder) which is added to gasoline or oil and is
intended to improve the characteristics of the original product.
Also see
anti-knock additive
fuel additive
oil additive
additive constant:
A survey term used in the computation of distance by tacheometric
methods. It is that length (usually constant and small) which must be
added to the product of staff intercept and multiplying constant to give the
true distance of the object.
Also see
anallatic lens

additive printer:
Photographic or motion picture printer or enlarger in which the intensity
and color of the exposing light is controlled by the separate variation of its
red, green, and blue components.
additive process:
Color reproduction in which the picture is presented by the combination
(addition) of red, green, and blue light representing these three
components in the original subject; it is effectively obsolete for general
photography and cinematography but is the basis for color TV display.
ADEFA:
Acronym for "Asociacion de Fabricas de Automotores" (Argentina).
adenine:
(A) One of the five bases in nucleic acids. It pairs with thymine in DNA
and uracil in RNA.
ADF:
Abbreviation for automatic direction finding.
adhara:
Avery bright blue-white giant star in the constellation Canis Major, which
is a visual binary. Distance 200 pc. Also called Epsilon Canis Majoris.
adhere:
To stick or be glued to something.
adherend:
[1] Each surface that is to adhere to another
[2] A material which is bonded by an adhesive.
adhesion:
[1] The force which causes two surfaces to adhere, the sticking together of
surfaces in contact with each other

[2] The bonding of materials with adhesives (glues, cements, binders, etc),
in which the intermolecular forces between adhesive and adherend provide
the bonds.
[3] The intimate sticking together of metallic surfaces under compressive
stresses by bonds which form as a function of stress, time, and
temperature. The speed of formation is related to dislocation, and may
occur virtually instantaneously under high shear stresses.
Also see
cold welding
[4] The ability of paint, primer, or glue to stick to the surface to which it is
applied.
[5] The ability of a tire to grip the surface of the road.
[6] Mutual forces between two magnetic bodies linked by magnetic flux,
or between two charged non-conducting bodies which keeps them in
contact
[7] Intermolecular forces which hold matter together, particularly closely
contiguous surfaces of neighboring media, e.g., liquid in contact with a
solid.
Also see
intercoat adhesion failure
limits of adhesion
adhesion failure:
See intercoat adhesion failure
adhesive:
[1] A substance (like glue) that is used to join two substances. An adhesive
must bond both mating surfaces through specific adhesion (molecular
attraction), through mechanical anchoring (by flowing into holes in porous
surfaces), or through fusion (partial solution of both surfaces in the
adhesive or its solvent vehicle). Various descriptive adjectives are used
with the term adhesive to indicate types, such as:
a. physical form
liquid adhesive, film adhesive, etc.
b. composition
resin adhesive, rubber adhesive, silicone based, mastic, etc.
c. end use
metal-to-metal adhesive, plastic adhesive, rubber adhesive
d. application
sprayable adhesive, hot melt adhesive, etc.

[2] Agent for joining materials by adhesion, usually polymeric material.
May be based on thermoplastic resin (e.g., polystyrene cement) or
thermoset (e.g., epoxy resin). Viscosity is important for gap filling (high,
as in epoxies) or surface penetration (low, as in cyano-acrylates). Also
called binder, cement, or glue
Also see
automotive adhesive
air drying adhesives
impact adhesive
separate-application adhesive
adhesive binding:
Unsewn binding in which the back of the sections are trimmed and
roughened before adhesive is applied to bind the leaves and the cover.
adhesive film:
A thin layer of dried adhesive. Also describes a class of adhesives
provided in dry film form with or without reinforcing fabric and which are
cured by means of heat and pressure.
adhesive tape:
A tape with a sticky substance on one side. It usually comes in a roll of
various widths. Sometimes used to insulate electrical wires (e.g., electrical
tape) or to wrap a larger object (e.g., duct tape). Often the non-sticky side
is shiny (but not always).
adhesive wear:
Mechanism of wear due to the welding together and subsequent shearing
off of the contact areas between two surfaces sliding over one another.
adhesive weight:
Lead wheel weights which have a sticky backing. It comes in strips and is
applied to a wheel rim. Also called tape weight..
adiabatic:
A property of being able to maintain heat evenly. It does not gain any heat
or lose it.
Also see

thermal efficiency
adiabatic change:
A change in the volume and pressure of the contents of an enclosure
without exchange of heat between the enclosure and its surroundings.
adiabatic compression:
Compressing refrigerant gas without removing or adding heat.
adiabatic curve:
The curve obtained by plotting pressure against volume in the adiabatic
equation.
adiabatic demagnetization:
A method of obtaining very low temperatures. A paramagnetic salt is
cooled to 1K by liquid helium. The salt is magnetized under isothermal
conditions and then magnetized under adiabatic conditions. As a result the
temperature falls. Temperatures below 10-2
K can be obtained this way.
adiabatic efficiency:
[1] Of a steam engine or turbine, the ratio of the work done per unit mass
of steam to the available energy represented by adiabatic heat drop.
[2] Of a compressor, the ratio of that work required to compress a gas
adiabatically to the work actually done by the compressor piston or
impeller.
adiabatic engine:
An engine which is very efficient in transferring combustion heat to those
parts of the engine which are being cooled by the flow of anti-freeze
coolant -- thus maintaining an even temperature of the engine. In this way
the engine is warm enough for efficient running and it does not overheat.
adiabatic equation:
The equation PVγ = constant, expressing the law of variation of pressure
(P) with the volume (V) of a gas during an adiabatic change, γ being the
ratio of the specific heat of the gas at constant pressure to that at constant
volume. The value of γ is approximately 1.4 for air at standard temperature

and pressure.
adiabatic expansion:
An adiabatic change in which a substance expands.
adiabatic heating:
Self-heating effect which occurs in extruder or injection molding barrel
from action of rotating screw on polymer melt. Attributed to dissipation of
mechanical shear forces as heat. Important in injection molding of rubbers.
Also called shear heating.
Also see
damping
adiabatic lapse rate:
The rate of decrease of temperature which occurs when a parcel of air rises
adiabatically through the atmosphere.
adiabatic process:
A process which occurs without interchange of heat with surroundings.
adiactinic:
Said of a substance which does not transmit photochemically active
radiation, e.g., safelights for darkroom lamps.
adinole:
An argillaceous rock that has undergone albitization during contact-
metamorphism.
adipo-:
Prefix from Latin adeps "fat".
A-display:
Co-ordinate display on a cathode-ray tube in which a level time base
represents distance and vertical deflections of beam indicate echoes.
adit:

A horizontal passage or tunnel into a mine.
adjacent channel:
A channel whose frequency is immediately above or below that of the
required signal.
adjust:
The action of putting something into its proper alignment or position. It
may involve one component (e.g., He adjusted the gasket to fit properly.)
or a series of components (e.g., He adjusted the poor idle -- might mean he
set the ignition timing, adjusted the carburetor screws, changed the choke
setting, cleaned or replaced the spark plugs, etc.)
Also see
tweak
adjustable:
A characteristic of something that can be changed, removed, or give
different properties.
Also see
height adjustable steering column
adjustable bottom bracket:
[1] A component of a bicycle through which the crank fits. It has two
bearing cups on either side. One cup is fixed in place while the other is
removable or adjustable.
[2] This is the older type of bottom bracket before sealed cartridge bottom
brackets became prevalent. The adjustable bottom bracket requires fixed
and adjustable cup tools to properly tension the bearings. The bearings are
not sealed, but they're easily accessible for cleaning and lubrication.
Also see
bottom bracket
adjustable cup:
The left-hand cup in a bottom bracket of a bicycle, used in adjusting the
bottom bracket bearings and removed during bottom bracket overhaul. The
other cup is the fixed cup.
adjustable off-idle air bleed:

Some emissions-era Rochester carburetors have a separate air passage to
bleed air past an adjustment screw into the idle system. this screw is preset
by the factory to produce precise off-idle air/fuel mixture ratios to meet
emission-control requirements.
adjustable part throttle:
(APT) a supplementary circuit on some carburetors that can be adjusted to
control part-throttle mixtures more accurately than a fixed orifice. The
APT detours around the main jet, going directly from the float bowl to the
discharge nozzle feed well.
adjustable-pitch propeller:
See propeller
adjustable-port proportioning valve:
Air and fuel valves for oil or gas burners, motor operated in unison by
automatic temperature-control equipment.
adjustable rocker arm:
A type of rocker arm with an adjusting nut that can be tightened or
loosened to adjust valve lash.
adjustable shock:
See adjustable shocks
adjustable shock absorbers:
Shocks with adjustable jounce and rebound characteristics can be stiffened
to compensate for wear or to fine tune a suspension for a particular
application such as rough roads, heavy loads, or racing.
adjustable shocks:
Shock absorbers which can compensate for varying needs of stiffness or
softness. Manual types (especially on motorcycles) require that you
physically make the adjustment from one level to another. Automatic types
are controlled by a computer as it senses particular changes in road

condition.
adjustable spanner:
British term for adjustable wrench.
adjustable steering:
See height adjustable steering column
adjustable steering column:
See height adjustable steering column
adjustable variable exhaust port:
A device used on two-stroke engines which automatically alters or varies
the exhaust port size.
adjustable wrench:
A crescent wrench or pipe wrench. A tool which has a fixed jaw and a
movable jaw which is controlled by a spiral gear. It is used to install or
remove bolts and nuts of various sizes. The wrench itself comes in a
variety of lengths and jaw sizes. A crescent wrench has smooth jaws while
a pipe wrench has serrated jaws. British term is "adjustable spanner."
adjusted:
See factory adjusted
adjuster:
A device for moving something into the correct position or into a different
position such as a seat adjuster.
Also see
automatic adjuster

automatic wear adjuster
brake adjuster
horizontal adjuster
jet adjuster
ride-height adjuster
adjuster cam:
A device for moving the shoes on drum brakes closer to the drum itself so
that there is less travel when the brakes are applied.
adjusting:
Also see
electrode adjusting tool
headlight adjusting screw
self-adjusting
adjusting gage:
See adjusting gauge
adjusting gauge:
A tool used to determine the small distance between two parts so that they
can be brought within specifications.
adjusting screw:
A small screw usually found on carburetors, brakes, or headlights which
change the way something operates, such as increasing or decreasing the
amount of fuel entering the engine; or changing the idle speed; or
tightening up the brakes; or changing the setting on rocker arms; or the
level of the headlights.
Also see
headlight adjusting screw
tappet adjusting screw
valve adjusting screw
adjusting shim:
A thin washer or plate which reduces or increases the clearance between
two components (depending upon where they are placed). While some
valves are adjusted by screws on the rocker arm, others are set by inserting
a shim to make the same adjustment.

adjusting sleeve:
A small threaded cylinder on the end of the tie rod which shortens or
lengthens the rod to make changes in the toe-in and toe-out.
adjusting spanner:
See brake adjusting spanner
adjusting tool:
Also see
brake adjusting tool
electrode adjusting tool
adjusting wrench:
See brake adjusting wrench
adjustment:
[1] Changing or modifying the position or alignment of two components.
[2] The distance of travel that a component has.
Also see
fore and aft adjustment
idle mixture adjustment screw
idle speed adjustment
adjustment screw:
See idle mixture adjustment screw
Adler:
The brand name of a vehicle. With required application the 1925-48
models are classic cars.
admiralty brass:
See Tobin bronze
admission:
The point in the working cycles of a steam or internal-combustion engine
at which the intake valve allows entry of the working fluid into the
cylinder.
admittance:

Property which permits the flow of current under the action of a potential
difference. The reciprocal of impedance.
a-dos:
See dos-a-dos
Adrastea:
A tiny natural satellite of Jupiter, discovered in 1979 by the Voyager 2
mission. Distance from the planet 129,000 km; diameter 24 km.
A-drier:
See a-dryer
ADS:
Abbreviation for air data system.
A-dryer:
A paint dryer which has the heating elements below the paint drying line.
ADS:
Acronym for "Association of Diesel Specialists".
adsorbent:
Substance with the property to hold molecules of fluids without causing a
chemical or physical change.
adsorption:
The bonding that takes place when a gas or vapor comes into contact with
a solid. The opposite is desorption.
adsorption canister:
adularescence:

A milky or bluish sheen shown by moonstone.
advance:
[1] The act of changing the ignition timing so that the spark occurs earlier
in the cycle. The opposite is retard.
[2] It may refer to the device which makes this adjustment.
[3] The length of railway track beyond a signal which is covered by that
signal
Also see
angle of advance
automatic advance
centrifugal advance
electronic spark advance
ignition advance
mechanical advance
ported vacuum advance
spark advance
speed control vacuum advance
vacuum advance
advance capsule:
See vacuum advance
advance curve:
As the speed of the engine increases the ignition advance also increases.
On paper, a pattern is drawn as a curve to represent this relationship.
advanced:
[1] A condition in which something occurs early.
[2] A product which is on the cutting edge of technology and shows the
latest in new ideas and concepts.
advanced gas-cooled reactor:
(AGR) Carbon-dioxide-cooled, graphite-moderated reactor using slightly
enriched uranium oxide fuel clad in stainless steel, in use in the UK.
advanced intelligent network:
A form of intelligent network, developed in the US from 1987 onward, in
which signalling, software, and accounting procedures are designed to
allow service providers to compete freely for network users' business.

advanced mobile phone system:
(AMPS) The American forerunner of the UK total access communications
system. Developed by Bell in 1978, AMPS like TACS, is an analog
cellular system using frequency modulation.
advanced rim taper:
A rim where both bead seats are tapered 5°.
advance mechanism:
See vacuum advance mechanism
advance metal:
Copper-base alloy with 45% nickel.
advance spring:
A small spring which pulls the advance weight back.
See picture in advance weight
advance unit:
See vacuum advance unit
advance weight:
One of two small weights located in a
centrifugal advance assembly.
advance workings:

In flat seams, mining in which the whole face is carried forward, no
support pillars being left.
advantage ratio:
Ratio between the radiation dosage received at any point in a nuclear
reactor and that of a reference position.
advection:
The transference of any quantity by horizontal motion of the air.
advection fog:
Fog produced by the advection of warm moist air across cold ground.
advection layer:
The region immediately adjacent to the event horizon where matter is
being continuously pulled into the black hole.
advertising:
A colloquial term for a police car with its emergency lights flashing.
Ae:
The transformation temperature at equilibrium of the phase changes in iron
and steel, subscripts indicating the designated change. Also called A.
AE:
Abbreviation for automatic exposure.
AEA:
Acronym for "Automotive Electric Association" or "Automotive
Electronic Association".
aeolian tone:
A musical note set up by vortex action on a stretched string when it is
placed in a stream of air.
Also see

Strouhal number
aeolotropic:
Having physical properties which vary with direction or position.
Also see
anisotropic
AERA:
Acronym for "Automotive Engine Rebuilders Association."
aeration:
A foaming of a liquid because air has been introduced into the fluid. When
it occurs in certain liquids, it decreases the efficiency of the liquid.
aeration test burner:
(ATB) Burner for measuring the combustion characteristics of commercial
gases.
aerial:
British term for antenna.
Also see
retractable aerial
whip aerial
aerial bunched conductors:
(ABC) Method of power transmission where the three conductors are
twisted into a thicker insulated cable. More expensive but better at
surviving blizzard conditions than normal separate conductors.
aerial fog:
Fog caused by exposure of portions of the film to air in the processing
machine.
aerial radiometric surveying:
Use of low-flying aircraft to measure gamma-ray intensity due to natural
radioactive emissions or radioactive contamination over large areas.
Scintillators are used with photomultipliers whose signals are fed to
multichannel analyzers to distinguish the energies of the gamma rays

received from a wide area; typically 90% of the gamma rays can be
recorded from an area with linear dimensions about five times the aircraft's
height above the ground. Also called airborne radiometric surveying.
aerial ropeway:
An apparatus for the overhead transport of materials in carriers running
along an overhead cable or cables supported on towers.
aerial surveying:
A process of surveying by photographs taken from the air, the photographs
being of two types:
1. those giving a vertical or plan view;
2. those giving an oblique or bird's-eye view.
Also see
vertical aerial photograph
oblique aerial photograph
AERO:
Abbreviation for "Air Education and Recreation Organization" in the UK.
aero-:
Prefix from Greek aer (αερ) indicating "air".
aero-acoustics:
Branch of acoustics that treats sound generation and transmission by fluid
flow.
aerobar:
An extension to bicycle handlebars which
project forward to give the rider an alternate
riding position and a lower, more aerodynamic
position. His elbows rest in the pads while he
grabs the upright ends of the bars. Aerobars
were popularized by triathletes and Greg
LeMond.

aerobars:
Sometimes referred to as Tri bars. Aerobars popularized by triathletes and
Greg LeMond, are attached to handlebars in order to provide a rider with a
lower, more aerodynamic position.
aerobic sealer:
A substance (such as room temperature vulcanizing (RTV), a common
silicone rubber sealing compound) that requires the presence of oxygen to
hold parts together.
Also see
anaerobic sealer
aerodynamic:
The efficient flow of air around an object.
aerodynamic balance:
[1] A balance, usually but not necessarily in a wind tunnel, designed for
measuring aerodynamic forces or moments.
[2] Means for balancing air loads on flying control surfaces, so that the
pilot need not exert excessive force, particularly as speed increases. The
principle is to use aerodynamic forces, either directly on a portion of the
control surface ahead of the hinge line or indirectly through a small
auxiliary surface with a powerful moment arm, to counterbalance the main
airloads. An example of the first is the horn balance, and of the second the
balance tab.
aerodynamic braking:
Use of a planet's atmosphere to reduce the speed of space vehicles.
aerodynamic center:
The point about which the pitching moment coefficient is constant for a
range of airfoil incidence.
aerodynamic coefficient:
A non-dimensional measure of aerodynamic force, pressure, or moment
that expresses the characteristics of a particular shape at a given incidence
to the airflow. Typically the lift coefficient is given by CL=L/½ρV²S, where
L is the lift, ρ is the air density, V is the air speed, and S is a typical area of

the body (e.g., wing area). Similarly for drag coefficient.
aerodynamic damping:
The suppression of oscillations by the inherent stability of a aircraft or of
its control surfaces.
aerodynamic drag:
The resistance of the air to forward movement, sometimes called "air
resistance." This is a factor of the shape of the vehicle (drag coefficient
and frontal area), the objects which stick out (i.e., mirrors, mufflers,
bumpers), the amount of turbulence at the rear of the vehicle, the nature of
the vehicle's skin surface, and the amount of air going through the vehicle
for cooling and ventilation. The faster you go, the greater the air friction
(air friction = velocity x velocity). The faster you go, the greater the
amount of power needed to overcome this drag (power = velocity x
velocity x velocity).
aerodynamic heating:
The heating of a vehicle passing through the atmosphere, caused by
friction and compression of air (or other gas).
aerodynamics:
The study of the flow of air as it passes over and around a moving object
as well as the forces which the air makes on the object. An airplane, for
instance, needs positive lift to get it airborne and negative lift to help it
land. Thus the shape of a land vehicle (car, bicycle, etc.) either promotes
positive or negative lift. Race cars may use spoilers and wings (air foils) to
control lift. In vehicle design, the airflow is monitored in a wind tunnel. As
well, aerodynamics also studies the most efficient shapes for increased
speed and fuel economy.
aerodynamic sound:
See flow noise
aerodynamic stance:
In order to create less drag, the vehicle is lowered closer to the ground.
This improves the flow of air over the vehicle. A better aerodynamic
stance helps the vehicle to go faster when it is going in a straight line as

well as give better fuel economy. Also, when a vehicle sits lower to the
ground, it has a low center of gravity which makes it more stable when
going through turns and enables the driver to maintain a higher speed.
aerodyne:
Any form of aircraft deriving lift in flight principally from aerodynamic
forces. Includes aircraft glider, kite, and helicopter. Commonly called
"heavier-than-air aircraft".
aero-elastic divergence:
Aero-elastic instability which occurs when aerodynamic forces, or
moments, increase more quickly than the elastic restoring forces or
couples in the structure. Generally applied to wing weakness where the
incidence at the tips increases under load, so tending to twist the wings off.
aero-elasticity:
The interaction of aerodynamic forces and the elastic reactions of the
structure of an aircraft. Phenomena are most prevalent when maneuvering
at very high speed.
aero-embolism:
Release of nitrogen bubbles into the blood stream resulting from too rapid
a reduction in ambient air pressure; the bends, encountered by undersea
divers.
Also see
caisson disease
aero-engine:
The power unit of an aircraft. Originally a lightweight reciprocating
internal-combustion engine, usually Otto cycle, as a general rule either air-
cooled radial, in-line, vee, or liquid-cooled vee; gas turbines gradually
superseded reciprocating engines from 1945 for large civil and military
aircraft but reciprocating engines are still widely used in small aircraft.
Also see
ducted fan
gas turbine
ramjet
turbojet
turboprop

turboramjet
turborocket
variable cycle engine
aerofoil:
British spelling for airfoil: a body shaped like a wing so as to produce an
aerodynamic reaction (lift) normal to its direction of motion, for a small
resistance (drag), in that plane; e.g., a wing, plane, aileron, tailplane,
rudder, or elevator.
Also see
air foil
aerogel:
A silicon-based solid with a porous structure with 99% of its volume as
open space, used as an insulator between sheets of things like glass.
aero-isoclinic wing:
A sweptback wing which has its torsional and flexural stiffness so adjusted
that the angle of attack remains constant as the wing bends under flight
loads, instead of decreasing with deflection toward the tip, which is the
normal geometric effect.
aerological diagram:
A thermodynamic diagram used for plotting the results of upper-air
soundings usually containing, as reference lines, isobars, isotherms, dry
adiabatics, saturated adiabatics, and lines of constant saturation humidity
mixing ratio.
aerology:
The study of the free atmosphere.
aeronautical engineering:
The branch of engineering concerned with the design, production, and
maintenance of aircraft structures, systems, and power units.
aeronautical fixed services:
(AFS) A telecommunication service between fixed stations for the
transmission of aeronautical information, particularly navigational safety

and flight planning messages.
aeronautics:
All activities concerned with aerial locomotion.
aerophone:
Group of musical instruments in which the air in a tube-shaped resonator
is excited to vibrate.
aeroplane:
British spelling for airplane.
Also see
aircraft
airplane
aerospaceplane:
Aircraft-like vehicle which can take off from and land on runways,
maneuver in the atmosphere, operate in space, and re-enter the
atmosphere.
aerostat:
Any form of aircraft deriving support in the air principally from its
buoyancy, e.g., a balloon or airship.
aero system:
A roof rack designed for cars without external rain gutters. The rack is
held on by clips that extend down into the door.
aerothermochemistry:
The chemical reactions which occur with airflow heating, e.g., a candle
flame in air or the combustion of kerosine in a jet engine.
aerothermodynamics:
The branch of thermodynamics relating to the heating effects associated
with the dynamics of a gas; in particular the physical effects produced in
the air flowing over a vehicle during launch and re-entry.

aerothermo-elasticity:
Aero-elasticity complicated by heating effects.
aether:
See ether
AEV:
Acronym for automatic expansion valve.
A/F:
[1] Abbreviation for "across flats" which is the distance on a nut (for
instance) from one flat surface to the opposite flat surface, i.e., this is the
size of the wrench needed to install or remove the nut.
Also see
across corners
[2] Abbreviation for "air/fuel."
See air-fuel ratio
[3] Abbreviation for "automatic focusing"
[4] Abbreviation for "audio-frequency".
AFB:
Acronym for "Aluminum four-barrel," as in Carter AFB carburetor.
AFC:
[1] Acronym for "air flow controlled"
[2] Abbreviation for "automatic frequency control".
AFCS:
Abbreviation for automatic flight control system.
affected zone:
See heat-affected zone
affine:

Said of characteristic curves of apparatus when these curves differ only in
the scales of one or both coordinates.
AFM:
Abbreviation for audio-frequency modulation.
A-frame
A chassis frame which is shaped like the letter "A" where the crossbar is
often the axle. It is usually found as the frame of a trailer.
Also see
shear-legs
A-frame barricade:
A traffic marker indicating that the
road is not usable.
A/F ratio:
See air-fuel ratio
AFS:
Abbreviation for aeronautical fixed services.
aft:
The back of a vessel.
Also see
fore and aft adjustment
aft adjustment:
See fore and aft adjustment
aft cg limit:
See cg limits

afterbody:
Rear portion of a flying-boat hull, aft of the main step.
after bottom dead center:
(ABDC) The position of the piston as it starts its way up.
afterburner:
A device for burning excess carbon wastes produced by the engine so that
air pollution is reduced.
Also see
reheat
afterburning:
In an internal-combustion engine, persistence of the combustion process
beyond the period proper to the working cycle, i.e., into the expansion
period.
afterburst:
Delayed further collapse of underground workings after a rockburst.
aftercooler:
[1] A device in a diesel engine which removes the relatively warm air
which enters the engine.
[2] Chamber in which heat generated during compression of air is
removed, allowing cool air to be piped underground.
afterdamp:
The non-flammable heavy gas, carbon dioxide, left after an explosion in a
coal mine. The chief gaseous product produced by the combustion of coal-
gas.
Also see
black damp
choke damp
fire damp
white damp
afterglow:

[1] The period during which the glow plugs of a diesel engine continue to
operate after the engine is started.
[2] The glow of a gaseous medium immediately after the cessation of
electric current or downstream of an electric discharge.
Also see
persistence
afterheat:
The heat which comes from fission products in a reactor after it has been
shut down.
after-image:
Formation of image on retina of eye after removal of visual stimulus, in
color complementary to this stimulus.
Also see
complementary after-image
aftermarket:
All products and services used in the repair and maintenance of vehicles
after the vehicle has been sold.
aftermarket equipment:
Accessories and replacement parts added to a vehicle after it has been
sold.
aftermarket overdrive:
An overdrive device which is not original equipment, but has been added
after it has been sold.
aftermarket part:
Goods not for use as original equipment in the production of light-duty
vehicles or heavy-duty vehicles, i.e., products and services used in the
repair and maintenance of these vehicles.
aftermarket rustproofing:
Although most vehicles come from the manufacturer with some
rustproofing, there is no guarantee that every part of the exposed chassis
and frame will be protected from the elements and the possibility of rust.

Therefore rustproofing is applied by the owner of the vehicle to reduce the
possibility of rust. If this rustproofing is not done when the vehicle is new,
it might seal in the rust and create a greater problem.
afterpeak:
Space abaft the aftermost bulkhead. Lower part frequently used as fresh-
water tank; upper part may be used as storeroom.
afterpeak bulkhead:
First main transverse bulkhead forward of the sternpost.
after perpendiculars:
A vertical line at the intersection of the summer load line and the after side
of the rudder post or sternpost, or the centerline of the rudder stock if there
is no rudder post or sternpost.
after-start enrichment:
When an engine is first started, it needs a little richer fuel-air mixture (i.e.,
more fuel, less air). In a carbureted engine, this is accomplished by the
choke (which restricts the amount of air). In a fuel injected engine, the
after-start enrichment device increases the amount of fuel. As the engine
warms up, the device gradually reduces the amount of enrichment. Some
devices just reduce the amount gradually over time without sensing the
temperature of the engine.
after top dead center:
(ATDC) A term used in timing the relation of the spark and the crankshaft.
The position of the piston as it starts its way down.
Ag:
Symbol for silver (argentum).
AG:
Acronym for "air-guard".
AGC:

Abbreviation for automatic gain control.
aged catalyst:
A catalyst which has already been in service. Opposite to a fresh catalyst.
age equation:
See age theory
age-hardening:
[1] Aluminum and some metal alloys will become hard and even brittle
with age which is an unwanted characteristic. On the other hand when
paint or cement harden over time, this process may be a desirable
characteristic.
[2] The production of structural change spontaneously after some time;
normally it is useful in improving mechanical properties in some respect,
particularly hardness.
Also see
precipitation hardening
ageing:
See aging
agency:
See driver and Vehicle Licensing Agency
energy Protection Agency
agent:
An intermediary with legal authority to operate on behalf of the
manufacturer.
Also see
activating agent
addition agent
aggressive agent
air-entraining agent
anti-knock agent
bonding agent
degreasing agent
oxidizing agent
reducing agent
release agent
rustproofing agent

softening agent
agent fee:
Although you can register your vehicle and obtain your licence from a
government office, some states and provinces permit an agent to perform
that same service and allow the agent to collect an extra fee for the service.
In this way the lineup at the government office is reduced.
age theory:
In nuclear reactor theory, the slowing down of neutrons by elastic
collisions. The age equation relates the spatial distribution of neutrons to
their energy. The equation is given by.
.
where q is the slowing-down density and τ is the Fermi age. It was first
formulated by Fermi who assumed that the slowing-down process is
continuous and so is least applicable to media containing light elements.
agglomerate:
Assemblage of particles rigidly joined together, as by partial fusion
(sintering) or by growing together.
agglomerating value:
Index of the binding (sintering) qualities of coal which has been subjected
to a prescribed heat treatment.
aggregate:
[1] Assemblage of powder particles which are loosely coherent
[2] Mixture of sand and gravel or crushed rock used in making concrete.
Graded aggregate has a graded size distribution so that the particles fit
better together, requiring less cement in the mix.
Also see
coarse aggregate
fine aggregate
[3] A mass consisting of rock or mineral fragments.
aggressive:

A French expression to indicate the reinforced front, rear, and side safety
structures of a vehicle. If the strengthened structure causes more than
normal damage to another vehicle, a pedestrian, or the occupants of the
vehicle, then that structure is aggressive.
aggressive agent:
A corrosive material or chemical which attacks metal to pit them. Also
called aggressive medium..
aggressive medium:
A corrosive material or chemical which attacks metal to pit them.
aggressivity:
See aggressive
aging:
[1] The cracking, checking, or general deterioration produced by exposure
of an adhesive, coating or sealer to the weather or some other given set of
conditions for a length of time
[2] The deterioration of rubber properties by oxidation over a period of
time.
[3] A change in the properties of some metals after heat treatment or cold
working (i.e., hammering or bending when metal is cold).
[4] The final stage of precipitation hardening, producing an increase in
strength and hardness in metal alloys, due to precipitation of second phase
particles from supersaturated solid solution over a period of days at room
temperature, or several hours at an elevated temperature (called artificial
aging)
[5] Loss of strength in the cladding or the pressure vessel in a nuclear
reactor due to irradiation. Artificial aging would be the simulation of such
processes by increasing the rate of irradiation to obtain information more
rapidly
[6] Change in the properties of a substance with time. A change in the
magnetic properties of iron, e.g., increase of hysteresis loss of sheet-steel
laminations; also the process whereby the subpermanent magnetism can be
removed in the manufacture of permanent magnets
[7] The exposure of freshly printed fabrics to steam to produce fully
developed colors.
Also see
artificial aging

tire aging
aging test:
See accelerated aging test
agitation:
Vigorous movement of film and solutions during processing to ensure that
fresh chemicals are brought in contact with the emulsion.
agitation cup:
A type of spray gun paint container which has an agitator.
agitator:
[1] A device used to cause motion in confined fluid
[2] A device for mixing paint by shaking the container.
[3] A tank, usually cylindrical, which has a mixing device such as a
propeller or airlift pump near the bottom. Finely ground mineral slurries
(the aqueous component perhaps being a leaching solution) are exposed to
appropriate chemicals for purpose of extraction of gold, uranium, or other
valuable constituents. Types include pachuca tank or Brown agitator.
A-glass:
Designation for a glass fiber of composition (percentage by weight).
SiO2 = 72%.
Na2O = 14%.
CaO = 10%.
MgO = 2.5%.
Al2O3 = 0.6%.
which is similar to that of the soda-lime-silica glass used for windows and
bottles. Its resistance to water, mineral acids, and alkalis is much less than
that of C-glass and E-glass fibers.
AGO:
Abbreviation for automotive gas oil.
AGR:

Abbreviation for advanced gas-cooled reactor.
agreement:
See Free Trade Agreement of the Americas
General Agreement on Tariffs and Trade
North American Free Trade Agreement
Agreement of the Americas:
See Free Trade Agreement of the Americas
Agreement on Tariffs:
See General Agreement on Tariffs and Trade
Agreement on Tariffs and Trade:
See General Agreement on Tariffs and Trade
aground:
See hard aground
AGS:
Abbreviation for aircraft general standard.
AGVS:
Acronym for "Automated Guided Vehicle System."
a.h.:
Abbreviation for ampere-hour.
AHAI:
Acronym for "Association of the Hungarian Automotive Industry".
AHAP:
Acronym for "As High As Possible."
AHARA:

Acronym for "As High As Reasonably Achievable".
ahm:
Abbreviation for ampere-hour meter.
ahoogah:
The sound of a particular kind of horn.
AHRA:
Acronym for "American Hot Rod Association."
AH Rim:
A wheel rim which is able to run even when the tire is flat and provides
safety in case of a puncture.
AIAA:
Abbreviation for American Institute of Aeronautics and Astronautics.
AIADA:
Acronym for "American International Automobile Dealers Association".
AIAM:
Acronym for "Association of International Automobile Manufacturers".
AIA-SAP:
Acronym for "Automotive Industry Association" (Czech Republic).
AIA-ZAP:
Acronym for "Automotive Industry Association" (Slovakia).
aided:
See computer-aided
aids:

See suspension aids
aileron droop:
The rigging of ailerons so that under static conditions their trailing edges
are below the wing trailing-edge line, pressure and suction causing them to
rise in flight to the aerodynamically correct position.
ailerons:
Surfaces at the trailing edge of the wing, controlled by the pilot, which
move differentially to give a rolling motion to the aircraft about its
longitudinal axis.
AIMA:
Acronym for "Associação dos Industriais de Montagem de Automóveis"
(Portugal).
aimer:
A tool for aiming headlights.
aiming:
Adjusting the direction of the headlight beams to shine without blinding
oncoming traffic and yet providing the maximum illumination whether in
low beam or high beam.
air:
[1] Abbreviation for "air conditioner."
[2] A bicycling or motorcycling term describing the space or gap between
the tires and the ground when the bike takes a jump. Both tires must be off
the ground before it can be called "air" as in the expression, "I really
caught air on that last jump."
[3] A gas containing approximately 80% nitrogen, 20% oxygen, and a
small portion of other gases. One of the essential factors in a combustion
engine (fuel, air, proper proportion of mixture, compression, timing, and
spark).
Also see
ambient air
bath air
external mix air
cap
L-jetronic air flow
meter
proper proportion of air
and fuel

charge air
cold air
driver air bag
electric air control
valve
electric air switching
valve
fuel air mixture
fuel air ratio
heater air pipe
idle air bleed
screw
idle air jet
internal mix air
cap
lateral air passage
low-profile air
cleaner
modular air strut
oil bath air cleaner
paper air cleaner
passenger-side air
bag
pulse air principle
pulse air system
ram air
secondary air
AIR:
An acronym for "Air Injection Reactor" system of reducing objectionable
exhaust emissions.
Also see
air injection
air absorption:
Absorption of sound waves propagating in air, caused by molecular
relaxation processes and viscosity.
air and fuel:
See proper proportion of air and fuel
air aspirator system:
(AAS) A passive air injection system that uses a one-way valve instead of
an air pump to introduce extra air into the exhaust stream.
air bag:
A device which is part of the passive safety system. In the event of an
accident, sensors will cause the airbag to be deployed so that your head
will be pillowed by the bag instead of hitting the dash.
Also see
driver air bag
passenger-side air bag
side impact air bag
airbag:
A device which is part of the passive safety system. In the event of an
accident, sensors will cause the airbag to be deployed so that your head
will be pillowed by the bag instead of hitting the dash.
Also see

driver air bag
side impact air bag
airbag module:
All the components that make up the airbag system: Airbag, inflator,
cover, and sensor. Also called airbag unit..
airbag restraint system:
A system which uses an airbag to restrain occupants in the event of a
collision. They may be placed on the dash or doors or even in the shoulder
strap. Also called passive restraint system..
air-bag system:
See supple mental restraint inflatable air-bag system
airbag unit:
All the components that make up the airbag system: Airbag, inflator,
cover, and sensor. Also called airbag module..
air bellows:
A rubber bladder or sleeve filled with compressed gas or air. Found on
some suspension systems to provide cushioning.
Also see
air suspension
air bells:
Minute bubbles which have adhered to the emulsion during processing of
film, leaving small circular spots where it has been protected from
chemical action.
air-blast circuit breaker:
A form of circuit-breaker or switch in which an arc is deliberately drawn
between two contacts. The arc is cooled by a blast of high pressure air
which removes ions, thereby extinguishing the arc and breaking the
circuit. Also called air-blast switch.
air-blast switch:

A form of circuit-breaker or switch in which an arc is deliberately drawn
between two contacts. The arc is cooled by a blast of high pressure air
which removes ions, thereby extinguishing the arc and breaking the
circuit. Also called air-blast circuit breaker.
air bleed:
See adjustable off-idle air bleed
auxiliary air bleeds
compensating jet
idle air bleed screw
air bleed screw:
See idle air bleed screw
airborne missile control system:
(AMCS) A method of controlling missile attacks from a secure command
position.
airborne radiometric surveying:
See aerial radiometric surveying
airbox:
The container which holds the air filter.
air brake:
[1] A system of braking which is usually found on large truck in which
compressed air pushes against a brake piston or diaphragm in order to
apply the brakes to stop or slow the vehicle.
[2] An extendable device, most commonly a hinged flap on wing or
fuselage, controlled by the pilot, to increase the drag of an aircraft.
Originally a means of slowing bombers to enable them to dive more
steeply, it is an essential flight control on clean jet aircraft and sailplanes
[3] A mechanical brake operated by air-pressure acting on a piston
[4] An absorption dynamometer in which the power is dissipated through
the rotation of a fan or propeller.
air break:
[1] An inverted opening placed in the chimney of a gas furnace to prevent
back pressure from outside wind from reaching the furnace flame or pilot.

[2] Term describing a switch or circuit breaker with contacts in air.
airbrush:
[1] A paint spray gun used for precise detailing work and custom painting.
[2] The act of using an airbrush.
air bypass valve:
(ABPV or ABV) a backfire-suppressor valve used in air injection systems.
During high engine vacuum conditions such as deceleration, it vents
pressurized air from the air pump to the atmosphere in order to prevent
backfiring. At other times, it sends air to the exhaust manifold. On vehicles
with a three-way catalyst, it sends air to the oxidation catalyst only when
the engine warms up. Also called an anti-backfire valve, diverter valve, or
gulp valve.
air cap:
See external mix air cap
internal mix air cap
air capacitor:
A capacitor in which the dielectric is nearly all air, for tuning electrical
circuits with minimum dielectric loss.
air capacity:
See breathing capacity
air cell:
A small auxiliary combustion chamber used in certain types of
compression-ignition engines, for promoting turbulence and improving
combustion.
air charge temperature:
(ACT) The temperature of the air being forced into the carburetor or fuel
injection system. An ACT sensor measures this temperature.
air charge temperature sensor:

(ACTS) a thermistor sensor that inputs the temperature of the incoming air
stream in the air filter or intake manifold to the computer. It can be located
in the intake manifold (EFI systems) or the air cleaner. On carbureted
vehicles, if the air is cold, it signals the choke to let off slowly. It then
alters engine speed after the choke is off and below a certain temperature,
dumps air from the air injection system to the atmosphere for catalyst
protection.
air classifier:
Appliance in which vertical, horizontal, or cyclonic currents of air sort
falling ground particles into equal-settling fractions or separate relatively
coarse falling material from finer dust which is carried out. Also called air
elutriator.
air cleaner:
A device which filters the air entering
the engine to remove airborne
impurities, dust, dirt, and
bumblebees. Also called air filter.
Also see
bath air cleaner
bath air cleaner
low-profile air cleaner
paper air cleaner
thermostatic air cleaner
air cleaner bi-metal sensor:
(ACL BI-MET) a component of a thermostatic air cleaner system. It
senses the temperature of incoming fresh air and bleeds off vacuum when
the air is warm. When the air is cold, the sensor directs vacuum to the air
cleaner vacuum motor.
air cleaner duct and valve vacuum motor:
(ACL DV) a component of thermostatic air cleaner systems. It opens and
closes the air duct valve to provide heated or unheated air to the engine in
accordance with the temperature of the incoming air.

air cleaner element:
The replaceable filter which prevents
impurities from the air which enters
the combustion chamber. Also called
air filter element.
air cleaner horn:
Many air cleaner canisters have a spout or horn extending from the edge of
the canister into which the air is taken in.
Also see
heated intake
air coil:
Coil on some types of heat pumps used either as an evaporator or a
condenser.
air compressor:
A device which compresses air and stores the air into a tank so that the
compressed air can be used in a shop to fill tires, run tools, spray paint,
etc. In a vehicle, it can be used in brake systems, leveling systems,
automatic tire inflation systems, and air supply systems.
air-conditioned:
The state of exchanging warm air for cold so that a vehicle or home is
cooler than the outside temperature.
air conditioner:
(A/C) or (Air)
[1] A device used to control temperature, humidity, cleanliness, and
movement and sometimes the air purity, in an enclosed space
[2] A system of devices which causes a reduction or control of the
temperature and humidity within the cab of a vehicle. It was first offered
on the 1941 Packard. Two types are used in vehicles: Receiver-dryer type
and accumulator type.
Also see
compressor

condenser
air conditioner clutch compressor signal:
(ACCC signal) the input to the computer regarding the status of the air
conditioner clutch (engaged or disengaged).
air-conditioning:
A system or process for controlling the temperature, humidity, air
movement, and sometimes the purity of the air in an enclosed space.
Also see
automatic air-conditioning
air conduction:
The passing of noise energy along an air path, as contrasted with structure-
borne conduction of vibrational energy.
air control:
See electric air control valve
air control valve:
(ACV) a vacuum-controlled diverter valve (or a combination
bypass/diverter valve) in an air injection system that diverts air pump air to
either the upstream (exhaust manifold) or downstream (oxidation catalyst)
air injection points as necessary.
Also see
electric air control valve
air-cooled apparatus:
An electric apparatus in the heat caused by the losses is removed solely by
natural or fan-assisted air flow.
air cooled:
See air cooled engine
air-cooled condenser:
A heat exchanger which transfers the heat of compression from
condensing coils to surrounding air. This may be done either by
convection or by a fan or blower.

air cooled engine:
An engine which generally has large fins or ribs and is
often exposed to the outside air. The heat of the engine
is dissipated through the fins of the engine. In contrast,
the heat in a liquid-cooled engine is reduced by
channels throughout the inside of the engine through
which liquid (antifreeze) passes. Most older
Volkswagens and motorcycles use air cooled engines.
air-cooled engine:
air-cooled machine:
A machine in which the heat caused by the losses is removed solely by
natural or fan-assisted air flow.
air-cooled transformer:
A transformer in the heat caused by the losses is removed solely by natural
or fan-assisted air flow.
air cooler:
[1] Mechanism designed to lower temperature of air passing through it
[2] The cold "accumulator" used in the Lindé process of air liquefaction
for the preliminary cooling of the air.
air cooling:
The cooling of hot bodies by a stream of cold air, instead of liquid (water)
cooling.
Also see
charge air cooling
air core:
Coil of wire not having a metal core.
air core solenoid:

Solenoid which has a hollow core instead of a solid core.
air correction jet:
A small orifice which permits air to enter the emulsion tube of a
carburetor.
aircraft:
Any mechanically driven heavier-than-air flying machine with wings of
fixed or variable sweep angle. Subdivision: landplane, seaplane (float
seaplane and flying boat), amphibian.
aircraft design:
The specification of an aircraft, following compromises between
requirements of performance, economy, and safety. It includes external
aerodynamic shape, and the spatial arrangement of flying surfaces,
engines, control surfaces and internal systems. Gross weight, take-off
weight, landing weight, and load are all legal values in specification and
contract, and verification is proof of the design by ground and flight tests.
New concepts include an inherently unstable aircraft controlled
continuously by on-board computers.
aircraft engine:
See aero-engine
aircraft flutter:
Term used for the rapid fluctuations in very-high-frequency reception,
affecting sound and vision; due to a secondary transmission path, or
rapidly shifting phase, set up by reflection from an aircraft.
aircraft General Standard:
(AGS) Term referring to small parts or items such as bolts, nuts, rivets,
fork joints, etc. which are common to all types of aircraft.
aircraft noise:
noise from propeller, engine, exhaust, and that generated aerodynamically
over the surfaces; characterized by unstable low frequencies.
Also see

jet noise
air cushion:
See airbag
air dam:
An attachment called a "spoiler" which is usually located below the front
bumper. Its design shape and placement helps to reduce the flow of air
under the vehicle. It may help to increase the flow of air to the radiator and
engine compartment, affect aerodynamic drag, or affect positive and
negative lift.
air data system:
(ADS) A centralized unit into which are fed the essential physical
measurements for flight, e.g., airspeed, Mach number, Pitot and static
pressure, barometric altitude, stagnation air temperature. From this central
source, data are transmitted to the cockpit dials, to flight and navigational
instruments, and to computers.
air deflector:
A panel which is positioned at an angle on the roof of a truck or on the
front of the hood to cause the air to flow over the vehicle. The hood air
deflector (often made of transparent plastic) is designed to prevent bugs
from hitting the windshield. British term is "air shield."
air diffuser:
Air distribution outlet or grille designed to direct airflow into desired
patterns.
air door:
In a mine ventilating system, a door which admits air or varies its
direction.
air dose:
The radiation dose in röntgens delivered at a point in free air.
airdox:

US system for breaking coal in fiery mine by use of injected high-pressure
air.
air drag:
Resistance to the motion of a body passing through the Earth's atmosphere,
most serious in the lower regions, producing changes in the geometry of
the orbit, even causing the body to re-enter. More generally the term
atmospheric drag is used in reference to other planets.
air drilling:
Drilling method which uses air instead of mud as the cooling and debris
removal medium. Faster and easier than mud drilling, it cannot prevent
water ingress and emergency mud equipment will then be necessary. Also
called gas drilling..
air dry:
[1] Allowing paint to dry at ambient (surrounding) temperatures, without
the aid of an external heat source.
[2] Said of minerals, pulp and paper in which moisture content is in
equilibrium with that of atmosphere. The basis of sale for wood pulp; pulp
with a conventionally accepted theoretical moisture content is usually
100% on total mass.
air-dry:
Allowing paint to dry at ambient (surrounding) temperatures, without the
aid of an external heat source.
air drying adhesives:
Adhesives that can be dried at room temperature without the use of heat.
This type of adhesive consists of solid particles dissolved or dispersed in a
liquid. When the liquid evaporates, it leaves the dry adhesive film. Most
elastomer based adhesives are of this type.
air duct:
A tube or channel which permits heated and ventilated air to enter the
passenger compartment, building, or machinery to provide heating,
cooling, or ventilation.

aired up:
Said of an oil plunger pump which no longer sucks because gas or air has
filled the suction chamber.
air ejector:
A type of air pump used for maintaining a partial vacuum in a vessel
through the agency of a high-velocity steam jet which entrains the air and
exhausts it against atmospheric pressure.
air elutriator:
See air classifier
air engine:
[1] An engine in which air is used as the working substance. Rapid heating
from an external source expands the air in the cylinder with consequent
motion being imparted to a piston. After transfer to a compression
cylinder, for rapid cooling, the air is returned to the working cylinder for
the next cycle. Also called hot-air engine.
[2] A small reciprocating engine driven by compressed air.
Also see
Stirling engine
air-entraining agent:
Resin added to either cement or concrete in order to trap small air bubbles.
air equivalent:
The thickness of an air column at 15°C and 1 atmosphere pressure which
has the same absorption of a beam of radiation as a given thickness of a
particular substance.
air escape:
Device for releasing excess air from a water pipe. A valve is opened by a
float when sufficient air has accumulated and closed in time to prevent
loss of water.
air exhauster:

[1] A suction fan.
[2] A vacuum pump.
airfield:
See alternate airfield
air filter:
A device for removing impurities from the air which enters the combustion
chamber.
Also see
air cleaner
canister air filter
centrifugal force air filter
air filter element:
The replaceable filter which prevents
impurities from the air which enters
the combustion chamber. Also called
air cleaner element.
air filtration:
See air filtration system
air filtration system:
A system that cleans smog, pollen, exhaust smoke, and odors out of the air.
Cleans both interior circulated air and that coming from the outside.
air-float table:
Shaking table in which concentration of heavy fraction in sand-sized feed
is promoted by air blown up through the porous deck. Used in desert work.
Also called air table..
airflow:

The passage of air which moves around an object (esp. a vehicle) or
through an air duct (e.g., ventilation system or exhaust system).
Also see
L-jetronic air flow meter
hot-wire airflow meter
mass airflow meter
air flow controlled:
(AFC) a Bosch term for its early pulse fuel injection systems; usually
refers particularly to the system which uses an L-Jetronic air mass sensor.
air flow meter:
[1] A meter which measures the rate at which air enters the engine. In
Bosch systems, any device that measures the amount of air being used by
the engine. The control unit uses this information to determine the load on
the engine. The two most common examples of airflow meters are the air-
flow sensor used in the Bosch L-Jetronic and the air mass sensor used in
the Bosch LH-Jetronic systems.
[2] An instrument, mainly experimental, for measuring the airflow in ducts
Also see
L-jetronic air flow meter
hot-wire airflow meter
mass airflow meter
airflow meter:
See air flow meter
airflow sensor:
A device in an electronically controlled fuel injection system which detects
the amount of air entering the combustion chambers. Continuous injection
systems use an airflow sensor plate to measure airflow volume; electronic
systems use a vane or flap-type airflow sensor.
air flue:
A flue which is built into a chimney stack so as to withdraw vitiated air
from a room.

air foil:
An
aerodyna
mic
device
used to
improve
traction by
increasing
the
downward
force on
either end
of the car.
It can be
compared
to an
airplane
wing with
this
primary
difference:
A wing is
designed
to provide
lift so it
can fly;
the air foil
pushes the
vehicle
closer to
the
ground.
Although
they may
be called
"wings,"
they are
properly
air foils.
They
increase
the

cornering
ability,
improve
stability,
but add
aerodyna
mic drag.
airfoil section:
The cross-sectional shape or profile of an airfoil.
airframe:
The complete aircraft structure without power plant, systems, equipment,
furnishing, and other readily removable items.
air frost:
A screen temperature below 0°C.
Also see
wind frost
air fuel:
See air-fuel ratio
air-fuel:
See air-fuel ratio
air/fuel:
See air-fuel ratio
air-fuel mixture:
See rich air-fuel mixture
lean air-fuel mixture
air fuel ratio:
See air-fuel ratio
air-fuel ratio:
(A/F ratio) The mass of air supplied to the engine divided by the mass of
fuel supplied in the same period of time. The stoichiometric, or chemically

correct, air-fuel ratio is the exact ratio necessary to burn all the carbon and
hydrogen in the fuel to carbon dioxide and water with no oxygen
remaining. The fuel-air ratio is the reciprocal of the air-fuel ratio.
Also see
lean air-fuel mixture
rich air-fuel mixture
air gap:
[1] The space bet magnetic poles or between rotating and stationary
assemblies in a motor or generator
[2] Usually found on regulators, it is the distance between the contact
armature and the iron core that when magnetized, draws the armature
down.
[3] It is also the distance between the two electrodes of a spark plug.
Also see
spark air gap
[4] Gap with points or knobs, adjusted to breakdown at a specified voltage
and hence limit voltages to this value.
[5] Section of air, usually short, in a magnetic circuit, esp. in a motor or
generator, a relay, or a choke. The main flux passes through the gap, with
leakage outside depending on dimensions and permeability.
air-gap torsion meter:
A device for measuring the twist in a shaft by causing the relative rotation
of two sections to alter the air-gap between a pair of electro-magnets, the
resulting change in the current flowing being indicated by an ammeter.
air gate:
Passage from interior of a mold to allow the escape of air and other gases
as the metal or plastic enters.
Also see
riser
airglow:
The faint permanent glow of the night sky, due to light-emission from
atoms and molecules of sodium, oxygen, and nitrogen, activated by
sunlight during the day.

air-guard:
(AG) An American Motors air injection system that uses an air pump to
supply air into the exhaust manifold to reduce HC and CO emissions.
air gulp system:
A system in vehicles with secondary air injection or induction, which
prevents an very rich mixture of air-fuel from entering the inlet manifold
during deceleration. If it did enter, unburned fuel would be forced over the
hot exhaust system causing backfiring (i.e., uncontrolled detonation). The
air gulp system prevents this condition by allowing a quantity of air to
combine with the rich mixture in the inlet manifold.
air gulp valve:
A diverter valve which adds an amount of air to the rich air-fuel mixture
entering the intake manifold during deceleration.
air hammer:
A hammer that is powered by compressed air
air handler:
Fan-blower, heat transfer coil, filter, and housing parts of a system.
air-hardening steel:
Steel with sufficient carbon and other alloying elements to allow sections
over 500 mm (20 in) to harden fully when cooled in air or other gas from
above its transformation temperature. Also called self-hardening steel..
airheads:
A term for older, air-cooled BMW Boxer Twin motorcycles.
air heater:
[1] Direct-fired heater, in which the products of combustion are combined
with the air.
[2] Indirect-fired heater, in which the combustion products are excluded
from the air flow. Both can be operated in a recirculation system, by which
a proportion of the heated air is returned to and passed through the heating
chamber.

Also see
air preheater
air hoist:
Air winch or other mechanical hoist actuated by compressed air.
air hold fitting:
A tool which uses air pressure to keep the valves closed when working on
an OHV engine. The device is screwed into the spark plug holes and air
pressure keeps the valves from dropping down. In this way the valve seal
or valve spring can be replaced without removing the cylinder head.
air horn:
[1] The upper part of a carburetor into which
the air is drawn. The choke butterfly is located
in this air horn.
[2] It is also a term used for a warning horn
which is operated by forcing compressed air
through a reed.
air horn baffle:
Used on some Rochester Quadrajet carburetors to prevent incoming air
from forcing fuel into the secondary wells through the bleed tubes.
Prevents secondary-nozzle lag during heavy acceleration.
air induction:
See air injection
cold air induction
air infiltration:
Leakage of air into rooms through cracks, windows, doors, and other
openings.
airing:
Removal of sulphur from molten copper in a wirebar furnace, together
with slag-forming impurities.

air injection:
A system that injects fresh air into the exhaust ports or a thermal reactor,
for additional conversion of carbon monoxide to carbon dioxide and
combustion of unburned hydrocarbons (unburned fuel vapors) found in the
exhaust gases as it comes in contact with the high heat in the exhaust
manifold. Also called air induction..
air injection manifold:
The duct inside the cylinder head or the tube outside the cylinder head
feeding secondary air into the exhaust ports.
air injection reaction:
See air Injection Reaction system
air injection reaction system:
(AIR system) The AIR system helps to reduce hydrocarbons and carbon
monoxide levels in the exhaust by injecting air into the exhaust ports of
each cylinder during cold engine operation, or directly into the catalytic
converter during normal operation. It also helps the catalytic converter to
reach proper operating temperature quickly during warm-up. If a GM cars
has an air pump, the system is an AIR otherwise it is a PULSAIR system.
air injection system:
(AIS) any system that injects air into the exhaust stream to promote more
complete oxidation of unburned exhaust gases.
air inlet valve:
An adjustable door, often vacuum operated, in the plenum blower
assembly that permits election of outside or inside air for automotive
heating and cooling systems.
air insulation:
Insulation for part of an electrical circuit provided by atmospheric air, e.g.,
a high-voltage transmission line, which is suspended between transmission
towers (pylons), is insulated for the section between the towers by
atmospheric air.

air intake:
[1] Any opening introducing air into an aircraft; the opening for the main
engine air is usually implied if unqualified.
[2] The opening through which air enters a component such as the
carburetor, fuel injection system, radiator, heating system, or ventilation
system.
[3] Vent in a carburetor through which air is sucked to mix with the
gasoline vapor from the jet.
Also see
auxiliary air intake
cold air intake
air-intake guide vanes:
radial, toroidal or volute vanes which guide the air into the compressor of
a gas turbine, or the supercharger of a reciprocating engine.
air interface:
The physical specification and operating protocols governing the radio
links to and from a mobile telephone.
air jet:
See idle air jet
air jet spinning:
Method of converting staple fibers into yarn: they are spun together by jets
of air which strike the fibers tangentially, making them rotate.
air jet texturing:
See textured yarn
air jig:
Use of pulses of air to stratify crushed ore into heavy and light layers.
Used in waterless countries.
airlance:
Length of piping used to work compressed air into settled sand or to free
choked sections of process plant, restoring aqueous flow.

air laying:
Method for forming a web by collecting fibers from an air stream on a
mesh ready for manufacturing a non-woven fabric.
air leg:
Telescopic cylindrical prop expanded by compressed air, used to support a
rock drill.
airless spraying:
A paint spraying process where the coating material (i.e., paint) is not
atomized by a stream of air. Instead, it is subjected to high pressure and
forced through a narrow jet or nozzle which causes it to be atomized.
airless spray gun:
A paint spraying tool used in airless
spraying.
airlift:
A jet of air or neutral gas used to move solid or liquid material during
processing to avoid necessity for pumps, particularly in "maintenance-
free" radioactive environments.
airlift pump:
An air-operated displacement pump for elevating or circulating pulp in
cyanide plants.

air line:
[1] A pipe, hose, or duct in a vehicle which permits the flow of air or
vacuum.
[2] The supply line coming from an air compression tank to drive air tools
or inflate tires.
[3] Straight line drawn on the magnetization curve of a motor, or other
electrical apparatus, expressing the magnetizing force necessary to
maintain the magnetic flux across an air-gap in the magnetic circuit.
air liquefier:
A type of gas refrigerating machine based on the "Sterling" or hot-air
engine cycle.
air lock:
[1] A bubble of air trapped in a fluid circuit which interferes with normal
circulation of the fluid.
[2] Device by which access is obtained to the working chamber (filled
with compressed air to prevent entry of water) at the base of a hollow
caisson. The worker at surface enters and is shut in an air-tight chamber
filled with air at atmospheric pressure. Pressure within this air-lock is
gradually raised to that used in the working chamber, so that the worker
can pass out through another door and communicate with the working
chamber.
air log:
An instrument for registering the distance travelled by an aircraft relative
to the air, not to the ground.
air management system:
(AMS) used to control the injected air to the exhaust manifold and
catalytic converter. This improves the pollutant conversion efficiency in
the converter.
air manometer:
A pressure gauge in which the changes in volume of a small quantity of air
enclosed by mercury in a glass tube indicate changes in the pressure to
which it is subjected.

airmanship:
Skill in piloting an aircraft.
air mass:
A part of the atmosphere where the horizontal temperature gradient at all
levels within it is very small, perhaps of the order of 1°C per 100 km.
Also see
frontal zone
air mass flow:
In a gas turbine power plant, the quantity of air which is ingested by the
compressor, normally expressed in pounds or kilograms per second.
air mass sensor:
An airflow meter that uses the changing resistance of a heated wire in the
intake airstream to measure the mass of the air being drawn into the
engine. Also referred to as a hot-wire sensor.
air meter:
An apparatus used to measure the rate of flow of air or gas.
air micrometer:
A control in a paint spray gun which adjusts the amount of air.
air-mileage unit:
An automatic instrument which derives the air distance flown and feeds it
into other automatic navigational instruments.
air miles per gallon:
The number of miles flown through the air for each gallon of fuel burnt by
the propulsion units.
air mixture:
See fuel air mixture
air monitor:

Radiation (e.g., γ-ray) measuring instrument used for monitoring
contamination or dose rate in air.
air outlet:
The vent or opening where the passage of air exits -- especially in systems
for air conditioning, ventilation, and defrosting as air enters the passenger
compartment or flows out of the compartment.
air outlet valve:
A vacuum operated door which directs air flow into the heater core or
ducts, usually located in or near the plenum blower assembly. A vacuum
operated door which directs air flow into the heater core or ducts, usually
located in or near the plenum blower assembly.
air passage:
See lateral air passage
air pipe:
See heater air pipe
air pocket:
Colloquial term for a localized region of rising or descending air current.
Causes an abrupt vertical acceleration as an aircraft passes through it,
severity increasing with speed and also with low wing loading. Also called
bump.
Also see
vertical gust
air pollution:
Contamination of the earth's atmosphere by various natural and man-made
pollutants such as smoke, gases, dust, etc.
airport markers:
Particolored boards defining areas on an airfield, e.g., boundary makers
which indicate the limits of the landing area, taxi-channel markers for taxi
tracks, obstruction markers for ground hazards, and runway visual
markers, situated at equal distances, by which visibility is gauged in bad
weather.

airport meteorological minima:
The minimum cloud base (vertical) and horizontal visibility (expressed as
runway visual range, RVR) in which landing or takeoff is permitted at a
particular aerodrome. ICAO standards:
CATEGORY HEIGHT RVR
1 200 ft (60 m) 2600 ft (800 m)
2 100 ft (30 m) 1300 ft (400 m)
3a zero 700 ft (210 m)
3b 150 ft (45 m) zero
air position:
The geographical position which an aircraft would reach in a given time if
flying in still air.
air-position indicator:
An automatic instrument which continually indicates air position,
incorporating alterations of course and speed.
air preheater:
System of tubes or passages, heated by flue gas, through which
combustion air is passed for preheating before admission to the
combustion chamber, thus appreciably raising flame temperatures and
returning to the combustion chamber some heat otherwise lost.
Also see
recuperative air heater
regenerative air heater
air pressure:
[1] The atmospheric pressure.
[2] Tire pressure.
[3] The force of air coming from a compressor used to power air tools or
apply air brakes.
air principle:
See pulse air principle

air pump:
[1] The device that supplies
the fresh air needed by the air
injection system.
[2] A reciprocating or
centrifugal pump used to
remove air, and sometimes the
condensate, from the
condenser of a steam plant.
Also see
air ejector
[3] Any device used for
transferring air from one place
to another. A compressor
increases the pressure, a
vacuum pump reduces the
pressure and a blower causes
a rapidly moving air blast
.
air quality:
The extent to which air is free from contaminants, conventionally taken to
be the respiratory irritants nitrogen dioxide and sulphur dioxide.
air ratio:
The ratio of actual intake air volume to the air volume theoretically needed
for complete combustion of a particular amount of the fuel. This ratio is
represented by the Greek letter lambda (which looks like the letter "y"
upside-down).
Also see
fuel air ratio
air receiver:
An air tank which holds the compressed air created by a compressor.
air-recirculation system:
See automatic air-recirculation system

Air Registration Board:
(ARB) The airworthiness authority of the UK until its functions were
taken over in 1972 by the Civil Aviation Authority.
air resistance:
The resistance of the air to forward movement, sometimes called
"aerodynamic drag." This is a factor of the shape of the vehicle, the objects
which stick out (i.e., mirrors, mufflers, bumpers), the amount of turbulence
at the rear of the vehicle, the nature of the vehicle's skin surface, and the
amount of air going through the vehicle for cooling and ventilation. The
faster you go, the greater the air friction (air friction = velocity x velocity).
The faster you go, the greater the amount of power needed to overcome
this drag (power = velocity x velocity x velocity).
air route:
In organized flying, a defined route between two aerodromes; usually
provided with direction-finding facilities, lighting, and emergency-landing
grounds.
Also see
airway
air scoop:
A forward
facing
aerodyna
mic
device or
opening
used to
duct cool
outside air
to some
part of the
vehicle
such as
the
carburetor
intake, the
brakes, the
radiator,

or an oil
cooler.
airscoop:
See air scoop
air screw:
Any type of screw designed to rotate in air; defined in 1951. Term now
obsolete and replaced by propeller, a device for propelling aircraft, and
fan, a rotating bladed device for moving air in ducts or wind tunnels.
Also see
bypass air screw
rotor.
air seal:
Curtain of air maintained in front of kiln or furnace door to aid retention of
heat or in front of a workstation to reduce dust entry.
air select valve:
A valve in a two-stage catalytic converter with secondary air injection. It is
operated by a solenoid and is triggered by the electronic control module. It
directs air to the exhaust valve ports or to the midbed catalytic converter,
depending on operating conditions.
air-sensing thermostat:
The unit in which sensing element is located in refrigerated space.
air sensor:
A device which checks for the presence of air pollutants entering the
passenger compartment. If the pollutant concentration is too high, it
operates flaps to cut off the external air to the air conditioning system.
air shaft:
An air passage, usually vertical or nearly vertical, which provides for the
ventilation of a tunnel or mine.
air shield:

British term for air deflector.
airship:
Any power-driven aerostat. In a non-rigid airship, the envelope is so
designed that the internal pressure maintains its correct form without the
aid of a built-in structure; small, and used for naval patrol work. A rigid
airship has a rigid structure to maintain the designed shape of the hull, and
to carry the loads; usually a number of ballonets or gas bags inside the
frame; large, used for military purposes in World War I, and having limited
commercial use until 1938. A semi-rigid airship has a partial structure,
usually a keel only, to distribute the load, and maintain the designed shape
of the envelope or ballonets; intermediate size.
air shock absorber:
A shock absorber or damper which has a rubber bladder filled with
compressed air. As the air pressure increases the vehicle is raised. The
system is used in automatic leveling suspensions.
air shooting:
[1]Charging of shot-hole so as to leave pockets of air, thus reducing the
shatter-effect of a blast.
[2] In seismic prospecting, producing an explosion in air, above the rock
formation under examination, to propagate a seismic wave.
air shower:
See cascade shower
air silencer:
A device which is placed in the air cleaner assembly to reduce the sucking
noise that air makes as it enters.
air solenoid:
See bypass air solenoid
air space:
The part of the atmosphere which lies above a nation and which is
therefore under the jurisdiction of that nation.

air-spaced coil:
Inductance coil in which the adjacent turns are spaced (instead of being
wound close together) to reduce self-capacitance and dielectric loss.
airspeed:
Speed measured relative to the air in which the aircraft or missile is
moving, as distinct from groundspeed.
Also see
equivalent airspeed
indicated air-speed
true airspeed
air spring:
A high pressure air-filled spring used in the suspension fork of some
bicycles."
Also see
air bellows
air suspension
air springing:
See air suspension
air, standard:
See standard air
air standard cycle:
A standard cycle of reference by which the performance of different
internal-combustion engines may be compared, and their relative
efficiencies calculated.
air standard efficiency:
The thermal efficiency of an internal-combustion engine working on the
appropriate air standard cycle.
air stop:

A registered trademark for Michelin tubes.
airstrip:
Unidirectional landing area, usually of grass or of a makeshift nature.
air strut:
See modular air strut
air superiority fighter:
Combat aircraft intended to remove hostile aircraft from a volume of
airspace and so establish control of the air.
air surveying:
See aerial surveying
air-suspended power booster:
A type of power booster that contains atmospheric pressure in both
chambers of the booster when the brake pedal is at res. When the pedal is
applied, the front chamber is opened to manifold vacuum, causing the
diaphragm of the booster to move toward the master cylinder which assist
the driver in the application of the brakes.
air suspension:
A suspension system using air
rather than metal springs to
support the vehicle and
control ride motions. Air
springing results in a
smoother ride, because the
natural frequency of vibration
of an air spring does not vary
with loading as it does with
metal springs. Air springs can
be made very soft for the
lightly loaded condition and
the pressure automatically
increased to match any
increase in load, thus
maintaining a constant sprint

vibration period any load.
air suspension power booster:
A type of power booster that contains atmospheric pressure in both
chambers of the booster when the brake pedal is at rest. When the pedal is
applied, the front chamber is opened to manifold vacuum causing the
diaphragm of the booster to move toward the master cylinder which assists
the driver in the application of the brakes.
air-swept mill:
in dry grinding of rock in a ball mill, use of a modulated current of air to
remove sufficiently pulverized material from the charge in the mill.
air switching:
See electric air switching valve
air switching valve:
(ASV) a valve in an air injection system that senses intake manifold
vacuum and during heavy loads, dumps part of the air pump output to the
air cleaner to reduce air injections system pressure.
Also see
electric air switching valve
AIR system:
See air injection reaction system
air system:
See pulse air system
air table:
See air-float table
air tank:
An air container which holds the compressed air created by a compressor.
air temperature:
See ambient air temperature

air-to-air intercooler:
A heat exchanger used on a turbocharged engine, which uses liquid
coolant from the rad to cool the air coming from the turbo into the intake
manifold.
air tool:
A tool such as an impact driver or drill which is powered not by electricity,
but by air pressure coming from an air compressor.
air traffic control:
(ATC) The organized control, by visual and radio means, of the traffic on
air routes, and into and out of aerodromes. ATC is divided into the
following categories:
a. general area control, including defined airways.
b. control zones of specified area and altitude around busy aerodromes.
c. approach control for regulating aircraft landing and departing.
d. aerodrome control for directing aircraft movement on the ground and
giving permission for take-off.
Air traffic control operates under two systems:
a. visual flight rules.
b. more severely, instrument flight rules.
Since World War II great advances in radar technology have enabled air-
traffic controllers to be given very complete "pictures" of the position of
aircraft, not only in flight, but also when maneuvering on the ground.
air-traffic control center:
An organization providing air-traffic control in a control area; and flight
information in a region.
air-traffic controller:
Someone who is licensed to give instructions to aircraft in a control zone.
air transformer:
A device which is placed between the compressor and a paint spray gun to
provide clean spraying air and to regulate the oil pressure.
Air Transport Association:

(ATA) A US organization noted particularly for its specification which sets
a standard to which manufacturers of aircraft and associated equipment are
required to produce technical manuals for the aircraft operator's use. The
specification is accepted by International Air Transport Association as the
basis for international standardization.
air trap:
A trap which, by a water-seal, prevents foul air from rising from a sink,
wash basin, drain, or sewer. Also called drain trap, stench trap, and U-
bend.
air valve:
A valve in a spray gun which controls the flow of air by the operation of
the trigger.
Also see
auxiliary air valve
air valve carburetor:
See air-valve carburetor
air-valve carburetor:
A type in which a spring-closed or weight-closed air valve opens in
response to engine demand. This valve, through suitable linkage, varies the
fuel-orifice opening to secure the desired mixture ratio throughout the
range of operation. SU and Stromberg CD carburetors operate on this
principle, referred to also as constant-vacuum, constant-depression, or
variable- venturi.
Also see
constant-vacuum carburetor
air vent:
Valve, either manual or automatic, used to remove air from the highest
point of a coil or piping assembly.
air volume:
The amount of air.
air volume spraying:

A method of spray application which involves higher volume and lower
pressure of air than high-pressure air spraying.
air wall:
Wall of an ionization chamber designed to give same ionization intensity
inside the chamber as in open space. This means the wall is made of
elements with atomic numbers similar to those for air constituents.
air washer:
Device used to clean air while increasing or lowering its humidity.
airway:
[1] A specified three-dimensional corridor (the lower as well as the upper
boundary being defined) between control zones which may be entered
only by aircraft in radio contact with air-traffic control
[2] Underground passage used mainly for ventilation.
airworthy:
[1] Fit for flight aircraft, aero-engine, instrument or equipment.
[2] Complying with the regulations laid down for ensuring the fitness of an
aircraft for flight.
[3] Possessing a certificate of Airworthiness.
Airy disk:
Circular image of a point source of light formed by a lens. Named after Sir
George Airy.
Airy points:
The optimum points for supporting a beam horizontally to minimize the
bending deflection. The distance apart of the points is equal to l/(n²-1)
where l is the length of the beam and n the number of supports.
Airy's integral:
The factor 1.22, by which the dimensions of the diffraction pattern
produced by a slit must be multiplied to obtain the dimensions of the
pattern due to a circular aperture.

Airy spirals:
The spiral interference patterns produced when quartz, cut perpendicularly
to the axis, is examined in convergent light circularly polarized.
AIS:
Acronym for " air injection system".
AIV:
Acronym for "atmospheric/automatic inlet valve," a system used on early
motorcycle engines in which the intake valve is held shut by a weak spring
and opens by atmospheric pressure when the falling piston creates a
vacuum in the cylinder.
Akermanite:
The calcium-magnesium end-member, Ca2MgSi2O7, of the melilite group
of minerals.
Akulon:
Trade Name for Dutch nylon-6 polymer used for moldings and fibers.
Al:
Abbreviation for "aluminum."
alabaster:
A massive form of gypsum, often pleasingly blotched and stained.
CaSO4.2H2O. Because of its softness it is easily carved and polished, and
is widely used for ornamental purposes. Oriental alabaster (also called
Algerian onyx and onyx marble) is a beautifully banded form of
stalagmitic calcite.
Alain:
See Prost, Alain
ALAP:

Acronym for "As Low As Possible."
ALARA:
Acronym for "As Low As Reasonably Achievable." Used of radiation
levels or decontamination.
alarm:
A warning sound made by a security or safety device to warn off thieves,
alert the driver to take some preventative measures (e.g., secure the seat
belts), or warn those around the vehicle (e.g., backup warning alarm).
Also see
back-up alarm
car alarm
alarm flag:
See flag indicator
alarm system:
A theft protection system which may do one or more of the following:
Sound the horn or an auxiliary siren, flash the lights, lock the hood and
trunk, make the ignition inoperative, put the engine in a "limp home"
mode (i.e., greatly reduce speed), notify the police, and alert the vehicle
owner.
alarmed:
Protected by an alarm system.
alaskite:
Leucocratic variety of alkali feldspar granite.
Albada viewfinder:
Viewfinder with a lightly silvered plano-concave objective which reflects
frame marks placed on the eyepiece and at the focus of the mirror. Also
called bright-line viewfinder.
albedo:

[1] A measure of the reflecting power of a non-luminous body, such as the
surface of a planet, expressed as the ratio of energy reflected in all
directions to total incident energy.
[2] Ratio of the neutron flow density out of a medium free from sources, to
the neutron flow density into it, i.e., reflection factor of a surface for
neutrons.
albert:
A former standard size of note-paper, 192x102 mm (6 x 4 in).
albertite:
A pitch-black solid bitumen of the asphaltite group.
albite:
The end-member of the plagioclase group of minerals. Ideally a silicate of
sodium and aluminum, but commonly contains small quantities of
potassium and calcium in addition, and crystallizes in the triclinic system.
albumen process:
Process in which dichromated albumen (egg white) is used as a light-
sensitive coating when preparing surface plates for lithography and line
blocks for relief printing.
ALCL:
Acronym for " assembly line communications link".
Alclad:
Composite sheets consisting of an alloy of the Dural type (to give strength)
coated with pure aluminum (to give corrosion resistance).
alcohol:
[1] A general term for compounds formed from hydroxyl groups attached
to carbon atoms in place of hydrogen atoms; in particular, ethanol.
[2] A substance used as fuel.
See methanol

[3] A beverage which impairs a driver's skill in operating a vehicle safely.
Although the law has set down limits of the amount of alcohol allowable
in the bloodstream before a person is considered drunk, the effects of the
slightest amount of alcohol can impair one's driving skill.
Also see
grain alcohol
methyl alcohol
wood alcohol
alcohol brine:
Water and alcohol solution which remains a liquid below 32°F (0°C).
alcohol content:
See blood alcohol content
alcohol fuel:
Volatile liquid fuel consisting wholly or partly of alcohol, able to
withstand high-compression ratios without detonation.
alcohol level:
See blood alcohol level
Alcomax:
UK equivalent of Alnico permanent magnet alloy.
aldehyde resins:
Highly polymerized resinous condensation products of aldehydes obtained
by treatment of aldehydes with strong caustic soda.
aldehydes:
A group of compounds containing the CO-- radical attached to both a
hydrogen atom and a hydrocarbon radical.
ALDL:
[1] Acronym for "assembly line diagnostic link" a diagnostic connector.
[2] Acronym for " assembly line data link".

alert:
See deer alert
voice alert system
alert system:
See voice alert system
alexandrite:
A variety of chrysoberyl, the color varying, with the conditions of lighting,
between emerald green and red.
Alfa-Romeo:
A vehicle brand of which all 1925-48 models are
classic cars. The following models are milestone cars:
• All 1956-64 Giuletta Spider models
• All 1959-61 Giuletta/Giulia Sprint Speciale
models
• All 1949 6C 2500 Super Sport models
.
Click for books on
Alfa
Alfa Romeo:
See Alfa-Romeo
Alfin:
A trade name to describe the bonding of a steel piece with a light alloy that
has fins. The fins help to dissipate the heat. For instance a steel brake drum
produces a lot of heat in the braking process (and thus reduces the
effective braking ability) so an alloy heat sink is bonded to the drum to
bleed off the heat.
Also see
Alfin process.
Alfin process:
A procedure developed by the Fairchild Engine and Airplane Corporation
to secure light alloy to steel.
Alford antenna:
Antenna comprising a vertical cylindrical tube with longitudinal slots,
often used to transmit very high or ultrahigh frequency.

al fresco driving:
Driving in a convertible with the top down.
algae:
Low form of plant life, found floating free in water.
algal corrosion:
Impairment of structure and systems by algae and other micro-organisms.
Algerian onyx:
See alabaster
aliasing:
[1] Error in making real-time spectra of short signals or of directivity in
sound fields. Caused by insufficient number of data points.
[2] Image imperfections resulting from limited detail in a raster display,
e.g., resulting in diagonal lines appearing stepped.
A-licence:
Basic private pilot's licence in the UK.
alien tones:
Frequencies, harmonic and sum-and-difference products, introduced on
sound reproduction because of non-linearity in some part of the
transmission path.
align:
[1] Process of bringing two or more items into mating conjunction so that
all the bolt holes and locating pins fit properly.
[2] Process of adjusting the wheels and other devices so that they are in a
straight line.
align bore:

A machining operation which corrects an engine's out-of-round and/or
warped main bearing housings. It may be done with either stationary or
portable equipment.
Also see
align hone
aligner:
See wheel aligner
align hone:
A machining operation which corrects an engine's out-of-round and
warped main bearing housings with a special honing mandrel. It must be
done with stationary equipment.
aligning punch:
A tool shaped like a thin rod used to make sure holes line up when
assembling two or more components. Especially used on items which may
move to one side before the other side can be aligned or another
component installed or when the gasket is likely to slip out of place.
aligning set:
See clutch aligning set
aligning tool:
See clutch aligning tool
alignment:
[1] When referring to wheel alignment, it is the proper adjustment of a
vehicle's front or rear suspension for camber, toe-in, toe-out, kingpin
inclination or steering axis inclination, and turning radius or toe-out on
turns, caster, and ride height. Four-wheel alignment is necessary for front-
wheel drive vehicles.
[2] The adjustment of two objects to bring them into the proper relation to
each other.
[3] The setting in line (usually straight) of successive lengths of a railway
which is to be constructed
[4] The plan of a road or earthwork
[5] The setting in a true line of a number of points, e.g., the centers of the
bearings supporting an engine crankshaft

[6] Process of orientation of e.g., electric or magnetic dipoles when acted
on by an external field. During magnetization, the alignment of domains is
changed by the magnetizing field
[7] Adjustment of preset tuned circuits to give optimum performance
Also see
door alignment
four-wheel alignment
four wheel alignment
front-end alignment
front end alignment
wheel alignment
alignment gap:
The distance between two adjacent auto body panels. When an alignment
gap varies too much, it is a sign of poor assembly quality.
alignment gauge:
See wheel alignment gauge
alignment pin:
A pin or stud used to align one part with another, such as the pins used to
align a cylinder head on an engine block.
alignment stud:
A pin or stud used to align one part with another, such as the pins used to
align a cylinder head on an engine block.
align ream:
Machining or hand process which enlarges the inside diameter of bushings
to the correct size.
aliquot:
A small sample of material assayed to determine the properties of the
whole, e.g., in process control, the representative fraction whose
quantitative analysis gives information on the assay grade. Term often
applied to radioactive material.
Also see
aliquot part

aliquot part:
In sampling for process control, a representative fraction whose
quantitative analysis gives information on the assay grade.
aliquot scaling:
In a piano, the provision of extra wires above the normal wires. These are
not struck, but are tuned very slightly above the octave of the struck
strings below, so that by sympathetic vibration the musical quality of the
note is enhanced.
aliquot tuning:
See aliquot scaling
alive:
See keep alive memory
alive memory:
See keep alive memory
alkaline battery:
A storage battery which uses an alkaline electrolyte (dilute potassium
hydroxide).
alkaline degreasing:
A process of removing an oily or greasy substance with the use of an
alkaline solution. Often used in preparing a surface for painting.
all-alloy engine:
An engine which uses a light alloy for the block, crankcase, sump, and
cylinder head.
all-aluminum body:
A body shell which is mostly made of aluminum.
Allan valve:
Once popular slide-valve design with an internal passage designed to
reduce valve travel and wear.

Allard:
A vehicle brand of which the 1946-56 Series J2, K2, K3 models are
milestone cars.
all-burnt:
The moment at which the fuel of a missile or spacecraft is completely
consumed.
all-electric signalling:
A railway system in which the signals and points are controlled and
operated electrically.
Also see
electropneumatic signalling
all electronic ignition:
See breakerless
all-electronic ignition:
See breakerless
Allen key:
See Allen wrench
Allen screw:
A fastening device (either a wood screw type or bolt threads) with a
recessed hexagon hole in the head. Also called a hex hole screw..
Allen's loop test:
A modification of the Varley loop test for localizing a fault in an electric
cable; it is particularly suitable for high-resistance faults in short lengths of
cable.
all-enveloping body:
A modern passenger car body style in which the fenders, headlamps, and
radiator grille are one smooth body line. It contrasts with the style before
World War II where the fenders and headlights were separate from the

main body.
Allen wrench:
An rod with six sides and often L-shaped. Used to remove certain screws
and fastenings, especially set screws. Sometimes called "hex wrenches" or
"Allen key."
alligator:
A colloquial term for a large piece of a tire on the road.
alligator clip:
A small spring clip which is "X-shaped." As you squeeze the two
"legs" of the clip, the other two jaws (usually serrated) open.
Used to make temporary electrical connections. Larger ones are
used at the ends of jumper cables. The British call it a "crocodile
clip."
all-insulated switch:
See shockproof switch
allithium:
Aluminum-lithium alloys.
all-moving tail:
A one-piece tailplane, also controlled by the pilot as is the elevator. Also
called flying tail and "stabilator."
Also see
T-tail
allobar:
A mixture of isotopes of an element differing in proportion from that
naturally occurring.
allochromatic:
Having photoelectric properties which arise from micro-impurities, or
from previous specific irradiation.

allochromy:
Fluorescent reradiation of light of different wavelength from that incident
on a surface.
Also see
Stokes' law
alloter:
A uniselector used to improve the efficiency of distribution of line-finders,
by automatically pre-selecting and pre-connecting the first available line-
finder in the group to which it has access.
all-out braking:
A situation where the driver uses the maximum braking effort possible.
Although this seems to be the best way to stop a vehicle, in fact it may not
because there may be the tendency to swerve or the brakes may overheat
and lose effectiveness. It is better to pump the brakes (if ABS is not
available) to control steering and get maximum braking.
allowable deficiencies:
Aircraft systems or certain items of their equipment, tabulated in the flight
or operating manual, which even if unserviceable will not prevent an
aircraft from being flown or create a hazard in flight.
allowance:
See mileage allowance
allowances:
Fuel reserves, usually specified as time factors under certain conditions, as
distance plus descent, or as a percentage (by weight or volume) of the
cruising fuel for a given stage.
allowed band:
Range of energy levels permitted to electrons in a molecule or crystal.
These may or may not be occupied.
allowed transition:
Electric transition between energy levels which is not prohibited by any
quantum selection rule.

alloy:
A mixture of two or more elements, especially where one is aluminum.
Also see
aluminum alloy
antimony alloys
eutectic alloy
minilite alloy wheel
polymer alloy
zinc alloy
alloy cast-iron:
Cast-iron containing alloying elements in addition to carbon and the
normal low levels of manganese and silicon, usually some combination of
nickel, chromium, copper, and molybdenum. These elements may be
added to increase the strength of ordinary irons, to facilitate heat
treatment, or to obtain martensitic, austenitic, or ferritic irons.
alloy engine:
See all-alloy engine
alloying:
[1] The process of making an alloy
[2] The addition of one or more elements to a pure metal to alter the pure
metal's properties such as strength, elongation, weight reduction, etc.
alloy junction:
A junction formed by alloying one or more impurity metals with a
semiconductor. Small buttons of impurity metal are placed at desired
locations on a semiconductor wafer; heating to melting point and rapidly
cooling again produces regions of p-type conduction or n-type conduction,
according to choice of impurity. Also called fused junction.
alloy layer:
See zinc-iron alloy layer
alloy piston:

A piston made primarily of aluminum.
alloy reaction limit:
Concentration in alloy of a specific component, below which corrosion
occurs in a given environment.
alloys:
Colloquial term for alloy wheels.
alloy steel:
[1] A steel to which elements not present in carbon steel have been added,
or in which the content of manganese or silicon is increased above that in
carbon steel.
[2] Molybdenum alloy steel of 150M psi and above after heat treating.
Used for clevis pins and (4037, 4137) some screws. Aircraft quality alloy
steel (4130,4340,8740) is used extensively in the Aerospace Industry for
bolts, screws and clevis pins. Tensile strength minimum of 120M psi.
Also see
high-speed steel
nickel steel
stainless steel
alloy wheel:
A generic term used to describe any non-steel road wheel. The usual alloys
are either aluminum or magnesium; the latter material led to the common
usage of the term " mag wheel," often referring to any non-steel wheel.
Also see
minilite alloy wheel
three-piece alloy wheel
two-piece alloy wheel
two-piece forged alloy wheel
all-pass network:
A network which introduces a specified phase-shift response without
appreciable attenuation for any frequency.
all-steel body:
A vehicle body shell which is made entirely of steel rather than one with a
wooden frame with steel panels or steel frame with aluminum panels.

Allström relay:
See relay
all terrain:
For use on any kind of ground surface (not on lakes or ocean, though).
all terrain bike:
(ATB) A bicycle with straight
handlebars, sturdy fat tires, and wide-
range gearing designed for off-road
use. Also called mountain bike.
all-terrain bike:
(ATB) A bicycle with straight handlebars, sturdy fat tires, and wide-range
gearing designed for off-road use. Also called mountain bike.
all terrain tire:
A tire which has a number of lugs or knobs used to propel the vehicle over
rough surfaces.
all terrain vehicle:
A vehicle used in rough surface conditions. Also called off-road vehicle..
allure libre:
A self-paced long-distance bicycle ride as promoted by the Audax Club
Parisien, the Randonneurs Mondiaux, and the Randonneurs USA. You can
ride at your own pace so long as you finish within the time limit. This is
not a race where riders are recognized for finishing ahead of other riders.
The important thing is to finish the ride.
all-weather tire:
A tire that can be used on roads that are bare or covered with rain, snow, or
ice.

all wheel drive:
See all-wheel drive
all-wheel drive:
(AWD) A variation of four-wheel drive (4WD) designed to improve on-
road traction in unfavorable road conditions or for ultra high performance
driving. All-Wheel Drive (AWD) reduces wheel slippage and provides
greater driver control over the vehicle. AWD usually does not require the
driver to actively engage the system and does not have a low range. AWD
automatically splits engine torque between the front and rear wheels as
needed. All-Wheel Drive is generally an on-road system and is not
designed for off-road use.
all-wheel steering:
See four-wheel steering
Alnico:
US trade mark for a high-energy permanent magnet material, an alloy of
aluminum, nickel, cobalt, iron, and copper.
Alnico magnet:
A magnet using (Al) aluminum, (Ni) nickel, and (Co) cobalt in its
construction.
Aloxite:
Trade name designating a proprietary fused alumina and associated
abrasive products.
alpaca:
The fine, strong hair of the alpaca of South America, the fabric made from
such hair. This animal belongs to the camel family and is a close relative
of the llama and the vicuña.
Alpert Gauge:
See Bayard and Alpert Gauge

alpha-beta brass:
Copper-zinc alloy containing38-46% (usually 40%) zinc. It consists of a
mixture of the α-constituent (see alpha brass) and the β-constituent (see
beta brass).
alpha brass:
A copper-zinc alloy containing up to 38% zinc. Consists constitutionally of
a solid solution of zinc in copper. Commercial alpha brasses of several
compositions are made. All are used mainly for cold-working.
Also see
copper alloys
alpha bronze:
A copper-tin alloy consisting of the alpha solid solution of tin in copper.
Commercial forms contain 4 or 5% of tin. This alloy, which differs from
gun metal and phosphor bronze in that it can be worked, is used for
example for coinage, springs, and turbine blades.
Also see
copper alloys
alpha chamber:
Ionization chamber for measurements of alpha radiation intensity. Also
called alpha counter tube..
alpha counter:
Tube for counting alpha particles, with pulse selector to reject those arising
from beta and gamma rays.
alpha counter tube:
See alpha chamber
alpha cut-off:
Frequency at which the current amplification of a transistor has fallen by
more than 3 dB (0.7) of its low-frequency value.
alpha decay:
Radioactive disintegration resulting in emission of alpha particle. Also
called alpha disintegration..

alpha decay energy:
The sum of the kinetic energies of the alpha particle emitted and the recoil
of the product atom in a radioactive decay. Also called disintegration
energy..
alpha disintegration:
See alpha decay
alpha emitter:
Natural or artificial radioactive isotope which disintegrates through
emission of alpha rays.
alpha iron:
One of the polymorphic forms of iron, stable below 1179K. Has a body-
centered cubic lattice, and is magnetic up to 1041K.
alpha particle:
Nucleus of helium atom of mass number four, consisting of two neutrons
and two protons and so doubly positively charged. Emitted from natural or
radioactive isotopes. Often written α-particle.
alpha pulp:
Wood pulp processed so that only a very small percentage of
hemicellulose remains. Also called dissolving pulp..
alpha radiation:
Alpha particles emitted from radioactive isotopes.
alpha ray:
Stream of alpha particles.
alpha-ray spectrometer:
Instrument for measuring the energy distribution of α-particles emitted by
a radioactive source.

alpine gearing:
A gearing system in which a shift between chainwheels on a bicycle is
equivalent to one-and-a-half shifts on the freewheel.
alteration:
See load alteration effect
alteration effect:
See load alteration effect
alternate airfield:
An airfield designated in a flight plan at which a pilot will land if
prevented from landing at the intended destination.
alternating current:
(AC) An electric current that first flows one way in the circuit and then the
other. This is the type used in homes. It contrasts with direct current.
alternating-gradient focusing:
The net focusing effect achieved using a series of alternate converging and
diverging lenses because, under suitable conditions, the rays will strike the
diverging lenses nearer to the axis. Using magnetic or electrostatic lenses,
the idea has been used for the design of electron synchrotrons and ion
linear accelerators.
alternating gradient synchrotron:
A synchrotron modified by having magnetic-field gradiens around the
orbit alternating toward and away from the center of the orbit. This
produces a focusing effect which reduces beam divergence caused by the
mutual repulsion of the particles in the beam. Proton energies of up to 500
GeV and electron energies of about 10 GeV can be achieved.
alternating light:
A navigation mark identified during darkness by a light showing
alternating colors.
Also see

flashing light
occulting light
alternating stress:
The stress induced in a material by a force which acts alternately in
opposite directions.
alternative routing:
The manual or automatic diversion, to a prearranged secondary route, of
traffic which originates at an instant when the primary route is not
available.
alternator:
(ALT) A device which produces
alternating current (AC) by
converting the engine's turning
(mechanical) energy into alternating
electrical current at all engine speeds.
The AC must be rectified (converted
from AC to DC) before reaching the
vehicle's electrical system. The
alternator is driven by a belt at the
front of the engine. Alternators
replaced the direct-current (DC)
generators used up to the 1960's
because they were less efficient
especially at idle. The electrically
demanding options like air
conditioning forced the use of
alternators over generators.
Altima:
A model of automobile manufactured by Nissan in
Japan
.
Click for books on
Altima

altimeter:
[1] An instrument to reveal the height (or barometric pressure) above sea
level.
[2] An aneroid barometer used for measuring altitude by the decrease in
atmospheric pressure with height. The dial of the instrument is graduated
to read the altitude directly in feet or meters, the zero being set to ground
or aerodrome level.
Also see
encoding altimeter
radio altimeter
recording altimeter
altitude:
[1] The height in feet or meters above sea level. For precision in
determining the performance of an aircraft, this must be corrected for the
deviation of the meteorological conditions from that of the International
Standard Atmosphere.
[2] The angular distance of a heavenly body measured on that great circle
which passes, perpendicular to the plane of the horizon, through the body
and through the zenith. It is measured positively from the horizon to the
zenith, from 0° to 90°.
[3] The line through the vertex of a geometrical figure or solid
perpendicular to its base.
[4] The length of the line of definition #3.
Also see
cabin altitude
pressure altitude
altitude compensation system:
A barometric switch and solenoid used to provide better drivability over
4000 feet (1200 meters) above sea level.
altitude compensator:
See aneroid altitude compensator
altitude level:
Sensitive spirit level which ensures that theodolite is truly horizontal with
respect to the telescope when vertical angles are measured.
altitude switch:

A switching device generally comprising electrical contacts, actuated by
an aneroid capsule which in turn is deflected by change in atmospheric
pressure. The contacts are adjusted to make or break a warning circuit at
the pressure corresponding to a predetermined altitude.
altitude valve:
A manually or automatically operated valve fitted to the carburetor of an
aero-engine for correcting the mixture strength as air density falls with
altitude.
alum.:
Abbreviation for " aluminum."
Alumel:
Trade name for an alloy of nickel with up to 5% aluminum, manganese,
and silicon, used with chromel in thermocouples.
alumina:
A form of aluminum oxide, Al2O3 used as a substrate for ceramic catalysts
and as an abrasive.
Also see
activated alumina
corundum
alumina beads:
Tiny beads of alumina used in some catalytic converters.
alumina trihydrate:
Al2O33H2O. Used as a fire-retarding additive in plastics.
aluminium:
British spelling for aluminum.
aluminous cement:
See high-alumina cement

aluminum:
(Al or Alum) A silver-white metal which is used in cars because of its
lightness. In pure form, it does not have the strength of the same size of
iron. Thus vehicle manufacturers use aluminum in an alloy form to
produce body panels, wheels, engine blocks, transmission housings,
differential housings, and even frames. British spelling adds an "i" near the
end of the word: "aluminium" and pronounces it al-you-MIN-ee-um
instead of ah-LOO-min-um.
Also see
cast aluminum
aluminum alloy:
A metal which is formed from aluminum and another metal.
aluminum anode cell:
A cell with an aluminum anode immersed in an electrolyte which does not
attack aluminum. The cathode may also be of aluminum or some other
metal, e.g., lead. Such cells can be used as rectifiers or as high-capacitance
capacitors.
Also see
electrolytic capacitor
aluminum antimonide:
A semiconducting material used for transistors up to a temperature of
500°C.
aluminum body:
See all-aluminum body
aluminum-brass:
Brass to which aluminum has been added to increase its resistance to
corrosion. Used for condenser tubes. Contains 1-6% Al, 24-43% Zn, 55-
71% Cu.
Also see
copper alloys
aluminum bronze:
Copper-aluminum alloys which contain 4-11% aluminum, and may also
contain up to 5% each of iron and nickel. These alloys have high tensile

strength, are capable of being cast or cold worked, and are resistant to
corrosion.
Also see
copper alloys
aluminum-steel cable:
See steel-cored aluminum
aluminum oxide:
A metallic abrasive used to manufacture sandpaper and sanding discs.
aluminum wheel:
See alloy wheel
aluminized:
Something that is coated with aluminum or aluminum paint.
aluminizing:
See hot-dip aluminizing
Alvis:
A vehicle brand of which the Speed
20, 25, and 4.3 litre models for 1925-
48 are classic cars.
AM:
Acronym for amplitude modulation.
amagat:
The unit of density of a gas at 0°C and one atmosphere pressure; usually 1
amagat-1 mole per 22.4 dm³.
amalgam retort:
Iron vessel in which the mercury is distilled off from gold or silver
amalgam obtained in amalgamation.

Also see
amalgamation pan
ambient:
Surrounding on all sides.
ambient air:
Air outside and surrounding the vehicle.
ambient air temperature:
The temperature of the surrounding air.
ambient illumination:
Background uncontrollable light level at a location.
ambient noise:
[1] Random uncontrolled and irreducible noise at a location, or in a valve
or circuit.
[2] The noise existing in a room or any other environment, e.g., the ocean.
ambient sensor:
A device which samples and detects changes in the temperature of the
ambient air.
ambient switch:
An outside air temperature sensing switch which prevents operation of the
compressor and the recirculating air mode below an outside temperature of
40°F.
ambient temperature:
The surrounding air temperature. The temperature of fluid (usually air)
which surrounds object on all sides.
ambient temperature switch:
A control device in an air conditioning system which delays the
compressor action when the outside temperature is low.

ambiophony:
Technique of sound reproduction which creates an illusion to the listener
of being in a very large room.
ambipolar:
Said of any condition or property which applies equally to positive and
negative charge carriers (e.g., positive or negative ions, holes, electrons) in
a plasma or semiconductor.
ambulance:
A vehicle designed for carrying sick
or injured people.
AMC:
Acronym for "American Motors Corp" an
organization which merged with Chrysler
Corporation.
.
Click for books on AMC
AMCS:
Acronym for airborne missile control system.
American Automobile Labelling Act:
(AALA) regulations requiring vehicle manufacturers to include content
information on vehicle labels for cars and trucks for sale in the U.S. after
October 1, 1994.
American Free Trade:
See North American Free Trade Agreement
American Free Trade Agreement:

See North American Free Trade Agreement
American Industrial Classification:
See North American Industrial Classification System
American Industrial Classification System:
American Motors:
A vehicle brand of which the 1968-70 AMX models are milestone cars.
American produced:
See North American produced
American Society for Testing Materials:
(ASTM) Society for developing and publishing agreed standards.
American standard pipe thread:
Type of screw thread commonly used on pipe and fittings to assure a tight
seal.
American Standard Wire Gauge:
See Brown and Sharpe Wire Gauge
American water turbine:
See mixed-flow water turbine
AM/FM:
A radio capable of receiving amplitude modulation (AM) and frequency
modulation (FM) signals.
AMIA:
Acronym for " Asocicion Mexicana de la Industria Automotriz".
amidship:

The middle portion of a ship or car.
Amilcar:
A vehicle brand of which the 1925-1948 Supercharged Sports models with
required application are classic cars.
aminoaldehydic resins:
See urea resins
aminoplastic resin:
One derived from the reaction of urea, thiourea, melamine, or allied
compounds (e.g., cyanamide polymers and diaminotriazines) with
aldehydes, particularly formaldehyde (methanal).
ammeter:
An electric instrument used to measure the rate of electrical current flow in
amperes.
ammonia:
Chemical combination of nitrogen and hydrogen (NH3). Ammonia
refrigerant is identified as R-117.
ammonia clock:
An accurate clock controlled by the periodic inversion of the ammonia
molecule with a frequency of 2.3786 x 1010
Hz.
Also see
atomic clock
amorphous:
Term describing a material without the periodic, ordered structure of
crystalline solids.
amorphous head:
A head composed of laminated amorphous alloy layers which improves
signal-to-noise ratio and reduces friction by comparison with ferrite-type
heads.

amorphous metal:
A material with good conductivity, electrical and thermal, and with other
metallic properties but with atomic arrangements that are not periodically
ordered as in crystalline metal solids.
Also see
metallic glass
amorphous semiconductor:
Semiconductor prepared in the amorphous state. It tends to have a much
lower electrical conductivity than its crystalline counterparts, and is
typically made from hydrogenated amorphous silicon or chalcogenide
glass.
amp:
Uncommon abbreviation for " ampere." It is preferred to use A.
amperage:
The strength of an electric current in amperes. Electron or current flow of
one coulomb per second past a given point in circuit.
amperage rating:
The strength of an electric current in amperes.
ampere:
[1] (A) A unit of measurement used in expressing the rate of electrical
current flow in a circuit. It is determined by dividing the voltage by the
resistance.
[2] A unit of electric current equivalent to flow of one coulomb per second
[3] That current which, if maintained in two parallel conductors of infinite
length, of negligible cross-section, and placed one meter apart in vacuum,
would produce between the conductors a force equal to 2x10-7
Nm-1
.
Also see
absolute ampere
ampere-hour:

[1] Measurement of the ability of a battery to deliver a stated amount of
current for a stated period of time. The higher the amp/hr. rating, the more
powerful the battery.
[2] Unit of charge equal to 3600 coulombs or 1 ampere flowing for one
hour.
ampere hour capacity:
A measurement of storage battery ability to deliver a specified current over
a specified length of time.
ampere-hour efficiency:
In an accumulator, the ratio of the ampere-hour output during discharge to
the ampere-hour input during charge.
ampere-hour meter:
(ahm) A meter designed to record the product of current and time
(ampere-hours) for a given circuit or passing at a given point. If the
voltage is constant, the meter can be calibrated as an energy (kilowatt-
hour) meter.
Ampère's law:
The relation between the magnetizing field H around a conductor, length l,
carrying a current i, given by the formula:
ampere-turns:
See back ampere-turns
Ampère's rule:
Rule giving the direction of
the magnetic field associated
with a current. If the
conductor is grasped with the
right hand, the thumb pointing
in the direction of the current,
the fingers will curl around
the conductor in the direction

of the field. Also called right-
hand rule.
Ampère's theory of magnetization:
A theory based on the assumption that the magnetic property of a magnet
is due to currents circulating in the molecules of the magnet.
ampere-turn:
(At) SI unit of magneto-motive force, which drives flux through magnetic
circuits, arising from one ampere flowing around one turn of a conductor.
ampere-turn amplification, gain:
Ratio of the load ampere-turns to the control ampere-turns in a magnetic
amplifier..
ampere turns:
Term used to measure magnetic force. Represents product of amperes
times number of turns in coil of electromagnet.
ampere-turns per meter:
SI unit of magnetizing force, magnetic field intensity.
amphibian:
Aircraft capable of taking off and landing on land or water, e.g., seaplane
or flying boat with retractable landing gear, or land plane with hydroskis.
amphoric:
Like the sound made by blowing across a narrow-necked vase.
amp/hr. rating:
Measurement of the ability of a battery to deliver a stated amount of
current for a stated period of time. The higher the amp/hr. rating, the more
powerful the battery.

amplidyne:
A rotating magnetic amplifier, widely used as a power amplification
device, in which a small increase in power input to the field coils produces
a large boost in power output.
amplified spontaneous emission:
Unwanted noise in an erbium-doped fiber amplifier arising from
amplification of spontaneous as opposed to stimulated emission. Its optical
power in bandwidth B centered on frequency v is (G-1)μhvB for each
polarization state of the fiber, where G is the power gain and μ the
inversion factor of the amplifier (unity when ideal).
amplifier:
A device used to increase the electron flow in an electric or vacuum
circuit. It produce a greater electrical signal such as the radio signal. Most
automobile radios have a built-in amplifier; but a few have a separate
amplifier which is sometimes located in the trunk.
Also see
acoustic amplifier
audio-frequency amplifier
balanced amplifier
booster amplifier
ignition amplifier
amplitude:
[1] A confusing term occasionally used for the argument of a complex
number. It would more naturally be taken to mean the modulus, and is best
avoided.
[2] The maximum value of a periodically varying quantity during a cycle,
e.g., the maximum displacement of a vibrating particle from its mid-
position, the maximum value of an alternating current or the maximum
displacement of a sine wave.
amplitude discriminator:
See pulse-height discriminator
amplitude distortion:
Distortion of waveform arising from the non-linear static or dynamic
response of a part of a communication system, the output amplitude of the
signal at any instant not having a constant proportionality with the

corresponding input signal.
amplitude limiter:
One which separates synchronizing signals in a TV signal from the video
(picture) signal. Also called limiter.
amplitude modulation:
(AM) A type of radio wave in which the amplitude changes rather than the
frequency.
Also see
frequency modulation
amplitude peak:
Maximum positive or negative excursion from zero of any periodic
disturbance.
amplitude shift keying:
A form of amplitude modulation in which the amplitude of the carrier
assumes only certain discrete values, allowing transmission of digitally
coded information.
AMPS:
Abbreviation for advanced mobile phone system.
amps:
See cold cranking amps
amputee spinner:
A device which is attached to a
steering wheel to allow disabled
people to steer a vehicle.
AMS:

Acronym for " air management system".
AMSL:
Abbreviation for above mean sea level.
AMVIR:
Acronym for " Association of Motor Vehicle Importers Representatives"
(Greece).
anaerobic sealer:
A substance used to prevent bolts and screws from loosening up and
backing out. Anaerobic sealers do not require oxygen for activation. The
Loctite® brand is the most widely used anaerobic sealer.
anaglyph:
Pair of stereoscopic images reproduced in two colors, generally red and
blue-green, for viewing with corresponding color filters, one for each eye,
to give a three-dimensional sensation.
anallatic lens:
Special lens which, when correctly placed between the object glass and the
eyepiece lens of a tacheometric telescope, optically reduces the additive
constant for the tacheometer to zero.
anallatic telescope:
Telescope which, when used in tacheometry, has a zero additive constant.
anallatism:
See center of anallatism
analog:
A display which uses a dial rather than a read-out of numbers (digital).
British spelling is analogue.
analog clock:

The traditional clock with rotating hands. Contrast with digital clock.
analog cluster:
An instrument panel display using dials. Opposite to electronic cluster.
analog filter:
Filter suitable for use with analog signals, i.e., those which are continuous
with time. Contrast with digital filter.
analog speedometer:
A speedometer which shows the speed by a
needle on the dial of a gauge. It contrasts with
a digital speedometer
analogue:
British spelling of analog.
analogue cluster:
See analog cluster
analogy:
Correspondence of pattern or form between mechanical and electrical
quantities, or vice versa; e.g., a network of resistance, capacitance and
inductance can be made to represent a complex mechanical system, or a
stretched rubber membrane for the potential distributions between
electrodes in electronic tubes.
analysis:
See Fe analysis
finite-element analysis
analysis meter:

A registering meter used to determine the loading of groups of circuits
with calls, particularly for determining the correctness or otherwise of
grading.
analyzer:
A device for evaluating something.
Also see
engine analyzer
exhaust-gas analyzer
exhaust gas analyzer
Ndir analyzer
non-dispersive infrared analyzer
anamorphic:
A widescreen image that has been laterally compressed or squeezed, either
optically by an anamorphic lens or electronically.
anamorphic lens:
Lens with cylindrical elements giving different magnification in horizontal
and vertical directions. In wide-screen cinematography the image is
compressed laterally in the camera and expanded to compensate in
projection. The equivalent term anamorphotic is rare.
anastigmat lens:
A photographic objective designed to be free from astigmatism or at least
one extra-axial zone of the image plane.
anatomic saddle:
A bicycle seat that is designed with cut out
sections or bumps to accommodate your
ischial tuberosities (i.e., sit-down bones).
ANC:
Acronym for "at no extra cost".
anchor:

[1] A mounting point on the vehicle frame or unibody for a non-structural
but stressed component, such as a seat or seat belt.
[2] The stationary portion of a leading/trailing drum brake on which the
heels of the brake shoes ride.
Also see
belt anchor
belt anchor
brake anchor
anchorage:
The point where something is attached -- such as where the seat-belt is
attached to the frame.
Also see
belt anchorage
seat belt anchorage
anchor bolt:
[1] A bolt used to secure frameworks, stanchion bases, etc. to piers or
foundations, and having usually a large plate washer built into the latter as
anchorage
[2] The bolt which goes through a bracket to secure something. British
term is "through bolt."
anchor clamp:
A fitting attached to the overhead contact wire of a tramway or railway to
support the wire, and also to take the longitudinal tension and prevent
movement of the wire in a direction parallel to the track.
anchor gate:
A heavy gate, such as a canal lock gate, which is supported at its upper
bearing by an anchorage in the masonry such as an anchor bolt.
anchor end:
The end of a brake shoe that's attached to or positioned against a fixed
point on the backing plate.
anchor pin:
The stationary portion of a duo-servo drum brake on which the tops of the
brake shoes rest. The secondary shoe bears against the anchor pin when

the brakes are applied and the vehicle is moving forward. Conversely,
when the vehicle is backing up and the brakes are applied, the primary
shoe bears against it.
anchor plate:
The stationary portion of a leading/trailing drum brake on which the heels
of the brake shoes ride.
Also see
caliper mounting bracket
anchor ring:
See toroid
torus
ancien:
A male veteran bicycle rider who has completed a 1200 kilometer
randonnée.
ancienne:
A female veteran bicycle rider who has completed a 1200 kilometer
randonnée.
ancillaries:
The various components attached to the main part of the engine and driven
by the engine itself -- such as the alternator, generator, power steering
pump, supercharger, fuel pump, and water pump.
anechoic room:
A room in which internal sound reflections are reduced to an ineffective
value by extremely high sound absorption, e.g., by using glass-fiber
wedges. Also called dead room.
anelasticity:
[1] Any recoverable deformation which deviates from linear elastic
behavior.
[2] Any structural inhomogeneity or discontinuity which would dampen or
attenuate an elastic wave propagating in a body.

anelectric:
Term once used for a body which does not become electrified by friction.
anemometer:
Instrument for measuring the rate of airflow or motion.
aneroid altitude compensator:
A bellows device, installed integrally with the APT system on some post-
1975 Rochester Quadrajet carburetors, that automatically compensates for
changes in altitude by raising or lowering the primary metering rods, thus
richening or leaning out the air/fuel mixture in accordance with changes in
air pressure.
aneroid-type thermostat:
An older style thermostat located in the engine coolant system. It has a
metal expandable bulb partially filled with acetone, alcohol, or another
volatile liquid. As the coolant reaches operating temperature, the liquid in
the bulb will boil and expand the bulb, closing the valve to allow coolant
to the radiator.
ANFAC:
Acronym for " Asociacion Espanola de Fabricantes de Automoviles y
Camiones" (Spain).
ANFAVEA:
Acronym for " Associação Nacional de Veículos Automotores" (Brazil).
ANFIA:
Acronym for " Associazione Nazionale Fra Industrie Automobilistiche"
(Italy).
angels:
Radar echoes from an invisible and sometimes undefined origin. High-
flying birds, insect swarms, and certain atmospheric conditions can be
responsible.

angle:
See
ackermann
angle
approach angle
attack angle
azimuth angle
blade angle
bragg angle
bunching angle
brewster angle
cam angle
caster angle
departure
angle
dwell
dwell angle
front triangle
heading angle
ignition angle
included
angle
lock angle
offset angle
opening angle
rake
ramp-over
angle
rear triangle
roll angle
shallow angle
slip angle
spark angle
spark ignition
angle
steep angle
steering angle
steering knuckle
angle
swivel angle
thread angle
tire deviation
angle
tire slip angle
toe-in angle
triangle-split
system
valve angle
yaw angle
angle bar:
See angle iron
angle bars:
On rotary presses, bars at an angle to transfer one or more webs of paper
over each other, or the web to the other side of the press, or at right angles
to its previous direction. Also called turner bars.
angle bead:
A small rounded molding placed at an angle formed by plastered surfaces
to protect from damage.
angle bearing:
A shaft-bearing in which the joint between base and cap is not
perpendicular to the direction of the load, but is set at an angle.
angle block:
A cylinder block that doesn't have a deck at 90 degrees to the cylinders
A small wooden block used in woodwork to make joints, esp. right-angle
joints, more rigid.
angle bracket:
[1] A bracket projecting from the corner of a building beneath the eaves,
and not at right-angles to the face of the wall.
[2] A bracket consisting of two sides set at right angles, often stiffened by
a gusset. Also called gallows bracket.

angle cutter:
A machine to which the cross cut knife is not at a right angle to the edge of
the reel, for cutting sheets of paper from the reel.
angled deck:
British term for canted deck.
angledozer:
A bulldozer with a blade able to be set in such a way to push material to
the side of the road. Usually called a grader or motor grader.
angle elevation:
The vertical angle measured above the horizontal, from the surveyor's
instrument to the point observed.
angle grinder:
A power tool (driven by electricity or
compressed air) which has abrasive
discs. The tool helps to remove old
paint or rough metal surface
angle iron:
Mild steel bar rolled to an L-shaped cross-section, used in structural work.
Legs may be equal or unequal and leg lengths up to 800 mm are available.
Also called angle, angle bar, angle steel, and L-iron.
angle modulation:
Any system in which the transmitted signal varies the phase-angle of an
otherwise steady carrier frequency, i.e., phase and frequency modulation.

angle-nose pliers:
A pair of pliers with long jaws that are bent at right angles to aid
in gripping something which cannot be reached with regular
pliers.
angle of advance:
[1] The angle in excess of 90° by which the eccentric throw of a steam-
engine valve gear is in advance of the crank.
[2] The angle between the position of ignition and outer dead center in a
spark-ignition engine, optimizes combustion of the fuel.
angle of approach light:
A light indicating an approach path in a vertical plane to a definite position
in the landing area.
angle of arrival:
Angle of elevation of a descending wave.
angle of attack:
The angle between the chord line of an airfoil and the relative airflow,
normally the immediate flight path of the aircraft. Also called (in error)
angle of incidence.
angle-of-attack indicator:
An instrument which senses the true angle of incidence to the relative
airflow, and presents it to the pilot on a graduated dial or by means of an
indicating light.
angle of bank:

See angle of roll
angle of bite:
Maximum angle obtainable between the roll radius where it first contacts
the metal and the line joining the centers of the two opposing rolls, when
rolling metal. Also called angle of nip PICTURE.
angle of contact:
[1] The angle subtended at the center of a pulley by that part of the rim in
contact with the driving belt.
[2] The angle made by the surface separating two fluids (one of them
generally air) with the wall of the containing vessel, or with any other
solid surface cutting the fluid surface. For liquid-air surfaces, the angle of
contact is measured in the liquid.
angle of cut-off:
The largest angle below the horizontal at which a reflector allows the
light- source to be visible when viewed from a point outside the reflector.
angle of deflection:
The angle of the electron beam in a cathode-ray tube relative to the axis.
angle of departure:
Angle of elevation of maximum emission of electromagnetic energy from
an antenna.
angle of depression:
The vertical angle measured below the horizontal, from the surveyor's
instrument to the point observed. Also called plunge angle.
angle of flow:
Angle, or fraction of alternating cycle, during which current flows, e.g., in
a thyristor. Also called conduction angle.
angle of friction:
The angle between the normal to the contact surfaces of two bodies, and
the direction of the resultant reaction between them, when a force is just

tending to cause relative sliding.
angle of heel:
The angle through which a floating vessel (boat or ship) or pontoon tilts
owing to eccentric placing of loads, etc.; the angle of inclination of a ship
due to "rolling" or to a "list." It is the angle formed between the transverse
center line of the ship when on "even keel" and when inclined.
angle of incidence:
Angular setting of any airfoil to a reference axis.
Also see
angle of attack
PICTURE @ PROPELLER.
angle of lag:
In ac circuit theory the phase angle by which the current lags behind the
voltage.
Also see
phase angle
angle of lead:
In ac circuit theory the phase angle by which the current leads ahead of the
voltage.
Also see
phase angle
angle of lock:
The angle between the line through the center of the wheel seen from
above when turning a corner and the same line when going straight.
angle of minimum deviation:
The minimum value of the angle of deviation for a ray of light passing
through a prism. By measuring this angle (θ) and also the angle of the
prism (α), the refractive index of the prism may be calculated by means of
the formula: PICTURE.

angle of nip:
The maximum included angle between two approaching faces in a
crushing appliance such as a set of rolls, at which a piece of rock can be
seized and entrained.
angle of obliquity:
The deviation of the direction of the force between two gear teeth in
contact, from that of their common tangent.
angle of pressure:
The angle between a gear tooth profile and a radial line at its pitch point
PICTURE @ gear wheel.
angle of reflection:
The angle which a ray, reflected from a surface, makes with the normal to
the surface. The angle of reflection is equal to the angle of incidence.
angle of refraction:
The angle which is made by a ray refracted at a surface separating two
media with the normal to the surface.
Also see
refractive index
Snell's law
angle of repose:
The greatest angle to the horizontal which the inclined surface of a heap of
loose material (e.g., a powder, earth, or gravel, or an embankment) can
assume and remain stationary.
angle of roll:
The angle through which an aircraft must be turned about its longitudinal
axis to bring the lateral axis horizontal. Also called horizontal angle of
bank.
angle of slide:
Slope at which heaped rock commences to break away.

angle of stall:
The angle of attack which corresponds with the maximum lift coefficient.
angle of twist:
The angle through which one section of a shaft is twisted relative to
another section when a torque is applied.
angle of view:
The angle subtended at the center of the lens by the limits of the image
recorded; in still photography this is taken as the diagonal of the negative
area; but in motion picture and TV work, it is the width of the frame.
angle parking:
A system of parking on the side of the street where the
car is about 45 degrees from parallel with the edge of
the street. The British term is "echelon parking"
angle plate:
Cast-iron plate with the faces machined truly square and having slots on
each face for clamping bolts. Used to hold work when marking off on a
surface plate or when machining on a lathe face plate or machine tool
table.
angle ply laminate:
Laminated material of wood or fiber-reinforced composites in which the
angles between the orientation directions of the laminae are not 90°;
commonly used angles are 30°, 45°, and 60°.
angle screwdriver:
A tool that is shaped like the letter "L" and has a blade at either end.
angle steel:

See angle iron
angle stone:
See quoin
angle valve:
Type of globe valve design, having pipe openings at right angles to each
other. Usually, one opening is on.
angora:
The hair of the angora rabbit or the soft yarn and fabric made from it.
ångström:
Unit of wavelength for electromagnetic radiation covering visible light and
X-rays. Equal to 10-10
m. The unit is also used for interatomic spacings.
Symbol Å Superseded by nanometer (=10-9
m) but still used widely in
crystallography. Named after the Swedish physicist A. J. Ångström (1814-
74).
angular acceleration:
The rate of change of angular velocity; usually expressed in rad s-2
.
angular contact bearing:
A ball bearing for radial and thrust loads in which a high shoulder on one
side of the outer race takes the thrust.
angular displacement:
The angle turned through by a body about a given axis, or the angle turned
through by a line joining a moving point to a given fixed point.
angular distribution:
The distribution relative to the incident beam of scattered particles or the
products of nuclear reactions.
angular frequency:

Frequency of a steady recurring phenomenon, expressed in rad s-1
, i.e.,
frequency in hertz multiplied by 2π. Symbol ω or p. Also called
pulsatance, radian frequency.
angular magnification:
The ratio of the angle subtended at the eye by an image formed by an
optical instrument to the angle subtended by the object at the unaided eye.
angular momentum:
The moment of the linear momentum of a particle about an axis. Any
rotating body has an angular momentum about its center of mass, its spin
angular momentum. The angular momentum of the center of mass of a
body relative to an external axis is its orbital angular momentum. In
atomic physics, the orbital angular momentum of an electron is quantized
and can only have values which are exact multiples of Dirac's constant. In
particle physics, the angular momentum of particles which appear to have
spin energy is quantized to values that are multiples of half of Dirac's
constant.
Also see
momentum
angular motion:
See rotation
angular thread:
See vee thread
angular velocity:
The rate of change of angular displacement, usually expressed in rad s- 1
.
angular vibration:
Side to side movement or shimmy of a tire.
Also see
dynamic balance
anharmonic:
Said of any oscillation system in which the restoring force is non-linear
with displacement, so that the motion is not simple harmonic.

anhedral:
See dihedral angle
anhydrous calcium sulphate:
Dry chemical made of calcium, sulphur, and oxygen (CaSO4)
aniline foils:
Blocking foils which contain dyestuff; used chiefly for leather.
anion:
Negative ion, i.e., atom or molecule which has gained one or more
electrons in an electrolyte, and is therefore attracted to an anode, the
positive electrode. Anions include all non- metallic ions, acid radicals and
the hydroxyl ion. In a primary cell, the deposition of anions on an
electrode makes it the negative pole. Anions also exist in gaseous
discharge. Compare cation.
anisodesmic structure:
A structure giving a crystal marked difference between its bond strengths
in the intersecting axial planes.
anisotropic:
Term describing any material whose physical properties depend upon
direction relative to some defined axes (e.g., crystalline axes, fiber
orientation, draw direction) in the material. These properties normally
include elasticity, thermal and electrical conductivity, permittivity,
permeability, refractive index, strength etc. Also said of such processes as
etching when certain directions are preferred.
anisotropic conductivity:
Property of a body which has a different conductivity for different
directions of current flow (electrical or thermal).
anisotropic dielectric:
Dielectric in which electric effects depend on the direction of the applied
field, as in many crystals.

anisotropic etching:
Describes an etching process which proceeds preferentially in one
direction. In semiconductor processing when dry etching is accomplished
with energetic ion bombardment, the lateral etch rate may be substantially
less than the vertical rate so that under- cutting is avoided, allowing
narrow, steep-sided features to be defined. Compare isotropic etching.
anisotropy:
[1] Something that has different mechanical properties when measured in
different directions
[2] Term describing a property of a substance when that property depends
on direction as revealed by measurement, e.g., crystals and liquid crystals
in which the refractive index is different in different directions, or when
magnetic dipoles align with certain crystal axes in magnetic materials.
Also see
anisotropic
anneal:
To remove hardness from metal by heating, usually to a red color, then
allowing it to cool slowly. Unlike steel, copper is annealed by heating, and
then plunging it into cold water. It is the reverse of hardening.
annealing:
Process of heat treating metal to get desired properties of softness and
ductility (easily formed in to a new shape). For example: heating and slow
cooling of a piece of iron.
Also see
back annealing
box annealing
bright annealing
annealing furnace:
An oven or furnace with controllable atmosphere in which metal is
annealed.
annealing point:

One of the reference temperatures in glass production.
annihilation:
Spontaneous conversion of a particle and its antiparticle into radiation,
e.g., positron and electron yielding two gamma-ray photons each of energy
0.511 MeV.
annihilation radiation:
The radiation produced by the annihilation of an elementary particle with
its corresponding antiparticle.
annual load factor:
The load factor of a generating station, supply-undertaking or consumer,
taken over a whole year.
annular:
Something in the form of a ring.
annular ball bearing:
A ball bearing with a non-adjustable inner and outer race or races.
annular combustion chamber:
A gas turbine combustion chamber in which the perforated flame tube
forms a continuous annulus within a cylindrical outer casing.
annular gap:
Something in a circular gap.
annular gear:
A ring in the shape of an annulus with gear teeth cut on the periphery for
engagement with a pinion. Usually shrunk fit on to a mating diameter, e.g.,
starter ring on automobile flywheel.
annulus:
A hollow gear which is in the form of a ring with internal teeth.

Also see
epicyclic gearbox
annunciator:
[1] Any device for indicating audibly the passage of a train past a point.
[2] Arrangement of indicators which display details on operational
condition and functioning of complex plant. Also called indicator.
anode:
[1] In an electrical circuit it is the positive pole. It is that part of an
electrical circuit to which electrons are flowing.
[2] British term describing the electrode, in a valve or tube, held at a
positive potential with respect to a cathode, and through which positive
current generally enters the vacuum or plasma, through collection of
electrons. The US term is plate
Also see
sacrificial anode
soluble anode
anode breakdown voltage:
The voltage required to trigger a discharge in a cold-cathode glow tube
when the starter gap (if any) is not conducting. It is measured with any
grids or other electrodes grounded to cathode.
anode brightening:
See electrolytic polishing
anode cell:
See aluminum anode cell
anode characteristic:
Graph relating anode current and anode voltage for an electron tube.
anode dark space:
Dark zone near the anode in a glow-discharge tube.
anode dissipation:

Generally, the energy produced at the anode of a thermionic tube and
wasted as heat owing to the bombardment by electrons, specifically, the
maximum permissible power which may be dissipated at the anode.
anode drop:
The voltage between the positive column and the anode of a gas discharge
tube. It may be positive, zero, or negative, depending on the gas pressure,
but not the discharge current. Also called anode fall.
anode efficiency:
Ratio of ac power in the load circuit to the dc power supplied to the anode
of a valve amplifier or oscillator.
anode fall:
See anode drop
anode feed:
Supply of direct current to anode of a tube, generally decoupled, so that
the supply circuit does not affect the condition of operation of the tube.
anode modulation:
Insertion of the modulating signal into the anode circuit of a valve, which
is oscillating or is rectifying the carrier. Also called plate modulation.
anode mud:
See anode slime
anode polishing:
See electrolytic polishing
anode saturation:
Limitation of current through the anode of a valve, arising from current,
voltage, temperature, or space charge.
anode slime:
Residual slime left when anode has been electrolytically dissolved. It may
contain valuable by-product metals. Also called anode mud.

anode strap:
Connecting strip between alternate anode segments of a multi-cavity
magnetron Used for mode selection and control.
anode tap:
Tapping point on the inductance coil of a tuned-anode circuit, to which the
anode is connected. The position of the tap is adjusted so that the tube
operates into the optimum impedance.
anodic:
See hard anodic coating
anodic coating:
A protective, decorative, or functional coating which is formed in the
anodizing process. Also called anodic film or anodic oxide layer.
Also see
hard anodic coating
anodic etching:
A method of preparing metals for electrodeposition by making them the
anode in a suitable electrolyte and at a suitable current density.
anodic film:
See anodic coating
anodic oxide layer:
See anodic coating
anodic protection:
System for passivating steel by making it the anode in a protective circuit
Compare cathodic protection.
anodic treatment:
See anodizing
anodize:

By electrolytic action, this is the process of coating or plating a metal
(usually aluminum) with a thin protective film or material such as chrome.
It is sometimes applied with colored dye.
anodized:
An electroplating process commonly performed on aluminum parts, which
forms a thin protective film on the surface of the metal. Anodizing is
sometimes accompanied by the use of a colored dye, which gives a
lustrous colored finish to the aluminum parts.
anodizing:
The process by which a hard, non-corroding oxide layer is deposited on
aluminum.
Also see
color anodizing
hard anodizing
integral color anodizing
anodizing bath:
A tub in which the anodizing process is performed.
anodizing tank:
A tub in which the anodizing process is performed.
anomaloscope:
An instrument for detection and classification of defective color vision.
Two colors are mixed, and the result matched with a third.
anomalous dispersion:
The type of dispersion given by a medium having a strong absorption
band, the value of the refractive index being abnormally high on the longer
wave side of the band, and abnormally low on the other side. In the
spectrum produced by a prism made of such a substance the colors are,
therefore, not in their normal order.
anomalous magnetization:
Irregular distribution of magnetization, e.g., when consequent poles exist
as well as main poles on a magnetic circuit.

anomalous scattering:
See scattering
anomalous viscosity:
A term used to describe liquids which show a decrease in viscosity as their
rate of flow (i.e., velocity gradient or shear strain rate) increases. Also
called non-Newtonian fluids or pseudo-plastic fluids. Advantage is taken
of this behavior when injection molding polymer melts.
anorthic system:
See triclinic system
ANS:
Acronym for "anti-noise system".
ANSI:
Acronym for "American National Standards Institute".
answer print:
First print from the edited negative of the film shown to the producer for
approval before release.
ant:
See p. ant
antagonizing screws:
See clip screws
antapex:
See solar antapex
antechamber:
A small auxiliary combustion-chamber, used in some compression-ignition
engines, in which partial combustion of the fuel is used to force the
burning mixture into the cylinder, so promoting more perfect combustion.

antenna:
A device which pulls in radio reception. A power antenna automatically
rises when the radio is turned on and lowers when it is shut off. Some cars
had the antenna wires imbedded in the windshield. Also called aerial.
Also see
adcock antenna
alford antenna
antifading antenna
aperiodic antenna
artificial antenna
balancing antenna
beam antenna
beavertail antenna
beverage antenna
power antenna
whip antenna
antenna changeover switch:
Switch used for transferring an antenna from the transmitting to the
receiving equipment, and vice versa, protecting the receiver.
antenna downlead:
Wire running from the elevated part or conductor of an antenna down to
the transmitting or receiving equipment.
antenna effect:
[1] Errors arising when a directional antenna, used in an electronic
navigation system, picks up radiation from a non-intended direction, as a
result of imperfections in the radiation pattern.
[2] Spurious effects in radio-direction finding systems caused by stray
capacitance between a loop antenna and ground.
antenna efficiency:
See radiation efficiency
antenna feeder:
The transmission line or cable by which energy is fed from the transmitter
to the antenna.

antenna field:
Map showing electromagnetic field strength produced by an antenna in the
form of contour lines joining points of equal field intensity; it may be in
azimuth or any plane of elevation. Also called radiation pattern.
PICTURE.
antenna gain:
Ratio of maximum energy flux from an antenna, to that which would have
been received from a non-directional aerial radiating the same power.
Also see
directional gain
antenna impedance:
Complex ratio of voltage to current at the point where the feeder is
connected.
antenna load:
See dummy load
antenna noise temperature:
The temperature of a black body which, when placed around an antenna
similar to the real one, but loss-free and perfectly matched to the receiver,
produces the same noise power, within a specified frequency band, as the
real antenna in its operating environment.
antenna resistance:
Total power supplied to an antenna system divided by the square of a
specified current, e.g., in the feeder, or at the ground connection of an open
wire antenna.
antenna-shortening capacitor:
A capacitor connected in series with an antenna to allow operation at a
frequency other than its natural resonant one.
Also see
loaded antenna

anthropogenic:
Man-made, the opposite of natural, used particularly of radiation and
nuclear particles.
anti-aliasing:
Treatment of video picture signal elements to reduce the effects of
aliasing.
antibackfire valve:
See anti-backfire valve
anti-backfire valve:
(anti-BFV) Valve used in air injection reaction ( exhaust emission control)
system to prevent backfiring during the period immediately following
sudden deceleration by diverting the air coming from the air pump away
from the exhaust ports. Otherwise the exhaust gases which contain
unburned gasoline could mix with fresh air and cause unwanted
backfiring.
Also see
air bypass valve
antibaryon:
Antiparticle of a baryon, i.e., a hadron with a baryon number of -1. The
term baryon is often used generically to include both.
anti-BFV:
Acronym for " anti-backfire valve".
antibonding orbital:
Orbital electron of two atoms, which increases in energy when the atoms
are brought together, and so acts against the closer bonding of a molecule.
anti-capacitance switch:
A switch designed to have very little capacitance between the terminals
when in the open condition.
anti-cathode:

The anode target of an X-ray tube on which the cathode rays are focused,
and from which the X-rays are emitted.
anti-chip coating:
A resilient coat of "paint" between the primer and the top coat to protect
the body shell from chipping damage caused by gravel or stones.
anticlutter:
Term describing a circuit or part of a radar system designed to eliminate
unwanted echoes (clutter) and permit the display of signals which might
otherwise abe obscured. Often takes the form of a gain control which
automatically reduces gain immediately after the transmitted pulse and
gradually restores it during the interval leading up to the anticipated return
echo.
anticoincidence counter:
System of counters and circuits which record only if an ionizing particle
passes through particular counters but not through the others.
anticollision beacon:
A flashing red or blue light which is mounted above and below an aircraft
to make it conspicuous when flying in control zones or other busy areas.
anti-corrosion:
A substance used to protect against rust.
Also see
Nordic Anti-Corrosion Code
Anti-Corrosion Code:
See Nordic Anti-Corrosion Code
anti-corrosion warranty:
Manufacturers usually state that all body sheet metal components are
warranted against rust-through corrosion for 6 years or 160,000 kilometers
(100,000 miles), whichever comes first.
anti-corrosive:

That which prevents or limits corrosion.
anticyclotron tube:
A type of travelling wave tube.
anti-dazzle mirror:
A mirror that can be set to reduce the glare of the lights from a vehicle
following your vehicle.
Also see
dimming mirror
anti-dieseling solenoid:
See idle-stop solenoid
antidive:
See anti-dive system
anti-dive:
See anti-dive system
anti-dive system:
A dive is the action of the front of the vehicle to point downward during
braking. The suspension in cars is designed to remove this tendency.
anti-drum compound:
A sticky material which is applied to the inside of panels to reduce the
noise caused by vibration or "drumming".
anti-extrusion ring:
Nylon or cetal ring fitted to heavy duty rubber seal to prevent extrusion
through sealed gap.
antifading antenna:
An antenna which confines radiation mainly to small angles of elevation,
to minimize radiation of sky waves which are prone to fading. For
medium-wave transmitters, the antenna is usually a vertical mast about
60% of a wavelength high. adaptive arrays are also used to combat fading

in higher-frequency applications.
antiferromagnetism:
Phenomenon in some magnetically ordered materials in which there is an
antiparallel alignment of spins in two interpenetrating structures so that
there is no overall bulk spontaneous magnetization. Antiferromagnetics
have a positive susceptibility. The antiparallel alignment is disturbed as the
temperature increases until at the Néel temperature the material becomes
paramagnetic.
antifouling composition:
A substance applied in paint form to ships' bottoms and structures subject
to the action of sea water, to discourage marine growths.
antifreeze:
A chemical (usually ethylene glycol) added to the cooling system to
prevent the coolant from freezing in cold weather. It also inhibits the
formation of rust and other deposits which may clog the radiator and other
cooling passageways. Its resistance to freezing is better with a mix of
50:50 with water than 100% antifreeze.
anti-friction bearing:
See antifriction bearing
antifriction bearing:
A bearing containing rollers, needles, or balls
plus an inner and outer race. The bearing is
designed to roll instead of slide thus
minimizing friction between two moving parts.
To avoid disintegration, the bearing must use
lubrication (i.e., wet friction)
anti-friction metal:

See white metal
anti-g:
Resistant to the effects of high acceleration, esp. of an astronaut's
equipment.
anti-g suit:
A close-fitting garment covering the legs and abdomen, which is inflated,
either automatically or at will by the wearer, so that counter-pressure is
applied when blood is displaced away from the head and heart during
high-speed maneuvers. Colloquially, g-suit.
anti-g valve:
[1] A spring-loaded mass type of air valve which automatically regulates
the inflation of an anti-g suit according to the acceleration (g) loads being
imposed.
[2] A valve incorporated in some aircraft fuel systems to prevent engines
being starved of fuel under specific g loads.
antihalation:
The use of backing to reduce halation in plates or films.
anti-icing:
Protection of aircraft against icing by preventing ice formation on
windshield panels, leading edges of wings, tail units, and turbine engine
intakes. The most common methods are to apply continuous heating by hot
air tapped from an engine, by electrical heating elements, or periodically
inflating rubber bags. Compare de-icing.
anti-incrustator:
A substance used to prevent the formation of scale on the internal surfaces
of steam boilers.
anti-induction network:
A network connected between circuits to minimize crosstalk.
anti-knock additive:

See anti-knock agent
antiknock agent:
anti-knock agent:
A substance like tetraethyl lead which is added to gasoline to raise the
octane number and reduce the gasoline's tendency to detonate, knock, or
ping. In unleaded gasoline, tetraethyl lead is not used because of its
environmental danger.
anti-knock agents:
anti-knock index:
The measure of the anti-knock properties of a brand and type of gasoline.
It is defined as half the sum of the research octane number (RON) and
motor octane number (MON).
antiknock substances:
Substances like lead (IV) ethyl added to fuel to lessen its tendency to
detonate or "knock" in an engine.
antiknock value:
The relative immunity of a volatile liquid fuel from detonation in a
gasoline engine as compared with some standard fuel.
Also see
knock rating
octane number
antilepton:
An antiparticle of a lepton. Positron, positive muon, antineutrinos, and the
tau- plus particle are antileptons.
antilift:
See anti-lift
anti-lift:

Lift is the action of the rear end of the vehicle to rise during braking. The
suspension in cars is designed to remove this tendency.
antilock brake:
(ABS)
See anti-lock brake system
anti-lock brake:
(ABS)
anti-lock brake controller:
CAB Chrysler Corporation's term for the electronic control unit.
anti-lock brake system:
(ABS) Sometimes called "anti-skid brakes." A device which senses that
one or more of the wheels are locking up during braking. It monitors the
rotational speeds of the wheels and reduces hydraulic pressure to any
wheel it senses locking up.It is controlled by both mechanical and
electronic components. When you apply the brakes, the ABS will regulate
the flow of brake fluid being delivered to the brake calipers. It must be
remembered that a wheel cannot be steered unless it is rolling; so if the
wheel is locked up, there is no steering control. By the use of electronic
computers, the brakes rapidly alternate (at a rate of 30 times per second)
from full pressure to full release. This process will also alternate from the
left-front wheel and the right-rear wheel and switch to the right-front
wheel and left-rear wheel. In this way both maximum braking and
maximum steering control is allowed during braking. Before the advent of
ABS, drivers were advised to pump the brakes to maintain the same effect.
However, the human foot cannot pump the brakes faster than the computer
control. Also, steady application of the brakes without ABS may cause
brake failure ( brake fade) because of the excess heat. Never pump the
brakes if you have ABS. When you firmly apply the brakes with ABS, you
may feel a pulsing sensation and hear a banging noise. The abbreviation
ABS comes from the German anti blockier system.
anti-lock braking system:
antimatter:

See antiparticle
antimonide:
See aluminum antimonide
antimony alloys:
Alloys containing antimony, which is an essential constituent in type
metals, bearing metals (which contain 3-20%), in lead for shrapnel (10%),
storage battery plates (4- 12%), roofing, gutters, and tank linings (6-12%).
antimony black:
Finely powdered antimony, which gives plaster casts a metallic look.
antimuon:
Antiparticle of a muon.
antineutrino:
Antiparticle to the neutrino. As for the neutrino there are three types of
antineutrino, associated with the electron, muon, and tau lepton.
antineutron:
Antiparticle with spin and magnetic moment oppositely oriented to those
of neutron.
antinode:
At certain positions in a standing wave system of acoustic or electric
waves or vibrations, the location of maxima of some wave characteristics,
e.g., amplitude, displacement, velocity, current, pressure, voltage. At the
notes these would have minimum values.
anti-noise:
See anti-noise system
anti-noise system:
(ANS) A noise counteraction system. This is a sophisticated system which
has a number of small microphones placed around the vehicle to detect
driving noises. A computer microprocessor analyzes these noises and

generates matching counter-frequencies which are sent to small speakers
located in the passenger compartment. In this way the road noises are
cancelled or erased.
anti-ozone compound:
See ozone compound
antiparallax mirror:
Mirror positioned on an arc adjacent to the scale of an indicating
instrument, so that the parallax error in reading the indication of the
pointer is avoided by aligning the eye with the pointer and its image.
antiparticle:
A particle that has the same mass as another particle but has opposite
values for its other properties such as charge, baryon number, or
strangeness. The antiparticle to a fundamental particle is also fundamental,
e.g., the electron and positron are particle and antiparticle. Interaction
between such a pair means simultaneous annihilation, with the production
of energy in the form of radiation.
antipercolation valve:
See anti-percolation valve
anti-percolation valve:
A device for venting vapors from the main discharge tube, or the well, of a
carburetor. The vented vapors are not released into the atmosphere, but
rerouted into an evaporative emission canister where they are stored until
the next time the vehicle is started. Thus it provides a richer mixture
needed for starting.
Also see
percolation
antipolarizing winding:
Winding on a transformer or choke which carries a direct current to
neutralize the magnetizing effect of another direct current.
antiproton:

Short-lived particle, half-life 0.05μs, identical to the proton, but with
negative charge; annihilating with normal proton, it yields mesons. Also
called negative proton.
antiquark:
The antipaticle of a quark.
anti-rattle spring:
A component in disc brakes shaped like the letter "X" and made of spring
steel. It applies radial pressure to the brake pads to prevent rattling. Also
called spreader spring.
antiresonance frequency:
Frequency at which the parallel impedance of a tuned circuit rises to a
maximum.
antiroll bar:
See anti-roll bar
anti-roll bar:
Sometimes called the "anti-sway bar,"
"stabilizer bar," or even (incorrectly) "roll-
bar." It is usually a round bar which connects
the left wheel suspension assembly with the
right side. It may be found at the front and/or
rear. Its main function is to keep both wheels
rolling at the same rate when meeting bumps;
but it also affects handling. A front anti-roll
bar increases understeer and a rear bar
increases oversteer.
antiroll device:
See brake anti-roll device
anti-roll device:
See brake anti-roll device
anti-rust treatment:

See rustproofing
antisag bar:
A vertical rod connecting the main tie of a roof truss to the ridge to support
it against sagging under its own weight.
antiscuffing:
The ability of a precision insert bearing to resist scuffing or scratching the
shaft journal in the event that the oil surface skin is destroyed.
anti-set-off spray:
Spray used to apply a layer of fine particles to the surface of each freshly
printed sheet to prevent contact with the succeeding sheet so that set-off
does not occur.
anti-set-off tympan cover:
A top cover for the second cylinder of any perfecting press, flat-bed, or
rotary, consisting of a material coated with very small glass beads.
anti-siphon bleeds:
Small holes drilled into the cluster to prevent main-system fuel from
continuing to flow when the throttle is closed, stopping airflow through the
carburetor.
antiskid:
See anti-skid
anti-skid:
(ASBS) A computer controlled automotive device which senses when one
or more of the wheels are locking up during braking. It eases up on the
amount of hydraulic pressure to that wheel. It must be remembered that a
wheel cannot be steered unless it is rolling; so if the wheel is locked up,
there is no steering control. By the use of electronic computers, the brakes
rapidly alternate from full power to none so that both maximum braking
and maximum steering control is allowed. If you jam on the brakes, you
will feel a pulsing sensation. Sometimes called " anti-lock brakes."

antismog device:
A special part or system designed to reduce or eliminate emission of
noxious gases from exhaust of engine.
antisolar glass:
Glass which absorbs heat from sunshine and reduces glare, but transmits
most of the light.
antisound:
Sound signal with same amplitude but opposite phase of some unwanted
sound signal so that both signals cancel each other when superimposed.
Used in active control.
anti-spin parachute:
A small parachute, normally in a canister, which may be fixed to the tail
(occasionally to the wing tips) of an aircraft or glider for release in
emergency to lower the nose into a dive and so assist recovery from a spin.
It is jettisoned after use. Colloquially spin chute.
anti-spin regulation:
(ASR) The control or prevention of wheelspin under power, normally by
means of electronic sensing and in conjunction with anti-lock brakes.
anti-spin regulation traction control system:
(ASC) The system which prevents wheelspin.
Also see
anti-spin regulation
antispray film:
An oil film placed on the surface of accumulator cells to prevent the
formation of acid spray due to the bursting of gas bubbles during the
charging process.
anti-spray flap:
See mudflap
antisquat:

See anti-squat system
anti-squat:
See anti-squat system
anti-squat system:
Squat is the action of the rear end of the vehicle to point downward during
hard acceleration. The suspension in cars is designed to remove this
tendency. Contrasts with anti-dive system.
anti-squeal shim:
A shim (metal plate) placed behind the brake piston or the brake pad to
reduce noise when the brakes are applied.
anti-stall dashpot:
A diaphragm unit mounted on the carburetor that allows air to escape
slowly from its vacuum chamber to prevent throttle plate(s) in the
carburetor from closing too suddenly--and stalling the engine--during
deceleration.
anti-stokes lines:
Those in scattered or fluorescent light with frequencies greater than that in
the incident radiation, because of departure of atoms or molecules from
their normal states.
antisurge valve:
A valve for bleeding off surplus compressor air to suppress the unstable
airflow due to surge in a gas turbine engine.
anti-sway bar:
See anti-roll bar
antisymmetric:
Pattern or waveform in which symmetry is complete except for one
particular feature, e.g., sign of electric charge, direction of current, or of
components in waveform. A system containing several electrons must be
described quantum mechanically by an antisymmetric eigenfunction.

anti-theft system:
Any device (mechanical or electrical) which tends to reduce the theft of a
vehicle. It may involve an alarm system, ignition lockouts, steering locks,
steering wheel locks, transmission locks, and/or wheel locks.
anti-tipper:
An arm, usually with a small wheel attached at the outer end, which is
secured to the back of a wheelchair to prevent the chair from falling on its
back and thereby injuring the patient.
antitippers:
See anti-tipper
anti-transmit receive tube:
(ATR tube) Gas discharge tube which isolates a pulsed radar transmitter
from the antenna so that echoes can be received. Compare transmit receive
tube.
anti-vibration mounting:
[1] Because the engine, transmission, differential, and other components
tend to vibrate when in motion, noise increases and there is possible wear
at the points of contact with the frame members. Rubber blocks are used to
cushion the vibration at the mounting points.
[2] Rubber springs designed to absorb vibrations from engines, etc. Care
needed in design and materials selection to match vibration frequency with
main damping peak of elastomer.
antung:
Slub-free, plain-weave fabric made from wild silk.
A-number:
The telephone number from which a call originates in an intelligent
network Compare B-number and C-number.
anvil:

[1] A heavy iron block (often steel faced) on which something is placed for
forging or hammering.
[2] The lower wheel of a wheeling machine which shapes metals.
anvil chisel:
See anvil cutter
anvil cutter:
A chisel with a square shank for insertion in the hardy hole of a smith's
anvil, the cutting edge being uppermost.
A-panel:
The side panel used to fill the gap between the rear edge of the front
fender and the front edge of the doors.
α-particle:
See alpha particle
APEC:
See " Asia Pacific Economic Cooperation.
ape hangers:
A term coined at the height of the custom-bike movement to describe tall
handlebars that forced the rider to reach skyward to grasp the controls,
making the rider adopt an ape-like posture.
aperiodic:
[1] Said of any potentially vibrating system, electrical, mechanical, or
acoustic, which, because of sufficient damping, does not vibrate when
impulsed. Used particularly of the pointers of indicating instruments,
which having no natural period of oscillation, do not oscillate before
coming to rest in the final position, and so give their ultimate reading as
fast as possible.
[2] Said of any device or circuit (e.g., antenna, amplifier) which does not
exhibit any variation in characteristics with varying frequency of applied
signals.
aperiodic antenna:

An antenna with useful efficiency over a range of radio frequencies,
terminated to minimize resonance by reflection, e.g., rhombic antenna,
wave antenna. Also called non-resonant antenna.
aperture:
[1] The opening, usually circular, through which light enters an optical
system, such as a camera lens; its area may be varied by an iris diaphragm
to control the amount of light passing.
Also see
f-number
numerical aperture
stop
[2] The rectangular opening at which motion picture film is exposed in a
camera or projector.
[3] The effective area over which an aerial extracts power from an incident
plane wave. The aperture (A) and gain (G) are related by the equation:
G=4πA/λ², where λ is the wavelength.
Also see
door aperture
lamp aperture
valve aperture
windshield aperture
aperture correction:
One form of enhancement of signal differences at image boundaries to
increase apparent sharpness.
aperture distortion:
Distortion arising from the scanning spot having finite, instead of
infinitely small, dimensions.
aperture efficiency:
The ratio of an antenna's actual directivity to the theoretical figure which
would be obtained with ideal aperture illumination, i.e., with uniform
electromagnetic field strength over its aperture.
aperture grille:
The Trinitron picture tube equivalent of a shadowmask, with vertical slits
instead of holes through which the electron beams pass.

aperture number:
See f-number
aperture panel:
A large side panel of a vehicle making up the rear fender, door frame, and
side window frame.
Also see
side aperture panel
sunroof aperture panel
aperture plate:
Plate carrying the opening at which film is exposed or projected.
apex:
The top of a triangle. In racing, it is the point or area closest to the inner
corner.
apex seal:
A wedge shaped
device found on the
tips of the
triangular rotor in
rotary (Wankel)
engines. Its purpose
is to prevent the
escape of
compressed gas or
combustion gases.
It may also release
engine heat.
API:
Acronym for "American Petroleum Institute," the organization that
classifies oil.
APIA:
Acronym for "Association of Automotive Manufacturers and Importers"
(Romania).

API scale:
Abbreviation for American Petroleum Institute scale. Scale of relative
density, similar to Baumé scale. Degrees API=(141.5/s)-131s, where s is
the relative density of the oil against water at 15°C.
A pillar:
See A-post
A-pillar:
When you look at the side of a car, the pillar
that is attached to the windshield and supports
the roof is called the "A-post" or "A-pillar."
There are two to each car. Generally the
middle post is the B-post and the back post is
the C-post.
Apjohn's formula:
A formula which may be used for determining the pressure of water vapor
in the air from readings of the wet and dry bulb hygrometer. The formula
is:
pt=pw-0.00075H(t-t w)[1-0.008(t- tw)], where pw is the saturated vapor
pressure at the temperature (tw) of the wet bulb, H is the barometric height,
and t is the temperature of the dry bulb.
aplanatic:
Said of an optical system which produces an image free from spherical
aberration.
aplanatic refraction:
Refraction at a surface under conditions in which there is no spherical
aberration and in which the sine condition is satisfied.
apochromatic lens:

A lens so designed that it is corrected for chromatic aberration for three
wavelengths thus reducing the secondary spectrum.
apochromatic objective:
Microscope objective in which spherical and chromatic aberrations have
been corrected as completely as possible.
A-point:
Temperature above which steel can be hardened. The equilibrium point of
the transformation temperature. Also called Ae point.
Apollo:
A vehicle brand of which the 1963-66 models are milestone cars.
apomecometer:
Instrument based on optical square, for measuring heights and distances.
A post:
See A-post
A-post:
When you look at the side of a car, the post
that is attached to the windshield and supports
the roof is called the "A-post" or "A-pillar."
There are two to each car. Generally the
middle post is the B-post and the back post is
the C-post.
apostilb:
A unit of surface luminance used in the case of diffusing surfaces,
numerically equal to 1/100000 lambert (1/πc dm-2
).
apparatus:

See air-cooled apparatus
Beckmann apparatus
apparent cohesion:
Cohesion of silts and sands due to surface tension in the enclosed films of
water; these films tend to pull the silt grains together.
apparent expansion:
See coefficient of apparent expansion
apparent horizon:
See visible horizon
apparent particle density:
The mass of a particle of powder divided by the volume of the particle
excluding open pores but including closed pores.
apparent powder density:
The mass of the powder divided by the volume occupied by it under
specified conditions of packing.
apparent power:
The volt-amperes, i.e., the product of volts and amperes in an ac circuit or
system.
apparent resistance:
See impedance
apparent viscosity:
Term applied to the viscosity of many non-Newtonian fluids (e.g.,
polymers). Specifically to viscosity calculated using Poiseuille's formula.
appearing:
Term referring to the depth of the actual printed matter on a page,
exclusive of traditional white line at foot. Also called inclusive page depth.
appendages:

Structures extending beyond the main hull. They include items like
shafting, rudder, bossing, struts, and bilge keels.
Applegate diagram:
Presentation of the bunching and debunching of an electron beam in a
velocity-modulation tube, e.g., a klystron.
apple paint:
See candy apple paint
appleton layer:
See f-layer
appliance:
A British term for a fire engine.
application:
[1] The use to which something is put.
[2] The process of putting something on something else.
[3] The act of applying adhesives. For adhesives and coatings, the
principal methods of application are: brushing, spraying, dipping,
stencilling, flowing, stamp-padding, roll coating, knife coating,
squeegeeing, or trowelling with spatula or notched trowel. For sealers:
spatula, caulking gun, flow gun, pressure extrusion units and spray gun.
Also see
wet-on-wet application
applicator:
[1] A tool for putting something on something else, e.g., a spreader or
brush.
[2] Electrodes used in industrial high-frequency heating or medical
diathermy; often specially shaped to fit the sample or body.
Also see
heating inductor
applied potential tomography:
A system of medical imaging based on the measurement of the electrical
impedance, at about 50 kHz frequency, between many electrodes placed
around the body.

applied power:
For an electrical transducer, the power which would be received if the load
matched the source in impedance. That applied is not equal to the actual
power received, because of the reflection arising from non-equality of
impedance matching.
applied stress:
The stress induced in a member under load.
appliqué:
appliqué Ornament, frequently of fabric or plastic, attached to the surface
of a fabric to give a three-dimensional effect.
apply:
To put something on something else.
approach:
See arc of approach
approach angle:
The most sharply angled incline the vehicle can make without its front
scraping the ground. Measured in degrees, it's the angle formed on one
side by the horizontal axis, and on the other by a straight line connecting
the forward edge of the front tire and the most prominent front-end feature
extending beyond that line -- the bumper, fog lamps, tow hook, etc.
approach control radar:
(ACR) A surveillance radar which shows on a cathode-ray tube display the
positions of aircraft in an aerodrome's traffic control area.
approach lights:
Lights indicating the desired approach to a runway, usually of sodium or
high- intensity type and laid in a precise pattern of a lead-in line with
crossbars at set distances from the runway threshold.
Also see

angle of approach light
approach speed:
The indicated air speed at which an aircraft approaches for landing.
approval certificate:
See type approval certificate
approximation:
See born-oppenheimer approximation
Aprilia:
A well-regarded Italian motorcycle manufacturer, known for 250 GP race
bikes that are tiny and lightweight.
apron:
[1] The paved area directly below the racing surface that separates the
track from the infield.
[2] The panel under the vehicle's doors or the panel acting as an air dam at
the front of a vehicle.
[3] A kick panel.
[4] A firm surface of concrete or "tarmac" laid down adjacent to
aerodrome buildings to facilitate the movement, loading and unloading of
aircraft.
[5] In a lathe, that part of the saddle enclosing the gear operated by the
lead screw.
[6] Flexible strip used as film support in some types of processing tank.
[7] A strip of rubber, metal, or other material at the outlet from the flow
box to seal the gap between it and the machine wire.
Also see
fender splash apron
front apron
rear apron
apron conveyor:
A conveyor for transporting packages or bulk materials, consisting of a
series of metal or wood slats (also rubber, cotton, felt, wire, etc.) attached
to an endless chain. Also called slat conveyer.

APT:
Acronym for "adjustable part throttle"
APU:
Acronym for auxiliary power unit
AQL:
Acronym for " acceptable quality level".
Aquadag:
Trade mark for a colloidal suspension of graphite in water.
aquaplaning:
Also called hydroplaning. A dangerous tendency for a tire to ride on a thin
film of water, thus creating a loss of driver control until tire contact with
the road surface returns.
aquatread:
A tread pattern of a tire designed to dissipate water lying on the road and
provide good traction in the rain.
aqueduct:
An artificial conduit, generally elevated on columns, used to convey a
water supply
aqueous solution:
A water-based solution.
Ar:
The transformation temperature on cooling of the phase changes in iron
and steel, subscripts indicating the appropriate change.
AR:
Acronym for analytical reagent
Arago Point:

The bright spot found along the axis in the shadow of a disk illuminated
normally
Arago's rotation:
Experiments (conducted by Arago before the discovery of electromagnetic
induction by Faraday) in which a rotating copper disk was made to cause
rotation of a pivoted magnet
Araldite:
A trade name for range of epoxy resins used for adhesives, encapsulation
of electrical components, etc.
ARB:
Acronym for Air Registration Board
arbitration bar:
Test bar, cast with a given heat of metal, to determine whether the main
casting is to specifications.
arbor:
[1] A rotating shaft in a lathe or drill.
[2] Cylindrical or conical shaft on which a cutting tool or part to be
machined is mounted.
[3] The axis or shaft upon which a rotatable part is mounted: the shaft
upon which a gear or wheel is mounted.
Also see
mandrel
arc:
[1] The discharge of electric current across a gap of two electrodes. The
term given to the flow of electricity through a gaseous space or air gap.
[2] A welding term referring to the flow of electricity through the air
which produces high temperatures.
Also see
arc welding
shielded arc
short arc
spray arc

track arc
ARC:
[1] Acronym for Aeronautical Research Council in the UK.
[2] Acronym for Ames Research Center in the USA
arc absorber:
Same as a spark absorber , but referring to a discharge likely to be
destructive if not extinguished.
arc-back:
Flow of electrons, opposite to that intended, in a mercury-arc rectifier.
Caused by a heated spot on the anode acting as a cathode, leading to
possible damage.
arc baffle:
Means of preventing liquid mercury contacting an anode in a mercury-arc
rectifier. Also called splash baffle
arc blow:
A welding term referring to the tendency for an arc to wander or whip
from its normal course during arc welding. It is caused by magnetic
changes.
arc crater:
Depression formed in electrodes between which an electric arc has been
maintained. In arc welding, the depression which occurs in the weld metal.
arc cutting:
A welding term referring to making a kerf in a metal using the energy of
an electric arc.
arc duration:
Time during which an arc exists between the contacts of an opening switch
or circuit breaker. In ac circuits usually measured in cycles, varying
between half a cycle and perhaps 20 cycles.

arc furnace:
An electric furnace in which the heat is produced by n electric arc between
carbon electrodes, or between a carbon electrode and the furnace charge.
arch:
See
fender arch
flared wheel arch
wheel arch
arch bridge:
A bridge that depends on the principle of the arch for its stability.
Also see
rigid arch
three-hinged arch
arch dam:
Dam in which the abutments are solid in rock at sides of impounding area.
arch extension:
See wheel arch extension
Archimedean drill:
A drill in which to-and-fro axial movement of a nut on a helix causes an
alternating rotary motion of the bit
Archimedean screw:
An ancient water-lifting contrivance: a hollow inclined screw (or a pipe
wound in helix fashion around an inclined axis) which has its lower end in
water so that, on rotation of the "screw," water rises to a high level.
Archimedes' principle:
The principle that when a body is wholly or partly immersed in a fluid it
experiences an upthrust equal to the weight of fluid it displaces; the
upthrust acts vertically through the center of gravity of the displaced fluid.

architectural acoustics:
The study of propagation of sound waves in buildings, the results being
applied to the design of studios and auditoriums for optimum audition and
to the noise isolation of buildings.
arch piece:
See stern frame
arch protector:
See wheel arch protector
arch stone:
A wedge-shaped stone used as a constituent part of an arch. Also called
voussoir
arcing:
[1] The action of electricity when it leaps the gap between two electrodes.
Usually causes premature wear of breaker points.
[2] A faulty paint spraying technique where the spray gun is not moved
along the panel surface at a uniform distance. Instead it is moved toward
the panel when starting and moved away toward the end of the panel. The
result of this technique is an uneven application of paint.
[3] A process where the brake shoes are ground to the proper curvature for
the drums they are to be used with. Modern brake shoes are pre-arced.
arcing contact:
An auxiliary contact fitted to a switch or circuit breaker which opens after
and closes before the main contact and receives most of the damage due to
arcing. Designed for easy replacement. Also called arcing tips
arcing, electrical:
See electrical arcing
arcing-ground suppressor:
See arc suppressor
arcing ring:

Circular or oval ring conductor, placed concentrically with a pin insulator
or a string of insulators for deflecting an arc from the insulator surface
which could be damaged.
arcing shield:
See grading shield
arcing tips:
See arcing contact
arcing voltage:
Voltage below which a current cannot be maintained between two
electrodes.
arc lamp:
A form of electric lamp which makes use of an electric arc between two
carbon electrodes as the source of light. It has an extremely high intrinsic
brilliance, and is therefore used for searchlights and spotlights.
Also see
automatic arc lamp
carbon arc lamp
arc of approach:
The arc on the pitch circle of a gearwheel over which two teeth are in
contact while approaching the pitch point
arc of contact:
contact.
arc of recess:
contact while receding from the pitch point.
arc process:
See bredig's arc process

arc resistance:
The ability of an insulator to withstand high-voltage sparking
arc spectrum:
A spectrum originating in the non-ionized atoms of an element; usually
capable of being excited by the application of a comparatively low
stimulus, such as the electric arc.
Also see
spark spectrum
arc spraying:
Method of fusing (and thence depositing) refractory ceramic and metal
powders by blowing them through an electric arc or plasma. Used for
applying a variety of thin and thick film coatings. Also called plasma
spraying
arc-stream voltage:
Voltage drop along the arc stream of an electric arc, excluding the voltage
drops at the anode and cathode.
arc-suppression coil:
See Petersen coil
arc suppressor:
A device for automatically grounding the neutral point of an insulated-
neutral transmission or distribution line if an arc to ground occurs. Also
called arcing-ground suppressor
arc-through:
Overflow of electron stream into an intended non-conducting period.
arc voltage:
[1] The electrical potential (pressure or voltage) across the arc.
[2] The total voltage across an electric arc, i.e., the sum of the arc stream
voltage, the voltage drop at the anode and the voltage drop at the cathode.
The term is frequently used in connection with arc welding, and with the
arc in a switch or circuit breaker.

arc welding:
Welding by using an electric current to melt both the metal to be welded
and the welding rod or electrode that is being added.
Also see
atomic arc welding
automatic arc welding
inert arc welding
pulse arc welding
are:
A metric unit of area used for land measurement. 1 are=100m²=119.6
yard².
Also see
hectare
area:
[1] The sunken space around the basement of a building, providing access
and natural lighting and ventilation.
[2] A measure of the extent of a surface.
[3]In plane surveying, the superficial content of a ground surface of
definite extent, as projected onto a horizontal plane.
area-moment method:
A method of structural analysis based on the slope and displacement of
any part of the structure
area rule:
An aerodynamic method of reducing drag at transonic speeds by
maintaining a smooth cross-sectional variation throughout the length of an
aircraft. Because of the effect of the wing, this often results in a "wasp-
waist" on the fuselage or the addition of bulges to the wing or fuselage.
argand burner:
A form of gas-burner or oil-burner in which air is admitted to the inside of
a cylindrical wick, ensuring a large area of contact between the flame and
the fuel.

argon laser:
Laser using singly ionized argon. It gives strong emission at 488.0, 514.5,
and 496.5 nm.
ARINC:
Acronym for Aeronautical Radio Incorporated, an American organization
whose membership included airlines, aircraft constructors, and avionics
component manufacturers. It publishes technical papers and agreed
standards, and finances research.
arm:
A part attached to or projecting from something.
Also see
a-arm
a arm
actuator arm
adjustable rocker
arm
ball joint rocker
arm
breaker arm
branch
check arm
brush-holder arm
contact arm
control arm
crankarm
door check arm
drop arm
flex arm
suspension
forked rocker arm
high lift rocker
arm
idler arm
knuckle arm
lateral arm
leading arm
long and short arm
suspension
pitman arm
radius arm
rocker arm
rocker arm cover
rocker arm shaft
rotor arm
semi-trailing arm
stay
steering arm
steering gear arm
steering knuckle
arm
throttle arm
tie rod arm
torque arm
track control arm
trailing arm
transverse arm
ARM:
Acronym for anti-radiation missile
armature:
[1] In a relay, regulator, horn, etc., it is the movable part of the unit which
indicates the presence of electric current as the agent of actuation.
[2] Piece of low-reluctance ferromagnetic material (keeper) for
temporarily bridging the poles of a permanent magnet, to reduce the
leakage field and preserve magnetization.
[3] In a starter or generator, it is the portion that revolves between the pole
shoes, made up of wire windings of copper on an iron core or axle. When
it revolves, an electric current is induced.
Also see
bar-wound armature

armature bars:
Rectangular copper bars forming the conductors on the armature in large
electric machines having only a few conductors per slot.
armature brake:
A mechanical or electrical component in a starter used to stop the armature
movement after the starter motor has been switched off.
armature coil:
An assembly of conductors ready for placing in the slots of the armature of
an electric machine.
armature conductor:
One of the wires or bars on the armature of an electric machine.
armature end connections:
The portion of the armature conductors which project beyond the end of
the armature core, and which are used for making the connections among
the various conductors. Also called overhang
armature end plate:
The end plate of a laminated armature core. It is of sufficient mechanical
strength to enable the laminations to be clamped together tightly to prevent
vibration. Also called armature head
armature head:
See armature end plate
armature ratio:
Ratio of distance moved by the spring buffer of an electromagnetic relay,
to that moved by the armature.
armature reactance:
A reactance associated with the armature winding of a machine, caused by
armature leakage flux, i.e., flux which does not follow the main magnetic
circuit of the machine.

armature reaction:
The magnetic field in an electrical machine produced by the armature
current
armature relay:
A relay operated electromagnetically, thus causing the armature to be
magnetically attracted.
armature shaft:
The primary shaft on which the armature is mounted in a starter or
generator.
armature winding:
The complete assembly of conductors carried on the armature and
connected to the commutator or to the terminals of the machine.
Armco:
Trade name for a soft iron with less than 1% impurities. Can be rolled or
formed with deep corrugations as in circular culverts or traffic barriers.
arm cover:
See rocker arm cover
armé:
See béton armé
arming press:
A form of blocking press used for stamping designs on book covers
armor-clad switchgear:
See metal-clad switch gear
armor clamp:
A fitting designed to grip the armoring of a cable where it enters a box.
Also called armor gland and armor grip

armor gland:
See armor clamp
armor grip:
See armor clamp
armor plate:
Traditionally, specially heavy alloy steel plate hardened on the surface;
used for the protection of fighting vehicles and ships. There is also a form
of armor plate based on aluminum alloy particularly suitable for fast
moving military vehicles.
armor-plated:
Panels and glass that are extra thick to be bullet-proof.
armour:
British spelling of "armor"
armrest:
A projection upon which the occupants can rest or support their arms.
Usually located on the door panel and sometimes in the center of the front
seats or the center of the rear seat.
arms:
See bracket arms
control arms
high lift rocker arms
arm shaft:
See rocker arm shaft
armstrong:
A colloquial term for manual steering. Without power assist, steering will
need a strong arm, thus the name.
Armstrong oscillator:

The original oscillator, in which tuned circuits in the anode and grid
circuits of a valve are coupled.
Armstrong-Siddeley:
A vehicle brand of which the 1925-1948 models with required application
are classic cars.
arm suspension:
See flex arm suspension
long and short arm suspension
semi-trailing arm suspension
swing arm suspension
Arnolt:
See Arnolt Bristol
Arnolt Bristol:
array:
An assembly of two or more individual radiating elements, appropriately
spaced and energized to achieve desired directional properties.
Also see
active array
adaptive array
beam antenna
binomial array
arrested failure:
The taking of a cable off voltage before failure is complete and its
examination to determine the mechanism of breakdown.
arrester:
A device which prevents a certain action. For example, a spark arrester is a
special pipe mounted in the end of the exhaust pipe which prevents any
burning gasses from coming out with the possible danger of igniting any
combustibles in the area (i.e., setting the forest on fire).
Also see
lightning arrester

arrester gear:
[1] A device on aircraft carriers and some military aerodromes, usually
consisting of a number of individual transverse cables held by hydraulic
shock absorbers, which stop an aircraft when its arrester hook catches a
cable.
[2] A barrier net, usually of nylon or webbing, attached to heavy drag
weights, which stops fast aircraft from over-running the end of the runway
in an emergency.
arrester hook:
A hook extended from an aircraft to engage the cable of an arrester gear,
mainly on aircraft carriers.
arrest points:
Discontinuities on heating and cooling curves, due to absorption of heat
during heating or evolution of heat during cooling, and indicating
structural (phase) changes occurring in a metal or alloy.
Arrhenius's rate equation:
Equation giving the rate R of a thermally activated, physical process:
R=R0exp(Ea/kT) where R0 is a constant, Ea is the activation energy , k is
Boltzmann's constant and T is the absolute temperature.
arris edge:
Small bevel, of width not exceeding 1/16 in (1.5 mm), at an angle of
approximately 45° to the surface of the glass.
arrival:
See angle of arrival
arrive:
The finish line of a brevet or randonnée.
arrow:
Light steel wire pin, bent into ring at one end and perhaps flagged with
piece of bright cloth, used to mark measured lengths in chain traversing.

Also see
Pierce-Arrow
arsenical copper:
Copper containing up to about 0.6% arsenic. This element slightly
increases the hardness and strength and raises the recrystallization
temperature.
artesian well:
A well sunk into a permeable stratum which has impervious strata above
and below it, and which outcrops at places higher than the place where the
well is sunk, so that the hydrostatic pressure of the water in the permeable
stratum is alone sufficient to force the water up out of the well. Named
from Artois (France).
articulated:
Jointed. An articulated rod is made of two sections with a moveable joint
which permits its shape to go from perfectly straight to right angle.
Also see
articulated bus
articulated truck
articulated blade:
A rotorcraft blade which is mounted on one or more hinges to permit
flapping and movement about the drag axis
articulated bus:
A large bus with an accordion-like section in the middle of the
body which allows the bus to turn sharply around corners as it
articulates at that part of the bus.
articulated mounting:
A term used where parts are connected by links and links are anchored to
provide a double hinging action.
articulated truck:
A large truck with two sections to allow it to turn sharply around corners.

articulation:
[1] The means by which an architect gives definition to the individual
elements of a building.
[2] The connection of two parts in such a way (usually by a pin joint) as to
permit relative movement.
Also see
axle articulation
artificial aging:
Method of accelerating the hardening of particularly aluminum alloys at
slightly elevated temperatures.
Also see
precipitation hardening
artificial antenna:
Combination of resistances, capacitances, and inductances with the same
characteristics as an antenna except that it does not radiate energy. It is
used in place of the normal antenna for purposes such as repair and
checking of a transmitter, or for re-tuning of the transmitter on to a
different frequency. Also called dummy antenna, and phantom antenna.
artificial daylight:
Artificial light having approximately the same spectral distribution curve
as daylight, i.e., having a color temperature of about 4000K
artificial disintegration:
The transmutation of non-radioactive substances brought about by the
bombardment of the nuclei of their atoms by high-velocity particles, such
as alpha particles, protons, or neutrons
artificial ear:
Device for testing earphones which presents an acoustic impedance similar
to the human ear and includes facilities for measuring the sound pressure
produced at the ear.
artificial earth:
See counterpoise

artificial feel:
In an aircraft flying control system, esp. with automatic control of flying
surfaces, in which the pilot's control actions are modified to provide forces
moving the flying controls, a natural feel, opposing the pilot's actions,
which is fed back from the controls. Since these forces vary mostly with
dynamic air pressure as in q=½ev²
artificial feel is sometimes known as q-
feel
artificial ground:
See counterpoise
artificial horizon:
An apparatus, for example a shallow trough filled with mercury, used in
order to observe altitudes of celestial bodies with a sextant on land, i.e.,
where there is no visible horizon. The reflection of the object in the
artificial horizon is viewed directly and the object itself indirectly by
reflection from the index glass of the sextant.
Also see
gyro horizon
artificial line:
Repeated network units which have collectively some or all of the
transmission properties of a line. Also called simulated line
artificial rubber:
See synthetic rubber
artificial stability:
An automatic flight control system which provides positive stability to an
otherwise unstable or neutrally stable aircraft.
artificial traffic:
Automatically generated calls which are deliberately mixed with
subscriber- originated traffic to sample the overall service provided by the
switching equipment of an automatic exchange, by recording or holding
faults recognized by test equipment.
artificial voice:

Loudspeaker and baffle for simulating speech in testing of microphones.
ASA:
Formerly, abbreviation for American Standards Association. Now known
as American National Standards Institute.
ASA speed:
Abbreviation for American Standards Association photographic speed
rating, expressed on a arithmetic scale. Now replaced by ISO speed
asbestos:
A heat resistant and non-burning fibrous mineral widely used for brake
shoes, clutch linings, etc. Asbestos is a health hazard and the dust created
by brake systems should never be inhaled or ingested.
asbestos-free:
Something that has no asbestos -- especially brake and clutch linings.
asbestosis:
An incurable lung disease caused by the inhalation of asbestos fibers.
ASBS:
See anti-skid braking system
ASC:
See anti-spin regulation
ascending stroke:
See up-stroke
ASD:
Acronym for automatic slip-control differential.
asdic:
Abbreviation for allied submarine detection investigation committee.
Underwater acoustic detecting system which transmits a pulse and

receives a reflection from underwater objects, particularly submarines, at a
distance. Also used by trawlers to detect shoals of fish. Equivalent to US
<SONAR< I>, now the preferred term.
ASE:
National Institute for Automotive Service Excellence.
ASEAN:
Acronym for Association of South East Asian Nations.
ash frame:
A frame of a car made of wood from the ash tree and covered with
aluminum panels.
ashtray:
A device for holding cigarette ashes.
ASIA:
Acronym for "Automotive Service Industry Association".
Asia Pacific Economic Cooperation:
(APEC) An organization established in 1989 to promote trade and
investment in the Pacific Basin. APEC now comprises eighteen countries
located in and around the Pacific Ocean: Australia, Brunei, Canada, Chile,
China, Hong Kong, Indonesia, Japan, Malaysia, Mexico, New Zealand,
Papua New Guinea, the Philippines, Singapore, South Korea, Taiwan,
Thailand, and the United States.
ASME:
Acronym for "American Society of Mechanical Engineers."
ASME boiler code:
Standard specs issued by the American Society of Mechanical Engineers
for the construction of boilers.

aspect:
On railways the indication given by a colored light signal, as contrasted
with that of a semaphore arm signal. A multiple-aspect signal (MAS)
conveys more information.
Also see
attitude
aspect ratio:
[1] The ratio of length to width of rectangular air grille or duct.
[2] The relationship in a tire or wheel between the distance from the rim to
the tread and the tire's width (i.e., ratio of section height to section width).
Thus, in a P185/80R13 tire, 80 is the aspect ratio, showing the height is
80% of the width. A lower aspect ratio describes a shorter, wider tire.
[3] In a wing, it is the relationship of its span (horizontal length) to its
chord (height). Important for induced drag and range/speed characteristics.
Defined as S²/A where S is the span and A is the area. Normal figure
between 6 and 9, lesser values than 6 being low aspect ratio, greater than 9
high aspect ratios.
[4] Ratio of the length of a fiber or wire to its width or diameter.
[5] (AR) Ratio of the width to the height of the reproduced picture or
computer screen, e.g., 4x3, often expressed with the height as unity.
1.33:1. Wide-screen systems have aspect ratios between 1.65:1 and 2.35:1.
[6] In a Tokamak type of fusion machine, the ratio of the major to minor
radii of the torus.
Also see
ULP
aperity:
Slightly raised parts of a surface which form the actual points of contact
between two surfaces at a microscope level, elastically and plastically
flattened to take the load (normal force).
asphalt:
[1] A bituminous substance found naturally in oil-bearing strata from
which the volatiles have evaporated
[2] a residue in petroleum distillation
[3] a mixture of asphaltic bitumen and granite chippings, sand, or
powdered limestone. Asphalt is used extensively for paving, road-making,
damp-proof courses, in the manufacture of roofing felt and paints and as
the raw material for certain moulded plastics.
Also see

bitumen
aspheric surface:
A lens surface which departs to a greater or lesser degree from a sphere,
e.g., one having a parabolic or elliptical section
aspirated:
See aspirated engine
aspirated engine:
See naturally aspirated engine
normally aspirated engine
aspirating psychrometer:
Device which draws sample of air through it to measure humidity.
aspiration:
The process of sucking or inhaling the air-fuel mixture into a combustion
engine.
aspirator:
The air intake of a sensor.
aspirator system:
See air aspirator system
aspirator valve:
A check valve in an air injection system.
Aspire:
A model of automobile manufactured by Ford
.
Click for books on Ford Aspire

ASR:
[1] Acronym for anti-spin regulation.
[2] Acronym for Acceleration Slip Regulation.
assay ton:
Used in assaying precious metals. It is equivalent to 29.160 g and 32.670 g
for the short and long ton respectively. The number of milligrams of
precious metal in an assay ton of ore indicates the assay value, since 1 mg
of precious metal per assay ton equals 1 troy oz of precious metal per
avoirdupois ton of ore.
assay value:
Troy ounces of precious metal per avoirdupois ton of ore.
assemble:
The action of putting something together from a number of component
parts.
assemble edit:
Videotape editing in which a new scene is added to follow directly on
existing material
assembly:
[1] The finished union of a number of parts to make a component.
[2] Construction of product from several or many components. Methods
used for attachment include welding, fastening, push-fit, snap-fit, lock-fit,
adhesive bonding, ultrasonic welding, etc. Many products are now
designed for robotic assembly.
Also see
body assembly
bearing assembly
assembly line:
The production line where a vehicle is put together from its component
parts. Often one team will work on just the engine of each vehicle while
another team works on another part, etc.

assembly line communications link:
(ALCL) An electrical connector used to check a vehicle engine
management system while it is on the assembly line and later once it is in
operation, to output its trouble codes.
Also see
ALDL
assembly line data link:
(ALDL) An electrical connector used on GM vehicles to check a vehicle
engine management system while it is on the assembly line and later once
it is in operation, to output its trouble codes.
assembly Line Data Link connector:
(ALDL) a diagnostic connector used in General Motors vehicles.
assembly lube:
A special lubricant used to coat parts that rub or rotate against each other
during initial assembly.
assigned frequency:
The frequency assigned as center frequency of a class of transmission,
with tolerance, by authority.
assigning authority:
A national body authorized to assign load lines to ships
assist:
See autofocus assist
assisted take-off:
Take-off in which the full power of the normal engines is supplemented by
auxiliary means, which may or may not be jettisonable. Small turbojet or
rocket motor units, powder, or liquid rockets may be used.
Also see
JATO
RATOG

assist power steering:
See variable assist power steering
assist steering:
See variable assist steering
assisted:
See hydraulic assisted brakes
integral-type power assisted steering
power assisted brakes
servo-assisted
assisted brakes:
See hydraulic assisted brakes
power assisted brakes
vacuum assisted brakes
assisted steering:
See integral-type power assisted steering
associated emission:
Emission which brings about equilibrium between incident photons and
secondary electrons in ionization.
association:
In rotary printing, the bring together of separate webs, after printing, to
pass through the folder as a complete product.
Association of South East Asian Nations:
(ASEAN) An organization of states (including Brunei, Myanmar, Burma,
Indonesia, Laos, Malaysia, the Philippines, Singapore, Thailand, and
Vietnam) founded in 1967 to present an united front that addresses the
political, economic, and strategic dynamics of the region.
assy:
Abbreviation for assembly.
astable circuit:

An active circuit, having two quasi-stable states, which alternates
automatically and continuously between them, e.g., certain multivibrators
a-stage:
Stage at which a synthetic resin of the phenol formaldehyde type is fusible
and wholly soluble in alcohols and acetone.
astatic galvanometer:
Moving magnet galvanometer in which adjustable magnets form an astatic
system
astatic system:
Ideally an arrangement of two or more magnetic needles on a single
suspension so that in a uniform magnetic field, such as the Earth's field,
there is no resultant torque on the suspension.
astern:
A backward movement of a vessel.
ASTM:
Acronym for " American Society for Testing Materials".
ASTM standards:
Standards issued by the American Society of Testing Materials.
Aston dark space:
The space in the immediate vicinity of a cathode, in which the emitted
electrons have velocities insufficient to ionize the gas.
Aston-Martin:
A vehicle brand of which the 1927-1939
models with application and all others from
1925-48 are classic cars. .
Click for books on Aston-
Martin

Aston Martin:
A vehicle brand of which the 1948-63 models are milestone cars. All the
DB4, DB5, DB6 from 1964-67 are milestone cars.
Aston whole-number rule:
Empirical observation that relative atomic masses of isotopes are
approximately whole numbers.
Also see
mass spectrograph
astrafoil:
A thin, dimensionally stable transparent plastic sheet used for mounting
lithographic negatives or positives
astrakhan:
A curled-pile woven, warp-knitted, or weft-knitted fabric designed to
resemble the fleece of a still-born or very young astrakhan lamb.
astrocompass:
A non-magnetic instrument that indicates true north relative to a celestial
body.
astrodome:
A transparent dome, fitted to some aircraft usually on the top of the
fuselage, with calibrated optical characteristics, for astronomical
observations.
ASV:
Acronym for " air switching valve".
asymmeter:
An instrument having three movements so arranged that any lack of
symmetry when these are connected to a three-phase system can be
observed by a single reading.
asymmetric:

A pattern in which one side does not correspond to the other side.
asymmetrical:
[1] A pattern in which one side does not correspond to the other side.
[2] Said of circuits, networks, or transducers when the impedance (image
impedance, or iterative impedance) differs in the two directions. Also
called <DISSYMMETRICAL< I>or non-symmetrical.
asymmetrical beam:
A headlight system in which one beam is of greater intensity than the
other.
asymmetrical conductivity:
Phenomenon whereby a substance, or a combination of substances as in a
rectifier, conducts electric current differently in opposite directions.
asymmetrical power distribution:
A system in a four-wheel vehicle in which more power is transmitted to
the front wheels than the rear wheels or more to the rear wheels than the
front wheels.
asymmetrical tread:
The tread of a tire which has different
shapes/patterns and sizes of grooves
in the same tire. Often they are
divided into three distinct patterns:
The outside shoulder, the center zone,
and the inside shoulder. The outside
shoulder tread will have larger
shoulder elements with very few
sipes to provide increased cornering
stability. The center tread zone
enhances steering control. The inside
shoulder tread zone provides
additional traction because the shape
of the tread elements, sipes and larger
shoulder slots help disperse water and
slush. Obviously these tires must be
mounted only one way so that the

outside pattern is actually on the
outside of the wheel
asymmetric conductor:
Conductor which has a different conductivity for current flowing in
different directions through it, e.g., a diode.
asymmetric flight:
The condition of flying with asymmetrically balanced thrust, weight, drag,
or lift forces, as could occur, e.g., with one external weapon mounted
under one wing, or in a twin- engine aircraft with one engine inoperative.
asymmetric reflector:
A reflector in which the beam of light produced is not symmetrical about a
central axis.
asymmetric refractor:
A refractor in which the light is redirected, unsymmetrically, about a
central axis.
asymmetric rim:
A wheel rim where the well is located outside the centerline of the wheel.
Opposite of symmetric rim.
asymmetry potential:
The potential difference between the inside and outside surface of a hollow
electrode.
asymptotic freedom:
The property that at small distances quarks behave asympototically as free
particles. In quantum chromodynamics, strong interaction between quarks
becomes stronger with distance.
asynchronous motor:
See non-synchronous motor
at:

Acronym for ampere-turn
ATA:
[1] Acronym for "American Trucking Association."
[2] Acronym for Air Transport Association
ATB:
[1] Acronym for all-terrain bike.
Sometimes called MTB (mountain
bike), but ATB is the preferred
acronym.
[2] Acronym for aeration test burner
ATC:
[1] Acronym for " automatic temperature control."
[2] Acronym for air-traffic control
ATCRBS:
Acronym for air-traffic control radar beacon system. A direct
development of the World War II IFF system. Operating at about 1GHz, it
gives air-traffic controllers three- dimensional positional information and
full identification of aircraft.
ATDC:
See after top dead center
ATE:
Acronym for " automatic test equipment".
ATF:
See automatic Transmission Fluid
transmission fluid.
athermal transformation:
A solid-state reaction e.g., the martensitic transformation of steel, in which
thermal activation is not required. The transformation is driven by

increasing thermodynamic instability of a metastable phase, which
eventually transforms by physical shear of the crystal lattice.
A thread:
See class A thread
athwartship:
Across the ship, at right angles to the fore-and-aft centerline.
ATM:
Abbreviation for standard atmosphere.
Also see
atmospheric pressure
ATM adaptation layer:
In an asynchronous transfer mode network, the equipment and procedures
that interface between its standardized cells and the many data types to be
carried. Telephony, for example, requires a constant data rate over a fixed
channel, while switched multimegabit data service will tolerate a variable
data rate over a changeable connection path.
ATM cell:
the basic data packet handled by an asynchronous transfer mode network,
consisting of a five octet header followed by 48 octets of user information.
The header is used to route the cell between switches, and receives new
labels at each switching point. The user information is carried unchanged
across the ATM network for delivery at the far terminal.
atmospheric absorption:
Diminution of intensity of a sound wave in passing through the air, apart
from normal inverse square relation, and arising from transfer of sound
energy into heat.
atmospheric acoustics:
Study of the propagation of sound in the atmosphere, of importance in
sound ranging and aircraft noise.

atmospheric boundary layer:
(ABL) The region of the Earth's atmosphere that interacts directly with the
Earth's surface.
atmospheric corrosion:
A gradual oxidation of metal as a result of acid rain and other corrosive
substances in our polluted air.
atmospheric dust spot efficiency:
Measurement of a device's ability to remove atmospheric air from test air.
atmospheric engine:
Earliest form of practical steam engine, in which a partial vacuum created
by stem condensation allowed atmospheric pressure to drive down the
piston.
atmospheric gas-burner system:
A natural-draft burner injector, in which the momentum of the gas passing
into the injector throat inspirates part of the air required for combustion.
atmospheric line:
A datum line drawn on an indicator diagram by allowing atmospheric
pressure to act on the indicator piston or diaphragm
atmospheric pressure:
Pressure or weight exerted by the gasses in the air exert upon the earth and
on all things exposed to it. It is measured in pounds per square inch or
kilopascals. At sea level it is about 1 kg. per square centimeter or 14.72
pounds per square inch (psi). (The standard value is 1.01325x105
Nm-2
,
1.01325 bar, or 14.7 lbfin-2
). Variations in the atmospheric pressure are
measured by means of the barometer.
Also see
barometric pressure
standard atmosphere
atmospheric radio wave:

Any radio wave which reaches its destination after reflection from the
upper ionized layers of the atmosphere. Commonly called skip
atom:
See Bohr atom
Bohr-Sommerfeld atom
atomospherics:
British term for interfering or disturbing signals of natural origin. Also
called <SPHERICS< I>. The US term is strays.
Also see
static
atmospheric waveguide duct:
Atmospheric layer which acts as a waveguide for high-frequency (>20
MHz) radio waves under certain conditions of temperature and humidity,
giving reception far outside the normal service area.
atom:
A tiny particle of matter made up of electrons, protons, and neutrons.
Atoms or combinations of atoms make up molecules. The electrons orbit
around the center or nucleus made up of the protons and neutrons.
atomic absorption coefficient:
For an element, the fractional decrease in intensity of radiation per number
of atoms per unit area. Symbol μa. Related to the linear absorption
coefficient μ by where the material contains ni atoms of
element i in a volume V.
atomic arc welding:
Welding using heat created by hydrogen atoms, created by an electric arc
recombining to form hydrogen molecules. The heat is used to weld
delicate joints, and the hydrogen forms a shield over the weld.
atomic bomb:
A bomb in which the explosive power, measured in terms of equivalent
TNT, is provided by nuclear fissionable material such as uranium-235 or

plutonium-239.
atomic clock:
A clock whose frequency of operation is controlled by the frequency of an
atomic or molecular process. The inversion of the ammonia molecule with
a frequency of 2.3786 x 1010
Hz provides the basic oscillations of the
ammonia clock. The difference in energy between two states of a caesium
atom in a magnetic field giving a frequency of 9,192,631,770 Hz is the
basis of the caesium clock which has an accuracy of better than one in
1013
.
atomic disintegration:
Natural decay of radioactive atoms, as a result of radiation, into
chemically different atomic products.
atomic displacement cross-section:
The probability of a neutron displacing an atom from its place in a
crystalline solid. Measured in barns as for other cross-sections. Important
in determining the lifetime of graphite moderator and structural parts of
reactors.
atomic frequency:
A natural vibration frequency in an atom used in the atomic clock
atomic plane:
A solid is crystalline because its atoms are ordered in intersecting planes
(i.e., atomic planes) corresponding to the planes of the crystal.
Also see
X-ray crystallography
atomic scattering:
The scattering of radiation, usually electrons or X-rays, by the individual
atoms in the medium through which it passes. The scattering is by the
electronic structure of the atom in contrast to nuclear scattering which is
by the nucleus.
atomic scattering factor:

The ratio of the amplitude of coherent scattered X-radiation from an atom
to that of a single electron placed at the atomic center. The atomic
scattering factor depends on the electron-density distribution in the atom
and is a function of the scattering angle.
atomic spectrum:
Characteristic pattern of light frequencies emitted or absorbed by a given
element due to electronic transitions between the discrete energy states of
the atoms accompanied by the emission or absorption of photons.
Also see
absorption lines
atomic structure:
The arrangement of the parts of an atom.
atomic transmutation:
The change of one type of atom to another as a result of a nuclear reaction
The transmutation can be produced by high-energy radiation or particles
and is most easily produced by neutron irradiation. The change in atomic
number means the chemical nature of the atom has been changed. Also
called transformation
atomization:
See lateral atomization orifice
rotational atomization unit
atomization orifice:
See lateral atomization orifice
atomization unit:
See rotational atomization unit
atomize:
The process of changing liquid to minute particles or a fine spray. The
extent to which a spray gun breaks up paint into a fine mist, fog, or spray.
atomized powder:

A powder produced by the dispersion of molten metal or other material by
spraying under conditions such that the material breaks down into powder.
atomizer:
A device for producing a fine spray such as used on a paint spray gun.
atomizing pressure:
The pressure needed to atomize a liquid like paint.
ATR:
Acronym for attenuated total reflection
atramentizing:
A corrosion protection process in which steel is coated with phosphate
using a zinc phosphate solution at 90° C (194° F).
ATR tube:
Abbreviation for anti-transmit-receive tube
attachment:
A fitting or accessory to be used in conjunction with a tool, such as a
grinding disc for use with an electric drill.
Also see
bearing attachment
inner attachment face
attachment face:
See inner attachment face
attack:
[1] Chemical corrosion of metal.
[2] To damage something by corrosion.
Also see
angle of attack
base metal attack
pickling attack

attack angle:
The angle of the rear spoiler where it is most effective against lift.
attendant parking:
Parking which is left to a valet and supervised by an attendant.
attenuated total reflection:
Spectroscopic method of analyzing thin films on reflective substrates, esp.
using infrared radiation.
attenuation:
[1] A reduction of noise or emission.
[2] General term for reduction in magnitude, amplitude, or intensity of a
physical quantity, arising from absorption, scattering, or geometrical
dispersion. The latter, arising from diminution by the inverse square law, is
not generally considered as attenuation proper.
attenuation coefficient:
The coefficient which expresses energy losses of electromagnetic radiation
due to both absorption and scattering in a medium. Relevant to narrow
beam conditions. Also called total absorption coefficient
attenuation compensation:
The use of networks to correct for frequency-dependent attenuation, e.g.,
in transmission lines.
Also see
pre-emphasis
attenuation constant:
The real part of α in the relationship ρ=ρe- αx
, where ρ is a physical
quantity, such as the amplitude of a wave propagating along a transmission
path, and x is the distance along the path. The imaginary part of α is
known as the phase constant. More simply, but less commonly defined by
μ = αλ where μ is the attenuation and λ is wavelength, i.e., α is the
attenuation per wavelength distance of propagation.
Also see
decibel
neper

propagation constant
attenuation distortion:
Distortion of a complex waveform resulting from the differing attenuation
of each separate frequency component in the signal. This form of
distortion is difficult to avoid, e.g., in transmission lines.
attenuation of X-rays:
Absorption and scattering of X-rays as they pass through an object.
attenuator:
An arrangement of fixed or variable resistive elements designed to reduce
the strength of any signal (audio- or radio-frequency) without reducing
appreciable distortion. Attenuators also incorporate impedance matching to
the transmission lines or circuits to which they are connected, regardless of
the attenuation they introduce. For lower frequency applications they may
be simply variable or fixed resistances, for high frequencies they may be
pieces of resistive material, introduced into transmission lines, stripline, or
waveguide. Fixed attenuators are sometimes referred to as pad.
attitude:
Of an aircraft in flight, the angle made by its axes with the relative airflow;
the aspect is the angle made by its axes with the ground when the aircraft
is on the ground.
attitude indicator:
A gyro horizon which indicates the true attitude of the aircraft in pitch and
roll throughout 360° about these axes.
Also see
heading indicator
attracted-disk electrometer:
Fundamental instrument in which potential is measured by the attraction
between two oppositely charged disks.
attrition:

A process of wearing out an object by friction.
attrition test:
A test for the determination of the wear-resisting properties of stone,
particularly stone for road-making. Pieces of the stone are placed in a
closed cylinder, which is then rotated for a given time, after which the loss
of weight due to wear is found.
Attwood's formula:
A formula for determining the moment of static stability at large angles of
heel of a ship. Taking angle of heel θ, and the weight of the ship W, the
moment where v is the volume of emerged
wedge, hh1 is the distance between the cg's of emerged and immersed
wedges, V is the volume of displacement, B is the center of transverse
buoyancy, and G is the center of gravity.
ATV:
Acronym for "All Terrain Vehicle."
at your back door:
Trucker slang for "behind your truck" as in "You got a Smokey at your
back door!".
Auburn:
A vehicle brand of which all 8 and 12-cylinder
models from 1925-1948 are classic cars.
.
Click for books on
Auburn
audax:
A style of group bicycle touring found in Europe (esp. France) where a
road captain sets a steady pace for a group of riders. All riders are to finish
together, but (unlike regular randonneuring) a sag wagon is permitted.
Audax Club Parisien:

A cycle-touring club in Paris, France which begun in 1904 to promote the
audax style of randonneuring.
Audi:
A German automobile manufacturer which
began in 1899 has four interlocking rings as its
emblem. These rings represent the 1932 union of
four automakers (Audi, DKW, Horch, and
Wanderer). Later NSU joined in 1969. Audi was
owned by Daimler-Benz from 1958 to 1965, and
then by Volkswagen. .
Click for books on Audi
audibility:
Ability to be heard; said of faint sounds in the presence of noise. The
extreme range of audibility is 20-20,000 Hz in frequency, depending on
the applied intensity; and from 2 x 10-5
Nm-2
(ms) at 1000 Hz (the zero of
the phon scale, selected as the average for good ears) to 120 dB.
audible ringing tone:
An audible tone fed back to a caller as an indication that ringing current
has been remotely extended to the called subscriber's telephone. On
circuits in UK it is heard as a double beat recurring at 2 second intervals.
Also called audible signal
audible signal:
See audible ringing tone
audio codec:
A codec for use in a multimedia system, designed to handle a range of
sound signals in addition to speech
au diode:
See backward diode

audio dub:
Replacing the existing audio with new
audio-frequency:
Frequency which, in an acoustic wave, makes it audible. In general, any
wave motion including frequencies in the range of 20 Hz to 20 kHz.
audio-frequency amplifier:
Amplifier for frequencies within the audible range.
audio-frequency choke:
Inductor with appreciable reactance at audio-frequencies.
audio-frequency modulation:
Method of facsimile transmission in which tone values from black to white
are represented by a graded system of audio-frequencies
audio-frequency transformer:
Transformer for use in a communication channel or amplifier, designed
with a specified, normally uniform, response for frequencies used in sound
reproduction.
audiogram:
Standard graph or chart which indicates the hearing loss (in bels) of an
individual ear in terms of frequency.
Also see
objective noise meter
sound-level meter
audiometer:
Instrument for measurement of acuity of hearing. Specifically to measure
the minimum intensities of sounds perceivable by an ear for specified
frequencies.
Also see
noise audiometer
auditory perspective:

See stereophony
auger effect:
For an atom which has been ionized by the ejection of an inner electron,
the loss of energy by the ejection of an outer electron. Energies of the
Auger electrons emitted are characteristic of the atomic energy levels,
provided a method of determining surface composition and character.
auger yield:
For a given excited state of an atom of a given element, the probability of
de- excitation by Auger process instead of by X-ray emission.
augmentor:
[1] Means of increasing forces by afterburning in a gas turbine.
[2] Means of increasing forces by induced airflow in a rocket.
[3] Means of increasing forces in a wing of STOL aircraft by ducting
compressed air flow from a gas turbine into circulation-increasing slots
and flaps to create high lift coefficients, thereby giving slow landing
speeds.
aural masking:
See masking
aureole:
Liminous glow from the outer portion of electric arc which has a spectrum
different from that of the highly-ionized core.
auroral zone:
Zone where radio transmission is affected by aurora
ausforming:
Working an alloy steel in the metastable austenite condition. The material
is first heated to a temperature where the austenite is stable, i.e., above the
Ac3 temperature, and is then cooled rapidly to the region of 550°C and
worked to shape before any transformation to pearlite or bainite takes
place. It transforms to martensite on cooling at ambient temperature and is
then tempered. Strength and toughness are enhanced compared with the

same material worked conventionally in the austenite region and quenched
and tempered as separate operations.
Also see
isothermal transformation diagram
austempering:
Heating a steel to transform it to austenite followed by cooling rapidly to a
temperature above the martensitic change point, but below the critical
range, so that the austenite isothermally transforms to bainite, which has
properties resembling a quenched and tempered steel of the same
composition.
Also see
isothermal transformation diagram
austenite:
The higher density, high-temperature, face-centered cubic, γ form of iron
and of solid solutions based on it. In pure iron it is stable between 1183K
and 1663K.
austenite bay:
The shape of the region around 550°C in an isothermal transformation
diagram which defines the zone where austenite is metastable and remains
in that condition pending transformation to pearlite or bainite
austenitic steel:
Steel containing sufficient amounts of nickel, nickel and chromium, or
manganese to retain austenite at atmospheric temperature, e.g., austenitic
stainless steel and Hadfield's manganese steel
Austin Healey:
A vehicle brand of which the 100-6 models from
1956-59 are milestone cars. The 3000 models
from 1959-67 are milestone cars. The 100/100M
model from 1953-56 are milestone cars.
.
Click for books on Austin

Austro-Daimler:
A vehicle brand of which the 1925-1948 models are classic cars.
authentication center:
A node within a personal communications network containing the database
files needed to check that potential users have authority to use the system.
authority:
See Lean Authority Limit Switch
Authority Limit:
See lean Authority Limit Switch
Authority Limit Switch:
See lean Authority Limit Switch
authorized dealer:
A company which sells and services a particular brand of vehicle and is
appointed or recommended by a manufacturer.
auto:
[1] Abbreviation for automatic transmission.
[2] Abbreviation for automobile.
auto-adhesion:
Bonding together of identical surfaces, as with contact adhesives.
auto-assemble:
System of videotape editing in which selected scenes are transferred in
their required sequence according to a pre-selected program of time-code
information.
auto bonnet:
A British term for a car cover.
autocapacitance coupling:

Coupling of two circuits by a capacitor included in series with a common
branch
autochoke:
A term for automatic choke.
autoclave:
A sealable high-pressure container used for polymerization and in tire
production.
auto coarse pitch:
The setting of the blades of a propeller to the minimum drag position if
there is a loss of engine power during take-off
autocollimator:
[1] An instrument for accurately measuring small changes in the
inclination of reflecting surfaces. Principally used for engineering
metrology measurements.
[2] A convex mirror used to produce a parallel beam of light from a
reflecting telescope. It is placed at the focus of the main mirror.
autocorrelation:
Technique for detecting weak signals against a strong background level.
Signal is subjected to controlled delay, the original delay signals then
being fed to the autocorrelation unit which responds strongly only if delay
is an exact multiple of signal period.
autocross:
A timed competition of low-to-medium speed driving, with one driver at a
time navigating a small course defined by traffic cones. Drivers compete
against one another for the fastest timed lap (sometimes multiple laps)
through the course.
autocue:
A visual prompter which displays a script to persons in front of a TV
camera. Normally mounted on the camera to give eye contact with the
viewers.

autocycle:
An obsolete moped which is a form of a light motorcycle with a small
engine (usually below 100cc) that uses pedals to start the engine and
provide some extra help getting up hills.
auto dealer:
A retail outlet that carries one (or in some cases in the U.S., a number of)
manufacturer's product line and sells to general consumers and fleet
operators. The outlet will also provide service and sell parts for the brand
of vehicle that it carries. In some instances, a dealer may dual for another
manufacturer's product line.
autodealership:
A retail outlet that carries one (or in some cases in the U.S., a number of)
manufacturer's product line and sells to general consumers and fleet
operators. The outlet will also provide service and sell parts for the brand
of vehicle that it carries. In some instances, a dealer may dual for another
manufacturer's product line.
autodyne:
Term describing an electrical circuit in which the same elements and
valves are used both as oscillator and detector. Also called endodyne, or
self-heterodyne.
autodyne receiver:
A receiver utilizing the principle of beat reception and including an
autodyne oscillator.
autoflare:
An automatic landing system which operates on the flare-out part of the
landing, using an accurate radio-altimeter.
autofocus assist:
Device which improves autofocus performance in low light by projecting a
high contrast light pattern onto the subject.
Also see

automatic focusing
auto graveyard:
An auto wrecker where a large number of older or disabled cars and trucks
are located.
autoignition:
[1] The rapid burning of the air-fuel mixture as a result of a flame or hot
surface, not from a spark plug.
[2] The self-ignition or spontaneous combustion of a fuel when introduced
into the heated air charge in the cylinder of a compression-ignition engine.
Also called automatic ignition.
Also see
spontaneous ignition temperature
auto-inductive coupling:
Coupling of two circuits by an inductance included in series with a
common branch.
autojumble:
A British term for a "swap meet" where parts for old cars are displayed for
sale in various stalls.
autoland:
A landing in which the descent, forward speed, flare-out, alignment with
the runway, and touchdown are all automatically controlled.
Also see
autoflare
autothrottle
automated guided vehicle system:
(AGVS) Vehicles equipped with automatic guidance equipment which
follow a prescribed path, stopping at each machining or assembly station
for manual loading and unloading of parts.
automatic:
[1] Colloquial term for automatic transmission.
[2] Anything that operates without the direct control of the driver.

Also see
automatic choke
automatic gearbox
automatic level control
automatic temperature control
automatic transmission
automatic transmission fluid
automatic adjuster:
Brake adjusters that are actuated by the application of the park brake or by
normal brake operation to compensate for lining wear. At one time, in
order to activate the brake adjuster, it was necessary to operate the vehicle
in reverse and hit the brakes.
automatic adjusters:
Brake adjusters that are actuated by the application of the parking brake or
by normal brake operation, to compensate for lining wear.
automatic advance:
A mechanism which adjusts the ignition advance by means of centrifugal
weights or by a diaphragm controlled by intake manifold vacuum.
automatic air-conditioning:
An air-conditioning system which automatically maintains a preset
temperature.
Also see
automatic temperature control
automatic air-recirculation system:
A heating and ventilation system which automatically switches to the
recirculation mode when the pollutant levels of the air inside the vehicle
exceed certain levels; but after a certain period of recirculation, opens the
intake air doors again to let some fresh air in, even if its quality is still
questionable.
automatic arc lamp:
An arc lamp in which the feeding of the carbons into the arc and the
striking of the arc are done automatically, by electromagnetic or other
means.

automatic arc welding:
Arc welding carried out in a machine which automatically moves the arc
along the joint to be welded, feeds the electrode into the arc, and controls
the length of the arc.
automatic beam control:
(ABC) System in a TV camera which momentarily alters the beam current
in the camera tube to reduce the tailing effects on moving highlights. Also
called automatic beam optimizer
automatic beam optimizer:
See automatic beam control
automatic brightness control:
Circuit used in some television receivers to keep average brightness levels
of screen constant
automatic call distribution:
An intelligent network service which takes account of factors such as time
of day or caller location to route calls to the appropriate point within an
organization.
automatic camera:
Camera in which the focus lens aperture and shutter speed are selected
automatically, film advance by motor drive may also be included. Priority
selection may be available, for example, exposure based on either general
or spot areas and with aperture or shutter speed limitations.
automatic car wash:
See car wash

automatic choke:
A device attached to the carburetor that
automatically reduces the amount of air
entering the carburetor by sensing changes
in engine temperature. It is usually
controlled by a coil spring which changes
length as the engine is warmed or cooled.
automatic circuit-breaker:
A circuit breaker which automatically opens the circuit as soon as certain
predetermined conditions (e.g., an overload) occur.
automatic closing system:
A system which automatically closes the doors, windows, sunroof, trunk,
and hood.
automatic contrast control:
Form of automatic gain control used in video signal channel of a television
receiver.
automatic control:
[1] Valve action reached through self-operated or self-actuated means, not
requiring manual adjustment.
[2] Switching system which operates control switches in correct sequence
and at correct intervals automatically.
[3] Control system incorporating servomechanism or similar device, so
that feedback signal from output of system is used to adjust the controls
and maintain optimum operating conditions.
automatic cut-out:
A term frequently applied to a small automatic circuit breaker suitable for
dealing with currents of a few amperes.
automatic defrost:

System of removing ice and frost from evaporators automatically.
automatic direction finding:
(ADF) Airborne navigational aid tuned to radio source of known position.
Using rotatable loop aerial mounted above in aircraft to detect the
direction of the radio source by rotating until the signal is zero.
automatic expansion valve:
(AEV) pressure-controlled valve which reduces high-pressure liquid
refrigerant to low-pressure liquid refrigerant.
Also see
expansion valve
automatic exposure:
(AE) A control system using a photosensor in the camera to measure scene
brightness and automatically set the lens aperture/shutter speed
combination. Refinements include measuring particular areas of the scene
and program exposure modes. A video camera uses the video signal to
determine exposure.
automatic flight control system:
(AFCS) A category of automatic pilot for the control of an aircraft while
en route. It can be monitored by speed and altitude data signals, signals
from an instrument landing system and VOR, has automatic approach
capability, and is disengaged before landing. Compare autoflare, autoland,
autothrottle
automatic focusing:
(AF) Control system for automatically setting the lens focus to the subject
distance; in a simple form, this may be by means of coupled range-finder
but advanced types employ completely automatic examination of the
image. In an enlarger or rostrum camera, lens focus is mechanically set by
the distance from the base.
automatic four-wheel drive:
(A4WD) A driving system that automatically engages 4WD as needed,
usually by monitoring differences in individual wheel speeds and thus
sensing when a tire is slipping.

automatic frequency control:
(AFC) FM stations tend to drift a little, so radios have incorporated the
frequency control to maintain the desired frequency automatically.
automatic frost control:
Control which automatically cycles refrigerating system to remove frost
formation on evaporator.
automatic gain control:
(AGC) System in amplifiers which compensates for a wide range of input
signals to give a more uniform level of output and thus accommodate for a
wide range of conditions including fading, masking of antenna, and
ambient light.
automatic gearbox:
See automatic transmission
automatic generating plant:
A small generating station, e.g., a gasoline or diesel driven generator and
battery which is automatically started when the battery voltage falls below
a certain value and stopped when it is fully charged. The term is also
applied to the plant in small unattended hydroelectric generating stations.
automatic ice cube maker:
Refrigerating mechanism designed to automatically produce ice cubes in
quantity.
automatic ignition:
Rapid, out of control combustion of the air-fuel mixture in a spark ignition
engine, but not caused by an external ignition source such as a spark,
flame; instead, its caused by a hot spot such as a carbon deposit in the roof
of the combustion chamber. Also called auto-ignition.
automatic level control:
A component of the suspension which raises or lowers either (or both) the
front or rear of the vehicle when there is a change in the amount of load in

the vehicle.
automatic mixture control:
A device for adjusting the fuel delivery to a reciprocating engine in
proportion to air density.
automatic muting:
An automobile radio which cancels noise output when you turn the station
dial.
automatic observer:
An apparatus for recording, photographically or electronically, the
indications of a large number of measuring instruments on experimental
research aircraft.
automatic parachute:
A parachute for personnel which is extracted from its pack by a static line
attached to the aircraft.
automatic phase control:
In reproducing color TV images, the circuit which interprets the phase of
the chrominance signal as a signal to be sent to a matrix.
automatic pilot:
A device for guiding and controlling an aircraft on a given path. It may be
set by the pilot or externally by radio control. Also called autopilot.
Colloquially called George
automatic quiet gain control:
Joint use of automatic gain control and muting
automatic reel change:
On rotary machines, equipment to attach a new reel to an old web, without
stopping the machine and severing the butt end of the old web. Also called
autopaster or flying paster.

automatic ride control:
Electronically operated soft or firm ride as required.
automatic screw machine:
Fully automatic single-spindle or multiple-spindle bar stock turret lathe.
automatic seat belt:
See inertia reel seat belt
automatic shutter:
In a film projector, a shutter which cuts off the light when the mechanism
stops, to protect the film from heat.
automatic signalling:
A system of railway signalling, usually with electric control, in which the
signals behind a train are automatically put to "danger" as soon as the train
has passed, and held in that position until the train has attained the next
section of line.
automatic slip-control differential:
(ASD) An electronically controlled, automatic locking differential
developed by Mercedes-Benz.
automatic speed control:
See cruise control
automatic stabilizer:
A form of automatic pilot, operating about one or more axes, adjusted to
counteract dynamic instability. Also called autostabilizer.
Also see
damper
automatic starter:
A starter for an electric motor which automatically performs the various
starting operations (e.g., cutting out steps of starting resistance) in the
correct sequence, after being given an initial impulse by means of a push-

button or other similar device.
automatic steering effect:
Built in tendency of an automobile to resume travel in a straight line when
released from a turn.
automatic stoker:
See mechanical stoker
automatic substation:
A substation containing rotating machinery which, as occasion demands, is
started and stopped automatically, e.g., by a voltage relay which operates
when the voltage falls below or rises above a certain predetermined value.
automatic synchronizer:
A device which performs the process of synchronization in an ac circuit
automatically
automatic tap-changing equipment:
A voltage-regulating device which automatically changes the tapping on
the winding of a transformer to regulate the voltage in a desired manner.
automatic temperature control:
A system which regulates the heater and air conditioner so that the
temperature inside the vehicle meets the preset temperature.
automatic test equipment:
(ATE) An electronic equipment for testing ignition, wiring, fuel injection
systems, etc.
automatic tracking:
[1] Servo control of radar system operated by a received signal, to keep
antenna aligned on target.
[2] Maintenance of head-track alignment in a helical scan VTR over a
range of playback speeds. This may be achieved by control signals
recorded in the video tracks (instead of a control track) or by sensing
variations in radio-frequency amplitude caused by azimuth recording, with

either being used to adjust the servo mechanism or the position of heads
on piezoelectric mounts.
Also see
dynamic track following
automatic train stop:
A catch, used in conjunction with an automatic signalling system, which
engages a trip-cock on the train passes a signal at danger.
automatic transmission:
A mechanism of the drivetrain
which takes the power from
the engine and transfers it to
the driveshaft or wheels.
Without using a clutch, it uses
a torque converter and fluid
coupler to change the gear
ratio. It automatically effects
gear changes to meet varying
road and load conditions.
Gear changing is done
through a series of oil
operated clutches and bands.
automatic transmission fluid:
(ATF) A very thin viscosity liquid designed for use in automatic
transmissions to transfer the movement of the torque converter to the
driveshaft. However it is also recommended for use in the forks of
motorcycles. When poured into the throat of an automobile carburetor, it
helps to remove a build-up of carbon on the cylinder head and the domes
of pistons.
automatic trolley reverser:
An arrangement of the overhead contact line of a tramway, located at
terminal points, which ensures that the trolley collector is reversed when
the direction of motion of the car is reversed.
automatic tuning:

[1] System of tuning in which any of a number of predetermined
transmissions may be selected by means of push-buttons or similar
devices.
[2] Fine tuning of receiver circuits by electronic means, following rough
tuning by hand.
automatic voltage regulator:
A voltage regulator which automatically holds the voltage of a distribution
circuit or an alternator constant within certain limits, or causes it to vary in
a predetermined manner.
Also see
automatic tap-changing equipment
moving-coil regulator
automatic volume compression:
Reduction of signal voltage range from sounds which vary widely in
volume, e.g., orchestral music. This is necessary before they can be
recorded or broadcast but ideally requires corresponding expansion in the
reproducing system to compensate.
automatic volume control:
(AVC)[1]Alteration of the contrast (dynamics) of sound during
reproduction by any means. By compression (compounder) a higher level
of average signal is obtained for modulation of a carrier, the expansion
(expander) performing the reverse function at the receiver. In high-fidelity
reproduction, arbitrary expansion can be disturbing because of variation in
background noise, if present.
[2] An automobile radio which automatically limits the maximum volume
to a preset level.
automatic volume expansion:
Expansion of dynamic range, e.g., by keeping peak level constant and
automatically reducing the lower levels. Used to counteract loss of
dynamic range through studio or recording equipment, or during
transmission.
automatic wear adjuster:

A device that automatically compensates for the wear of brakes or clutch.
automatic welding:
Welding in which the work, the torch, and/or the arc is mechanically
moved and controls are used to control the speed and/or the direction of
travel.
automatic white balance:
(AWB) A self-adjusting balancing system which monitors the lighting and
corrects for changes in color temperature
automatic wire stripper:
A tool which removes the outer insulation
from a wire by automatically adjusting to the
size of the wire thus avoiding damaging the
wires.
automixte system:
A system of operation of gasoline-electric vehicles in which a battery,
connected in parallel with the generator, supplies current during starting
and heavy-load periods and is charged by the generator during light-load
periods. Also called Pieper system
automobile:
Four-wheeled passenger motor vehicle having a seating capacity for not
more than 10 people. It includes police cars and racing cars but not
ambulances, hearses, or trucks. In Britain, the word "automobile" is not in
frequent use and has been replaced by "motor car."
automobile association:
A motoring club which provides assistance to drivers including insurance,
maps, travel arrangements, etc.
Also see
AA
AAA
Royal Automobile Club

Automobile Club:
See
AA
AAA
automobile engineering:
See automotive engineering
automobile industry:
The manufacturing industry for building automobiles. Also called motor
industry.
automobile insurance:
A plan which a motorist can purchase for his vehicle which will offset the
repair costs of a vehicle which has been involved in an accident. Some
plans are offered by a government agency while others are run by
independent agencies. All plans offer the basic coverage of property
damage and public liability. Others offer extra benefits which cover glass
damage, theft, vandalism, etc.
Automobile Labelling Act:
See American Automobile Labelling Act
automobile manufacturer:
An company which designs, builds, and distributes cars and trucks. Also
called motor manufacturer.
automobile mechanic:
An individual who repairs and maintains cars and trucks. Also called
(especially in Britain) motor mechanic.
automobile polish:
A wax or synthetic which is designed to give a glossy, protective finish to
a painted surface. Also called car polish..

automotive:
Relating to or occurring in automobiles.
automotive adhesive:
A glue used in the manufacturing of automobiles.
automotive electrician:
An individual who works with designing the electrical system for
automobiles.
automotive electronics:
The use of electronic equipment in automobiles.
automotive emissions:
All the different types of fumes that are expelled into the atmosphere
(exhaust gas, fuel fumes, crankcase fumes) as well as the noise it makes.
automotive engineering:
The design and construction of automobiles.
Automotive Engineers:
See society of Automotive Engineers
automotive gas oil:
(AGO) US term for gas oil used mainly as diesel fuel; same as the UK
term DERV
Automotive Repair and Service Council:
See Canadian Automotive Repair and Service Council
automotive tool:
Any of the tools used in the construction, maintenance, or repair of
automobiles.

autonomics:
Study of self-regulating systems for process control, optimizing
performance.
autonomous vehicle:
Generally unmanned aircraft operating without external assistance
Auto Pact base year:
With respect to the Auto Pact, the 12 month period beginning on August 1,
1963, and ending on July 31, 1964.
Auto Pact Canadian value added:
The aggregate of the costs of parts, material, labour costs, and
transportation costs that are reasonably attributed to the production of
vehicles or parts by manufacturers producing vehicles in Canada.
Autopar:
Trade name of Chrysler Corp for its automobile parts (i.e.,
AUTOmobilePARts). Chrysler also uses the name Mopar to indicate its
motor parts (i.e., MOtorPARts).
auto parts store:
Jobber and retail auto parts stores which primarily sell automotive
products and conduct business at the retail level.
autopaster:
See automatic reel change
autopilot:
See automatic pilot
autoplate:
A machine which can deliver a curved stereoplate for rotary printing; built
to suit the requirements of each particular rotary machine.
autoradiograph:

Photographic record, usually of a biological specimen, produced by
exposure to radiation from self-contained radioactive material which has
been injected or absorbed.
auto-reclose circuit breaker:
A circuit breaker which, after tripping due to a fault, automatically
recloses after a time interval which may be adjusted to have any value
between a fraction of a second and 1 or 2 minutes
auto reverse:
A feature on a cassette player which will automatically play the next side
of a cassette tape when one side is finished.
autorotation:
[1] The spin; continuous rotation of a symmetrical body in a uniform air-
stream due entirely to aerodynamic moments.
[2] Unpowered rotorcraft flight, in a helicopter with engine stopped, in
which the symmetrical airfoil rotates at high incidence parallel with the
airflow.
autoset level:
A form of dumpy level for rapid operation, in which the essential features
are a quick-levelling head, and an optical device which neutralizes errors
of levelling so that the bubbles need not be central while an observation is
being made.
autostabilizer:
See automatic stabilizer
autostick:
A trademark name for a form of semi-automatic transmission. It combines
an automatic transmission with the gear-shifting feature of a manual
transmission without the use of a foot-operated clutch. In the normal
automatic transmission drive mode, the transmission behaves like any
other automatic. The manual-shifting feature allows more control over the
full range of rpms an engine offers. Porsche and Audi offer a related
transmission technology called "Tiptronic." The Lexus GS400 also has a
similar transmission but instead of using a stick to change gears it employs

buttons on the steering wheel. Several other automakers offer similar
technologies.
autosynchronous motor:
See synchronous induction motor
autothermic piston:
An aluminum piston in which steel or alloy inserts are cast to control
expansion of the piston skirt.
autothrottle:
A device for controlling the power of an aero-engine to keep the approach
path angle and speed constant during an automatic blind landing.
autotransductor:
Transductor in which the same winding is used for power transfer and
control
autotransformer:
Transformer in which both primary and secondary coils have turns in
common. Step-up or step-down of voltage is accomplished by taps on
common winding.
autotransformer starter:
A starter for squirrel-cage induction motors, in which the voltage, applied
to the motor at starting is reduced by means of an autotransformer.
auto wrecker:
A place where old and disabled cars and truck go. The parts are removed
and sold. Also called an auto graveyard.
AUX:
Abbreviation for "auxiliary" usually indicating those terminals on the fuse
panel for non-standard equipment.
auxiliary:

Additionally, supplementary.
auxiliary acceleration pump:
(AAP) a pump that increases driveability during cold engine operation by
providing an extra amount of fuel to the acceleration nozzle to supplement
the main acceleration pump.
auxiliary air bleeds:
Used on some idle systems to add air to the idle system downstream from
the regular idle air bleed; they act in parallel with idle air bleed.
auxiliary air intake:
[1] An air intake for accessories, cooling, cockpit air, etc.
[2] Additional intake for turbojet engines when running at full power on
the ground, usually spring loaded so that it will open only at a
predetermined suction value.
auxiliary air valve:
A device which allows air to bypass a closed throttle during engine start
and warm-up, in order to maintain a higher idle speed. The auxiliary air
valve provides extra air into the intake manifold during cold engine
starting for a higher idle speed during warm-up.
auxiliary brake light:
Additional brake lights mounted at eye level in the rear window or on the
rear fenders. They are designed to give a following vehicle more notice of
your presence and intention of stopping.
auxiliary contact:
See auxiliary switch
auxiliary drive shaft:
A secondary drive shaft which powers the fuel pump, water pump, or
distributor.
auxiliary driving lamp:

A light which supplements the headlights such as a fog light or spot light.
auxiliary driving light:
A light which supplements the headlamps such as a fog light or spot light.
auxiliary gearbox:
An extra gearbox used in conjunction with the main (manual) gearbox to
provide an additional range of speeds.
auxiliary gauge:
The gauge which indicates compressor inlet pressure on older Chrysler
Corporation vehicles with an Evaporator Pressure Regulator (EPR) valve;
also used to measure evaporator pressure on some Ford vehicles with a
Suction Throttling Valve (STV).
auxiliary leaf:
An extra leaf in a set of leaf springs. Also called helper leaf or helper
spring.
auxiliary lighting:
Extra lighting such as fog lights, spot light, and driving lights which are
intended to improve visibility under adverse conditions.
auxiliary plant:
A term used in generating-station practice to cover the condenser pumps,
mechanical stokers, feed-water pumps, and other equipment used with the
main boiler, turbine, and generator plant.
auxiliary pole:
See compole
auxiliary power unit:
(APU) An independent airborne engine to provide power for ancillary
equipment, electrical services, starting, etc. May be a small reciprocating
or turbine.

auxiliary rotor:
A small rotor mounted at the tail of a helicopter, usually in a perpendicular
plane, which counteracts the torque of the main rotor; used to give
directional and rotary control to the aircraft.
auxiliary shaft:
In an overhead cam engine, a separate shaft that drives devices such as the
fuel pump, the oil pump, and the distributor.
auxiliary switch:
A small switch operated mechanically from a main switch or circuit
breaker; used for operating such auxiliary devices as alarm bells,
indicators, etc. Also called auxiliary contact
auxiliary tanks:
See fuel tank
auxiliary transmission:
Additional gear box increasing the gear ratio combinations when used with
main transmission or multi-speed axles.
auxiliary venturi:
See booster venturi
auxiliary winding:
A special winding on a machine or transformer, additional to the main
winding.
auxometer:
An apparatus for measuring the magnifying power of an optical system
available power efficiency:
The ratio of electrical power available at the terminals of an
electroacoustic transducer to the acoustical power output of the transducer.
The latter should conform with the reciprocity principle so that the
efficiency in sound reception is equal to that in transmission.

available power gain:
The ratio of the available power output of an amplifier to the input power;
equal to power gain only when the output of the device or circuit is
correctly matched to the load.
available power response:
For an electroacoustic transducer, the ratio of mean square sound pressure
at a distance of 1 meter, in a defined direction from the "acoustic center" of
the transducer, to the available electrical power input. The response will be
expressed in dB above the reference response of 1 μbar²W-1
of available
electrical power.
avalanche:
Self-augmentation of ionization.
Also see
Townsend avalanche
Zener effect
avalanche diode:
A semiconductor breakdown diode, usually silicon, in which avalanche
breakdown occurs across the entire p-n junction, giving a voltage drop
which is constant and independent of current. Avalanche diodes break
down much more sharply than Zener diodes. Used in high-speed switching
circuits and microwave oscillators.
avalanche effect:
Cumulative multiplication of carriers in a semiconductor because of
avalanche breakdown. This occurs when the electric field across the
barrier region is strong enough to allow production and cumulative
multiplication of carriers by ionization.
avalanche photodiode:
A photosensitive avalanche diode used as the detector in optical fiber
systems. Its avalanche multiplication factor improves the receiver signal-
to-noise ratio by enhancing signal power without increasing thermal noise.

avalanche transistor:
A transistor depending on avalanche breakdown to produce hole-electron
pairs. It can give very high gain in the common-emitter mode or very rapid
switching.
Avalon:
Toyota
.
Click for books on Toyota
Avalon
avant:
See traction avant
AVC:
Acronym for " automatic volume control".
average:
[1] A calculation in which the mean value or rate is determined. The
average speed is determined by dividing the distance by the time (e.g., 273
kilometers divided by 3 hours = 91 kph). Average fuel consumption is
determined as a ratio of fuel and distance. In the metric system, this is
determined by multiplying the number of liters by 100 and dividing the
result by the number of kilometers (e.g., 31.38 liters times 100 divided by
273 kilometers = 11.49 liters / 100 km). In the Imperial system divide the
number of miles by the amount of fuel in gallons (e.g., 173 miles divided
by 6.9 gallons = 25 mpg).
[2] Loss or damage of marine property, less than total: compensation
payment in proportion to amount insured.
average current:
The current obtained by adding together the products of currents flowing
in a circuit and the times for which they flow and dividing by the total
time considered. For direct current the average value is constant; for true
alternating current, the average value is zero.

Average Fuel Economy:
See Corporate Average Fuel Economy
average haul distance:
The distance between the center of gravity of a cutting and that of the
embankment formed from material excavated from the cutting.
average power output:
In an amplitude-modulated transmission, the radio-frequency power
delivered by a transmitter, averaged over one cycle or other specified
interval of the modulating signal.
average weekly earnings:
Gross taxable payrolls divided by the number of employees.
avgas:
Abbreviation for aviation gasoline.
Also see
aviation spirit
aviation bi-phase shift keying:
A digital modulation scheme in which a "1" is represented by a +90° phase
transition and a "0" by a -90° transition of the carrier
aviation fuel:
A high octane fuel used primarily in aircraft but also used in racing
vehicles to improve performance. Generally liquid hydrocarbons, because
of high heat of combustion per unit of fuel mass (specific energy) and
volume (energy density), ease of combustion, moderate volatility and
viscosity, and good thermal stability and capacity. Liquid hydrogen and
pentaborane (B5H9) have also been used experimentally.
Also see
aviation gasoline
aviation kerosine
aviation gasoline:

(AVGAS) Blends of liquid hydrocarbons, almost all petroleum products
boiling between 32° and 220°C, with anti-knock rating from 80 octane
number to 145 performance number. Only small quantities are now used.
Also see
aviation fuel
aviation kerosine
aviation kerosine:
For gas turbine engines, fuel which typically boils over the range 144°-
252°C. Variants include Jet A-1 (AVTUR), the international jet fuel; Jet B
(AVTAG), a blend of naphtha with kerosine now being phased out except
for use in cold climates; AVCAT, a naval jet fuel with high flash-point for
safety in enclosed spaces in ships; AVPIN, an aviation isopropyl nitrate;
and AVGARD, trade name for an additive with anti-misting properties.
Also see
aviation gasoline
aviation spirit:
(avgas) A motor fuel with a low initial boiling point and complying with a
certain specification, for use in aircraft. Ranges from 73 to 120/130 octane
rating.
Also see
aviation kerosine
wide-cut fuel
aviatrix:
Female aviator
avionics:
The collective word for a spacecraft or aircraft's subsystem elements
which involve electronic principles. A contraction of "aviation
electronics."
a-vis:
See vis-a-vis
avoidance system:
See collision avoidance system
avpin:

Abbreviation for aviation isopropyl nitrate
avpol:
Abbreviation for aviation petrol, oil, and lubricant
avtag:
Abbreviation for aviation wide-cut turbine fuel.
Also see
wide-cut fuel
avtur:
Abbreviation for aviation turbine fuel.
Also see
aviation kerosine
AWACS:
Abbreviation for airborne warning and control system
aware:
See environmentally aware
AWB:
Acronym for automatic white balance
AWD:
Acronym for " all-wheel drive."
awl:
A pointed or flat tool used to probe nail holes and injuries as well as for
installing a repair plug.
awning:
A canvas roof which is stretched out from a parked trailer or camper to
give protection from the sun and rain.
awning deck:

A superstructure deck, as the name implies. In its simplest form, it is the
top deck of a two-deck ship, and places the ship in a certain category for
scantling and freeboard.
Axe:
Trade name for a range of digital switches manufactured by the Swedish
company I. M. Ericsson Telefonaktiebolaget.
axes:
Plural of axis
axial compressor:
[1] A compressor characterized by the unusual piston arrangement. The
pistons are arranged horizontally around and parallel to the crankshaft axis
or centerline.
[2] A multistage, high-efficiency compressor comprising alternate rows of
moving and fixed blades attached to a rotor and its casing respectively.
axial engine:
Turbine engine with an axial-flow compressor.
axial-flow compressor:
A compressor in which alternate rows of radially-mounted rotating and
fixed airfoil blades pass the air through an annular passage of decreasing
area in an axial direction.
axial-flow turbine:
Characteristic aero-engine turbine, usually of 1-3 rotating stages, in which
the gas flow is substantially axial
axial pitch:
The distance from any point on one thread or helix to the corresponding
point on the next thread or helix measured along the axis of the screw or
helix.
axial ratio:

Ratio of major to minor axis of polarization ellipse for e.g., a wave
propagated in waveguide, polarized light. Also called ellipticity
axial response:
The response of a microphone or loudspeaker, measured with the sound-
measuring device on the axis of the appearance being tested.
axial runout:
Variation from the plane normal to its axis of a rotating part. Its wobble,
rather than its eccentricity. Compare radial runout
axiotron:
Valve in which the electron stream to the anode is controlled by the
magnetic field of the heating current
axis:
[1] The centerline, whether real or imaginary, around which a thing
rotates.
[2] One of the three axes of an aircraft, which are the straight lines through
the center of gravity about which change of attitude occurs: longitudinal or
drag axis in the plane of symmetry (roll); normal or lift axis vertically in
the plane of symmetry (yaw); and the lateral or pitch axis transversely
(pitch).
Also see
wind axes
[3] Of a lens, the line of symmetry of the optical system; the line along
which there is no refraction.
Also see
cam-ground piston
eccentric bolt
hotchkiss drive
kingpin axis
kingpin inclination
moment of inertia
pivot axis
roll axis
self-aligning torque
static balance
steering-swivel axis
steering axis inclination
steering axis
steering geometry
steering knuckle angle.
swivel axis
torque
trailing arm
axis inclination:
See steering axis inclination
swivel axis inclination
axis of a weld:

An imaginary line along the center of gravity of the weld metal and
perpendicular to a cross section of the weld metal.
axle:
An axle is a shaft on which
the wheels revolve. A full-
floating axle is used to drive
the rear wheels. It does not
hold them on nor support
them. A semi-floating or one-
quarter floating axle is used to
drive the wheels, hold them
on, and support them. A three-
quarter floating axle is used to
drive the rear wheels as well
as hold them on, but it does
not support them. A live axle
holds the wheels and
transmits power to the wheels.
A dead axle or beam axle
merely holds the wheels, but
does not transmit power to the
wheels.
Also see
ackermann axle
back axle
banjo axle
beam axle
cambered axle
dead axle
de Dion axle
driven axle
driving axle
drop-center
axle
dropped axle
dual axles
Elliot axle
Elliot type axle
front axle
full-floating axle
gross axle weight rating
hypoid axle
I-beam axle
Jeantaud axle and
steering
live axle
low pivot swing axle
rear axle crossmember
rear axle differential
rear axle housing
rear axle ratio
reverse-Elliot type
axle
reversed Elliot axle
rigid axle
rigid axle connection
semi-floating axle
slewed axles
spread axle
steering axle
stub axle
swing axle .
tandem axle
three-quarter floating
axle
torque tube axle
trailing axle
twin axle
twist-beam rear axle
two-speed axle
weissach axle
z-axle.
axle and steering:
See jeantaud axle and steering
axle articulation:

The degree to which an axle can move up and down. Off-road vehicles
need a great deal of axle articulation to allow for extremely uneven terrain,
such as rocks or gullies.
axle-box:
Box-shaped housing containing the axle bearings and lubricant.
Constrained laterally on guides and supports the weight of vehicle through
springs.
axle casing:
A British term indicating a tubular housing which encloses the differential
and half-shafts along with their bearings. The US term is " axle housing".
axle connection:
See rigid axle connection
axle crossmember:
See rear axle crossmember
axle differential:
See rear axle differential
axle drive:
The ring gear and pinion inside a differential housing.
Also see
final drive
axle end gear:
See axle end gears
axle end gears:
The two gears, one per axle, that are splined to the inner ends of the drive
axles. They mesh with and are driven by the spider gears.
axle flange:
Flange to which a road wheel attaches at the end of an axleshaft.

axle housing:
An American term indicating a tubular housing which encloses the
differential and half-shafts along with their bearings. The British term is "
axle casing."
Also see
rear axle housing, banjo type
rear axle housing
rear axle housing, split type
axle housing banjo:
See rear axle housing, banjo type
axle housing banjo type:
See rear axle housing, banjo type
axle housing split:
See rear axle housing, split type
axle housing split type:
See rear axle housing, split type
axle load:
See axle weight
axle parallelism:
Axles are determined to be parallel, thus minimizing tire wear, if a
measurement between two or more axles is equal at both ends of the axle.
axle ratio:
See back axle ratio
rear axle ratio
axles:
See dual axles
axle shaft:
[1] The short shaft which connects the differential and the drive shaft on
each side of an independent suspension configuration.

[2] The drive shaft or halfshaft of a rigid axle.
axle stand:
An adjustable height tripod used to support a vehicle when working
underneath it. Although you can raise the car with the jack, use an axle
stand for safety.
axle track:
Distance between centerlines of tire tread measured across axle.
axle tramp:
A form of wheel hop which is usually found in live rear axle cars. It occurs
when sudden torque loads on the suspension cause the driven wheels to
shake violently by slightly rotating the wheels and then springing back.
axle tube:
The part of the axle housing which covers the half-shaft or a tubular rigid
axle.
axle weight:
The part of the weight of the vehicle which rests on the wheels of the axle.
Also see
gross axle weight rating
axle weight rating:
See gross axle weight rating
axle wind up:
The phenomenon in which the torque
transmitted to the wheels by the axle
which causes the live axle to turn in
its own centerline.

axonometry:
Measurement of the axes of crystals
Ayrton:
See Senna, Ayrton
azeotrope:
Having constant maximum and minimum boiling points.
azeotropic mixture:
Example of azeotropic mixture: refrigerant R-502 is mixture consisting of
48.8 % refrigerant R-22 and 51.2% R-115. The refrigerants do not
combine chemically, yet azeotropic mixture provides refrigeration
characteristics desired
azimuth:
[1] The angle between the vertical plane containing a line or celestial body
and the plane of the meridian, conventionally measured from north
through east in astronomical computations, and from south through west in
triangulation and precise traverse work.
Also see
azimuth angle
[2] The angle, normally 90°, between the direction of motion of the film or
tape and the slit or gap in the optical or magnetic head.
Also see
bearing
azimuthal power instability:
Abnormal neutron behavior which results in uneven nuclear conditions in
the reactor
azimuth angle:
Horizontal angle of observed line with reference to true north.
azimuth marker:
Line on radar display made to pass through target so that the bearing may
be determined.

azimuth recording:
Employing heads with opposed azimuth angles to minimize crosstalk
between adjacent tracks, each head attenuating the other recorded signal.
Removes the need for guard bands. Also called slant-azimuth recording
azimuth stabilized PPI:
Form of plan position indicator display which is stabilized by a
gyrocompass, so that the top of the screen always corresponds to north.
azodicarbonamide:
(ADC) Blowing agent used in structural foam molding to create foam
core. Decomposes at about 190° C to give CO, CO2, and N2 gases.
azusa:
US radio-tracking system for missile guidance.
BA:
An abbreviation for "British Association" which is a term used to describe
a series of fine, small diameter threads for electrical and precision
equipment
babbitt:
An alloy of tin, copper, and antimony having good antifriction properties.
Used as a facing for bearings.
babbitt metal:
See babbitt

baby seat:
A specially designed seating device (which is not
generally standard equipment) to hold safely very
young children (usually under the weight of 10
kilograms).
BAC:
Acronym for "Blood Alcohol Content"
back:
See
blow back
die-back
die back
kamm back
popping back
spine-back
back axle:
The rear axle
back axle ratio:
See final drive ratio
backbone:
See backbone frame.
backbone chassis:
See backbone frame

backbone frame:
A frame, having the cross-section of a
rectangular box, that runs along the center of
the vehicle and occupies the space between
the seats. This box generally divides at the
front, running along each side of the gearbox
and engine up to a crossmember to which the
front suspension pieces are attached. At the
rear a similar triangular frame encloses the
final-drive housing and provides attaching
points for the rear suspension. Lightness
combined with high torsional rigidity are
features of this frame design, made famous
by Colin Chapman with the Lotus Elan.
Also see
tubular backbone frame
backfire:
[1] Passage of unburned fuel mixture into the exhaust system where it is
ignited and causes an explosion (backfire) prematurely.
[2] Sometimes ignition takes place in the intake manifold by a flame from
a cylinder because the intake valve leaks. Burning of the fuel mixture in
the intake manifold may be caused by faulty timing, crossed plug wires,
leaky intake valve, etc.
[3] A welding term referring to a short "pop" of the torch flame followed
by extinguishing of the flame or continued burning of the gasses
backfiring:
Repeated backfires in the exhaust or the cylinders
backflow scavenging:
See loop scavenging
backflushing:
See flushing the cooling system.
backhand welding:
Welding in the direction opposite to the direction that the gas flame is
pointing. Also called "backward welding."

backing:
Some material placed on the root side of a weld to aid control of
penetration.
Also see
steel backing
backing pad:
A rubber disc which is secured to a spindle which in turn is attached to a
drill or other tool which rotates the spindle. An abrasive disc or polishing
disc is secured to the backing pad.
backing plate:
The part of a drum brake to which the wheel cylinder(s) and the brake
shoes are attached. See brake backing plate.
backlash:
The amount of "play" or clearance between two parts. In the case of gears,
it refers to how much one gear can be moved back and forth without
moving the gear into which it is meshed.
backlight:
The rear window of a vehicle. Most people call it a "rear window" and
think of "backlight" as the taillight
backlight heater:
Heated rear window
backlight defogging system:
Heated rear window
back panel:
The panel of the body shell set underneath the trunk lid. It is sometimes
referred to as the rear valance if the area below the trunk lid consists of
only a single panel that extends down to the bottom of the body; in many
designs, however, the rear valance is a separate horizontal panel that

extends from the rear bumper area downward. The British term is "rear
panel"
backplate:
British term for brake backing plate
back pressure:
[1] The resistance to the flow of exhaust gases through the exhaust system.
By rerouting the exhaust gases for noise suppression, a muffler causes
back pressure, but a straight pipe alone causes only minimal back pressure.
Some engines require back pressure, so that removing the exhaust system
will cause internal damage.
[2] Pressure in low side of refrigerating systems; also called suction
pressure or low-side pressure
Also see
exhaust back pressure
negative back pressure valve
negative back pressure modulated valve
back pressure modulated:
See negative back pressure modulated valve
back pressure modulated valve:
See negative back pressure modulated valve
back pressure valve:
See negative back pressure valve
backpressure variable transducer:
(BVT) a system combining a ported EGR valve and a backpressure
variable transducer to control emissions of NOx
backrest:
The back (upright) part of the seat against which your back reclines
back-seat:

An air conditioning term which means to rotate a service valve
counterclockwise all the way down until the valve is back-seated. When
referring to a stem type service valve, the term has a more specific
meaning-in the back-seated position, the valve outlet to the system is open
and the service port in the valve is closed (its normal operating position)
back seating:
fluid opening/closing such as a gauge opening; to seat the joint where the
valve stem goes through the valve body
back-step welding:
Welding small sections of a joint in a direction opposite the direction that
the weld as a whole is progressing.
back up:
To go in reverse
back up alarm:
An annoying loud beeping which is repeatedly sounded when a vehicle
(usually a large truck) is placed in reverse. It is designed to warn
pedestrians behind the vehicle. The British term is "reversing warning
signal"
back up light:
A white light which is located at the rear of the vehicle and is illuminated
when the transmission is placed in reverse. The British term is "reversing
light"
back-voltage:
Voltage which opposes the current when the current in an inductive circuit
changes and the magnetic field cuts the conductors.
Also see
self-induction back-voltage
backward welding:

See backhand welding
BAC level:
Blood Alcohol level
badge:
An emblem with a manufacturer's name and/or logo on a plate to identify a
model or component.
Also see
hood badge
badge engineering:
When a manufacturer sells two identical vehicles but the model names are
different, he is badge engineering. For example, General Motors may sell a
vehicle as a Chevrolet or a Pontiac where the only difference is the model
name, logo, and more or less chrome or other minor alterations.
badging:
The tendency of a manufacturer to engage in badge engineering
baffle:
An obstruction (e.g., plate or vane) used to
slow down or divert the flow of gases,
liquids, sound, etc. They are found in the
fuel tank, crankcase, muffler, and radiator.
baffle plate:
A metal plate that acts as a baffle.
bag:
See
air bag
courier bag
cruiser bag
driver air bag
shot bag

side impact air bag
tank bag
bagger:
a motorcycle equipped with saddlebags and other touring amenities
bake:
A process of drying or curing paint by using heat
Bakelite:
The trademark for a synthetic thermosetting plastic resin used in electrical
parts because it is a good insulator. The name comes from its inventor, L.
H. Baekeland, 1863-1944.
baking finish:
Paint that requires baking in order to dry
baking temperature:
The temperature at which a varnish or paint must be baked to develop
desired final properties of strength and hardness
balance:
[1] The state in which weight is evenly distributed.
[2] The action of applying weights or drilling holes in something to
establish even weight distribution so that vibration is reduced.
Also see
balance shaft
counter balance
crankshaft counter-balance
dynamic balance
harmonic balancer
heat balance
kinetic balance
off-car balance
on-car balance
spool balance valve
static balance
steering wheel balance
tire balance
wheel balancer
balance control:
A switching device on a stereo radio which adjusts the amount of sound
coming from the left and right speakers or from the front and rear speakers

balanced crankshaft:
A crankshaft with extended reinforcements to form counterbalancing or
act as a vibration damper
balance disc:
A disc-shaped device in a centrifugal pump which is attached to the pump
shaft. The disc lifts when a force is applied to the underside of the disc
allowing pressure to leak past until the axial forces are balanced
balanced engine:
An engine in which all the reciprocating parts such as pistons and
connecting rods are adjusted to exactly the same weight
balance patch:
A factory installed patch used to bring a new tire within quality control
balance tolerances before distribution and sale. It is placed inside the tire
casing and looks much like a nail hole repair patch.
balance pipe:
A tube which joins two or more carburetors to even out the flow
difference.
balancer:
See
harmonic balancer
wheel balancer
balance shaft:
An engine will normally vibrate because of the up-and-down motion of the
pistons which turn a crankshaft in one direction. A balance shaft rotates
(often in the opposite direction) so that its vibration cancels some of the
vibration of the engine. Sometimes an engine will have two balance shafts
turning in opposite directions located on either side of the crankshaft.
balance valve:

See spool balance valve
balance weight:
A lead weight attached to the rim of a wheel. See wheel weight.
balancing:
[1] Dismantling engine and reassembling it to exact specifications and
tolerances. This process may help to improve engine performance,
smoothness, and reliability. Sometimes called "blueprinting." See balanced
engine.
[2] Keeping wheels in balance.
Also see
wheel balancing
off-the-car balancing
on-the-car balancing
balancing machine:
See wheel balancing machine
balancing weight:
See wheel weight
bald tire:
A tire on which the tread is all worn away. A slick also has no tread, but
this is done deliberately for racing purposes
balk ring:
A friction-regulated pawl or plunger used to
make the engagement of gears easier. British
spelling is "baulk ring"
ball:

A sphere usually made of metal when used in automotive applications.
Also see
ball and spring
ball bearing
ball joint
ball joint rocker arm
check ball
detent ball and spring
hitch ball
impact swivel ball universal joint
recirculating ball and nut steering
recirculating ball steering
recirculating ball worm and nut
recirculating ball
towing ball
ball and nut:
See recirculating ball and nut steering
ball-and-nut steering:
See recirculating ball steering
ball and socket:
See ball joint
ball and socket joint:
See ball joint
ball and spring:
See detent ball and spring.
ballast:
Any liquid or solid weight placed in a ship to change the trim, increase the
draft, or to regulate the stability.
Also see
dry ballast
lead ballast
liquid ballast
ballast ignition system:
An ignition system which uses a ballast resistor connected in series with
the coil primary winding and which is bypassed when the starter is
engaged so that the spark is more efficient under cold weather starting

ballast tank:
Tanks at the bottom or sides of a ship which are filled with seawater for
ballasting purpose.
ballasting:
The addition of liquid or dry weight inside the tire to act as a
counterbalance, to increase traction, reduce wheel spin, and dampen out
bounce.
ballast resistor:
(BAL RES) A resistor constructed of a special type wire, the properties of
which tend to increase or decrease the voltage in direct proportion to the
heat of the wire.
ball bearing:
An antifriction bearing consisting of an inner and outer hardened steel race
(or cage) separated by a series of hardened steel balls.
ball bearing puller:
A tool for removing a ball bearing from a shaft or from a housing
ball cage:
A circular frame which holds the balls in place in a ball bearing
ball check valve:
valve assembly which permits flow of fluid in one direction only
ball end hexagon screwdriver:
A tool that looks like an Allen wrench except it has a small ball at the very
end. This arrangement allows it to work at various angles.

ball joint:
A flexible
joint using a
ball and
socket type of
construction,
used in
steering
linkage
setups,
steering
knuckle pivot
supports, etc.
Their
flexibility
helps to
compensate
for the
changes in
the wheel and
steering when
turning or
hitting a
bump on the
road. There
are usually
upper and
lower ball
joints
attached to
the upper and
lower A-
arms.
ball joint rocker arm:
A rocker arm that instead of being mounted on a shaft, is mounted upon a
ball-shaped device on the end of a stud.
ball joint separator:
A tool for forcing out ball or tapered joints. One style is shaped like a two-
prong fork with a wedge-shaped jaw which is struck with a hammer to
separate the joint. Another style uses direct pressure from a screw or

screw-activated lever action to split the joint.
ball joint steering knuckle:
A steering knuckle that pivots on ball joints instead of on a kingpin.
balloon tire:
A type of low pressure tire which was first introduced in the 1920s. Its
width and height were the same which gave it a rounded shape. This style
was used on bicycles as well as automobiles.
Ballot:
A vehicle brand of which the 1925-1948 model automobiles with required
application are classic cars.
ball pien hammer:
A hammer with two ends on the head. One is round and the
other is flat. They are best used for hammering and shaping
metal. Also spelled "ball peen"
ball peen hammer:
A hammer with two ends on the head. One is round and the other is flat.
They are best used for hammering and shaping metal. Also spelled "ball
pien"
ball socket:
A recessed spherical well for receiving the ball in a ball joint
ball steering:

See recirculating ball steering
ball universal:
See impact swivel ball universal joint
ball universal joint:
See impact swivel ball universal joint
ball valve:
A check valve in which a ball in a tube is used to control the flow of
liquid.
ball worm:
See recirculating ball worm and nut
ball worm and nut:
See recirculating ball worm and nut
BAL RES:
Abbreviation for ballast resistor
Bambi:
Trucker slang for a deer (dead or alive) as in "There's a Bambi on the side
at the 43 yardstick."
band:
Bands are like a metal belt which is in the shape of a circle where the two
ends are close, but do not meet. They wrap around parts inside the
transmission called "drums." The drums house the gears and clutches and
freewheel until a certain gear needs to be applied. When first gear needs to
be applied, the drum for first gear is locked up by the application of the
band. By locking up the drum, the gears now drive the wheels rather than
freewheel inside the drum.
Also see
brake band
power band

squish band
band brake:
See brake band
band radio:
See citizens band radio
bands:
See band.
bandwidth:
The range of audio frequencies that an audio component (radio) can
handle
B & S:
bore and stroke.
B & S gage:
Abbreviation for "Brown and Sharpe." A standard measure of wire
diameter.
B & S gauge:
Abbreviation for "Brown and Sharpe." A standard measure of wire
diameter.
banger:
[1] A colloquial term used to express the cylinders in an engine. Often
used with a number such as "six banger."
Also see
four banger
[2] A British colloquial term for beater (an older, cheaper, well-worn car
which is still usable).
[3] One who fakes an accident. See car banger

banger racing:
A competition of speed on small racing tracks where older cars are driven
as fast as they can go and where bumping other racing cars is permitted
(encouraged??)
banging:
See car banging
banjo:
[1] Besides being a musical instrument, this is a fitting which is shaped
like a banjo. It has round end that is doughnut shaped with a tube coming
out from one side. It is usually used to transfer fluid from the center hole
of the round end and out the lateral tube.
[2] A drum-shaped central part of an axle casing containing the
differential.
Also see
rear axle housing, banjo type
axle housing banjo
banjo fitting:
a type of hydraulic fitting, shaped like a banjo, through which a hollow
bolt passes, allowing fluid transfer from a hydraulic line to a hydraulic
component
bank:
See cylinder bank
banking:
The slope of a track from the wall to the apron, generally measured in the
corners.
bar:
[1] A unit of pressure. One bar equals 100 kilopascals or 14.5 psi.
[2] A rod.
Also see
anti-roll bar
anti-sway bar
antiroll bar
header bar
hi-way bar
highway bar
port bar
push bar
roo bar
test bar
tommy bar
torsion bar

boring bar
bull bar
bumper bar
busbar
compensating bar
compensator
extension bar
freeway bar
gunwale bar
hood bar
ladder bars
landau bar
landau bars
levering bar
locking bar clamp
main bar
nerf bar
nudge bar
side impact bar
sissy bar
spring bar
stabilizer bar
stringer bar
strut bar
sway bar
t-bar
targa bar
track bar
traction bar
tread bar
wear bars
wheelie bar
wheelie bars
wobble extension bar
Barach:
The author and compiler of this dictionary at Motorera.com
barbershop:
Trucker slang for a low overpass as in "I saw a driver take his trailer to the
barbershop last week."
bar clamp:
A tool with a stationary head and a sliding foot for clamping
purposes. Also see locking bar clamp
bar ends:
Short handlebar extensions which are attached
to the ends of a mountain bike handlebar.
bar end shifter:
A bicycle gear shifter that is inserted
into the each of the ends of a
handlebar.
bare shell:

The shell of a car body in which all parts have been removed including
doors, hood, and trunk lid
barge:
A flat-bottomed boat for carrying cargo or bunker oil, usually pulled by
tugs.
Also see
tank-barge
barge carriers:
Ships designed to carry barges.
BARO:
[1] Acronym for barometric pressure sensor.
[2] Acronym for barometric absolute pressure sensor
barometric absolute pressure sensor:
(BARO or BP) sends a variable voltage signal to the computer which
varies in accord with atmospheric pressure, allowing adjustment of the
spark advance, EGR flow, and air/fuel ratio as a function of altitude. Also
called a barometric pressure sensor
barometric and manifold absolute pressure sensor:
(BMAP) a housing containing both BP and MAP sensors
barometric pressure sensor:
(BARO or BP) A sensor found in the engine management system which
detects the ambient barometric pressure so that precise fuel mixture can be
maintained at different altitudes
barrel:
[1] The air horn in the carburetor. In particular, it is that part where the
throttle valve is located. If a carburetor has four openings with a throttle
valve in each, it is called a "four-barrel carburetor."
Also see
carburetor barrel
four barrel carburetor

four barrel
[2] Another name for the carburetor barrelcylinder, cylinder barrel, four
barrel, polishing barrel, and single barrel.
[3] To travel fast as in "We barrelled down the highway well above the
speed limit."
barrel carburetor:
See
single barrel carburetor
twin barrel carburetor
barrel tappet:
A hollow rocker arm shaped like a barrel
barrier:
See crash barrier
barrier cream:
A special cream which is applied to your hands before working on a
greasy engine. When the job is over, you can wash your hands and easily
remove the grease stains. Also called "invisible glove" or "silicon glove"
barrier effect:
The effect produced by coating metal to shield it from corrosion
barrier paint:
A primer which is used on bare metal to prevent corrosion.
bar roof:
See T bar roof
bars:
See
ladder bars
landau bars

wear bars
wheelie bars
bar suspension:
See torsion bar suspension
base:
[1] The lowest supporting part of an upright member.
[2] The bottom layer or coating in a series of paint coats.
[3] The major ingredient, other than pigments and filler, that make up the
non-volatile portion of an adhesive, coating, or sealing compound
Also see
bead base
edison base
flat base rim taper
flat base rim
lithium base grease
load base
negative load base
rim well base
base and clear system:
Paint finish which is made up of a colored base coat (usually a metallic
finish) and clear lacquer coat
base circle:
As applied to the camshaft the lowest spot on the cam, the area of the cam
directly opposite the lobe or nose. No lift is produced by the base circle.
Also called cam heel
base coat:
The first coat in a paint system. It is either the undercoat or primer or a
colored coat which is covered by clear lacquer
base gasket:
The gasket directly below the cylinder and between the cylinder and
crankcase. Also called "cylinder gasket."
base grease:

See lithium base grease
base idle:
The idle speed determined by the throttle lever setting on the carburetor or
throttle body while the idle speed control (ISC) motor, or any other
computer-controlled idle speed control device, is fully retracted and
disconnected.
base interest rate:
The interest paid on the usage of the vehicle during a lease. It is the "cost"
of a lease before factoring in discounts, fees, and penalties and is not
directly comparable to the APR for a loan. Lowering the base interest rate
is one of the methods manufacturers use to subsidize leases. The phrase
"money factor" measures the same cost and can be converted into a base
interest rate. For example, to convert a money factor of 0.00276 into an
approximate base interest rate would multiply the money factor by 24. The
result would be 0.0662 or 6.6%.
baseline:
A fore-and-aft reference line at the upper surface of the flat plate keel at
the centerline for flush shell plated vessels. Vertical dimensions are
measured from a horizontal plane through the baseline, often called the
molded baseline.
base material:
Any material (metal or plastic) which needs to be coated
base metal:
[1] Metal that is under a coating or that needs to be coated.
[2] Metal to be welded, cut, or brazed.
base model:
The least expensive vehicle with the least amount of features as standard
equipment. It has the smallest engine and often manual transmission as
well as few power equipment. Base models constitute only a small
percentage of the cars sold. Sometimes called a "stripper" or "stripped
down" unit.

baseplate:
A strong metal plate which is the main support for something. See
distributor baseplate
base rim:
See
flat base rim
flat base rim taper
base rim taper:
See flat base rim taper
basic ignition setting:
The ignition setting on a non-running engine according to the
specifications. After the engine is running, the timing can be set more
accurately
basic ignition timing:
The ignition timing on a non-running engine according to the
accurately
basic price:
The price of a vehicle without including any optional accessories, taxes,
delivery charges, etc.
basic timing:
The ignition timing on a non-running engine according to the
accurately
basin:
See building basin
basket case:

An old car which probably does not run. Often many engine and
transmission parts have been removed and are either missing or stored in
the trunk or a "basket"
bastard:
A file (a tool) which
has a coarse cut
bastard file:
A file with a coarse cut
bat:
A lump or collection of something.
Also see
fibreglass
batch:
[1] A number of things which are produced as a group.
[2] A mixture of natural and synthetic rubber with other material such as
fillers, chemicals, and vulcanizing agents in the production of tires
batch number:
A number which may be added to a serial number to identify when the
product was manufactured. In this way, when a problem occurs to some
products of the same batch, action can be taken to correct or replace others
from the same batch.
bath:
[1] A tub into which something is immersed.
[2] A liquid solution used for cleaning, plating, or maintaining a specified
temperature.
Also see
anodizing bath
galvanizing bath
primer bath
sealing bath

zinc bath
bath air:
See oil bath air cleaner
bath air cleaner:
See oil bath air cleaner
bathtub:
Bodywork resembling an upside-down bathtub used on the rear of some
Triumph motorcycles. It was introduced in 1957 and dropped in the early
1960s. It was also used on Nash cars of the 50's
battens:
See
cargo battens
hatch battens
battery:
An electrochemical device for producing
electricity by converting chemical energy.
The typical automotive lead-acid battery
supplies the source of power for cranking
the engine and also provides the
necessary electrical energy for the
ignition system. In addition, it can (for a
limited time) furnish current when the
electrical demands of the vehicle exceed
the alternator or generator output. Also
called the "storage battery."
Also see
accumulator battery
alkaline battery
booster battery
charged battery
check the battery
dead battery
discharged battery
disconnect the battery
dry battery
dry charged battery
flat battery
gel cell battery
high energy battery
isolate the battery
lead-acid battery
low-maintenance battery
low battery
maintenance-free battery
primary battery
rechargeable battery
secondary battery
sodium-sulphur battery
storage battery
top up the battery

battery acid:
Electrolyte (usually sulphuric acid) in each of the battery cells
battery brush:
A specially designed brush set which
cleans the outside terminals of the
battery post as well as the inside of
the battery cable so that good contact
is made.
battery cap:
Small caps which seal each battery cell
battery capacity:
The amp-hour capacity
battery cell:
Individual compartments in a battery which is filled with electrolyte. Six-
volt batteries have three cells, 12-volt batteries have six cells
battery case:
The box made of polypropylene holding several chambers (cells) which
have lead plates and filled with electrolyte.
battery charge:
The condition or state of the amount of electricity in a battery
battery charge indicator:

An instrument which shows the state of charge in a battery
battery charger:
An electric device which is plugged into an electrical outlet (e.g.,
110 volt AC) and connected to the two terminals of the battery to
restore the state of charge in the battery. One of leads coming
from the charger is red and the other is black. The red lead is
clamped on the positive post of the battery while the other is
clamped on the frame of the vehicle.
battery charging:
The process of renewing the battery by passing an electric current through
the battery in a reverse direction.
battery charging station:
With the advent of electric cars, there needs to be places where their
batteries can be recharged periodically -- thus is born the battery charging
station. Also called a "charging point."
battery clamp:
A hold down device which secures the battery from moving around
battery compartment:
A place in the vehicle where the battery is located. In cars and trucks it
may be found under the hood (usually toward the front), under one of the
seats, or in the trunk. In motorcycles it is found in the middle of the bike,
under the seat
battery condition:
See battery charge
battery connector:
A plug on battery-powered vehicles to connect the batteries to the charging
station
Battery Council International:

A group which makes decisions related to battery composition and
disposal.
battery cover:
The top of the battery case. It has several holes (covered with caps) for
access to the battery cells.
battery discharge controller:
A device on a vehicle which is driven by an electrical motor. It triggers a
warning indicator when the battery power drops below a certain level.
battery discharge indicator:
An instrument on a vehicle which is driven by an electrical motor which
indicates the percentage of the maximum charge of the battery
battery earth:
British term for battery strap or ground strap
battery filler:
A device with a long hollow tube with a rubber bulb at one end. It is used
for inserting into a container of battery acid and sucking up the acid, then
inserting into the battery cell to fill it. However, motorcycle batteries
arrive from the manufacturer with no electrolyte (battery acid). Battery
acid comes in a large plastic container with a rubber hose to which a
metering clamp is attached. The container is usually placed on a higher
shelf so that it is fed into the battery by gravity and regulated by the
metering clamp
battery fill line:
A horizontal line on the side of a translucent battery case which indicates
the level to which you fill it with electrolyte. Usually there are two lines
indicating a minimum level and maximum level.
battery fluid:
See battery acid

battery hold down clamp:
See battery clamp
battery ignition:
Any system where the battery supplies the initial voltage to power the
starter motor and fire the spark plugs
battery ignition system:
See battery ignition
battery is dead:
The battery does not have enough electrical power to start the car
battery is flat:
The battery does not have enough electrical power to start the car
battery post:
The terminal on a battery to which the cable is attached. Older automobile
batteries used a round post which stood up from the top of the battery. To
avoid confusion, the positive post has a larger diameter than the negative.
On newer batteries the post may or may not be abandoned in favor of a
terminal on the side of the battery. On motorcycle batteries, the posts are
usually flat with a hole for bolting the cables to them.
battery state indicator:
See battery charge indicator
battery strap:
[1] A wire cable or braided wire strap to transfer electricity. It can be found
between the engine block and the chassis because the engine is isolated
from the chassis by rubber mounts. Also called ground strap. See ground
wire.
[2] A rubber strap with metal hooks at each end and is used to secure a
battery in place, especially on motorcycles
battery terminal:

[1] A battery post on the top of the battery or a lug with a hole on the side
of the battery.
[2] The clamp at the end of a battery cable
battery tester:
[1] A voltage meter or hydrometer for
checking the state of charge of a
battery.
[2] An instrument for checking the
condition of the battery cells
battery tray:
A metal or plastic on which the battery sits.
baudelot cooler:
heat exchanger in which water flows by gravity over the outside of the
tubes or plates
baulk ring:
British spelling for balk ring
bay:
See engine bay
bayonet bulb:

See bayonet cap
bayonet cap:
A cylindrical base of an electric bulb, usually with two pins
projecting on either side, which engage in J-shaped slots to lock the
bulb securely in its socket.
bayonet fitting:
See bayonet socket
bayonet socket:
A socket for receiving a bayonet cap. It has two slots on either side
(usually J-shaped) to accommodate the bulb's pins.
BBDC:
Acronym for "before bottom dead center."
bbl:
Abbreviation for "barrel," as in 4-bbl carburetor.
BCDD:
Acronym for boost-controlled deceleration device
BCI:
Acronym for "Battery Council International."
BCM:
Acronym for body computer module
BDC:
Acronym for "bottom dead center."
bead:

[1] The portion of a tire which fits onto the rim of the wheel. On a tubeless
tire, the contact of the bead with the rim seals the air into the tire. Bead
heel, bead sole, and bead toe form a foot-like shape. Also see tire bead.
[2] A small ball-like particle used in bead blasting or in some catalytic
converters.
[3] In welding, it is the appearance of the finished weld. It describes the
neatness of the ripples formed by the metal while it was in a semi liquid
state.
Also see
dual bead tire
rim bead seat taper
rim bead seat
rolled bead
single bead
bead base:
The part of the tire bead which is in contact with the rim bead seat
bead blaster:
A cleaning device for removing paint and contaminants from an object.
See bead blasting
bead blasting:
A cleaning process which uses glass beads which are forced by air
pressure against the object to be cleaned. This system removes paint and
contaminants from objects which are awkwardly shaped.
bead breaker:
A device used to remove a tire from its rim by releasing the tension the
bead has upon the rim.
bead core:
The ring of steel wires in the tire's bead. Also called bead wires
beaded edge:
The edge of a body panel or upholstery panel wrapped around a wire or
other stiffening item

beaded edge tire:
An older form of high-pressure tire with projecting beads
beader:
A power tool for forming beads on the edges of body panels
bead expander:
A device used in the mounting of tubeless tires to prevent inflation air
from escaping and bring the tire beads against the tapered bead seat area
(rim).
bead heel:
The portion of the tire bead in contact with the rim flange
beading:
The action of forming a step in the middle of a panel (not at the edge)
which creates a shallow indentation to reinforce the panel.
Also see
fender beading
bead lock:
See tire bead lock
bead movement:
Movement of the bead on the rim caused by improper inflation, excessive
loading, improper design, improper seating, or improper rim or tire size.
Also called "bead rocking." See bead unseating
bead point:
A feathered rubber extension of the bead toe used where a flap is not
required; protects the tube from chafing between bead toes and rim base.
beads:
See lubricate beads
bead seat:

The portion of the wheel rim below the rim flange providing radial support
to the bead of the tire.
See also
rim bead seat taper
rim bead seat
safety bead seat
bead seat mat:
A seat cover made of a network of wood beads
bead seats:
See contre pente on both bead seats
bead seat taper:
See rim bead seat taper
bead seat diameter:
The measurement of tire diameter, at the bead heel, where it seats on the
rim. It is marked on the tire sidewall following section width.
bead separation:
A situation where the bead comes off the wheel rim
bead tire:
See dual bead tire
bead toe:
The bottom portion of the tire bead in contact with the rim bead seat
bead unseating:
Shifting of the tire bead from its seat on the wheel rim which often leads to
the removal of the tire. See bead movement
bead wires:
Steel wires wound around the circumference and placed in the beads.
Their tension prevents the beads from lifting over the rim flanges. Also

called bead core
beam:
[1] A projection of light.
Also see
dipped beam
headlight beam setting
high beam
high beam indicator
low beam
main beam
main beam indicator
sealed beam
[2] A supporting bar.
Also see
asymmetrical beam
cant beam
deck beam
door beam
hatch beam
I-beam
knee, beam
molded beam
pulling beam
side impact intrusion beam
transom beam
[3] The width of a ship. Also called breadth.
beam axle:
A rigid or dead axle which supports the non-driven wheels. See axle.
beam indicator:
A light on the instrument panel which comes on when the high beams are
activated. Also called high beam indicator
beam headlight:
See sealed beam headlight
beam indicator:

See
high beam indicator
main beam indicator
beam knee:
Bracket between a deck beam and frame
beam setting:
See headlight beam setting
beam unit:
See sealed beam unit
bear:
[1] To turn, as in the expression, When you get to the corner, bear right.
[2] Trucker slang for a highway patrol police officer named for Smokey
the Bear because they both wore similar hats.
bear bait:
Trucker slang for a leader in a group of trucks as in "Looks like Swift is
the bear bait tonight" where "bear" refers to a police officer (i.e., Smokey
the Bear).
bear cave:
Trucker slang for a police station on the highway (also called a zoo) as in
"The bear cave is empty tonight so watch out."
bearing:
[1] The area of a unit in which the contacting surface of a revolving part
rests in order to minimize wear and friction between two surfaces.
[2] An antifriction reducing device that is usually found between two
moving parts. The babbitt bearings found between the connecting rod and
the crankshaft are lubricated and cushioned with oil, and the front wheel
bearings must be repacked with grease at regular intervals. Bearings can
be ball or roller type.
Also see
antifriction bearing con rod bearing quill-type bearing sleeve bearing

ball bearing
big-end bearing
camshaft bearing
carrier bearings
clutch pilot bearing
clutch release bearing
clutch throwout
bearing
clutch thrust bearing
connecting rod
bearing
friction bearing
insert bearing
jet bearing
main bearing
support
main bearing
needle bearing
pilot bearing
plain bearing
precision insert
bearing
quill bearing
radial bearing
re-metalling the
bearings
release bearing
rod bearing
roller bearing
rolling bearing
sealed bearing
shell bearing
small end bearing
spigot bearing
split bearing
tapered roller
bearing
throw-out bearing
throwout bearing
thrust bearing
timken bearing
timken roller
bearing
wheel bearings
bearing assembly:
When more than one load needs to be supported, several bearings are used
making up the bearing assembly. For instance, a crankshaft may have two
bearings (one at each end) as well as a few more in the middle
bearing attachment:
See split bearing attachment
bearing block:
The two halves of metal which encase a bearing.
bearing cage:
See ball cage
bearing cap:
A rigid, semicircular part which encloses and holds the outer shell of a
shell bearing
bearing clearance:
The amount of space left between a shaft and the bearing surface, this
space is for lubricating oil to enter.
bearing cone:
[1] taper roller bearing.

[2] The inner race in an adjustable axial or radial ball bearing
bearing crush:
The additional height which is purposely manufactured into each bearing
half to ensure complete contact of the bearing back with the housing bore
when the engine is assembled
bearing cup:
[1] Retainers, held in place by bolts and nuts, that hold the bearings in
place. Also called bearing shell.
[2] The bearing race that curves around the outside of a ring of ball
bearings and works in conjunction with a cone.
bearing face:
The bottom part of a nut or bolt head which clamps down on the surface of
the part it is securing.
bearing housing:
The cavity into which the bearing fits
bearing knock:
The noise created by movement of a part in a loose or worn bearing
bearing material:
The metal layer which forms the surface of the wear part of the bearing
bearing puller:
A tool used to remove bearings from a shaft by
pulling them off. It has two or more arms
which circle around the back side of the
bearing and a center post which butts up
against the end of the shaft. As the center post
is screwed down, the arms pull the bearing
toward the end of the shaft.
Also see
ball bearing puller

bearing race:
In ball or roller bearings, it is one of the two steel rings on either side of
the ball or roller
bearing scraper:
A small, triangular tool that looks like a file without teeth. Used for
deburring and chamfering the edges of camshaft bearings
bearing separator:
A tool used to separate double bearings or
close-fitting gears when a conventional
bearing puller cannot be used
bearing shell:
One of a pair of thin semicircular steel cups lined with an alloy such as
coper-lead or lead-indium, which together enclose a shaft or other rotating
member, and are held in a circular housing which can be divided into two
halves.
bearing spin:
A type of bearing failure in which a lack of lubrication overheats the
bearing until it seizes on the shaft, shears its locking lip, and rotates in the
housing or block
bearing spread:
A purposely manufactured small extra distance across the parting faces of
the bearing half, in excess of the actual diameter of the housing bore. Thus
the diameter is slightly greater than the housing into which a shell bearing
is being placed. Thus the bearing is forced into place to reduce its
movement. See interference fit
bearing support:
See main bearing support

bearing surface:
The area of the bearing that is in actual contact with the shaft or other
supporting member
bearing tang:
A notch or lip on a bearing shell used to correctly locate the bearing during
assembly
bear in the air:
Trucker slang for an overhead highway patrol as in "Slow down
Roadrunner you got a bear in the air past the next rest area."
bear meat:
Trucker slang for a speeding truck without a radar detector as in "That
gearjamming large car is bear meat."
bear report:
Trucker slang for asking for the location of the cops as in "Can I get a bear
report there Covenant."
beast:
A vehicle which performs very well.
beater:
[1] An old or collectible vehicle that is in drivable condition, but looks
terrible inside and out, and probably is missing many original parts. Often
used to describe a vehicle that is past the easy restoration stage but still
contains many good driving miles. It is also a term for "urban combat car"
and is usually used in conjunction with the word winter, as in winter
beater, which is a vehicle that is so far gone, it is sacrificed to the salt
covered roads of winter. It is a disposable collectible that is driven until it
disintegrates. In other words, it looks as if someone had been beating it for
quite a while. British term is banger.
[2] A device for hitting something.
Also see
panel beater

beating:
See
off-the-dolly panel beating
on-the-dolly panel beating
panel beating
spring beating
beating spoon:
See spring beating spoon
bed:
Any flat surface used as a support.
Also see
catalyst bed
low bed
test-bed
bedbuggers:
Trucker slang for moving companies as in "Bedbuggers on the side of the
road."
bedding-in oil:
British term for break-in oil
bed in:
British term for break-in
beefed-up:
[1] Colloquial term for making something stronger.
[2] Colloquial term for modifying or improving something so it will work
faster or more efficiently. Similar to souped up
Beema:
Colloquial term for BMW
Beemer:

Beetle:
Colloquial term for the original rear-engined volkswagen.
Also see
split-window Beetle
before bottom dead center:
(BBDC) As the crankshaft rotates, it brings the piston down to a place just
before it reaches bottom dead center.
before top dead center:
(BTDC) As the crankshaft rotates, it pushes the piston up to a place just
before the top of its movement.
before upper dead center:
(BUDC) As the crankshaft rotates, it pushes the piston up to a place just
before the top of its movement.
bell:
[1] A device mounted on a bicycle and used to warn pedestrians and other
bikes of your approach.
[2] A component that is shaped like half a ball or egg. Also see spray bell
bell housing:
Sometimes called "clutch housing." The metal covering around the
flywheel and clutch (of a manual transmission) or torque converter
assembly (of an automatic transmission).
bell mouth:
Bell-shaped air intake attached to some carburetors
bellows:
A sealed, accordion-type chamber (gas filled or vacuum) which expands
and contracts in accordance with temperature changes or provides a seal
during movement of parts. Used as an air conditioning control device on

many systems. Also see air bellows
bellows seal:
method of sealing the valve stem. The ends of the sealing material are
fastened to the bonnet and to the stem. Seal expands and contracts wit the
stem level
belt:
[1] A reinforcing band, normally textile, fiberglass, or steel, which runs
around the circumference of a tire and strengthens the tread area.
Also see
cog belt
[2] A circular band which is used to transfer power from one component to
another. For instance, a fan belt is used to transfer power from the engine
to the alternator, water pump, and air conditionercompressor.
Also see
cam belt
camshaft drive belt
cog belt
cogged belt
diagonal belt
drive belt
fan belt
ring belt
serpentine belt
stabilizer belt
static belt
steel thrust belt
timing belt
toothed belt
v-belt
vee-belt
[3] An attaching strap.
See
automatic seat belt
hip belt
inertia reel seat belt
integrated safety belts
lap belt
rear seat belt
safety belt
seat belt
shoulder belt
three-point seat belt
Y-belt
belt anchor:
The point where the end of the seat belt is attached
belt anchorage:
The point where the end of the seat belt is attached. See seat belt
anchorage
belt drive:
In order to transmit power from a source to a destination, some kind of
connection is needed. A bicycle, for instance, uses a chain drive to transmit
the power from pedalling action to the rear wheel. A belt drive uses a

leather or rubber belt to transfer power from one pulley to another thus
increasing or decreasing the speed of rotation of the driven pulley through
mechanical advantage. For instance the alternator is rotated by a belt
(sometimes called the "fan belt") which is driven by a shaft which is
directly attached to the crankshaft. Some motorcycle models (like Harley
Davidson and Honda) have a belt drive to transmit power to the rear
wheels. Since a belt drive requires no lubrication (in contrast with chain
drive) it is one of the cleanest final drive systems.
belt-drive system:
A final-drive system that transmits the power to the rear wheel via a drive
belt
belted bias tire:
A tire which uses both cross-ply and radial-ply patterns with added belts
(such as used on radial-ply tires) on diagonal body plies (as in cross-ply
tires). As a result the tire has stiffer sidewalls than tires with just straight
radial plies.
belted piston:
A piston with a continuous steel band cast into the skirt below the rings for
controlling skirt expansion.
belted radial tire:
See steel belted radial tire
belted tire:
A tire with a stabilizing belt of two or more plies of steel, fiberglass, etc.,
running circumferentially around the tire between the carcass and the tread
rubber. The carcass can be either radial or bias ply. See bias belted tire.
belt end:
The part of the seat belt which has the bracket which is attached to the
floor pan. Some cars attach this end to the car seat itself.
belt line:

The horizontal line that runs around the body of the vehicle just below the
bottom of the glass panels(greenhouse). The British term is "waistline"
belt mounting:
See belt anchor
belt pulley:
See timing belt pulley
belt retractor:
A device which automatically pulls the seat belt back into its reel
belts:
See integrated safety belts
belt sander:
A power sanding tool with a rotating
belt of sandpaper
belt slack:
The looseness of a belt (either the drive type belt or a seat belt)
belt slip:
When a drive belt is not as tight as it should be, it will slip on the pulley
and thus will not transmit power. If a driven pulley is seized, the belt will
also slip.
belt system:
See

seat-integrated belt system
seat-integrated seat belt system
belt tensioner:
A device consisting of an idler pulley which is usually located between the
drive and driven pulleys. It can be adjusted to increase the tension on the
belt.
See
seat belt tensioner
timing belt tensioner
belt transmission:
See
belt drive
variable belt transmission
belt up:
A British term for buckle up
belt warning light:
See seat belt warning light
belt webbing:
Strong fabric material used for seat belts
bench:
[1] A workbench.
[2] A test bed for studying or repairing an engine.
Also see
bench test
straightening bench

bench grinder:
A power tool mounted on a
workbench with one or two grinding
wheels
bench seat:
A front seat which runs from the left door to the right door. The alternative
is bucket seats.
Also see
split bench seat
bench test:
A determination of the power output of an engine when it is mounted on a
test bed. Also it can be checked for oil leaks, fuel consumption, emission
levels, etc.
bench vise:
A vise which is mounted on a workbench
bend:
See free bend test
bender:
See
fender bender
tube bender
bending:
See lower bending die
bending die:
See lower bending die

bending pliers:
Pliers with flat, smooth jaws used to hold sheet metal in place
bending spring:
coil spring which is placed on inside or outside of tubing to keep it from
collapsing while bending it
bending strength:
The ability of metal to resist bending
Bendix:
See
Bendix type starter drive
pre-engaged Bendix starter
Bendix drive:
See Bendix type starter drive.
Bendix screw:
A helical screw on the shaft of a starter motor
Bendix starter:
A starter motor with a Bendix drive.
Also see
pre-engaged Bendix starter
Bendix type starter drive:
A self-engaging starter drive gear, the gear moves into engagement when
the starter starts spinning and automatically disengages when the starter
stops. Also called inertia drive
bend test:
See free bend test
benefits:

See employee benefits
Bentley:
A vehicle brand of which the 1925-1945
models are classic cars. The 1946-67 models
are milestone cars.
Click here for books on
Bentley
Benz:
are classic cars.
Also see
Mercedes-Benz
benzene:
(C6H6) A constituent of gasoline
benzol:
A by-product of manufacture of coke. Sometimes it is used as an engine
fuel
berline:
A term used during World War I which describes a closed luxury vehicle
with small windows. The passengers were able to see out; but their privacy
was maintained because it was difficult to see in.
bernoulli's Theorem:
in stream of liquid, the sum of elevation head, pressure head, and velocity
remains constant along any line of flow provided no work is done by or
upon liquid on course of its flow; decreases in proportion to energy lost in
flow
better half:
Trucker slang for a husband or wife as in "I sure do miss my better half."
between duals:

See kissing between duals
between perpendiculars:
See length between perpendiculars
between wheel spacer:
An obsolete circular metal plate having a bolt hole circle and center bore
and fitting between the faces of disc wheels to provide additional dual
clearance.
bevel:
The angle that one surface makes with another when they are not at right
angles.
Also see
gutter bevel
bevel differential:
A differential which has bevel gears for its main elements. This allows the
input and output shafts to be at right angles to one another.
Also see
spur differential
bevel drive shaft:
A shaft with a bevel gear at one end or both ends. It is used primarily for
driving an overhead camshaft
bevel gear:
A gear shaped like the wide end (frustum) of a cone, used to transmit
motion through an angle. They are found in differentials.
Also see
spiral bevel gear.
bevel gear drive:
A transmission which is used to drive one or more shafts which do not line
up with the output shaft. Also called bevel gear transmission
bevel gear transmission:

A transmission which is used to drive one or more shafts which do not line
up with the output shaft. Also called bevel gear drive
bevel joint:
A piston ring gap in which the two ends of the ring are tapered.
beverage holder:
A circular clip located on the center console, door panel, or dashboard
which is designed to hold a cup or bottle. Also called cup holder
bezel:
The crimped edge of metal that
secures the glass face to an
instrument. A bezel can be either
decorative or functional. Some bezels
are threaded and secure switches and
control buttons to the dash, console,
or steering column.
B-flange:
A type of passenger car wheel
bhp:
Abbreviation for brake horsepower.
Also see
SAE gross bhp
BHS:
Acronym for bimetal heat sensor
bias:
The acute angle at which the cords in the tire fabric intersect the
circumferential centerline of the finished tire.
Also see

brake bias.
bias belted tire:
A type of tire construction in which there are
bias plies as well as a belt of steel or
synthetic (rayon, nylon, or fiberglass) cords
between the carcass and the tread. The belt
overlaps the bias plies and wraps around the
circumference. The cords and belt cross
each other at bias angles.
biased:
See spring-biased
bias ply tire:
A tire having two or more carcass plies arranged in a criss-cross manner
and diagonally to the beads and travels approximately 1/3 the distance
around the circumference before attaching to the other bead. Each cord in
the next ply is arranged in the same manner, but in the opposite direction.
Also called a "conventional tire" or "cross-ply tire"
bias tire:
A type of tire construction in which the tire
cords or plies run diagonally from bead to
bead. Generally in passenger cars, there are
two plies of fabric. In a P185/80D13 tire, the
"D" indicates a bias-ply tire. Sometimes
called a "conventional" tire.
Also see
belted bias tire
bib:
A leather or vinyl covering for the front of a vehicle. See tank bib

bicycle:
A two-wheel non-motorized vehicle in which
the two wheels are not side-by-side but in line.
Also called "bike."
Also see
all terrain bike
coaster
girl's bike
loaded tourer
mixte frame
mountain bike
penny-farthing
quadricycle
randonneuring
sports tourer
tandem
tourist
tricycle
unicycle
velocipede.
bicycle carrier:
A device which is attached to the rear bumper
or to the roof of a vehicle to carry a bicycle
bicycle lock:
A horseshoe-shaped metal locking device which will
reach around a small pole (e.g., parking meter) and
the frame of a bicycle.
big-block:
See big-block engine
big-block engine:
A large V-8 engine produced in the '60s and '70s. It typically has a cast-
iron block and head and is fed by a carburetor. Contrasts with small-block
engine. Although both engines were of the same displacement, the big-
block engine was larger in overall size than the small-block engine. Thus,
as vehicles grew smaller and more equipment was stuffed into the engine
bay, the small-block engine was favored over its larger brother.

big end:
The end of the connecting rod which fits around the crankpin
big-end bearing:
See big-end bearing
big-end bearing:
The bearing in the end of the connecting rod
that attaches to the crankshaft.
big-end bolt:
One of the bolts attaching the big-end cap to the connecting rod
big-end cap:
The detachable end of the connecting rod which fits on the crankpin
Big Jim:
A colloquial term for a device for opening door locks. It is a flexible metal
strip about an inch wide and very thin and has a J-shaped end. It is inserted
between the door window and the door frame to trigger the latch
big rig:
A large truck -- usually a tractor-trailer unit
big/tall rubber:
Trucker slang for 24 inch tires as in "I just bought new big rubber for my
rig."
big three:

General Motors, Ford, and Chrysler.
big Twins:
The engines in the larger Harley-Davidson bikes
bihexagon:
A twelve-sided figure. Some nuts and bolt heads have twelve sides.
bihexagonal:
Having 12 sides
bihexagon socket:
A tool socket which fits 12-sided nuts and bolts
bike:
A two-wheel vehicle -- either a bicycle or a motorcycle.
Also see
all-terrain bike
girl's bike
mountain bike
street bike
touring bike
bike crossing:
A place on the highway (usually marked by a
sign) indicating a relatively safe place for a
bicycle to cross to the other side. Motorists are
advised that slow moving bicycles may be on
the road.

bike lock:
A horseshoe-shaped metal locking device which will
reach around a small pole (e.g., parking meter) and
the frame of a bicycle.
BIL:
Acronym for "Bilimportorenes Landsforening" (Norway). Also Acronym
for "Bilindustrief”reningen" (Sweden)
bilge:
A recess area fitted at the curved section between the bottom and the side
into which water drains from holds or other spaces.
bilge bracket:
A vertical transverse flat plate welded to the tank top or margin plate and
to the frame in the area of the bilge.
bilge keel:
A long longitudinal fin fitted on the curved of a ship at the turn of the bilge
to reduce rolling
bilge strake:
Shell plates at the bilge area
billet:
[1] A section of a log split lengthwise as you would make firewood.
[2] A small bar of iron or steel
bill of lading:
The cost or the paperwork describing the cost of a vehicle's load or freight.

bimetal:
Two types of metal bonded into a strip and formed into a coil. Each type of
metal has different thermal expansion characteristics, so the coil
straightens when heated and coils up when cold. Bimetals are used mainly
to open and close choke plates on carbureted vehicle
bimetal heat sensor:
(BHS) a strip (usually coiled) consisting of two metals with different
expansion characteristics. Bimetal strips are used in thermostatically
controlled devices because they move or bend toward the metal that
expands least when heat is applied
bimetallic corrosion:
When two different metals are attached to each other, some electrons tend
to move from one metal to the other. This action happens especially when
there is a little moisture between the two pieces.
Also see
galvanic corrosion
bimetallic sensor:
Consists of thermocouple, an arm made of two dissimilar metals with
different rates of thermal expansion, that flexes in accordance with
temperature changes. Used as a temperature sensor. Also called bimetal
sensor
bimetal sensor:
Consists of a thermocouple, an arm made of two dissimilar metals with
different rates of thermal expansion, that flexes in accordance with
temperature changes. Used as a temperature sensor. Also called bimetallic
sensor
Bimmer:
binder:

The ingredient in a paint that holds or suspends the pigment particles
together.
Also see
binders.
binder bolt:
On a bicycle, the bolt used to fasten a stem inside a steerer tube or a
seatpost inside a seat tube. Some are quick-release type.
binders:
Vehicle brakes.
binding:
[1] The rubbing of brake shoes against the drum or of brake pads against
the disc.
[2] The strip material turned over along the edge of a carpet or mat.
Also see
edge binding
bingo cards:
Trucker slang for the paper cards that hold trucking permits from different
states as in "Better get your bingo cards out, they're checkin' em at the
chicken coop."
binnacle:
The cluster of instruments and switches mounted in a circular casing on or
near the steering column
biocide:
A product which kills any fungus or microbes that may have contaminated
diesel fuel.
biodegradable:
A product which is capable of being decomposed by bacteria into harmless
elements without danger to the environment.
biodiesel:

Diesel fuel made from animal or vegetable fats
bit:
[1] A tool for boring or cutting which fits into a drill. See drill bit.
[2] The tip of a screwdriver.
Also see
hexagon bit
hex bit
screwdriver bit
socket bit
twisty bits
bit adapter:
A tool (like a screwdriver) with a hollow socket (instead of the blade) to
accept a variety of bits
bite:
[1] A vehicle's ability to adhere to the road (especially to a racing track).
[2] The ability of a tool to secure itself to a fastener as in I want my
wrench to get a good bite on that bolt.
bits:
See twisty bits
bitter end:
The inboard end of a ship's anchor chain that is secured in the chain locker
bituminous paint:
Black or dark colored tarry paint which contains bitumen. Used for the
protection of exposed metal parts.
BL:
Acronym for "British Leyland"
black:

See carbon black
black and white checkered flag:
A flag which is waved at the finishing line in races to indicate the winner.
black box:
[1] A recording device which reveals conditions just prior to a crash.
[2] A control unit
black chromium plating:
An electroplating deposit of a black chromium layer for decorative
purposes
blackening:
See
bulb blackening
lamp blackening
black flag:
A flag which is colored black and is waved at a race. It indicates that the
driver must return to his pit for consultation. It means that the driver has
violated a serious racing rule such as spilling fluid on the track or was
speeding on the pit road.
black flag with orange circle:
As with the black flag for infractions, the black flag
with orange circle means the driver must bring the car
to the pits on the next lap. This flag indicates there is
a serious mechanical problem with the car that can
endanger the driver or others. Ignoring this black flag
can bring severe penalties as it represents a dangerous
situation
Blackhawk:

blacksmith hammer:
A special hammer for hitting and shaping heated iron.
black smoke:
Incompletely burned fuel in the exhaust indicating the fuel mixture is too
rich
blackwall:
Tires which do not have any white or red coloring.
See
whitewall
red line
black and white flag:
The black and white flag is used in some series to
indicate unsportsmanlike conduct. This is typically
held motionless next to a pit board with the car
number on it. The driver may be penalized when this
flag is shown
bladder:
A hollow bag which can be inflated. In some instances, fuel tanks will
become rusty inside. A possible cure is to install a bladder. This is done by
flushing out the rust chips, applying an acid solution to remove any oil/gas
residue, and coating the inside with a plastic compound. When done
correctly, this plastic coating does not dissolve when it comes in contact
with gasoline.
blade:
[1] A straight narrow flat part like the end of a screwdriver or knife.

[2] The part of a windshield wiper (blade rubber) which contacts the
windshield.
[3] One of the vanes of a rotor or impeller.
Also see
bumper blade
bumping blade
fan blade
feeler blade
fork blade
blade connector:
A plain metal tongue for forming electrical connections
bladed impeller:
A rotating part of a centrifugal pump that has blades or vanes
blade rubber:
The rubber strip that fits into the arm of a windshield wiper
blades:
See fork blades
blank:
See sheet metal blank
blanking piece:
A flat piece of metal which closes off a tube. Also called a "blanking plate"
blanking plate:
A flat piece of metal which closes off a tube. Also called a "blanking
piece"
blanking plug:
A rubber stopper for filling in the holes of sheetmetal such as drain holes
in the floorpan

blast:
See
ocean liner blast horn
sand blast
blast cleaning:
The removal of corrosion, dirt, paint, etc. by a blast of abrasive particles.
Also see
bead blasting
sand blasting
blaster:
See bead blaster
blast freezer:
low -temperature evaporator which uses a fan to force air rapidly over the
evaporator surface
blast horn:
See ocean liner blast horn
blasting:
See
bead blasting
grit blasting
shot blasting
bleed:
[1] To remove air bubbles from hydraulic lines and components of a
system.
Also see
air bleed
air bleed screw
compensating jet
.
[2] To reduce the air pressure in tires that have been run, warmed up, and
thus increased from their starting pressure -- an action which should be

avoided.
bleed down:
The collapse of a hydraulic lifter as oil drains out
bleeder:
The valve or screw used to vent the air out of a liquid-filled system.
See
brake bleeder
pressure bleeder
bleeder nipple:
See bleeder screw
bleeder screw:
A hollow screw used to open a bleeder valve to allow fluid and air bubbles
from a system like the brake system during a bleeding process.
Also see
bleeder valve:
[1] A valve on a wheel cylinder, caliper, or other hydraulic component that
is opened to purge the hydraulic system of air
[2] The device which vents air from the brake system.
bleeding:
See brake bleeding
bleed screw:
A screw used to release the air from a system like the brake system.
Also see
bleed valve:
[1] A valve with small opening inside which permits a minimum fluid flow
when valve is closed.

[2]The device which vents air from the brake system.
bleeding:
[1] The action of venting air from a liquid-filled (hydraulic) system.
[2] Reducing the air pressure in tires that have been run, warmed up, and
thus increased from their starting pressure -- an action which should be
avoided.
[3] Slowly reducing the pressure of liquid or gas from a system or cylinder
by slightly opening a valve
[4] The separation of components of a dried adhesive, coating, or sealer
film, resulting in an oil-like stain on the surfaces to be bonded, or on
finishes
[5] A lower (older or previous) color coming through a fresh coat of paint.
bleeding a system:
Remove air bubbles from a brake system, a fuel injection system, or a
cooling system so that they won't impede the flow of liquid through that
system.
bleeding the brakes:
This refers to the removal of air from the hydraulic system, bleeder screws
are loosened at each wheel cylinder, (one at a time) and brake fluid is
forced from the master cylinder through the lines until all air is expelled.
blem:
An abbreviation for blemish.
blemish:
A tire with a slight imperfection in appearance that will not affect tire life
or safety. Also called a "blem."
blind:
See car blind
blind quarter:

An unusually wide C-pillar enclosing the rear seat area
blind rivet:
A pop rivet
blind spot:
An area not visible from the driver's seat. It is usually the area behind the
rear quarter and not visible in the mirrors. When approaching another
vehicle in a lane beside you, avoid being in its blind spot. Also do a
shoulder check before switching lanes to check for vehicles in the blind
spot
blinkie:
A red taillight on a bicycle which has a switch which
turns it to a steady light or a flashing (blinking) light
blister:
[1] A bubble on a paint surface.
[2] A localized bubble on the surface of a tire, normally caused by a
separation between plies or between surface rubber and a ply.
blistering:
The formation of bubbles on the paint surface.
BLM:
Acronym for the "Bureau of Land Management."
BLMC:
Acronym for "British Leyland Motor Corporation"

block:
That part of the
engine containing
the cylinders.
Also see
bearing
block
big-
block
block
heater
brake
block
brake
pad
cylinder
block
die
EN-
block
en block
engine
block
heater
engine
block
hollowing
block
hydraulic
control
block
long block
long block
engine
monoblock
rubbing
block
sanding
block
short block
tread block
valve block
keel blocks
block coefficient:
The ratio of the underwater volume of a ship to the volume of a
rectangular block with the same effective lengths, draft and beam
block deck:
The cylinder head gasket surface
block engine:
See
long block engine
short block engine
block heater:
A devices which, during very cold weather, keeps the engine warm when
the vehicle is not being used -- thus making cold starts easier. The free end

is plugged into 110 volt AC wall socket. It is especially important for
starting diesel engines at very low temperatures.
Also see
cylinder block heater
engine block heater
blocking ring:
See balk ring
blocks:
See keel blocks
block sanding:
The process of using a wooden block wrapped in sandpaper to sand the
material.
blood alcohol content:
The amount of alcohol in the bloodstream as a result of drinking liquor
blood alcohol level:
The amount of alcohol in the bloodstream as a result of drinking liquor
bloom:
A surface film on rubber, caused by the migration to the surface of sulphur,
wax, or other unreacted ingredients of the compound. It may be protective
to the tire and detrimental only if appearance is a major factor.
blooming:
A formation of an undesired thin surface film or a milky white haze or
mist on paintwork. It is caused when paint is applied during humid, cold
conditions as moisture is trapped in the wet film
blow:
To become defective either by leaking or burning through.
Also see
arc blow

striking blow
blow back:
Because of a sticky valve or the intake valve closing late, some of the air-
fuel mixture is blown back through the carburetor
blowby:
The mixture of fuel-air which is lost past the piston rings and causes fumes
that form acid and sludge in the crankcase and smoking from the oil filer
hole. Generally there is a loss of engine power. Most are removed through
the PCV system.
blow-by:
The mixture of fuel-air which is lost past the piston rings and causes fumes
that form acid and sludge in the crankcase and smoking from the oil filer
hole. Generally there is a loss of engine power. Most are removed through
the PCV system.
blowdown:
The escape of gases between the opening of the exhaust valve and the
piston reaching bottom dead center, or in a two-stroke engine between
exhaust port opening and transfer port opening.
blowdown period:
In a two-stroke engine, it is the time between the exhaust port opening and
the transfer port opening which should be sufficiently long enough to
allow time for the cylinder pressure to drop below the crankcase pressure,
so that the exhaust gases can be expelled more easily
blower:
[1] Also called a "supercharger" or "turbocharger." This is a pump which
forces air into the cylinders at higher than atmospheric pressure. The
increased pressure forces more air into the cylinders than what would be
drawn in normally. In this way the engine can burn more fuel and thus
produce more power. There are two main types of blowers: the
turbocharger, which uses some of the waste heat energy in the exhaust
gases to drive a compressor and pump the air; and the belt-driven or shaft-
driven supercharger which uses engine power to pump air.

[2] A fan for an interior heating and ventilating system or even for an air-
cooled engine.
Also see
heater blower
blower fan:
An electric motor-driven fan which forces air through the evaporator and
duct assembly, then forces the cooled air out of the duct work and
circulates it through the vehicle passenger compartment
blower motor resistor:
A device which regulates fan speed
blow gun:
A paint spray gun with a wide nozzle which is fed by air pressure.
It is used to blow out crevices in material that is otherwise hard to
reach.
blowlamp:
A British term for blow torch
blown:
[1] An engine equipped with a turbocharger or supercharger.
[2] An engine which is ruined. Usually the piston is seized.
Also see
blown head gasket.
blown head gasket:
A gasket that has a break between the opening for the cylinder and an
opening for the coolant. The coolant will leak into the combustion
chamber. This condition can be diagnosed by a loss in coolant and white
smoke out the exhaust.
blowoff valve:
A one-way valve that opens to the atmosphere above a certain set
pressure to relieve excessive internal pressure buildup; often used
with a turbocharger installation to limit boost pressure to the
engine. Also called pressure-relief valve.

Also see
wastegate
blow-off valve:
See blowoff valve
blow out:
To clean a dirty or blocked pipe by blowing compressed air through it
blowout:
A sudden rupturing of tire body, causing complete loss of air pressure
which flattens the tire.
blow-out:
A sudden rupturing of tire body, causing complete loss of air pressure
which flattens the tire.
blow-over:
A respray of doubtful quality, often poorly prepared and carelessly
masked.
blowpipe:
Another term applied to the oxyacetylene torch
blow through:
A turbocharger system in which the turbocharger blows air through the
carburetor(s) or fuel injector(s), i.e., the air and fuel mixing occurs
downstream from the turbocharger

blow torch:
A tool which is attached to a bottle of
flammable gas. The gas is ignited to
give an intense flame for brazing and
soldering. The British term is
"blowlamp"
bluebird:
Trucker slang for a Martin Truck company's truck as in "Can I get a
smokey report there Bluebird."
blue book:
A listing of the current prices for used cars, based on age, condition, and
optional equipment. Available at banks, loan offices, libraries, and
insurance companies.
blue flag:
The blue or passing flag has different meanings
depending on how it is held and whether it is used
during practice, qualifying or racing. Generally when
it is held motionless it is an indication to a driver that
there is a faster car following closely behind, but not
yet close enough for a pass. A waving flag generally
indicates that the driver is about to be overtaken and
should take care to permit the following vehicle a safe
pass. Some drivers resist moving over for an over-
taking car when they feel they are racing for position.
Controversy can follow the use of the passing flag.
Some tracks use a blue flag with a diagonal yellow
stripe.

blueing:
The blue color that appears on chrome pipes when subject to intense heat.
In some cases, it can be removed; but most often it is permanent.
blueprinting:
Dismantling engine and reassembling it to exact specifications and
tolerances. This process may help to improve engine performance,
smoothness, and reliability. Sometimes called "balancing."
blue smoke:
The color of the exhaust which indicates that oil is escaping into the
combustion chamber and abeing burned. It is probably due to worn rings,
valve seals, etc.
blushing:
The formation of a whitish or misty appearance on the finish color of the
paint surface.
BMAP:
Acronym for barometric and manifold absolute pressure sensor
BMC:
Acronym for "British Motor Corporation"
BMEP:
Acronym for brake mean effective pressure
BMW:
Acronym for "Bayerische Motoren Werke." A
vehicle brand of which the 1925-48 models 327,
328, 327/328, and 335 are classic cars. The 507
models for 1957-59 are milestone cars.
Click here for books on
BMW

BMW roundel:
The little black, blue, and white BMW checkerboard logo.
board:
A printed circuit board.
Also see
circuit board
dash board
on board diagnostics
printed circuit board
running board
shifting board
board diagnostics:
See on board diagnostics
board test:
A test of a printed circuit board
boardwalk:
Trucker slang for a bumpy road as in "I don't run 78 often cause it's a real
boardwalk."
boat chock:
A cradle or support for a lifeboat.
boat trailer:
A trailer for carrying a boat
BOB:
Acronym for break-out box
bobbers:
the custom bikes American riders built after WWII where the owners cut
off, or "bobbed," much of the bodywork.

bobtail:
Trucker slang for traveling without a trailer as in "It sure can be hairy to
bobtail in the rain."
bodge:
A British term to describe work that is done poorly or with defective
materials
bodily harm:
Physical injury to a person caused by an accident
bodily injury:
Physical injury to a person caused by an accident
body:
[1] The main portion of an automobile. Often it refers just to the outside
shell.
[2] The main part of a housing.
[3] The shank of a bolt.
[4] In welding, it refers to the main structural part of a regulator.
[5] A term used in describing the thickness or consistency (viscosity) of an
adhesive, coating or sealer
Also see
all-aluminum
body
all-enveloping
body
all-steel body
aluminum body
coachbuilt body
distributor body
dump body
fabric body
fibreglass body
fully galvanized
body
half-round body file
headlight body
integral body and frame
construction
parallel middle body
spark plug body
special body
stressed body
throttle body
tire body
torpedo body
unit body
valve body
body and frame:
See integral body and frame construction
body and frame construction:
See integral body and frame construction

body assembly:
The building up of the automobile body from its various components
body builder:
A person who builds automobile bodies, i.e., coachbuilder.
body-colored:
Something that is painted the same color as the body.
Also see
color-coded
body component:
Any structural part that makes up the body of a vehicle.
body computer module:
(BCM) Key element of self-diagnostic system used to control vehicle
functions based on monitored inputs
body construction:
The manufacturer of a vehicle body
body file:
When patching hole in a body panel and filling it with body putty, a body
file, which is a hand tool, is used for smoothing the putty to conform to the
contour of the body.
Also see
half-round body file
body filler:
A substance (often with the name Bondo) which is a paste used to fill
minor imperfections in a body panel. It hardens and is shaped to fit. It can
also be painted to match the rest of the vehicle.
body flange:
A point on the body where two panels overlap, forming a small step

body framing:
An assembly of the body components
body fuel injection:
See throttle body fuel injection
body glass:
The windshield, backlight (rear window), and side windows of a vehicle
body hammer:
A hammer with a large flat pounding surface for removing dents
body housing:
See valve body housing
body-in-white:
In the process of building a vehicle, this is a body shell after everything is
welded but before it is painted
body injection:
See throttle body injection
body jack:
A hydraulic tool for pushing or pulling body panels into shape
body lead:
An alloy of lead and tin which is used to fill dents and seems in a body
panel to establish a smooth surface. When heated it flows easily to fill the
imperfections
body panel:
The sheet metal that forms the outside body pieces.
body plan:

A drawing showing the forms of the various cross sections, the curvature
of the deck lines at the side, and the projections, as straight lines of the
waterlines, the buttock lines, transverse elevations and the diagonal lines
body putty:
A malleable material designed to smooth on dented body areas, upon
hardening, the putty is dressed down and the area painted. Also called
"bondo."
body rattle:
A noise in the bodywork usually cased by loose parts, badly fitting doors,
hood, or trunk lid
body repair:
After a vehicle has suffered an accident or has corroded panels, the body
needs to be repaired to bring it back to like-new condition
body roll:
The rocking or tilting motion of a vehicle when it goes around the corner
body sealer:
A tar-like substance which is used to seal body joints
body separator plate:
See valve body separator plate
body shell:
The bare skeleton of a vehicle with all the wheels, doors, hood, trunk lid,
etc. removed
body shop:
A service outlet specializing in vehicle body repair work.
body side molding:

A protective stripe along each side of the vehicle running from the leading
edge of the front fender, along the door panel(s) to the rear end of the back
fender. It may be solid plastic or rubber attached directly to the panels
while others are attached to a metal strip which in turn is attached to the
panels.
body spoon:
A tool with a flat contoured working surface like a spoon. It is used to slap
out dents and is sometimes used in place of a dolly when it is too difficult
to reach behind the panel
body stripe:
A decorative stripe applied to a motorcycle fuel tank or the outside of a car
to enhance the appearance. Sometimes model names are also part of the
stripes.
body styling kit:
An additional set of bolt-on parts (like spoilers, air dams, fender skirts,
laker pipes, wings) which are intended to improve the looks, performance,
and efficiency
body tub:
The bare body shell (minus the doors, trunk lid, hood, fenders) which is
lowered onto the chassis at the time of assembly
bodywork:
The complete body structure mounted on the chassis of a vehicle with a
separate chassis, and the complete sheet metal panel for unibody vehicles.
bog:
A hesitation usually experienced when starting out.
bogie:
An assembly of four wheels on two axles with common suspension,
usually on heavy commercial vehicles, trailers, and older Ski-Doos®

bogie wheel:
One of the suspension wheels on an older Ski-Doo
boil:
The process of change from a liquid to a gas through the application of
heat.
boiler:
closed container in which a liquid may be heated and vaporized
boiler, high-pressure:
see high-pressure boiler
boiler horsepower:
term now seldom used, meaning equivalent to a heating capacity of 33,475
BTU/hr (9804 watts)
boiler, hot water and low-pressure steam:
a boiler furnishing hot water at pressures not more than 30 psi gauge (308
kPa) or steam at pressures not more than 15 psi gauge (205 kPa)
boiling point:
The exact temperature at which a liquid begins to boil or changes to a gas
(i.e., vaporizes). The boiling point of a liquid decreases with increasing
altitude, and increases with pressurization. The coolant in a modern
radiator/coolant system can be as high as 260°F (127°C).
Also see
dry boiling point
wet boiling point
boiling temperature:
temperature at which a fluid changes from a liquid to a gas
bold-up:
The application of retread or repair rubber.

bolster:
[1] A supporting brace.
[2] The act of supporting.
Also see
hexagonal bolster
bolt:
A securing device upon which a nut is threaded. It usually has a nut-type
head. It is usually measured not so much by the size of the wrench
required to secure the bolt; but by the diameter of the threads, the thread
pitch, the length of the bolt under the head, and the strength of the bolt.
Also see
anchor bolt
big-end bolt
binder bolt
carriage bolt
coach bolt
countersunk bolt
crankarm fixing bolt
cylinder head bolt
eccentric bolt
fixing bolt
flange bolt
four bolt mains
hexagon bolt
hex bolt
locking lug bolt
lug bolt
mounting bolt
octagonal bolt
octagonal head bolt
pivot bolt
round head bolt
shear bolt
stirrup bolt
through bolt
u-bolt
wheel bolt
wheel lug bolt
bolt and nut:
A pair of objects with matching screw threads. When either the bolt or the
nut is turned, it moves with great force. Often used as fixing devices. The
nut is the circular piece that looks like a ring with threads on the inside
hole. The bolt is the shaft with threads.
Also see
pivot bolt.
bolt hole:
The hole in metal through which a bolt must be inserted or screwed in
place.
Also see
wheel bolt hole.
bolt hole circle:
See wheel bolt hole circle.
bolt mains:

See four bolt mains
bolt-on:
Accessories which are easily secured to an automobile with just a few
bolts rather than having to be welded in place. Usually done by the owner.
bolt-on fender:
A fender which is secured with bolts rather than being welded in place.
bolt-on goodies:
Accessories which are easily secured to an automobile, but are often for
show rather than function.
bolt-on kit:
A group of parts available in one package which the owner can attach
himself.
bolt-on wing:
British term for bolt-on fender
bomb:
A vehicle which is in very poor shape, "The car is a bomb and not worth a
nickel." In contrast, it can mean a vehicle which has great acceleration,
"The car flew down the track like a bomb."
bond:
[1] A state of adhesion.
[2] The act of connecting two components by means of a glue or adhesive
or to cause them to adhere
[3] The junction of the weld metal and the base metal
[4] The grip exerted by one material on another.
[5] The attachment between two surfaces that have been joined.
bonded abrasive:
A grinding part which is made of very hard particles which have been
glued together to form a wheel, bar, rod, or cone used to wear down or

smooth metal.
bonded brake lining:
brake lining that is attached to the brake shoe by an adhesive rather than
by rivets.
bonded lining:
Brake lining cemented to shoes or bands with high-temperature adhesive
and cured under pressure and heat resulting in the elimination for the need
for attaching rivets
bonding:
See
adhesive bonding
panel bonding
bonding agent:
A material which provides adhesion
bonding method:
A procedure of joining two components with adhesive
bonding range:
the time during which a satisfactory bond can be made. It is usually
expressed in two numbers, the first number being the time in minutes one
must wait after applying adhesive before trying to bond the surfaces, and
the latter number being the longest drying period within which satisfactory
bonds can be made, usually ten to 30 minutes after applying the adhesive
bondo:
See body putty.
bond strength:
the force or strength necessary to break a bond between 2 adhering
surfaces or materials

bone:
See
A bone
T-Bone
backbone frame
herringbone gears
wishbone.
boned:
See T-boned
bonk:
A term used to describe a condition experienced when running out of
energy while riding a bicycle or running.
bonnet:
British term for vehicle hood.
Also see
auto bonnet
bonnet badge:
British term for hood badge
bonnet bump rubber:
British term for hood bump rubber
bonnet bumper:
British term for "hood bumper" or hood bump rubber
bonnet landing panel:
British term for hood landing panel
bonnet liner:
British term for hood liner
bonnet lock:

British term for hood lock
Bonnet pin:
British term for hood pin
bonnet pin kit:
British term for hood pin kit
bonnet release:
British term for hood release
bonnet stay:
British term for hood rod
bonnet support:
British term for hood rod
bonnet tape:
British term for hood tape
bonus:
See no-claims bonus
boogie:
Trucker slang for top gear as in "I've got 'er up in the boogie now"
book:
See
blue book
paint chip book
booming:
[1] A noise caused by interruptions to the flow of air such as an open
windows.
[2] Low pitched resonance, especially in the exhaust.

[3] Thumping sound coming from large stereo woofers
boost:
[1] The amount of positive pressure created in an intake system above
normal atmospheric pressure by a turbocharger or supercharger. Normal
atmospheric pressure is 14.7 psi. A blower providing 10 psi boost
increases the pressure to 24.7 psi. Boost is sometimes measured in
atmospheres where one atmosphere equals 14.7 psi. Thus 24.7 psi is about
1.7 atmospheres.
Also see
on boost
off-boost
[2] The action of jump starting one battery from another.
[3] To increase power, charge, or pressure, etc.; or to amplify volume,
audio sound, etc.
boost-activated ignition retard:
On a turbocharged engine, a system which retards the ignition timing
when the intake manifold is under pressure, in order to reduce the chance
of detonation
boost-controlled deceleration device:
(BCDD) a valve that, during deceleration, is triggered into action by high
intake manifold vacuum the BCDD valve allows an additional source of
air and fuel to enter the intake manifold during deceleration to obtain a
more burnable mixture
boost control valve:
See blowoff valve
booster:
[1] A radio device which amplifies the signal or the audio output to the
speakers. Because of its size it is mounted in the glovebox, under the dash,
in the center console, under the seat, or in the trunk.
[2] A device incorporated in vehicle system (such as brakes and steering),
to increase the pressure output or decrease amount of effort required to
operate, or both.

[3] A common term applied to the case of a compressor when used as the
first stage in the cascade refrigerating system
Also see
brake booster
hydraulic brake booster
power booster
spring booster
vacuum booster
vacuum brake booster
booster battery:
A second battery used in commercial vehicles to give a little more power
when starting.
booster cable:
See jumper cables
booster coil:
A secondary ignition coil which increases the intensity of the spark
booster venturi:
A small venturi located immediately above and concentric with the main
venturi in a carburetor. Boosters are designed to amplify the weak venturi
vacuum signal that occurs during low airflow conditions
boost gauge:
An instrument or meter which indicates boost pressure
boosting:
See start boosting
boost pressure:
Pressure in the intake system of a supercharged engine when the
supercharger operates. See the first definition of boost.
boost sensor:

A sensing device in a supercharger. It is located in the choke tube which
sends a signal to the ignition control unit according to pressure conditions.
In turn, the control unit adjusts the ignition timing for the best
performance.
boost valve:
A valve in a hydraulic system which increases the pressure
boot:
[1] British term for a trunk.
[2] The rubber or plastic cover located at either end of the spark plug cable
to insulate the connections between the cable ends and the spark plug and
distributor terminal. Always grasp the cable by the boot when removing it.
See spark plug boot.
[3] The protective cover of the ball joint that holds the grease.
[4] The cover that protects the suspension forks on a bicycle or motorcyle
from dirt and grime.
Also see
dust boot
CV joint boot
[4] The covering around the CV joint.
[5] A simple protective device (sometimes a piece of tube, tire, etc., cut to
size) placed between the casing and tube. It offers temporary protection for
the tube against pinching by an injury in the casing. It is not a repair of the
injury and is unsafe to use.
[6] A denver boot, which is a device which clamps on the wheels of a
parked car to immobilize it. Also called a heavy yellow boot.
[7] A colloquial term for the action of going very fast as in, We were
booting along as fast as the snowmobile would go.
booted:
A vehicle which has been disabled by a denver boot is said to be "booted."
booted version:
British term for trunk model
booth:
See

low-bake booth
paint booth
spray booth
boot handle:
British term for trunk handle
bootlid:
British term for trunk lid
boot puller:
See spark plug boot puller
boots:
See boot.
boot spoiler:
British term for trunk spoiler
border shopping:
See Canadian cross border shopping
bore:
[1] The cylinder hole itself.
Also see
piston bore.
[2] The diameter or width of the cylinder.
[3] As a verb, it means to cut a circular hole.
[4] With the word "full" it means to go fast.
Also see
full bore
center bore
cylinder bore
wheel center bore
bored:
To increase the diameter of the cylinder.

Also see
stroked.
bore diameter:
The diameter of the cylinders. It is usually measured in either inches or
millimetres. When a cylinder is bored out because of scoredwalls, it is
increased by "ten thou" of an inch (0.01") or 0.25 mm.
bore-stroke ratio:
The relation between the diameter of the cylinder bore and the length of
the stroke of the piston. If the stroke is longer than the cylinder bore
diameter then the engine is called a long stroke engine. If the stroke is
shorter than the cylinder bore diameter then the engine is called a short
stroke engine. If the stroke is the same as the distance of the cylinder bore
diameter then the engine is called a square engine
Borgward:
A German automobile manufacturer which began
by Carl F. W. Borgward in 1921.
Click for books on
Borgward
boring bar:
A machine with a stiff bar that has multiple cutting bits used to cut engine
cylinders to a specific size. As used in garages, to cut worn cylinders to a
new diameter or bearing bores in proper alignment with each other.
boring:
Renewing the cylinders by cutting them out to a specified size, a boring
bar is used to make the cut.
boss:
An extension or strengthened section that holds
the end of a pin or shaft. For example, the holes
in the piston through which the piston pin is
placed would easily break the thin walls of the
piston when under pressure. The area around the
hole (on the inner side of the piston) are

strengthened to prevent breakage. This area is
the piston boss.
Also see
gudgeon pin boss
horn boss
piston pin boss.
bossing mallet:
A hammer with a pear-shaped wooden head used for shaping and
stretching metal over a sandbag or wooden block.
botch:
[1] A repair job which is very poorly done.
[2] To do a repair job poorly
botched-up job:
A colloquial term for a poor repair which will not be permanent.
bottle:
See acetylene bottle
bottle cage:
A water bottle holding bracket which is
mounted to the frame of bike either with a
clamp or by screws into a pair of braze-on nuts
bottled gas:
(LPG) (liquefied petroleum gas or propane) gas compressed into strong
metal portable tanks. The gas, when confined in the tank, under pressure,
is in liquid form.

bottle jack:
A hydraulic lifting device which is in the shape
of a bottle
bottleneck:
A traffic situation where the road narrows to the point where traffic is
excessively slowed
bottom:
[1] The lowest point. See door bottom.
[2] To lower something.
[3] To reach the end of its travel (i.e., bottom out).
[4] To make contact with the road.
Also see
double bottom
bottom bracket:
Bicycle component that is inserted into the
bottom bracket shell. The bottom bracket
consists of the crank axle (bottom bracket
spindle), ball bearings, and (in older style
bottom brackets) a fixed cup and an adjustable
cup. Crankarms are bolted to the bottom
bracket. Also see adjustable bottom bracket.
sealed bottom bracket, splined bottom bracket,
and square tapered bottom bracket
bottom bracket, adjustable:
See adjustable bottom bracket

bottom bracket, sealed:
see sealed bottom bracket
bottom bracket shell:
The barrel shaped portion of the frame into which the bottom bracket is
inserted. The seat tube, down tube, and chain stays are connected to the
bottom bracket shell.
bottom bracket spindle:
The axle to which both of the crankarms are attached. The spindle length
is measured in millimeters from one end of the spindle to the other.
bottom bracket, splined:
See splined bottom bracket
bottom bracket, square tapered:
see square tapered bottom bracket
bottom dead center:
(BDC) The lowest point of the piston and connecting rod travel in a
cylinder. In a horizontally opposed engine, it is sometimes called the outer
dead center. Opposite to top dead center.
Also see
after bottom dead center
before bottom dead center
bottom dumps:
Trailers that unload through bottom grates.
bottom end:
[1] All the moving parts in the crankcase and their bearings.
[2] the bottom part of the engine, where the crankshaft and usually the
transmission resides
[3] The lower range of engine revolutions
bottom end gasket kit:

All the gaskets below the base gasket (crankcase gaskets and inspection
cover gaskets) and all the O-rings and replaceable spacers in the bottom
end of an engine.
Also see
top end gasket kit.
bottom gear:
The lowest gear in a transmission.
bottoming:
[1] A situation where the suspension reaches the end of its travel.
[2] A situation where the lowest part of the chassis touches the ground,
especially on a bump
bottom out:
To reach the end of its travel.
bottom tank:
In a thermosyphon water-cooling system, this is the bottom radiator tank.
Also see
header tank
radiator tank
boulevard:
Trucker slang for interstate highway as in "Once we hit the boulevard we
can put some miles behind us."
bounce:
[1] When referring to valves, it indicates a condition where the valve is not
held tightly closed in the seat even though the camshaft has not opened it.
Also called "flutter" or valve bounce
[2] When referring to a distributor, it indicates a condition where the
points make erratic contact when they should remain closed. See contact
bounce.
[3] When referring to suspension, it indicates an up-and-down motion
called "jounce" and "rebound." You can test it by pushing down and
releasing a corner of a vehicle

bound electron:
See bound electrons.
bound electrons:
Electrons in the inner orbits around the nucleus of the atom, they are
difficult to move out of orbit.
bourdon tube:
A circular, hollow piece of thin metal tubing that is used in some
instruments, pressure on the hollow section causes it to attempt to
straighten, the free end then moves a needle on the gauge face. Used in
pressure gauges
bow:
See
header bow
hinge bow
hood bow
main bow
spring bow
bowden cable:
a cable or wire inside a metal or rubber housing used for remote control of
a valve or other device
bowed:
A bent shape.
bowden cable:
A wire control cable within a metal or rubber sheath and used for
activating a valve, clutch, choke, or accelerator
bowl:
See float bowl.
bowl vent:

(BV) connects the float bowl to the carburetor's air inlet. Depressurizes the
fuel being pumped into the float bowl by the fuel pump and acts as a vapor
separator by allowing vapors in the float bowl to escape into the carburetor
air inlet. Bowl vents are cut at a 45-deg angle and face incoming air so that
reference pressure remains the same regardless of airflow
bowl vent port:
(BVP) the port in the carburetor which vents fumes and excess pressure
from the float bowl to maintain atmospheric pressure
bowser:
A tanker used for refuelling military ground vehicles or airplanes
bow thrusters:
A propeller at the bow of the ship, used during maneuvering to provide
transverse thrust
bow wow:
A vehicle in very bad shape. A dog.
bow-wow:
A vehicle in very bad shape. A dog.
box:
[1] Colloquial term for a transmission.
Also see
crash gearbox
[2] A term for an electrical or electronic device.
Also see
E-box
control box
control unit
crash recorder
fuse box
[3] A silencer.
Also see
black box
cdi box
crash box
rocker box
roof box
steering box
stuffing box
tail light box
trigger box

panhard rod mounting box
slush box
squirt box transfer box
boxed rod:
A connecting rod in which the I-beam section has been stiffened by
welding plates on each side of the rod.
boxer:
a two-cylinder engine with the pistons opposing each other, resembling
fists flying away from each other.
boxer engine:
A horizontally opposed engine.
box member:
A structural part made as a box section
box section:
A closed panel structure of square cross section which is used to
strengthen a vehicle's underbody
box spanner:
A British term for a hollow tube with a socket at each end and two holes
through which a bar can be inserted to turn the wrench. The bar is called a
T-bar; but the British call it a tommy bar
box van:
A British term for a cube van with a large cargo box behind the driver's
cab.
box wrench:
A tool designed to secure or remove a bolt or nut. Each end of the wrench
fits around the bolt head or nut. British term for "ring spanner." In contrast,
see open end wrench.
boxy:

A derogatory description of a car that has square angles instead of smooth
curved lines.
boy:
See low boy
boyle's Law:
law of physics: volume of a gas varies as pressure varies, if temperature
remains the same. Example: if absolute pressure is doubled on quantity of
gas, volume is reduced one half. If volume becomes doubled, gas has its
pressure reduced by half
boy racer:
A low-cost car without much sophistication or performance; but it does
have a very sleek and sporty appearance.
boy scouts:
Trucker slang for State police as in "There's a bunch of boyscouts waiting
for you at the 157."
BP:
Acronym for barometric absolute pressure sensor or barometric pressure
sensor
BPA:
Acronym for bypass air solenoid
B-pillar:
The center body pillar on sedans. It connect
the sills and provides roof support. Sometimes
referred to as simply post, as in 1957 Chevy
two-door post. On a true hardtop design these
pillars are missing, leaving uninterrupted glass
area along the sides of the car. Also called "B-
post."
B pillar:

See B-post.
B post:
B-post.
B-post:
The center body post on sedans. It connect the
sills and provides roof support. Sometimes
referred to as simply post, as in 1957 Chevy
two-door post. On a true hardtop design these
pillars are missing, leaving uninterrupted glass
area along the sides of the car. Also called "B-
pillar."
BPS:
Acronym for exhaust back pressure transducer valve
BPV:
[1] Acronym for bypass valve.
[2] Acronym for exhaust back pressure transducer valve
bra:
A protective cover, usually of leather or vinyl,
which is mounted to the front of a vehicle to
protect the finish from stones.
Also see
stealth Bra
brace:
A support beam to give reinforcement between two objects.
Also see
roof brace
speed brace
bracing:
[1] To stiffen something by using a brace.
[2] A brace. See cross bracing
bracket:
a support device which is often a right-angled shape.

Also see
bilge bracket
bottom bracket
bumper bracket
drive end bracket
end bracket
fender support bracket
margin bracket
slip-ring end bracket
spring bracket
towing bracket
tripping bracket
wing support bracket
bracket set:
See chassis bracket set
braided hose:
A rubber hose which is covered in a woven material or braided wire. Used
for various hoses under the hood.
brake:
[1] To slow down a vehicle.
[2] The mechanism that converts motion (kinetic energy) into heat energy
through friction. The most common instance is found in the wheels of cars
where the brake shoes or disc pads are designed to press against the brake
drum or brake disc.
Also see
air brake
anti-lock brakes
anti-lock brake
system
armature brake
assisted brakes
band brake
bleeding the
brakes
bonded brake
lining
cable brake
caliper disc brake
cantilever brakes
clutch brake
E-brake
emergency brake
engine brake
fixed-caliper disc
brake
fixed-cam brake
flexible brake pipe
floating caliper disc
brake
flushing the brakes
foot brake
forward brake shoe
four wheel disc
brakes
high-mounted brake
jam on the brakes
jam the brakes
juice brake
leading brake shoe
low brake pedal
master brake
cylinder
maximum brake
power
mechanical brakes
non-servo brake
park brake
park brake
extension
parking brake
primary forward brake
shoe
prony brake
pumping the gas brakes
pump the brakes
reverse brake shoe
rim brake
riveted brake lining
rollercam brake
self-energizing brake
shoe
service brake
servo action brake
servo brake

coaster brake
disc brake
disc brake gauge
disc brake rotor
disc brakes
double leading
brake shoe
drum brake
dual brakes
duo-servo brake
light
hinged-caliper disc
brake
hub brake
hydraulically-
activated brakes
hydraulically-assisted
brakes
hydraulic assisted
brakes
hydraulic brake
booster
hydraulic brakes
inboard brake
jake brake
console
parking brake lever
strut
parking brake lever
parking brake pedal
parking brake
pin slider caliper
disc brake
power assisted
brakes
power brake
press brake
primary brake shoe
shooting brake
single-anchor self-
energizing brake
sliding-caliper disc
brake
sprag brake
spring brake
U-brake
uni-servo brake
vacuum assisted brake
ventilated brakes
brake adjuster:
A device which moves the brake drum shoes closer to or further apart from
the drum.
brake adjusting spanner:
A British term for brake wrench
brake adjusting wrench:
A wrench which is used to adjust the brake shoes
brake anchor:
A steel stud or pin upon which one end of the brake shoes is either
attached to or rests against. The anchor is firmly affixed to the backing
plate.
brake, anti-lock:
See anti-lock brakes.
brake antiroll device:
See brake anti-roll device.
brake anti-roll device:

A unit installed in the brake system to hold brake line pressure when the
vehicle is stopped on an upgrade, when the vehicle is stopped on the
upgrade and the brake pedal released, the anti-roll device will keep the
brakes applied until either the clutch is released or as on some models, the
accelerator is depressed.
brake backing plate:
A rigid metal (steel) plate,
located inside the brake drum,
on which the wheel cylinder,
brake shoes, and other brake
parts are mounted. The
braking force applied to the
shoes is absorbed by the
backing plate.
brake balance:
the ratio of front-to-rear braking force
brake band:
A band, faced with brake lining, that encircles a brake drum, it is used on
several parking brake installations. It differs from brake shoes in that brake
shoes squeezes against the inside surface of a drum while a brake band
squeezes against the outside surface of a drum.
brake bias:
The front/rear distribution of a vehicle's braking power. For the shortest
stopping distance, brake bias should match the vehicle's traction at each
end during hard braking brake modulation -- the process of varying pedal
pressure to hold a vehicle's brakes on the verge of lockup. Ideally, the
brakes will unlock with only a slight reduction in the pressure needed to
lock them. Typically, however, a considerable pressure reduction is
required.
brake bleeder:

A valve attached to each wheel brake. This valve can be opened and closed
to allow air to be removed or bled from the brake lines.
brake bleeding:
See bleeding the brakes.
brake block:
See brake pad.
brake booster:
[1] A mechanical device
which attaches to the brake
system to multiply the force
the driver applies with his
foot (or hand as in the case of
a motorcycle). The device
uses air, vacuum, or hydraulic
fluid to accomplish this
purpose. Sometimes called
"power assisted brakes,"
"vacuum assisted brakes,"
"hydraulically assisted
brakes," or just "power
brakes." In most cars, the
boost comes from engine
intake vacuum. In
motorcycles it comes from
hydraulic fluid.
[2] An arch (usually built
from aluminum or carbon
fiber) which attaches to the
brake bosses of a bicycle in
conjunction with the brake.
The powerful braking force of
V-Brakes or linear pull brakes
can cause frames and forks to
flex and waste energy which
could have been applied to the
rims. The booster acts as a
brace to prevent frame flex

induced during braking.
Also See
hydraulic brake booster
vacuum brake booster
brake boss:
The brazed-on pivots attached to frames and forks for cantilever and "V"
style brakes. Shift lever bosses are brazed-on pivots for down-tube-
mounted shift levers. Most newer "road" bicycles have the shifters
mounted on the handlebars, so they use the old-style lever bosses as
attachment points for housing stops
brake cable:
[1] A wire cable which activates the brakes. Used on motorcycles, trailers,
and automobile parkbrakes.
[2] A wound steel cable running from the brake levers of a bicycle to the
brake calipers.
brake cable housing:
The outer, colored housing into which a brake cable is inserted.
brake caliper:
The component of a disc brake that converts hydraulic pressure into
mechanical energy. See calipers.
brake check:
Trucker slang for jamming on your brakes in traffic as in "Watch out we're
doing a break check up ahead."
brake console:
See
parking brake console
computer brake control
brake cylinder:
A cylinder containing a movable piston actuated by hydraulic pressure to
push fluid through the lines and wheel cylinders and force the brake lining
or pads against a drum or disc.

Also see
wheel cylinder
master brake cylinder
brake disc:
The component of a disc brake that rotates with the wheel and is squeezed
by the brake caliper and pads, which creates friction and converts the
energy of the moving vehicle into heat. A British term for brake rotor.
brake disc type:
A braking system that instead of using the conventional brake drum with
internal brake shoes, uses a steel disc with caliper type lining application,
when the brakes are applied, a section of lining on each side of the
spinning disc is forced against the disc thus imparting a braking force. This
type of brake is very resistant to brake fade.
Also see
disc brake.
brake dive:
The action of the front end of a vehicle as it dips down when the brakes
are applied. Opposite to squat.
Also see
anti-dive system
anti-lift
anti-squat system
brake drum:
A cast iron or
aluminumhousing bolted to
the wheel, that rotates around
the brake shoes. When the
shoes are expanded, they rub
against the machined inner
surface of the brake drum and
exert a braking effect upon the
wheel to slow or stop the
vehicle.
brake drum lathe:

A machine to refinish the inside of a brake drum.
brake dust:
The dust created as the brake linings wear down in normal use. Brake dust
usually contains dangerous amounts of asbestos
brake extension:
See park brake extension
brake fade:
Reduction or loss in braking force due to loss of friction between brake
shoes and drum (or brake pads and disc). Caused by heat buildup through
repeated or prolonged brake application.
brake failure:
The total inability of the brakes to function. May be caused by worn out
pads or shoes, broken hydraulic lines, broken cable or other linkage, non-
functioning master cylinder, low or empty brake fluid reservoir, etc.
brake feel:
A discernible, to the driver, relationship between the amount of brake
pedal pressure and the actual braking force being exerted. A special device
is incorporated in power brake installations to give the driver this feel.
brake fluid:
A special fluid used in hydraulic brake systems to stop or slow the vehicle.
Never use something else in place of regular fluid. There are four types of
brake fluid on the market. DOT 3, DOT 4, DOT 5, and DOT 5.1.
Also see
silicone brake fluid
brake fluid reservoir:
In an automobile, it is a translucent tank located in front of the master
cylinder. It usually has two chambers containing brake fluid. In a
motorcycle, it may be found on the handlebar (for the front brake) or near
the back of the bike (for the rear brake).

brake flushing:
Cleaning the brake system by flushing with alcohol or brake fluid. This is
done to remove water, dirt, or any other contaminant, flushing fluid is
placed in the master cylinder and forced through the lines and wheel
cylinders where it exits at the cylinderbleed screws.
brake gauge:
See disc brake gauge
brake hood:
A plastic, rubber, or leather covering mounted
around the brake levers to keep out the dust
and to provide a non-abrasive placement for
the hands during cycling
brake horsepower:
(bhp) A measurement of the actual usable power (not calculated power)
measured at the output shaft (usually the crankshaft) rather than at the
driveshaft or the wheels. Thus none of the auxiliaries (gearbox, generator,
alternator, differential, water pump, etc.) are attached. It is called the brake
horsepower because the shaft power is usually measured by an absorption
dynamometer or "brake." This is not the brake on the vehicle's wheels but
a testing device applied to the shaft. This instrument is applied to stop or
absorb the rotation of the output shaft and returns a value. Compare SAE
gross horsepower and SAE net horsepower.
Also see
horsepower
brake hose:
A flexible high-pressure hose that is reinforced. It connects between the
brake pipes and the brake assembly. It needs to be flexible because of the
constant movement of the suspension
brake lathe:
The machine used to resurface the friction surfaces of brake discs or drums

brake lever:
[1] A blade attached to the right side of a
motorcycle handlebar which usually activates
the front brake.
[2] A device for activating the park brake.
[3] A curved blade found on either side of a
bicycle handlebar which activates the front or
rear brakes
Also see
parking brake lever
brake lever strut:
See parking brake lever strut
brake light:
A red light at the rear of the vehicle which is activated when the brakes are
applied. Also called "stop light."
Also see
high-mounted brake light
auxilliary brake lights
brake line:
See brake lines.
brake lines:
A system of hoses and metal tubes through which the brake fluid flows
from the master cylinder to the brake calipers at each wheel. Cracks or
breaks in these lines will cause the fluid to leak out and result in loss of
brakes.
brake lining:

A heat-resistant friction material (usually asbestos) that is attached to the
brake shoe (either riveted or bonded). When the shoe is pressed against the
brake drum, the lining grabs the inside of the drum, which stops the
vehicle and also prevents the drum and the shoe from wearing each other
away.
Also see
bonded brake lining
riveted brake lining
brake lock:
See steering wheel and brake lock
brake master cylinder:
The part of the hydraulic
brake system which stores the
brake fluid. As the brake
pedal is applied pressure is
forced against a small
movable piston in the master
cylinder to push hydraulic
fluid through the lines to the
wheel cylinders and force the
brake linings against the drum
(in the case of drum brakes)
or force the brake pads
against the disc (in the case of
disc brakes).
brake mean effective pressure:
(BMEP) The average pressure in the cylinders of an engine divided by its
mechanical efficiency, i.e., the ratio of the power actually delivered at an
output shaft to the power developed in the cylinders. It is used as an
indication of torque.

brake pad:
[1] The friction material or lining which is
secured to metal plates. They press against the
brake disc or rotor to enable the wheel to stop.
They are to be distinguished from brake shoes
which press against the inside of a drum.
[2] On a bicycle, brake pads are blocks of
rubber-like material fastened to the end of the
brake caliper; they press against the wheel rim
when the brakes are applied. Also called
"brake block." Sometimes the term "brake
pad" refers to both the pad and the metal
backing.
Also see
ceramic brake pad
sintered metal brake pad
brake pads:
See brake pad.
brake pad wear indicator:
A device which detects the thickness of the brake pad by using an L-
shaped strap which will scrape against the disc when the pad thickness is
below tolerance. Others use an electrical circuit in which a worn pad
closes an electrical circuit that illuminates a light on the dash panel.
brake pedal:
A foot operated device which engages the brakes to stop or slow the
rotation of the wheels.
Also see
low brake pedal
parking brake pedal
spongy brake pedal
brake pipe:
A steel pipe used to transmit the brake fluid. See flexible brake pipe

brake piston:
On a motorcycle, pressure from the brake lever (when squeezed) forces the
brake fluid to flow from the master cylinder down through the brake line
and into the caliper. The pressure of the brake fluid causes the piston to
push the brake pad to rub against the disc, thus stopping movement of the
motorcycle.
brake, power:
See
power brakes
maximum brake power
brake pressure modulator valve:
(BPMV) a combined assembly of the electronic control unit and hydraulic
control unit, used in tome GM vehicles, Also called the Electro-Hydraulic
Control Unit (EHCU)
brake puck:
See brake pads.
brake pucks:
See brake pads.
brake pulling:
A situation where the vehicle moves to one side when the brakes are
applied. It is usually due to uneven application of the brakes from side to
side.
brake, parking:
See
parking brake
emergency brake

brake proportioning valve:
A valve that limits braking
force to the front or rear
wheels, usually as a function
of pedal effort or line
pressure, loading of the
vehicle or front-rear weight
transfer, to prevent wheel
locking and provide the most
effective braking.
brake rod:
A long rod which connects between the brake pedal and the brake
actuating lever.
brake rotor:
The brake disc which is attached to the wheel and is surrounded by a brake
caliper.
Also see
disc brake rotor
brakes, antilock:
brakes, anti-lock:
brakes, cantilever:
see cantilever brakes
brake servo:
A device which multiplies the driver's physical effort in applying the
brakes by using manifold vacuum
brake servo unit:
See brake servo

brake shoe:
That part of the brake system,
located at the wheels, upon
which the brake lining is
attached. There are usually
two shoes (curved or arc-
shaped pieces) in each wheel.
When the wheel cylinders are
actuated by hydraulic pressure
they force the brake shoes
apart and bring the lining into
contact with the brake drum.
In this way the vehicle is
slowed or stopped. On a
bicycle, it is the metal part
that holds a brake pad and is
bolted to the end of a brake
caliper.
Also see
double leading brake shoe
forward brake shoe
leading brake shoe
primary brake shoe
primary forward brake shoe
reverse brake shoe
secondary brake shoe
self-energizing brake shoe
single leading brake shoe
trailing brake shoe.
brake shoe grinder:
A grinder used to grind brake shoe lining so that it will be square to and
concentric with the brake drum.
brake shoe heel:
That end of the brake shoe closest to the anchor bolt or pin.
brake shoe return spring:
A spring which is attached to the two brake shoes. After the brake is
applied, this spring pulls the shoes away from the drum

brake shoes:
The components of a drum brake assembly that are surfaced with brake
lining and forced against the brake drum to generate friction
brake shoe toe:
The free end of the shoe, it is not attached to or resting against an anchor
pin.
brake sidepull:
See sidepull brake
brakes linear pull:
see linear pull brakes
brakes, power:
See power brakes.
brakes V:
see V brakes
brake system:
A system that uses hydraulic pressure to enable your vehicle to slow and
stop safely. Consists of the master cylinder, brake lines, and disc or drum
brakes at each wheel.
Also see
anti-lock brake system
brake system cleaner:
A type of solvent designed exclusively for cleaning brake system
components. It will not destroy plastic, rubber, or synthetic rubber
components and it dries quickly, without leaving a residue
brake test:
A testing procedure which determines the efficiency of a vehicle's brakes
in order to pass safety tests

brake torquing:
A procedure generally used in performance tests to improve the off-the-
line acceleration of a vehicle equipped with an automatic transmission. It
is executed by firmly depressing the brake with the left foot, applying the
throttle with the vehicle in gear to increase engine rpm, then releasing the
brakes. Brake torquing is particularly effective with turbocharged cars
because it helps overcome turbo lag.
brake warning light:
An indicator light on the dash which indicates problems such as low fluid
level in the brake fluid reservoir, a malfunction in any of the hydraulic
brake circuits, or excessive wear of the brake pads or shoes. It also
illuminates when the parkbrake is applied. When the ignition is first
started, the light will illuminate momentarily to show that the light is
working.
brake wrench:
A wrench which is used to adjust the brake shoes. The British call it a
"brake adjusting spanner."
braking:
The action of operating the devices for slowing the motion of a vehicle.
Also see
active braking time
all-out braking
cadence braking
diagonal split braking
system
dual-circuit braking
system
dual-line braking
system
dual braking system
engine braking effect
heavy braking
hydraulic braking
system
late braking
light braking
regenerative
braking
stab braking
trail braking
braking distance:
A measurement of the distance that a vehicle will travel from the time the
brakes are first applied to the actual moment it stops.
Also see
stopping distance
braking effect:
See engine braking effect

braking efficiency:
braking effort as a percentage of the weight of the vehicle
braking effort:
The amount of strength needed by the operator to bring a vehicle to a stop
or the amount of resistance in the brake system
braking force:
The amount of strength needed by the operator to bring a vehicle to a stop
or the amount of resistance in the brake system
braking ratio:
The distribution of braking effort between the front and rear wheels
braking system:
All the components that contribute to stopping the vehicle.
Also see
anti-lock braking system
diagonal split braking system
dual-circuit braking system
dual-line braking system
dual braking system
hydraulic braking system
secondary braking system
single-circuit braking system
single-line braking system
braking time:
See active braking time
brand number:
A series of identifying numbers and letters which some companies burn
into the sidewall rubber of a truck tire to show their initials, mounting
date, etc.
brass hammer:
A hammer with a brass head. Because the head is softer than steel it is
used for hitting a steel object without damaging that object

brass punch:
A drift or punch made of brass which is used to remove bushings and
bearing races because brass does not score or mark steel.
brass hammer:
A hammer with a brass head which is used to pound steel
pins etc. into place without damaging them.
braze:
To join two pieces of metal together by heating the edges to be joined and
then melting drops of brass or bronze on the area. Unlike welding, this
operation is similar to soldering, except a higher melting point material is
used.
braze on:
See braze-ons.
braze-on:
See braze-ons.
braze-ons:
Parts for mounting shift levers, cable guides, pump pegs, chain hangers,
front and rear eyelets, derailleurs, water bottle cages, and racks, which are
fastened to a bicycleframe through a type of soldering process known as
brazing.

braze welding:
Making an adhesion groove, fillet, or plug connection with a brazing alloy
brazing:
Making an adhesion groove, fillet, or plug connection with a brazing alloy
brazing flux:
Substance applied to surfaces to be joined by brazing or soldering to keep
oxides from forming and to produce joints.
breadth:
See beam
break:
[1] The action of an item when it no longer holds integrity -- usually
resulting in unusable pieces.
See
impact break
circumferential break
[2] To dismantle a vehicle for parts.
[3] To separate as when a switch breaks contact when it is shut off
[4] Trucker slang for "I'd like to break-in" or "interrupt" as in "Can I get a
break."
break-10:
Trucker slang for "I want to talk (on channel 10)" as in "Can I get a break
one-oh."
break away:
See breakaway
breakaway:
The action of a wheel when it turns very rapidly and loses traction so that
there is no contact with the ground. Bias-belted tires and radial tires resist
the breakaway action better than a bias ply tire. Also see spark breakaway

breakaway barricade:
A road obstruction which is designed to warn
motorists that the road is unpassable or that
there is construction in a particular lane. It is
easily dismantled (thus "breakable").
breakbulk vessel:
A general, multipurpose, cargo ship that carriers cargoes of nonuniform
sizes
break down:
[1] To cease to operate as in our car broke down on the highway.
[2] To lose its insulating effectiveness
breakdown:
[1] A failure of a mechanism or vehicle as in we had a breakdown on the
highway.
[2] A loss of insulating effectiveness
breakdown recovery:
Rescue of a vehicle that has suffered a breakdown by towing it to a service
station, etc.
breakdown service:
A service provided by a tow-truck in providing repairs at the place where
the breakdown occurred
breakdown truck:

A tow-truck
breaker:
[1] A person who dismantles a vehicle for parts. Also called a dismantler.
[2] A cushioning layer between the belt layers and the tread in radial tires.
[3] A device for removing contact.
[4] Trucker slang for a CB'er who asks to use a channel as in "Who's that
breaker out there."
Also see
bead breaker
chain breaker
circuit breaker
contact breaker
dual breaker points
glaze breaker
breaker arm:
The movable part of a pair of contact points in a distributor or magneto.
breaker cam:
The lobed cam rotating in the ignition system
which interrupts the primary circuit to induce a
high tension spark for ignition.
breaker gap:
See contact breaker gap
breaker plate:
The movable plate inside the distributor to which the points and the
condenser are attached.
Also see

contact breaker plate
breaker point:
See
breaker points
contact breaker point
breaker points:
A mechanical switch in the distributor with
two metal contact points (usually made of
silver, platinum, or tungsten) that open and
close. When the points are closed, energy is
stored in the primary windings of the coil.
When the breaker points open, this energy is
transferred to the secondary windings of the
coil and stepped up, resulting in a high
voltage to fire the plugs. The air gap
between the breaker-point surfaces is
critical. If the gap is too small, the timing is
retarded, if too wide advanced. Also called
"points," "contact points," and "ignition
points."
Also see
dual breaker points
contact breaker point.
breakerless:
A distributor or ignition system where the mechanical switching device
(such as points or contacts) are replaced by an electronic switching device
through the use of transistors. They are also called "contactless" or "all-
electronic ignitions."
breaker strip:
Strip of wood or plastic used to cover joint between outside case and
inside liner of refrigerator
breaker's yard:
A British term for a salvage yard

breaker-triggered transistorized ignition:
A transistorized ignition system whose distributor is the same as that of a
coil ignition system, but whose contact breaker switches only the control
current of the transistor, not the primary current. Usually not fitted as
original equipment.
break in:
See break-in.
break-in:
Period of operation between the installation of new or rebuilt parts and the
time in which the parts are worn to the correct fit, driving at a reduced and
varying speed for a specified mileage to permit parts to wear to the correct
fit. British term is "run-in."
break-in oil:
Special formulated oil used in a new engine for a specified amount of time
so that all bearing surfaces, etc. are properly seated.
break one-oh:
Trucker slang for "I want to talk (on channel 10)" as in "Can I get a break
one-oh."
break-out box:
(BOB) a service tool that tees-in between the computer and the multi-pin
harness connector. Once connected in series with the computer and the
harness, this test device permits measurements of computer inputs and
outputs
breakover:
The area of a dent in a panel where the sheet metal is actually buckled into
the opposite direction of its normal shape
break time:
The length of time the contact breaker points remain open. Opposite to
dwell

break up:
British term for dismantling a vehicle and selling the parts. Similar to part
out
breakwater:
Plates fitted on a forward weather deck to form a V-shaped shield against
water that is shipped over the bow
breasthook:
A triangular plate bracket joining port and starboard side stringers at the
stem.
breathalyze:
To administer a breathalyzer test
breathalyzer:
A device into which a driver blows to determine the amount of alcohol in
his breath (and thus in his blood)
breathalyzer test:
A test given by the police to determine if a driver has exceeded the
allowable alcohol content in his system.
breather:
A vent in the crankcase for relieving internal pressure or admitting air.
Also see
crankcase breather
oil breather pipe
oil breather
breather pipe:
A pipe opening into the interior of the engine. It is used to assist
ventilation the pipe usually extends downward to a point just below the
engine so that the passing air stream will form a partial vacuum thus
assisting in venting the engine.

Also see
oil breather pipe
breather port:
The small passage between the master cylinder fluid reservoir and the area
behind the primary cups of the pistons. This port allows fluid from the
reservoir to fill the area behind the cups when the brakes are applied,
which prevents air bubbles from traveling around the lips of the primary
cups as the brakes are released. See replenishing port
breathing:
The action of taking in air for combining with fuel for burning as energy
and then exhausting it. See breathing capacity.
breathing capacity:
The volume of air that enters the cylinder during each intake stroke.
Volumetric efficiency is determined by comparing the actual volume of air
with the maximum possible amount. Also called "air capacity."
breath test:
See breathalyzer test
breeching:
Space in hot water or steam boilers between the end of the tubing and the
jacket
brevet:
Literally, the word means "certificate," "patent," or "diploma" in French.
In randonneuring, it means two things: certification of having successfully
done a randonné, and the long-distance bicycle event itself of at least 200
kilometers. Brevet and randonnée are often interchangeable terms, but a
randonnée might be considered to be less structured or less formal than a
brevet.
Brewster:
are classic cars.

BRG:
Acronym for British Racing Green
bricklayer hammer:
A special hammer for chipping cement blocks and bricks
bridge:
A metal support which is installed in the valve slot of a wheel rim and
prevents the flap and tube from bulging through the slot under high
pressure and high heat conditions. Also called "lemna."
Also see
flying bridge
house bridge
navigating bridge
port bridge
bridge bolts:
High-strength bolts used to fasten together the halves of a split brake
caliper
bridged:
See diode.
bridge igniter:
A device for detonating the air bag
bridge washer:
A protective thin metal washer installed at the valve stem between the flap
and rim base to prevent the tube and flap from protruding through the
valve slot as a result of high pressure and high temperature.
bridging:
A characteristic of undercoats that occurs when a scratch or other
imperfection in the surface isn't completely filled. Usually due to under-
reducing the primer or using a solvent that dries too fast.

Also see
gap bridging
bright:
A lustrous, shiny finish. Opposite to matt
brightening:
See chemical brightening
brine:
Water saturated with a chemical such as salt
Brinell hardness:
A test of a metal's hardness by hydraulically pressing a hard ball into the
metal
Bristol:
See Arnolt Bristol.
British Association:
(BA) A term used to describe a series of fine, small diameter threads for
electrical and precision equipment
British Leyland:
(BL) A former manufacturer of British automobiles, now called the Rover
Group
British Motor Corporation:
(BMC) A former manufacturer of British automobiles which changed its
name to British Leyland and then to the Rover Group
British Racing Green:
(BRC) A dark green color which used to be the official racing color for
British cars

British Standard Fine:
(BSF) The fine screw thread used on most British vehicles before
metrication. The coarse thread was British Standard Whitworth
British Standards Institution:
(BSI) An organization which prepares and issues British standard
specifications
British Standard Whitworth:
A coarse screw thread used on British vehicles before metrication
British thermal unit:
(BTU) A measurement of the amount of heat required to raise the
temperature of one pound of water, one degree Fahrenheit.
brittle point:
A low extreme temperature at which a substance (like rubber) fractures on
sudden impact.
broach:
Bringing a metal surface to the desired shape by forcing (pushing or
pulling) a multiple-edged cutting tool across the surface.
broken-in:
A condition in which a new engine has overcome any wear-in problems.
broken storage:
The spaces between and around cargo packages, including dunnage, and
spaces not usable because of structural interference.
broker:
an intermediary with legal authority to operate on behalf of the
manufacturer.
bronze:

An alloy of copper and tin.
See
phosphor-bronze
sintered bronze
bronze welding:
See braze welding
Brough:
A vehicle brand of which the 1925-1948 Superior with required
application are classic cars.
Brougham:
See Cadillac Eldorado Brougham
BROW:
A small inclined ramp to allow passage of trucks over a hatch coaming or
bulkhead door sills etc
bruise:
Any tire injury which weakens, breaks, or separates the carcass cords
without damaging the visible rubber surface.
brush:
[1] A paintbrush. See airbrush.
[2] The pieces of carbon, or copper, that rub against the commutator on the
generator or starter motor or against the slip rings on an alternator. As they
wear down, they need to be replaced.
Also see
carbon brush
card brush
cup-shaped wire brush
file card brush
spark plug brush
third brush
wire brush
brushes:

See brush.
brush holder:
A device which keeps the carbon brushes in an electric motor in contact
with the commutator or slip ring
brush spring:
A spring which pushes against the back end of a carbon brush in an
electric motor to force it against the commutator or slip ring.
Also see
carbon brush spring
BSF:
Acronym for British Standard Fine
BSI:
Acronym for British Standards Institution
BSW:
Acronym for British Standard Whitworth
BTDC:
before top dead center. Spark occurs on the compression stroke, before the
piston reaches top dead center.
B thread:
See
internal thread
class B thread
BTU:
Acronym for "British thermal unit." The amount of heat that must be
added to one pound of water to raise its temperature one Fahrenheit
degree.
bubble:

A small blister in the finish of paint
bubble car:
A type of small car which was popular in the 1950s. It had a bulbous-
shaped glass front to provide maximum interior room in spite of its small
size. The door opened to the front of the driver. Examples are the BMW
Isetta and Heinkel Trojan
Bucciali:
are classic cars.
bucket:
See
headlight bucket
rust bucket
shim under bucket
bucket seat:
An individual seat which is found in pairs in
the front of a vehicle. Named because the
curvature of the backrest and cushion
resembles a cut-out bucket.

bucket tappet:
valve lifters that are hollow, cylindrical, and
closed at one end and used with some
overhead camshafts. The flat, closed end of the
tappet (bottom of the bucket) rests against the
camshaft lobe with part of the valve spring and
valve stem enclosed by the cylinder. Called
"bucket tappets" because they are shaped like
upside-down buckets.
Buckland:
See AC Buckland Open Tourer.
buckle:
[1] A locking clasp usually found on seat belts and tie-down straps.
[2] To crumple up, especially when metal bends in a vehicle accident
buckled plates:
Battery plates that have been bent or warped out of a flat plane
buckler:
A portable cover secured over the deck opening of the hawsepipes and the
chain pipes to restrict the flow of water through the openings
buckle up:
To put your seat belt on. British term is "belt up"
BUDC:

before upper dead center. Same as BTDC.
budd mounting:
See double cap nut.
buff:
As a verb it means to polish. As a noun it indicates an expert in a field or a
person greatly interested in the field as in Jim is a car buff.
Also see
nut
buff contour:
The specked shape of a buffed retread tire.
buffer:
A machine used to rasp the old tread from the tire.
Also see
jounce buffer
buffered radius:
A dimension that ensures the proper contour of the buffed surface
according to tire size and type and matrix dimensions.
buffeting:
Severe, pulsating force of wind. When you drive in a convertible with the
top down, you will often experience this buffeting action of the wind. It is
also noticeable when a vehicle is driven quickly with the windows down.
buffing:
[1] Smoothing and polishing a surface by using a buffing wheel and
polishing paste or liquid.
[2] Grinding or rasping off remaining tread rubber to give the casing
proper texture to accept new retread stock and proper dimensions to fit the
matrix.
buffing template:

A machined device of a specific shape used to obtain the required buffed
contour.
buffing wheel:
A disc which is covered in soft cloth or lambswool. It is powered by a tool
like a drill which spins the disc to give a high gloss shine to the surface of
a vehicle.
buff line:
The dividing line in the cross section of a tire between the buffed surface
of the original tire and the new retread rubber.
bug and tar remover:
A solution which will dissolve bugs and tar residue. After application, it
needs to be washed off or it will also remove the paint.
Bugatti:
A vehicle brand of which the 1925-1948 models are
classic cars. The 1951 Type 101 model is a milestone
car.
Click for books on
Bugatti
bug deflector:
A length of clear plastic which is
attached to the front of the hood to
prevent bugs from hitting the
windshield. Also called a bug shield
bug out:
Trucker slang for leaving a CB radio channel as in "I better bug out and
get some shut eye."
bug shield:
see bug deflector

Buick:
A vehicle brand of which the Riviera for 1949 and 1963-
70 are milestone cars. The 1931-32 series 90 with
required application are classic cars. The 1953-54 Skylark
are milestone cars.
Click for books on
Buick
Buick Century:
Buick
Click for books on Buick
Century
Buick Electra:
Buick Click for books on Buick Electra
Buick Grand National:
Buick
Click for books on Buick Grand
National
Buick Park Avenue:
Buick
Click for books on Buick Park
Avenue

Buick Regal:
Buick
Click for books on Buick Regal
Buick Riviera:
Buick
Riviera
Buick Skylark:
Buick
Skylark
build:
The thickness of the paint film deposited on the body during spraying
(measured in mils).
Also see
heavy film build
build date code:
A code which tells you what day, month, and year the engine was made.
Expressed alpha-numerically and stamped somewhere on the block
builder:
In retreading a tire, a machine used to apply tread rubber to a casing.

Also see
body builder
Builders and Repairers Association:
See vehicle Builders and Repairers Association
building basin:
A structure in which one or more ships may be built and floated by
flooding the basin.
build quality:
The quality of workmanship and material composition in the construction
of a vehicle.
build up:
[1] To increase the surface level of metal by welding more material on it
(and later grinding it to shape) or by adding filler to it.
[2] To assemble or put something together.
[3] To add material to something.
See
carbon build-up
pressure buildup
buildup:
[1] The amount a weld face is extended above the surface of the metals
being joined.
[2] An excess of some material as in, "There was a buildup of carbon on
the top of the piston."
Also see
carbon build-up
built-up crankshaft:
A crankshaft which is not cast or forged as one piece, but made of several
different parts.
bulb:
An electronic device which gives off light by the heating of an element
contained with a glass enclosure. The metal base which conducts the

electricity may be a barrel with locating pins, or it may have small
filament wires protruding from the base. In some cases it is a tube with
contacts at either end. When replacing bulbs, especially high intensity
bulbs like halogen, be sure to avoid touching the glass. The oil from your
fingers will cause the bulb to overheat and burn out quickly. If you do
touch the glass, you need to clean it with air dry it.
Also see
alcohol
bayonet bulb
double filament bulb
festoon bulb
halogen bulb
light bulb
outer bulb
quartz-halogen bulb
quartz halogen bulb
tungsten-halogen bulb
bulb, sensitive:
See sensitive bulb
bulk cargo:
Cargo such as oil, coal, ore, woodchips, etc. not shipped in bags or
containers
bulk carrier:
Ship designed to carry cargo such as grain, woodchips, ore, coal, etc. in
bulk
bulk charging:
Using large containers of refrigerant to charge the system. Commonly
employed with charging stations to perform complete system charges
bulkhead:
[1] A structural partition that separates compartments. This is generally a
metal wall that extends from one side of a vehicle to the other. In the
engine compartment, you would find a radiator bulkhead near the front
and a firewall near the back. Another bulkhead separates the passengers
from the trunk. The dashpanel is also a bulkhead.
Also see

rear bulkhead.
[2] Vertical partition walls which separates the interior of a ship into
compartments or rooms.
Also see
afterpeak bulkhead
collision bulkhead
forepeak bulkhead
screen bulkhead
swash bulkhead
bulkhead connector:
An OEM device used to connect wiring inside the vehicle body with
wiring outside the body. Usually located at the bulkhead or firewall
bulkhead deck:
The uppermost deck to which the transverse watertight bulkheads are
carried
bulk refrigerant drum:
A large (e.g., 10 lbs, 25 lbs, 30 lbs) container of refrigerant generally used
in professional air conditioning service shops which employ charging
stations to perform complete system charges
bull bar:
The upward extension of a bumper to protect lights and the grille.
Also see
nerf bar
bulldog:
Trucker slang for a Mack truck as in "Who we got in that eastbound
bulldog."
bullet-point pick hammer:
See pick hammer
bull horn:

A warning horn that sounds like the bellow of a bull or the moo of a cow
bull low:
The lowest gear in a transmission. Some older transmissions listed their
gears as bull low (used for getting out of a stuck condition or climbing a
very steep hill), low or first (used for starting out from a stop or for
climbing a moderate hill), second (used for town driving or slight hills),
third (used for highway cruising).
bulwark:
Fore-and-aft vertical plating immediately above the upper edge of the
sheer strake
bump:
[1] A slight rising of the pavement possibly
caused by a frost heave and if severe enough
will be indicated by a sign
[2] The upward movement of the wheels and
suspension. Also called "jounce."
Also see
hood bump rubber
bump and rebound:
The two stages of suspension movement requiring damping.
Also see
bump
rebound
bumper:
Originally a bumper was a separate metal bar or blade at each end of a
vehicle to prevent damaging the main part of the vehicle from damage
occurred by a slight bump into an obstruction or another vehicle.
Also see
bumper system

energy-absorbing bumper
energy absorbing bumper
front bumper
hood bumper
jounce bumper
quarter bumper
rear bumper skirt
absorbing bumper
bonnet bumper
bumper to bumper
wrapround bumper
bumper bar:
A tubular bar or series of bars which are designed to protect the front of a
vehicle
bumper blade:
A flat bar which is designed to protect the front or rear of a vehicle.
bumper bracket:
A device to which the bumper is attached to the frame, body, or chassis
bumper filler:
A small panel usually made of plastic which fits between the bumper and
the body of the vehicle.
bumper horn:
A short bumper extension which is mounted vertically (i.e., perpendicular
to the main bumper), usually one on each side of the bumper. The British
term is "overrider."
bumper insert:
A rubber or plastic strip fitted to the width of a bumper to prevent scoring
of the bumper.
bumper iron:
A bumper bracket

bumper jack:
A device for lifting one corner of a vehicle to change a tire.
Older cars used a long bar which fitted into a base. A device
on the long bar had a hook which was placed in a strategic
place on the vehicle. A lug wrench was inserted into the
other end of the device and used to move the device up the
long bar thus lifting the vehicle.
bumper panels:
See side bumper panels
bumpers:
See jounce bumpers
bumper skirt:
See rear bumper skirt
bumper sticker:
[1] A piece of rectangular paper with a sticky back which can be attached
to the back of a vehicle to promote something
[2] Trucker slang for a car following too closely as in "Hey Charlie better
watch out you got a bumper sticker on your backdoor."
bumper system:
An energy-absorbing system with some type of deformable material
including hydrauliccylinders which enable the bumpers to protect the
vehicle from damage in low-speed impacts.
bumper to bumper:
[1] A traffic condition in which a line of vehicles are stopped one after the
other or are moving very slowly.
[2] A way of expressing the entire vehicle from one bumper to the other.

bumping blade:
An autobody tool used for slapping out slight dents (sometimes without a
supporting dolly). It has slight serrations which hold the metal to avoid
stretching. Also called a "bumping file."
bumping file:
An autobody tool used for slapping out slight dents (sometimes without a
supporting dolly). It has slight serrations which hold the metal to avoid
stretching. Also called a "bumping blade."
bumping hammer:
An autobody hammer used with a dolly for restoring a panel's shape.
Also see
fender bumping hammer
bumping out:
An autobody term in which a damaged panel is hit with a hammer until it
is nearly the correct shape.
bumping spoon:
See spring beating spoon
bump rubber:
See hood bump rubber
bump start:
[1] A method of starting a manual transmission (not for automatics)
vehicle by pushing it (especially down a hill) and letting in the clutch
while in second gear and the ignition set to the "on" position.
[2] To start a car using a bump start
bump steer:
When an uneven road surface causes a vehicle to steer or lose directional
stability, this is called "bump steer." At the front, bump steer is associated
with the tie-rod and linkage-arm relationship. It is caused by the method of
locating the rear suspension, the type of rear suspension, and the geometry
of the various linkages. In race cars, bump steer is designed out of the

suspension so that the handling is as precise as possible. In most cars it is
present to some degree. In fact, it can be useful to allow engineers to
design a small amount of understeer or oversteer into the chassis.
bump stop:
A cushioning
device,
usually
rubber, that
limits the
upward
movement of
the wheels
and
suspension to
prevent
metal-to-
metal contact
that could
lead to
suspension
damage or
failure. Also
called
"jounce
bumpers."
bundled out:
Trucker slang for Trailer is fully loaded as in "As bundled out as I am
those hills will really slow me down."
bungee cord:
A rubber tie down strap of various lengths (usually 10 mm diameter) with
a metal hook on each end. Most are covered with fabric. The hooks are
often plastic coated to minimize scratching. Some have an extra hook
attached in the middle. Others are linked with a second cord to produce an
X-shape. They are used to secure objects to a luggage rack. See bungee
net.
bungee net:

A specialized bungee cord shaped in the pattern of 25 squares with plastic
covered hooks on two opposite sides of the net. It is used to secure objects
to a luggage rack. See bungee cord and cargo net.
bunk:
A built-in bed on a ship
bunker:
Space where ice or cooling element is placed in commercial installations
bunkers:
Fuel consumed by the engines of a ship
buoyancy:
See center of buoyancy
Bureau of land management:
(BLM) The United States government agency within the U.S. Department
of the Interior which has divided trails into four classes: Type I is at least 7
feet (213 cm) wide (enough for a family vehicle), paved, easy to traverse.
Type II is also at least 7 feet (213 cm) wide, not paved, but is usually
improved. However it may be rough or rutted and contain washboards. It
is best travelled by high-clearance 4WD vehicles. Type III is a narrow
unimproved dirt road, often with rocks, steep hills, and mud over which
only 4WD should use. Type IV trails are for mountain bikes, dirt bikes,
and ATVs. 2WD or 4WD vehicles are not allowed.
burglar:
See car burglar
burned metal:
A term occasionally applied to the metal which has been combined with
oxygen to the end that some of the carbon has been changed into carbon
dioxide and some of the iron into iron oxide.
burned valves:

Valves that have become pitted so that they do not close properly
burner:
[1] A device which tends to consume a lot of material.
[2] Device in which burning of fuel takes place.
Also see
fuel burner
gas burner
lead burning
oil burner
burning:
[1] The violent combination of oxygen with any substance to produce heat.
[2] The action of consuming something to produce heat, i.e., combustion.
Also see
lead burning.
[3] The action of erosion or eating away. Electrical contacts are burning
when they wear away; exhaust valves are burning when they pit and don't
close properly.
[4] flame cutting.
Also see
afterburning
lead burning
burnish:
[1] To bring a surface to a high shine by rubbing with a hard, smooth
object.
[2] The process of "breaking-in" new brake pads or shoes so the linings
conform to the disc or drum friction surfaces
burn rate:
See
cbr process
controlled burn rate
burn rubber:
The action of rapid acceleration where the wheels make rapid rotation, but
there is only very little momentum. As a result, the driving wheels leave
some rubber behind on the pavement.
Also see

peel rubber.
burnt valves:
See burned valves
burr:
A roughness left on a cut or punched metal. A rough edge or ridge.
burred wheel:
A wheel which has metal slivers or roughness around the edge of the rim.
burr walnut:
A wood veneer used for dashboards and door trim on some cars.
Also see
zebrawood
burst:
To explode and suddenly lose all the air in a tire.
bury the needle:
Going beyond the displayed maximum speed. For example, a digital
speedometer may show speeds from zero to 137 kph (85 mph) on its
display. When the needle goes beyond the maximum displayed point, it
may go beyond the line of sight and is considered buried.
bus:
[1] A large public or private passenger vehicle used for transporting many
(at least 10) passengers.
Also see
articulated bus
single-decker bus
double-decker bus.
[2] A busbar which is a heavy conductor used to carry or make a mutual
connection between several circuits.
busbar:

A heavy conductor used to carry or make a mutual connection between
several circuits. Also called a "bus."
bush:
British term for bushing.
bushing:
[1] A protective liner or sleeve that cushions noise, friction, or movement.
Suspension bushings are often made from two pipes (one inside the other)
with a sleeve of rubber in the space between the two pipes.
[2] Rubber bushings on the suspension system should be lubricated
regularly.
[3] A bearing for a shaft, spring shackle, piston pin, etc., of one piece
construction which may be removed from the part.
Also see
valve bushing
buster:
See lock buster
busy intersection:
A road junction where there is a lot of traffic and may be controlled by
signal lights or not. Usually a place where accidents are more likely to
occur.
butane:
A petroleum gas that is a liquid, when under pressure. Often used as
engine fuel in trucks.
Also see
LPG.
butt:
[1] The end joint between two plates or other members which meet end to
end.
[2] The square ends of a piston ring
butt connector:

A solderless wire connector used to permanently join two wire ends
together
butted tubing:
Tubing whose outside diameter remains constant but whose thickness is
reduced in midsection where less strength is needed.
buttermilk:
Trucker slang for Any beer as in "When I get home I'm gonna get me some
buttermilk."
butterfly:
See
butterfly valve
throttle butterfly
butterfly valve:
A nut with wings to be turned by thumb and finger. Sometimes called a
"wing nut."
butterfly valve:
A small metal disc located in the carburetor that controls the flow of air
into the carburetor. It is so named due to its resemblance to the insect of
the same name.
butt joint:
[1] A piston ring gap in which the two ends of the ring are squared off.
[2] A weld where the two panels are not overlapped but fit against each
other end to end.
button:
A small disk or knob which activates something electrical when it is
pressed such as a starter button.
Also see
abs override button
eject button
frequency scan button

horn button
memory button
override button
preset station button
push button
release button
reset button
scan button
button head:
A bolt with a round head
buttons:
See button.
buttress:
A thick rubber reinforcement in the shoulder of a tire. It provides support
at the edge of the tread, limits shoulder area flexing, and protects the
shoulder of off-road tires. See fender strengthening buttress
buttressed thread:
A screw thread with one vertical and one inclined flank
butt strap:
A strap that overlaps the butt between two plates, serving as a connecting
strength strap between the butted ends of the plating
butyl:
A non-porous synthetic rubber used in making inner tubes and tubeless tire
liners.
butyl rubber:
A synthetic rubber used as a base for one type of adhesive. It has poor
resistance to petroleum oils and gasoline but excellent resistance to
vegetable and mineral oils; to such solvents as acetone, alcohol, phenol,
and ethylene glycol; and excellent resistance to water and gas adsorption
and sunlight

butyl tube:
The typical material for tubes. Inexpensive, easy to repair.
buy at end-of term interest rate:
The effective net interest rate for the lease if, at the end of the lease, the
car is purchased at the end-of-lease purchase price.
buying decisions:
the act of determining whether or not a product purchase or repair, will be
made, and/or which product or service will be purchased.
BV:
Acronym for bowl vent
BVP:
Acronym for bowl vent port
BVT:
Acronym for backpressure variable transducer
B/W:
Black and white, usually referring to photographs.
BW:
Acronym for "blackwall," as in BW tires.
bypass:
[1] A road which avoids the congested area of a city traffic.
[2] An alternate route for a flowing substance.
[3] To go around something to avoid it.
[4] A passage at one side of, or around, a regular passage
Also see
oil cooler bypass valve
oil filter oil filter bypass valve

start bypass
bypass air screw:
A screw located on the airflow sensor of a fuel injection system. It adjusts
the amount of air allowed into the air-fuel mixture.
bypass air solenoid:
(BPA) a device used to control the idle speed on some fuel-injected
vehicles
bypass filter:
An oil filter that constantly filters a portion of the oil flowing through the
engine.
bypass valve:
(BPV) A valve that can open and allow fluid or gas to pass through in
other than its normal channel.
Also see
oil cooler bypass valve
oil filter oil filter bypass valve

C:
[1] Abbreviation for Celsius or centigrade.
[2] Abbreviation for coulomb.
[3] Abbreviation for comfort.
[4] Symbol for the speed of light in a vacuum.
[C]:
One of the Fraunhofer lines in the red of the solar spectrum. Its
wavelength is 656.3045 nm; it is due to hydrogen.
χ:
(chi) Symbol for magnetic susceptibility
C-3:
Acronym for a computer command control system
C3I:
Acronym for computer controlled coil ignition
C-4 system:
Acronym for computer-controlled catalytic converter
CA:
API classification for diesel engine oil widely used in the late '40s and
'50s.
CAA:
Acronym for Civil Aviation Authority
CAAM:
Acronym for "China Association of Automobile Manufacturers."
CAB:

Acronym for Civil Aeronautics Board
cab:
[1] A taxi or car for hire.
[2] The closed part of a truck (or even a car) where the driver sits.
Also see
chassis cab
cabbage:
Trucker slang for a long steep incline in Eastern Oregon as in "I jammed
the brakes pullin' off of Cabbage"
cab chassis:
A truck chassis which includes the driver compartment.
cab-forward design:
A car design in which the front end is short and the footwells extended to
the front axle. This design gave more passenger space and pushed the
windshield further from the passengers
cabin:
A passenger compartment.
Also see
rear cabin pillar
cabin altitude:
The normal pressure altitude maintained in the cabin of a pressurized
aircraft.
cabin blower:
An engine-driven pump, usually of displacement type, for maintaining an
aircraft cockpit or cabin above atmospheric pressure. Also called cabin
supercharger.
cabin differential pressure:
The pressure in excess of that of the surrounding atmosphere which is
needed to maintain comfortable conditions at high altitude. For an aircraft

flying at 9000 m this differential would be about 60 kNm-2
.
cabin forward:
< d>See cab-forward design
clear=all>
cabin-forward design:
< d>See cab-forward design
clear=all>
cabin pillar:
< d>See rear cabin pillar
cabin superharger:
See cabin blower
cable:
A cord generally made of strands of thin wire. Electrical cables are
covered with a protective non-conducting material. Control cables are
housed within an outer sleeve.
Also see
booster cable
bowden cable
brake cable
clutch cable
control cable
gearchange cables
heavy cable
ignition cable
jumper cables
light cable,
shift cables,
spark plug cable,
speedo cable,
speedometer cable,
speedometer drive
cable,
starter switch control cable,
stirrup cable,
straddle cable,
transverse cable
cable activated:
A device which is controlled by a cable. As a lever or pedal is engaged, the
device is correspondingly moved. The longer the cable the less efficient is
the system. Cables tend to stretch and fray with use.
cable-angle indicator:
An indicator showing the vertical angle between the longitudinal axis of a
glider and its towing cable, also its yaw and roll attitude relative to the
towing aircraft.
cable brake:

A braking device which is activated by a cable
cable buoy:
A buoy attached to an anchor and serving to mark its position.
cablecar:
A tram pulled by a moving underground cable, in the same manner as the
cable railway.
cable clamp:
[1] A device for securing a cable end to the point where it connects.
[2] A device which secures the outer sheath of a cable
cable cover strip:
See spark plug cable cover strip
cable cutter:
A tool for severing a cable
cable ducts:
Earthenware, steel, plastic, or concrete pipes containing cables.
cable form:
The normal scheme of cabling between units of apparatus. The bulk of the
cable is made up on a board, using nails at the appropriate corners, each
wire of the specified color identification being stretched over its individual
route with adequate skinner. When the cable is bound with twine and
waxed, it is fitted to the apparatus on the racks and the skinners connected,
by soldering, to the tag blocks.
cable grip:
A flexible cone of wire which is put on the end of a cable. When the cone
is pulled, it tightens and bites into the sheath of the cable, and can be used
to pull the cable into a duct.

cable guide:
A tube which is secured in place to channel the cable which runs through it
cable-laid rope:
A rope formed of several strands laid together so that the twist of the rope
is in the opposite direction to the twist of the strands. Compare lang lay
cable lock:
A thick cable with a lock at one end and which can be wrapped around a
bicycle frame and a post to protect the bike from being stolen.
cable loom:
See spark plug cable loom
cable marker:
See spark plug cable marker
cable operated:
An item which is controlled by a cable
cable railway:
Means of transport whereby carriages are pulled up an incline by an
endless overground or underground cable.
cables:
See cable.
cable separator:
See spark plug cable separator
cable-stayed bridge:
A bridge type for medium spans in which the decking is suspended by
diagonal cables attached directly to the supporting tower. Can be of fan or

harp design. The decking is always in compression and is self-supporting
during construction. See bridge
cable-way:
A construction consisting of cables slung over and between two or more
towers, so that skips suspended from the cables may be moved often over
long distances. It is used for transport of ore etc. Also called blondin.
Cab Plus:
A type of pickup truck (by Mazda) which has a second row of seating; but
unlike a crew cab (which has four full size doors) it has a "half-door" that
can be opened only after the main door is opened. The seating is usually a
little more cramped than in a crew cab. Also called club Cab, extended
Cab, king Cab, xtracab, access Cab, supercab
cabriolet:
Similar to the sport coupé, it has a provision for converting to an open-
type body (i.e., convertible). A rumble seat is a common on older vehicles,
but not mandatory feature. Mercedes-Benz distinguishes the cabriolet from
the roadster in that the former has a soft-top which folds up while the
roadster has a hard-top which is stored in the trunk. Also called a
"drophead coupé."
CACIS:
Acronym for "Continuous AC Ignition System"
CAD:
Acronym for "computer aided design"
cadastral survey:
Land survey, boundary delineation.
Caddy:
An euphemistic name for Cadillac
Also see
plug caddy

cadence:
The speed your bicycle pedals turn. Professional bicycle riders have
cadence of over 100 rpm
cadence braking:
A braking method in which the driver rapidly depresses and releases the
brake pedal to bring a vehicle to an emergency stop
Cadillac:
The following Cadillacs are classic cars:
• All 1925-35 models
• All 12-cylinder models
• All 16 cylinder models
• All 1938-41 60 Special models
• All 1936-48 series #67, #70, #72, #75, #80,
#85, #90
For a history of Cadillac, see Cadillac History.
Click for books on
Cadillac
Cadillac DeVille:
A model of automobile manufactured by General
Motors' Cadillac division
Click for books on Cadillac
DeVille
Cadillac Eldorado:
A vehicle brand of which the 1953-58, 67-70
Eldorado models are milestone cars. Also see the
history of Cadillac Eldorado.
Click for books on
Cadillac Eldorado

Cadillac Eldorado Brougham:
A vehicle brand of which the 1957-58 models are milestone cars. Also see
history of Cadillac Eldorado.
Cadillac Seville:
Click for books on Cadillac
Seville
Cadillac 60 Special:
history of Cadillac.
Cadillac 61 Coupe Fastback:
history of Cadillac.
Cadillac 62:
A vehicle brand of which the Sedanet and Convertible DeVille for 1948-49
are milestone cars. Also see history of Cadillac.
Cadillac 75:
A vehicle brand of which the Sedan/Limo for 1946-70 are milestone cars.
Also see history of Cadillac.
cadmium cell:
A reference voltage standard, giving 1.0186 V at 20°C. Also called Weston
standard cadmium cell.
cadmium copper:
A variety of copper containing 0.7 to 1.0% cadmium. Used for trolley,
telephone, and telegraph wires because it gives high strength in cold-

drawn condition combined with good conductivity.
cadmium photocell:
A photoconductive cell using cadmium disulphide or admium selenide as
the photosensitive semiconductor. Sensitive to longer wavelengths and
infrared. It has a rapid response to changes in light intensity.
cadmium-plated:
Something that is covered with a coating of cadmium. It is usually used to
protect aluminum and steel nuts and bolts
cadmium red line:
Spectrum line formerly chosen as a reproducible standard of length,
wavelength 643.8496 nm.
CAE:
Acronym for Computer Aided Engineering
caesium:
British spelling for cesium
CAFE:
Acronym for "Corporate Average Fuel Economy."
café chop:
Converting a stock motorcycle into a café racer is known as doing a café
chop on a bike
café racer:
[1] Motorcycle modified to resemble racing motorcycles from the 1950s
and 60s. They are called "café racers" because their owners supposedly
raced from café to café in London, where the bikes first appeared in the
1960s
[2] An early sportbike motorcycle which originated in Europe. They had a
low windshield and the rider was bent forward to optimize the flow of air.
Its name came from those who raced from one restaurant (café) to another.

cage:
[1] Any enclosure.
[2] On a front derailleur of a bicycle, it is a pair of parallel plates that push
the chain from side to side; on a rear derailleur, it is a set of plates in
which pulleys are mounted to hold and guide the chain from cog to cog.
[3] Any device for holding or securing something, e.g., a bottle cage on a
bicycle.
[4] When referring to bearings, it is the part which holds the balls or rollers
in place. Usually called ball cage.
Also see
bearing cage
needle cage
roller cage
[5] When referring to a vehicle, it is the safety enclosure called a "roll
cage."
See
differential cage
integrated roll cage
multi-reed cage
[6] The platform on which goods are hoisted up or lowered down a vertical
shaft or guides; in mines, the steel box used to raise and lower workers,
materials, or tubs. May have two or three decks.
cage pedal:
A bicycle pedal that is surrounded by a cage. It
is found on all terrain bikes.
cage rotor:
A form of rotor, used for induction motors, having on it a cage winding.
Also called squirrel-cage rotor.
cage winding:

A type of winding used for rotors of some types of induction motors, and
for the starting or damping windings of synchronous machines. It consists
of a number of bars of copper or other conducting materials, passing along
slots in the core and welded to rings at each end. Also called squirrel-cage
winding.
Cailletet's process:
A method for the liquefaction of gases based on the free expansion of a gas
from a higher to a lower pressure.
CAJAD:
Acronym for "Canadian Association of Japanese Automobile Dealers"
cake:
The rectangular casting of copper or its alloys before rolling into sheet or
strip.
cal:
Abbreviation for calorie
CAL:
Acronym for Computer Aided Lighting
calandria:
Closed vessel penetrated by pipes so that liquids in each do not mix. In
evaporating plant the tubes carry the heating fluid and in certain types of
nuclear reactor, e.g., CANDU reactors, the sealed vessel is called a
calandria
calcium chloride:
A chemical (salt) which is added to water in a liquid ballast.
calcium sulphate:
Chemical compound (CaSO4), which is used as a drying agent or desiccant
in liquid line driers

calcium tungstate screen:
A fluorescent screen used in a cathode-ray tube; it gives a blue and
ultraviolet luminescence.
calculation:
See load distribution calculation
calendering:
A thin layer of rubber inside the tire casing which covers the carcass cords
to protect them from moisture and to protect the tube from chafing by the
cord body. In tubeless tires, calendering consists of a layer of air proof
butyl rubber.
caliber:
[1] The internal diameter or bore of a pipe, esp. the barrel of a fire-arm.
[2] The arrangement of the various components of a watch or clock. Also
spelled calibre.
calibrate:
As applied to test instruments it is the procedure of adjusting the dial
needle to the correct zero or load setting to determine accurate
measurements.
calibrated airspeed:
(CAS) Indicated airspeed corrected for position error and instrument error
only. Not to be confused with equivalent airspeed or true airspeed. Also
called rectified airspeed
calibration:
[1] Marking the measuring units on an instrument or checking their
accuracy
calibration oil:
Oil which is used in a tester for checking injection nozzles, meeting SAE
J967D specifications

calibre:
See caliber
California wheel:
A name given to a spoked wheel produced by particular manufacturer.
Although the wheel is popular in the East and Midwest of United States, it
is not common in California or other Western states.
caliper:
[1] The apparatus on disc brakes which hold the disc
pads and straddles the disc. When actuated the pads
press against the disc to stop or slow the vehicle.
Also see
brake caliper floating caliper disc brake
pin slider caliper disc brake swinging caliper
[2] On bicycles, the brake arms that reach around the sides of a wheel to
press brake pads against the wheel rim.
[3] (British spelling is calliper). An
adjustable measuring tool that is
placed around (outside caliper) or
within (inside caliper) an object and
adjusted until it just contacts. It is
then withdrawn and the distance
measured between the contacting
points.
Also see
dial caliper
digital caliper
inside spring caliper
machinists' caliper
outside spring caliper
pocket caliper
pocket slide caliper
vernier caliper
caliper disc:
See

floating caliper disc brake
pin slider caliper disc brake
caliper disc brake:
See
caliper gauge:
A caliper (definition #3)
caliper mounting bracket:
The component that connects a brake caliper to the steering knuckle, hub
carrier, or rear axle
calk:
To fill seams in a wood deck with oakum or hammer the adjoining edges
of metal together to stop leaks. Also spelled "caulk"
calking:
See caulking
call:
See close call
calliper:
Alternate spelling for caliper
Cal-look:
A style modification of small vehicles which first started in California.
Most of the chrome is removed and the vehicle is painted a bright color
like yellow, light blue, and red.
calorescence:
The absorption of radiation of a certain wavelength by a body, and its re-
emission as radiation of shorter wavelength. The effect is familiar in the

emission of visible rays by a body which has been heated to redness by
focusing infrared heat rays onto it.
calorie:
Two different calorie units are used by scientists. The calorie used by
medical science is a small heat unit. It equals the heat required to raise the
them of one gram of water one degree Celsius. The calorie used by
engineering science is a large heat unit. It is equal to the amount of heat
required to raise the temperature of one kilogram of water one degree C. In
the SI system it is recommended that the Joule unit of energy be used in
place of the calorie
calorific value:
A measure of heating value of fuel
calorimeter:
An instrument to measure amount of heat given off by a substance when
burned
CAM:
Acronym for "Computer Aided Manufacturing"
cam:
[1] A designed bump on a shaft or disc which causes a rocking motion in
an adjacent part.
[2] A metal disc with irregularly shaped lobes used in the camshaft to
activate the opening and closing of the valves and in the distributor, to
force the points to open.
[3] A colloquial name for the camshaft.
[4] A name for the breaker cam.
Also see
adjuster cam
closing cam
distributor cam
double overhead cam
dual overhead cam engine
exhaust cam
fast idle cam
floating cam
inlet cam
intake cam
overhead cam
single-overhead cam
cam-and-lever steering:
A steering system in which a conical peg mounted on a lever engages in a
helically cut groove on a cylindrical drum. Also called "cam-and-peg

steering"
cam-and-peg steering:
See cam-and-lever steering
cam-and-roller steering:
A steering system in which a tapered disc or a set of discs or rollers engage
with a helically cut, tapered groove on a cylindrical drum
cam angle:
See dwell.
Camaro:
A series of pony cars from the Chevrolet division of
General Motors. It is often misspelled as "Camero"
because of a mispronunciation. The 1967-69 SS/RS V-8
and Z-28 models are milestone cars. Also see Chevrolet
Camaro
Click for books on
Camaro
cam belt:
See timing belt
camber:
[1] A wheel alignment adjustment of the
inward or outward tilt on the top of the
wheel when viewed from the front of the
vehicle. Tipping the top of the wheel center
line outward produces positive camber.
Tipping the wheel center line inward at the
top produces negative camber. When the
camber is positive, the tops of the tires are
further apart than the bottom. Correct
camber improves handling and cuts tire
wear. Camber is measured in degrees. See
wheel camber.

[2] The rise of a deck of a ship, athwartship
cambered axle:
An axle that has a slight arch which curves upward at the center so that the
wheels can tilt outward at the top. In this way it is better than an axle
which might sag under load.
camber thrust:
The side force generated when a tire rolls with camber. Camber thrust can
add to or subtract from the side force a tire generates.
cam chain:
A timing chain which controls the overhead camshaft.
cam design:
See cam profile
camel:
A padded fender to keep a vessel away from a pier or quay to prevent
damage to the hull or pier
camelback:
[1] Uncured retread rubber in crescent shape, available in various widths
and depths according to size and type of tire being retreaded.
[2] A container for supplying water for cyclists
Also see
die size

Camel Grand Touring Prototype:
(GTP) An International Motorsports Association's (IMSA) premier racing
category until 1993 when it was replaced by the controlled cars World
Sports Car Championship. GTP cars were the most powerful and the
fastest on most road racing circuits in North America at that time. Over the
years, many automakers fielded factory teams in this series including Ford,
Toyota, Jaguar, Nissan, and Porsche.
cam engine:
See
dual overhead cam engine
twin cam engine
camera:
Trucker slang for Police radar unit as in "There's a local yokal with a
camera just ahead."
camero:
See Camaro
cam face:
The surface of a cam lobe

cam follower:
The unit that
contacts the
end of the
valve stem
and the
camshaft.
The follower
rides on the
camshaft and
when the
cam lobes
move it
upward, it
opens the
valve. Also
called "valve
lifter" or
"tappet."
cam ground piston:
See cam-ground piston.
cam-ground piston:
A piston with a skirt that is ground slightly egg-shaped or oval-shaped.
The widest diameter of the skirt is at right angles to the piston-pin axis.
When it is heated, it becomes round. The design allows for a closer fit in
the cylinder so that there is a reduction of blowby gas, cylinder scuffing,
and
piston slap.
cam heel:
The lowest point of a cam opposite the lobe. Also called base circle
cam lobe:
See cam lobes.
cam lobes:

The bumps on a cam that contact and activate such devices as the lifters,
which operate the valves, and the rubbing block, which causes the points
to open and close, as the cam spins with the distributor shaft.
cam lubricator:
A device, often in the form of a wick, for lubricating the contact breaker
cam in the distributor
campaigning:
Racing a particular vehicle for an entire season.
camper:
A structure which fits into a truck bed
for camping purposes. It usually has
beds and possibly cooking and
washing facilities. Also called a
"truck camper" or slide-in camper.
Also see
van camper
camping:
See folding camping trailer
camping trailer:
A trailer containing camping equipment.
Also see
folding camping trailer
soft-top trailer
hard-top trailer
trailer
cam profile:
The shape of each lobe on a camshaft. These shapes determine when the
valves open or close.
cam/rocker:

See opening cam/rocker
cam/rocker:
See opening cam/rocker
cam roller:
Rotating wheel acting as a cam follower
Camry:
A model of automobile manufactured by Toyota
Click for books on Camry
camshaft:
A shaft with
cam lobes
(bumps)
which is
driven by
gears, a belt,
or a chain
from the
crankshaft.
The lobes
push on the
valve lifters
to cause the
valves to
open and
close. The
camshaft
turns at half
the speed of
the
crankshaft.

Also see
double-overhead cam
double overhead
camshaft
exhaust camshaft
inlet camshaft
intake
camshaft
overhead cam
overhead camshaft
race camshaft
three-quarter race
camshaft
single-overhead
camshaft
twin camshaft
twin overhead camshaft
camshaft bearing:
Usually a plain bearing which supports the camshaft
camshaft drive:
A connection between the crankshaft and camshaft by means of gears,
chain, drive belt, shaft, or eccentric shaft to maintain the ratio of 1:2.
camshaft drive belt:
A timing belt
camshaft drive sprocket:
A sprocket attached to a crankshaft (either at one end or somewhere in the
middle) which drives the camshaft with the use of a chain
camshaft end play:
The amount of lateral movement of the camshaft once it is installed
camshaft engine:
See twin camshaft engine
camshaft gear:
A gear that is used to drive the camshaft.
camshaft housing:
That part of the engine which encloses the camshaft and often other parts
of the valve train.
camshaft journal:

That part of the camshaft that runs in one of its bearings
camshaft pulley:
The pulley on the end of the camshaft for the camshaft drive belt
camshaft sprocket:
The sprocket on the camshaft which (through a chain) is driven by the
camshaft drive sprocket
can:
[1] A tube in a canned motor pump which insulates the motor winding.
[2] A muffler.
[3] A container for liquid or other substances.
Also see
oil can
Canada-U.S. Free Trade Agreement:
(FTA) Implemented in January 1989 to eliminate all tariffs on U.S. and
Canadian goods by January 1998 and to reduce or eliminate many non-
tariff barriers.
Canadian Automotive Repair and Service Council:
(CARS) A not-for-profit organization established to serve the human
resource and training needs of the Canadian car and truck repair and
service industry.
Canadian cross border shopping:
cross border shopping describes the purchasing by Canadian consumers of
products in the United States. Of particular interest is the decision by these
buyers to obtain their products in the U.S., even though similar products
are available in the Canadian market.
Canadian Environmental Protection Act:
(CEPA) act where the goal is pollution prevention and protection of
Canadians from toxic substances.

cancellation:
See noise cancellation
candela:
(cd) A basic unit of luminous intensity. If, in a given direction, a source
emits monochromatic radiation of frequency 540 x 1012
Hz, and the radiant
intensity in that direction is 1/683 watt per steradian, then the luminous
intensity of the source is 1 candela.
candle:
See candle power.
candle power:
A measurement of the light producing ability of a light bulb.
candy apple paint:
A bright color (usually red) paint (often with metal flakes) with a
transparent clear coat
candy paint:
A bright color (usually red) paint (often with metal flakes) with a
transparent clear coat
canister:
A small metal box or can.
Also see
activated carbon canister
adsorption canister
charcoal canister
vapor canister
canister air filter:
A centrifugal force air filter
canister purge shut-off valve:
(CPSOV) a vacuum-operated valve that shuts off canister purge when the
air injection diverter valve dumps air downstream

canister purge solenoid:
An electrical solenoid that opens the canister purge valve between the fuel
vapor canister line and the intake manifold when energized
canister purge valve:
Valve used to regulate the flow of vapors from the evaporative canister to
the engine
canned motor pump:
A glandless pump with a special type of submersible or "canned" motor,
whose stator winding is insulated from the fluid pumped by a tube, the so-
called can
cannibalize:
The action of removing good parts from one vehicle in order to put them
into another vehicle.
canning:
The insertion of the catalyst element into the converter shell of a catalytic
converter
cannular combustion chamber:
A gas turbine combustion system with individual flame tubes inside an
annular casing.
canonical assembly:
Term used in statistical thermodynamics to designate a single assembly of
a large number of systems which are such that the number of systems with
energies lying between E and E+dE is proportional to e-Eθ
, where θ is a
parameter characteristic of the assembly
canopy:
[1] The transparent cover of a cockpit.

[2] The fabric (nylon, silk, or cotton) body of a parachute, which provides
high air drag. Usually hemispherical, but may be lobed or rectangular in
shape.
Also see
ribbon parachute
cant:
Slope of rail or road curve whereby outer radius is superelevated, to
counteract centrifugal thrust of traffic.
cant beam:
Beams supporting the deck plating in the overhanging portion of the stern.
canted deck:
The flight deck of an aircraft carrier prolonged diagonally from one side of
the ship, so that aircraft may fly off and land on without interference to or
from aircraft parked at the bows. The British term is angled deck
cant frame:
A frame connected at the upper end to the cant beams
cantilever:
An arm that projects from a source and supports cables.
Also see
cantilever brake
cantilever brake:
[1] A bicycle rim brake with pivoting arms mounted on fork blades or
seatstays at or below rim level. The two brake arms are connected by a
straddle cable with the brake cable attached to the midpoint of the straddle
cable.
[2] A type of ATB brake characterized by having the two brake arms
connected by a straddle cable with the brake cable attached to the midpoint
of the straddle cable. This type of brake was used on ATB bicycles (as well
as tandems, touring, and cyclocross bicycles) before the invention of the
V-Brake
cantilever brakes:

See cantilever brake.
cantilever bridge:
A bridge formed of self-supporting projecting arms built outward from the
piers and meeting in the middle of the span, where they are connected
together.
Also see
suspended span
cantilever deck:
A bridge where the deck slab is fixed above the main beams or trusses and
is cantilevered beyond the outer beams or trusses.
cantilever spring:
[1] A leaf spring which is mounted upside down and attached to the
vehicle at its mid-point. This system is no longer in use in modern
vehicles.
[2] A quarter-elliptic leaf spring
cantrail:
The roof rail
canvas top:
The convertible top.
canyon:
A nuclear energy term for a long narrow space often partly underground
with heavy shielding for essential processing of wastes from reactors.
cap:
[1] A protective round cover which is secured to something.
[2] A covering over the bed of a truck.
[3] The base of a light bulb which fits into a socket.
[4] Cleaner air package system of reducing the amount of unburned
hydrocarbons in the automobile exhaust.
Also see
air cap dust cap inner cap nut radiatorcap

battery cap
bayonet cap
bearing cap
big-end cap
car cap
cold cap
distributor cap
double cap nut
end cap
external mix air cap
filler cap
flip-top filler cap
fuel cap
full cap
hot cap
hubcap
insulating cap
net cap cost
oil filler cap
outer cap nut
plug cap
pressure cap
pressure radiator cap
radiator pressure cap
roto cap
safety pressure cap
spark plug cap
spindle cap
top cap
valve cap
valve spring cap
capacitance: (c)
[1] The property which opposes any change in voltage in an electrical
circuit. The property of a nonconductor by which it stores electrical energy
when separated surfaces of the nonconductor are maintained at a
difference of potential. Capacitance is measured by the ratio of the charge
induced to the potential difference and is proportional to the area of the
conducting plates and the dielectric constant of the nonconducting
material, and inversely proportional to the separation of the plates (mks
unit: farad).
[2] property of a nonconductor (condenser or capacitor) that permits
storage of electrical energy in an electrostatic field.
[3] Of an isolated conductor, the ratio of the total charge on it to its
potential; C=Q/V.
Also see
farad
stray capacitance
capacitance bridge:
An ac bridge network for the measurement of capacitance.
Also see
Schering bridge
Wien bridge
capacitance coefficients:
Charges (q1, ..., qn) of a system of conductors can be expressed in terms of
coefficients of electric induction (Cĳ) by the following equations:
q1 = C1∞V1 + C12(V1-V2 ) + ... + C1n(V1 - Vn)
q2 = C21(V2 - V1) + C2∞V2 + ... + C2n(V2 - Vn)
qn = Cn1(Vn - V1) + Cn2(Vn - V2) + ... + Cn∞Vn
where
Ckm = Ckm(m ≠ k)
and
Cm∞ = Cm1 + Cm2 + ... + Cm(n-1) + Cmn

They are the fundamental relations for partial capacitances of a number of
conductors, e.g., electrodes in valves, conductors in cables, variable air-
capacitors.
capacitance coupling:
Interstage coupling through a series capacitance or by a capacitor in a
common branch of a circuit.
capacitance grading:
Grading of the properties of a dielectric, so that the variation of stress from
conductor to sheath is reduced. The inner dielectric has the higher
permitivity. Ideally, the grading is continuous and the permittivity varies as
the reciprocal of the distance from the center. See condenser bushing
capacitance integrator:
Resistance-capacitance circuit whose output voltage is approximately
equal to the time integral of the input voltage.
capacitative load:
Terminating impedance which is markedly capacitative, taking an ac
leading in phase on the source emf, e.g., electrostatic loudspeaker.
capacitative reactance:
Impedance associated with a capacitor. Has a magnitude in ohms equal to
the reciprocal of the product of the capacitance (in farads) and the angular
frequency of the supply (in rads s-1
). Also introduces a 90° phase angle
such that the current through the device leads the applied voltage.
capacities:
See fluid capacities
capacitive discharge:
(CD) A type of ignition system. It can be either all-electronic or breaker
point controlled. The primary power is drawn from the engine's battery
and put into the CD power supply, where it is changed from 12 volts direct
current to about 300 volts of pulsating direct current that is stored in a
capacitor (condenser). The release of this energy through the coil is

governed by a silicon-controlled rectifier (SCR). When the SCR switch is
closed, the voltage stored in the capacitor is supplied to the coil, which
acts as a voltage step-up transformer boosting firing voltage to around
30,000 volts to fire the plugs.
capacitive reactance:
The opposition or resistance to an alternating current as a result of
capacitance; expressed in ohms
capacitor:
[1] A device which gives capacitance, usually consisting of conducting
plates or foil separated by layers of a dielectric. A potential difference
applied across the plates induces a separation of charge centers in the
dielectric, thus storing electrical energy.
[2] Type of electrical storage device used in starting and/or running
circuits on many electric motors
Also see
absorption capacitor
condenser
ignition capacitor
capacitor bushing:
See condenser bushing
capacitor controlled electronic ignition:
See
electronic ignition system
capacitive discharge
capacitor discharge ignition:
(CDI) See capacitive discharge
capacitor loudspeaker:
See electrostatic loudspeaker
capacitor microphone:

See electrostatic microphone
capacitor modulator:
Capacitor microphone, or similar transducer, which, by variation in
capacitance, modulates an oscillation either in amplitude or frequency
capacitor motor:
Single-phase induction motor with an auxiliary starting winding connected
in series with a condenser (capacitor) for better starting characteristics.
capacitor-resistance law:
(C-R law) Law relating to exponential rise or decay of charge on capacitor
in series with a resistor, and, by extension, to signal distortion on long
submarine cables.
capacitor start:
Starting unit for electric motor using series capacitance to advance phase
of current.
capacitor-start motor:
Motor which has a capacitor in the starting circuit
capacitor terminal:
See condenser bushing
capacitron:
See band ignitor tube
capacity:
[1] The ability to contain or hold something.
[2] Maximum production attainable under normal conditions. With regard
to normal conditions, the company's operating practices are to be followed
with respect to the use of production facilities, overtime, workshifts,
holidays, etc.
[3] The output of an electric motor or other electrical equipment.
[4] The volume of fluid which a pump can handle.

[5] A measure of the theoretical maximum amount of refrigeration-
produced output, measured in tons or BTUs per hour
[6] Refrigeration rating system. Usually measured in BTU per hour or
watts.
[7] Sometimes used to mean capacitance
Also see
air capacity
ampere hour capacity
battery capacity
breathing capacity
carrying capacity
cubic capacity
energy
engine capacity
fuse
fuse capacity
load capacity
net capacity
nominal capacity
passenger capacity
ply rating
rated capacity
reserve capacity
seating capacity
top off
work capacity
capacity plan:
A plan outlining the spaces available for fuel, cargo, ballast, fresh water,
etc, with guides on weight and volume for spaces at various drafts and
displacements
capacity rating:
See rated capacity
cap-and-pin type insulator:
A special form of the suspension insulator
cap cost:
See
capitalized cost
net cap cost
cap cost reduction:
See capitalized cost reduction
cape chisel:
A metal cutting chisel shaped to cut or work in channels or grooves
capillarity:
A phenomenon associated with surface tension, which occurs in fine bore
tubes or channels.

capillary:
A tube with a very small bore used for temperature gauges
capillary action:
The property of a liquid to move into small spaces if it has the ability to
"wet" these surfaces
capillary tube:
A tube usually gas-filled, with a precisely calibrated length and inside
diameter, used to connect the remote bulb or coil to the expansion valve or
thermostat. A tube with a very small bore used for temperature gauges.
Also called pressure sensing line
capitalized:
See net capitalized cost
capitalized cost:
The total price of the vehicle, in effect, its purchase price. In theory, the
cap cost should equal the amount you would pay for the vehicle if you
were purchasing the vehicle. When a lease is made, the dealer sells that
vehicle to the leasing company (for the cap cost), which then leases the the
vehicle to you.
Also see
net capitalized cost
capitalized cost reduction:
A fancy name for a cash down payment, money you pay up front that is
applied to the final purchase price of a lease. A large cap cost reduction
will, of course reduce the monthly payments, but it will also negate one of
the big advantages of leasing. However, if you own your present car, you
may be able to use it, as a trade-in, to satisfy the cap cost reduction to start
the lease. Remember, you must pay sales tax on any cap cost reduction
you make. Another source of capital cost reduction may be dealer or
manufacturer participation. Dealers and manufacturers will sometimes
lower the cap cost or offer a rebate that reduces the cap cost. A dealer or
manufacturer cap cost reduction does lower your total out-of-pocket
dollars, unlike a cap cost reduction that you must pay.

capital expenditures:
expenditures to acquire or add to capital assets that will yield benefits over
several accounting periods. Included are cost of procuring, construction,
installing new durable plants, machinery and equipment where for
replacement, addition or for lease or rent to other companies including
subsidies.
cap nut:
A nut that is closed at the threaded end often with a
dome. Also called box nut or dome nut.
Also see
double cap nut
inner cap nut
outer cap nut
capping:
[1] Installing a new tread on a tire carcass.
Also see
retreading.
[2] Door molding or capping
cap screw:
See socket head screw
capstan:
[1] A stump with a vertical axis used for handling mooring and other lines.
[2] A vertical drum or spindle on which rope is wound, it is rotated by
manpower or by hydraulic or electric motor.
[3] Roller providing the constant speed drive in a magnetic tape recorder.
capstan-head screw:
A screw having a cylindrical head provided with radial holes in its
circumference. It is tightened by a tommy bar inserted in these holes.

capstan lathe:
A lathe in which the tools required for successive operations are mounted
radially in a tool-holder resembling a capstan; by revolving this, each tool
in turn may be brought into position in exact location.
capstan nut:
A nut which is tightened in the same way as a capstan-head screw
capstan screw:
A screw or bolt with a round head and one or more holes through it into
which a bar may be inserted for securing or removing it
capstat:
A wax-type thermostat at the base of the jet of a SU carburetor, which
expands and reduces fuel flow when the underhood temperature rises.
Also see
temperature compensator
capsule:
See
advance capsule
vacuum capsule
captive:
Something that is permanently located in the desired position
captive balloon:
A balloon anchored or towed by a line. Usually the term refers only to
spherical balloons. Special shapes (e.g., for stability) are called kite
balloons
captive finance company:
A leasing or finance company which is affiliated with an automobile
manufacturer or distributor.

captive import:
an imported motor vehicle or part manufactured by another automaker
usually for sale under the brand name of the importer.
captive nut:
A nut which fits into a cage and is welded in place. This is done where the
nut is not easily accessible.
capture:
Any process in which an atomic or nuclear system acquires an additional
particle. In a nuclear radiative capture process there is an emission of
electromagnetic radiation only, e.g., the emission of gamma rays
subsequent to the capture of a neutron by a nucleus.
car:
[1] A wheeled vehicle such as an automobile, a section of a train, or a
streetcar. The word is an abbreviation of "carriage" -- a device to carry
people or goods.
[2] In an airship, the part intended for the carrying of the load (crew,
passengers, goods, engines, etc.). It may be suspended below, or may be
inside the hull of envelope.
Also see
49-state car
bubble car
champ car
city car
classic car
collector car
compact car
company car
competition car
concept car
cult car
cycle car
donor car
dream car
edwardian car
electric car
estate car
executive car
family car
fleet car
forty-nine state
car
full-size car
funny car
hybrid car
intermediate car
kit car
luxury car
mass-produced car
mid-size car
milestone Car
Society
milestone cars
motor car
multi-storey car
park
new car dealer
open car
pace car
parts car
passenger car
wheel
passenger car
pony car
production car
program cars
recycling car
shopping car
solar car
spares car
sports car
stock car
street car
sun car
super car
touring car
town car
veteran car
vintage car
volume car
car accident:
A collision between two or more vehicles (or between a vehicle and a
stationary object), whether the vehicles are cars or trucks. Some are minor
like a fender bender while others are totalled.
Also see

written off
caravan:
[1] A group of vehicles (belonging to one organization) which follows
after one another.
[2] A British term for camping trailer or a mobile home.
caravanning:
A British term for travelling with a camping trailer
carb:
An abbreviation for "carburetor."
car banger:
A British term for a person or organization which fakes a car accident in
order to defraud an insurance company
car banging:
The act of faking a car accident in order to defraud an insurance company
carbide:
A binary combound of metals with carbon. Carbides of group IV to VI
metals (e.g., silicon, iron, tungsten) are exceptionally hard and refractory.
In group I and II, calcium carbide (ethynide) is the most useful. See
cemented carbides and cementite
See silicon carbide
carbide tools:
Cutting and forming tools used for hard materials or at high temperatures.
They are made of carbides of tungsten, tantalium, and other metals held in
a matrix of cobalt, nickel, etc., and are very hard with good compressive
strength.
car blind:
A curtain or pull-down covering for the backlight (i.e., rear window) to
obscure the bright headlights of a following vehicle. Some are also used
for side windows for privacy. It is generally illegal to use them on the

driver's side window or the windshield.
carbon:
[1] The hard or soft, black deposits found in the combustion chamber, on
the plugs, under the rings, on and under the valve heads, etc. Although it is
not a metal, it is a good conductor of electricity.
[2] An element which forms various kinds of steel when combined with
iron. In steel, it is the changing carbon content which changes the physical
properties of the steel.
[3] Carbon is used in a solid form as an electrode for arc welding, as a
mold to hold weld metal, or for motor brushes.
Also see
activated carbon
high carbon steel
low carbon steel
medium carbon
carbon arc:
An arc between carbon electrodes, usually limited to pure carbon rather
than flame carbon electrodes
carbon-arc lamp:
Obsolete light source from the arc between carbon electrodes.
carbon-arc welding:
Arc welding carried out by means of an arc between a carbon electrode
and the material to be welded.
carbon black:
A by-product of the petroleum industry used as a pigment and to give body
in the manufacture of rubber products, both natural and synthetic. Carbon
is the black residue from burning petroleum.
carbon brush:
A block of carbon to which a copper wire (or braided cable) is attached at
one end and the other end rubs against a commutator, collector ring, or slip
ring to transmit electricity

carbon brush spring:
See brush spring
carbon build-up:
A deposit of burned oil which collects in the combustion chamber on the
top of the piston and the head. Too much carbon build-up can lead to an
inefficient engine and sticky valves.
carbon button:
See carbon microphone
carbon canister:
carbon contact:
In a switch, an auxiliary contact designed to break contact after and to
make contact before the main contact to prevent burning of the latter; it is
of carbon and designed to be easily removable.
carbon-core leads:
High tension wire going from the distributor to the coil or the spark plugs.
Each wire has a core of carbon or graphite rather than copper wire to
conduct the electricity. Carbon-core wire is not recommended for most
small engines such as motorcycle engines.
carbon dating:
Dating method which uses the fact that atmospheric carbon dioxide
contains a constant proportion of radioactive 14
C, formed by cosmic
radiation. Living organisms absorb this isotope in the same proportion.
After death it decays with a half-life 5.57x10³ years. The proportion of 12
C
to the residual 14
C indicates the period elapsed since death. Also called
radiocarbon dating
carbon dioxide:
(CO2) A colorless, odorless, non-toxic gas which is a product of breathing
and the combustion process. Sometimes used as refrigerant: Refrigerant #
is R-744

carbon dioxide laser:
Laser in which the active gaseous medium is a mixture of carbon dioxide
and other gases. It is excited by glow-discharge and operates at a
wavelength of 10.6 μm. Carbon dioxide lasers are capable of pulsed output
with peak power up to 100 MW or continuous output up to 60 kW.
carbon-dioxide welding:
Metal arc welding using CO2 as the shielding gas.
carbon gland:
A type of gland used to prevent leakage along a shaft. It consists of carbon
rings cut into segments and pressed into contact with the shaft by an
encircling helical spring or garter spring
carboned up:
covered with a thick deposit of carbon. In Britain it is called "coked up"
carbon fiber:
Threadlike strands of pure carbon that are strong and flexible. Carbon fiber
can be bound in a plastic resin matrix to form a strong composite. It is
light-weight and stronger than steel. Can also be spelled "carbon fibre."
carbon fibre:
A high-tech material favored in many motorcycle applications because it is
extremely strong, light and expensive. The distinctive look of carbon fiber
has become trendy. Also see carbon fiber.
carbon filter:
Air filter using activated carbon as a cleansing agent
carbon fouling:
The situation that occurs when the two electrical terminals of the spark
plug are coated with carbon causing a reduction in efficiency leading to
intermittent firing or complete failure.

carbonization:
The steeping of wool in a dilute solution of sulphuric acid, or its treatment
by hydrochloric acid gas (dry process). This converts any cellulosic
impurities into carbon dust and thereby facilitates their removal.
carbonize:
Building up of carbon on objects such as spark plugs, pistons, heads, etc.
carbonized filament:
Thoriated tungsten filament coated with tungsten carbide to reduce loss of
thorium from the surface.
carbonizing:
Another term for carburizing or reducing
carbon knock:
When there is a build-up of carbon in the combustion chamber,
uncontrolled ignition will take place causing a knocking noise.
carbon microphone:
A microphone in which a normally dc energizing current is modulated by
changes in the resistance of a cavity filled by granulated carbon which is
compressed by the movement of the diaphragm. The diameter of the cavity
is frequently very much less than that of the diaphragm, and it is then
known as a carbon button.
carbon monoxide:
(CO) A deadly, colorless, odorless, and tasteless gas found in the engine
exhaust. Toxic even in relatively small concentrations. Formed by
incomplete burning of hydrocarbons. Thus at its greatest with a rich
mixture.
carbon pile voltage transformer:
Variable electrical resistor made from disks or plates of carbon arranged to
form a pile.

carbon pin:
A thin cylinder of carbon located in the distributor cap to transfer high
tension electricity from the coil to the rotor to the high tension leads going
to the spark plugs.
carbon resistor:
Negative temperature coefficient, non-inductive resistor formed of
powdered carbon with ceramic binding material. Used for low-temperature
measurements because of the large increase in resistance as temperature
decreases.
carbon steel:
A steel whose properties are determined principally by the amount of
carbon present and contains no other deliberate alloying ingredient except
those necessary to ensure deoxidation and physical quality. Also called
plain carbon steel. See steel
See
high carbon steel
low carbon steel
carbon tetrachloride:
A liquid often used in fire extinguishers. The fumes are toxic -- avoid
inhaling.
carbon tracking:
A trace of carbon found inside the distributor cap which leads away some
electricity, thus causing the engine to misfire.
carbonyl powders:
Metal powders produced by reacting carbon monoxide with the metal to
form the gaseous carbonyl. This is then decomposed by heat to yield
powder of high purity.
carborundum:
Trade name for silicon carbide abrasives.

carborundum wheel:
See grinding wheel
carboy:
Large, narrow-necked container, usually of balloon shape, having a
capacity of 201 or more.
carbs:
Abbreviation for carburetors.
Also see
dual carbs
carburation:
British term for carburetion
carburetion:
The mixture of vaporized fuel and air in the proper proportions for
combustion in an engine
carburetor:
Optionally
spelled
"carburette
r" or
"carburetto
r." A
device that
vaporizes
fuel and
mixes it
with air in
proper
quantities
and
proportion
s to suit
the varying
needs of
the engine.

A filter
screens the
air which
is drawn
into the
carburetor.
Here the
gasoline
mixes with
the air and
this fuel
vapor
enters the
combustio
n chamber
through
the intake
valve
where it is
compresse
d and
burned.
Also see
air-valve carburetor
air valve carburetor
barrel carburetor
compound carburetor
cross-draft carburetor
double-barrel
carburetor
downdraft carburetor
dual carbs
dual carburetors
feedback carburetor
fixed-choke carburetor
fixed-jet carburetor
flood the carburetor
four-barrel carburetor
hif carburetor
horizontal draft
carburetor
progressive carburetor
sidedraft carburetor
single-barrel
carburetor
slide carburetor
starting carburetor
stromberg carburetor
su carburetor
tamperproof
carburetor
twin-choke
carburetor
twin barrel
carburetor
twin carburetors
two-stage carburetor
updraft carburetor
variable-choke
carburetor
variable-venturi
carburetor
vv carburetor
carburetor adapter:
An adapter that is used to fit or place one type of carburetor on an intake
manifold that may not be originally designed for it. Also used to adapt
four-barrel carburetors to two-barrel manifolds.

carburetor barrel:
The tube-like part of the vehicle through which air flows and is mixed
with vaporized fuel. The choke butterfly valve is located at the top of the
carburetor barrel, and the throttle valve is located at the bottom. Midway
through, the barrel narrows, and this part is called the "venturi."
Carburetors can have one, two, or four barrels.
carburetor circuit:
A series of passageways and units designed to perform a specific function
idle circuit, full power circuit, etc.
carburetor circuits:
See carburetor circuit.
carburetor engine:
A combustion engine which uses a carburetor instead of fuel injection.
carburetor icing:
The formation of ice on the throttle plate or valve during certain
atmospheric conditions. As the fuel nozzles feed fuel into the air horn it
turns to a vapor. This robs heat from the air and when weather conditions
are just right (fairly cool and quite humid) ice may form.
Also see
icing
carburetor throat:
See venturi
carburetor venturi:
See venturi
carburetter:
British spelling for carburetor.
carburettor:

See carburetor.
car burglar:
A person who steals object from a car, but does not steal the car itself.
Also see
car thief
carburization:
The process of creating carbon steel by increasing the carbon content of
steel to reach the desired degree of hardness
carburizing:
[1] A carburizing flame in welding terms is an oxygen-fuel gas flame with
a slight excess of the fuel gas.
[2] A method of case-hardening low carbon steel in which the metal
component is heated above its ferrite-austenite transition in a suitable
carbonaceous atmosphere. Carbon diffuses into the surface and establishes
a concentration gradient. The steel can subsequently be hardened by
quenching either directly or after re-heating to refine the grain structure. It
is usually lightly tempered afterwards, producing a hard case over a tough
core.
car cap:
A waterproof cover which encloses just the greenhouse (i.e., the roof,
windshield, side glass, and backlight)
car care product:
One of several items for taking care of the outward finish of the car (i.e.,
cleaners, polish, wax, preservers) as well as the interior pieces (e.g., dash
cleaners, upholstery cleaners and sealers)
carcass:
The primary structure of a tire body with its cords, plies, rim wires, etc.
apart from the tread itself. Structurally the carcass should hold air and
provide strength to the tire, but would not wear well without the tread.
Car Club of America:

See Classic Car Club of America
car cover:
A cover which encloses the entire vehicle to protect the finish from the
elements.
car crash:
A car accident
card:
The graduated dial or face of a magnetic compass to which the card and
needle are firmly connected.
See file card brush
cardan:
See cardan joint.
cardan joint:
A type of universal joint named after the Italian Cardan who
developed the concept in the 16th century. In the 17th century,
Robert Hooke of England developed and patented the
conventional universal joint. Sometimes it is called the "Cardan
universal" or the "Hooke universal." It has two yokes at right
angles to each other.
Cardan mount:
Type of gimbal mount used for compasses and gyroscopes.
cardan shaft:
A shaft with universal joints at each end
cardan universal:
See cardan joint.
card brush:

See file card brush
car dealer:
See new car dealer
cardinal planes:
In a lens, planes perpendicular to the principal axis, and passing through
the cardinal points of the lens.
cardinal points:
For a lens system, the two principal foci, the two nodal points and the two
principal points. For a lens used in air, the principal points coincide with
the corresponding nodal points. For a lens of negligible thickness the
principal points and the nodal points all coalesce at a single point at the
optical center of the lens.
cardioid:
A heart-shaped curve with polar equation r=2a(1+cosθ). An epicycloid in
which the rolling circle equals the fixed circle.
cardioid directivity:
Special shape of a directivity. It is produced by superimposing the fields of
a monopole and a dipole, and has the shape of a cardioid.
care product:
See car care product
car-floor contact:
A contact attached to the false floor of an electrically controlled lift; it is
usually arranged to prevent operation of the lift by anyone outside the car
while a passenger is in the lift.
cargo:
See
bulk cargo
general cargo

cargo area:
The space within a station wagon or van for carrying goods or the bed of a
pickup truck for carrying goods
cargo battens:
Strips of wood fitted inside the frames to keep cargo away from hull
steelwork. Also called sparring
cargo box:
A type of container mounted on the roof of a
vehicle
cargo net:
A type of bungee net usually found in the
trunk of a car to secure packages from moving
around; but also found behind or beside a seat.
cargo port:
Opening in a ship's side for loading and unloading cargo.
cargo shifting:
Movements or changing positions of cargo from one place to another
which can easily endanger the seaworthiness of the ship
cargo ship:
See dry cargo ship
Carina:
Click for books on Carina

car insurance:
An insurance policy (mandatory in most states and all of Canada) to cover
possible damage to the vehicle or property or passengers, etc. Sometimes
basic insurance is abbreviated PL&PD (public liability and property
damage). Also called "motor insurance"
car jacker:
A person who steals a car at gunpoint.
car jacking:
A process of stealing a car while the driver is still in it. The car may be
stopped at a traffic light when a car jacker appears with a gun and
demands that the driver get out, then he drives away with the car. If it
happens to you, give him the car -- your life is worth more than the
vehicle.
car key:
An unlocking device for the ignition switch, doors, trunk, gas cap, etc.
car lot:
A place where vehicles are sold by an independent dealer
car mechanic:
See mechanic
Carnot cycle:
An ideal heat engine cycle of maximum thermal efficiency. It consists of
isothermal expansion, adiabatic expansion, isothermal compression, and
adiabatic compression to the initial state.
Carnot's theorem:
Theorem stating that no heat engine can be more efficient than a reversible
engine working between the same temperatures. It follows that the
efficiency of a reversible engine is independent of the working substance
and depends only on the temperatures between which it is working.

car park:
A parking area usually located within a building.
Also see
multi-storey car park
carpeting:
The action of covering the passenger compartment floor (and sometimes
the trunk floor) with a form-fitting rug or carpet.
car phone:
A telephone that is installed in a vehicle, but has recently been replaced by
personal cell phones.
Also see
cellular phone
car polish:
A product which enhances the shine of the paintwork of a vehicle
car radio:
A radio receiver which is installed (usually in the dash) in a vehicle
carrene:
Refrigerant in Group One (R-11). Chemical combination of carbon,
chlorine, and fluorine
carriage:
[1] A horse-drawn vehicle for people to ride in.
[2] A railroad vehicle for passengers.

carriage bolt:
A bolt that has a smooth dome head
(like a mushroom) so that no
screwdriver or wrench can remove it
from the dome-side.
carriage spring:
See laminated spring
carriage-type switchgear:
See truck-type switchgear
carriageway:
See dual carriageway
carrier:
[1] A real or imaginary particle responsible for the transport of electric
charge in a material. In oxide ceramics, electrons hopping between ions,
diffusing oxygen ions and mobile cations can also transport charge. See
carriers.
[2] A device for conveying the drive of a face-plate of a lathe to a piece of
work which is being turned between centers. It is clamped to the work and
driven by a pin projecting from the face-plate.
[3] A frame for holding a negative in an enlarger or slides in a projector.
[4] Non-active material mixed with, and chemically identical to, a
radioactive compound. Carrier is sometimes added to carrier-free material.
[5] A vehicle for communicating in formation, when the chosen medium
itself cannot convey the information but can convey a carrier, on to which
the information is impressed by modulation.
[6] In radio transmission, the output of the transmitter before it is
modulated. See frequency modulation.
[7] The frequencies chosen for sending many signals simultaneously along
a single communication channel by frequency-division multiplex.
[8] A thin substance that helps another substance to reach its goal. For
example, a spray grease may have a carrier which transports the grease to
its destination. Then the carrier dries up leaving the grease behind.

See
barge carriers
bicycle carrier
bulk carrier
carrier bearing
contract carrier
differential carrier
hub carrier
jet carrier
lng carrier
luggage carrier
ore-bulk-oil carrier
ore carrier
pinion carrier
planet carrier
product carrier
spare tire carrier
carrier bearing:
The bearings upon which the differential case is mounted.
carrier bearings:
See carrier bearing.
carrier mobility:
The mean drift velocity of the charge carriers in a material per unit electric
field.
carrier noise:
Noise which has been introduced into the carrier of a transmitter before
modulation.
carrier, pinion:
See pinion carrier.
carrier, planet:
See planet carrier.
carrier power:
Power radiated by a transmitter in absence of modulation.
carriers:
In a crystal of semiconductor material thermal agitation will cause a
number of electrons to dissociate from their parent atoms; in moving about
the crystal they act as carriers of negative charge. Other electrons will
move from neighboring atoms to fill the space left behind, thus causing the
holes where no electrons exist in the lattice to be transferred from one
atom to another. As these holes move around they can be considered as
carriers of positive charge. See impurity.

See
barge carriers
top carriers
carrier wave:
An unmodulated radio wave produced by a transmitter on which
information is carried by amplitude or frequency modulation.
carrosserie:
French term for coachwork.
carrozzeria:
Italian term for coachwork.
carrying capacity:
The maximum load that a tire is allowed to carry with a particular wheel
and rim. Also called "load capacity."
carrying-current:
See instantaneous carrying-current
CARS:
Acronym for "Canadian Automotive Repair and Service Council"
car society:
See milestone Car Society
car sponge:
A large sponge for washing the exterior of a vehicle
car stereo:
A listening device in an automobile which usually has an AM/FM radio
and often a cassette player, CD player, and/or CD changer. It also includes
at least a pair of speakers.

car tax:
A government imposed tax which is added to the price of a new car. Some
governments charge a road-use tax and call it a car tax.
cartesian diver:
See diver
car test:
A test of a vehicle's roadworthiness, reliability, and performance.
car theft:
Unauthorized removal (i.e., stealing) of a car or the items in or on a car.
Also see
car jacking
car thief:
A person who steals a car. If someone steals just the objects from a car, he
is a car burglar.
Also see
car jacker
car tire:
An automotive tire which is used exclusively on a passenger car, not a
light truck, etc.
cartography:
The preparation and drawing of maps which show, generally, a
considerable extent of the Earth's surface.
cartridge:
See
can
filter cartridge
oil filter cartridge
cartridge bottom bracket:
A bottom bracket with protective seals to keep water and grime from
penetrating to the bearings. Also called "sealed bottom bracket"

cartridge brass:
Copper-zinc alloy containing approximately 30% zinc. Possesses high
ductility; capable of being heavily cold-worked. Widely used for cold
pressings, cartridges, tubes, etc. See copper alloys.
cartridge starter:
A device for starting aero-engines in which a slow-burning cartridge is
used to operate a piston or turbine unit which is geared to the engine shaft.
cart spring:
A leaf spring used in small trailers.
carvac:
A small, hand-held vacuum cleaner which is either battery-operated or
which is plugged into the accessory outlet or cigarette lighter socket.
car wash:
[1] A place where you can get your car cleaned. Some are automatic (you
drive through and large brushes clean the car) while others provide a bay
with spray wands and brushes for you to do the labor.
Also see
automatic car wash
[2] A product like soap which is added to water for the purpose of cleaning
a vehicle.
car wax:
A polish which may be in a paste or a cream and used in protecting the
finish of a car.
car wheel:
See passenger car wheel
CAS:

Acronym for "cleaner air system"
cascade:
The arrangement of stages in an enrichment or reprocessing plant in which
the products of one stage are fed either forward to the next closely similar
or identical stage or backward to a previous stage, eventually resulting in
two more or less pure products at each end of the cascade. The classic
examples are gaseous or centrifugal enrichment plants. An ideal cascade is
the arrangement of stages in series and in parallel which gives the highest
yield for a given number of units (e.g., centrifuges) and a given separation
factor.
cascade generator:
High-voltage generator using a series of voltage-multiplying stages, esp.
when designed for X-ray tubes or low-energy accelerators.
cascade particle: Particle formed by a cosmic ray in a cascade shower
cascades:
Fixed airfoil blades which turn the airflow around a bend in a duct, e.g., in
wind tunnels or engine intakes.
cascade shower:
Manifestations of cosmic rays in which high-energy mesons, protons, and
electrons create high-energy photons, which produce further electrons and
positrons, thus increasing the number of particles until the energy is
dissipated. Also called air shower.
cascade systems:
Arrangement in which two or more refrigerating systems are used in
series; uses evaporator of one machine to cool condenser of other machine.
Produces ultra-low temps
cascading of insulators:
Flashover of a string of suspension insulators; initiated by the voltage
across one unit exceeding its safe value and flashing over, thereby
imposing additional stress across the other units, and resulting in a
complete flashover of the string.

case:
That part near the surface of a ferrous alloy which as been so altered as to
allow case-hardening.
See
basket case
battery case
chain case
converter case
differential case
top case
transfer case
case harden:
The action of hardening the surface of steel.
casehardened:
A piece of steel that has had the outer surface hardened while the inner
portion remains relatively soft.
casehardening:
The action of adding carbon to the surface of a mild steel object and heat
treating to produce a hard surface.
cases:
The two clam-shell-like halves in the bottom end of the engine surrounded
by a metal shell
cash register:
Trucker slang for Toll booth as in "I'm comin' up on a cash register at
highway 88"
cash value:
See actual cash value
casing:
[1] The outside shell of something such as the shell of an alternator or
starter motor.

Also see
axle casing
differential casing
spiral casing
turbine casing
volute casing
[2] The tire casing.
casing factor:
That portion of the load supported by tire casing stiffness instead of air
pressure.
casing head gasoline:
A term used to describe the lighter parts of petroleum products, which
were obtained from natural gasoline by condensing natural gas from an oil
well
cask:
See flask
casket:
See flask
cassette:
[1] A type of bicycle gear cluster that slides on a freehub rather than
threads on it. The freehub body is attached to the rear hub.
[2] A cartridge containing magnetic tape that can be inserted into a player
for listening or viewing (e.g., an audio cassette or video cassette).
cassette cogs:
The individual cogs that make up a bicycle cassette.
cassette compartment:
A storage place for audio cassettes
cassette hub:

More recent type of rear hub designed to accept the cassette type of gear
cluster. The cassette hub has the rotating, ratcheting freehub body attached
to the hub for the cassette to slide onto and be secured by a lockring.
cassette player:
A unit which plays (but does not record) audio cassettes and is often linked
with a stereo unit in an automobile
cassette size:
The size of a bicycle cassette is described by the number of teeth on the
smallest cog and the number of teeth on the largest cog. An example of a
common size for road racing would be 12 x 21.
cast:
[1] To shape molten metal by pouring it into a mold.
[2] A model or result made by pouring metal into a mold.
See
cast iron
casting
die cast
castellate:
Formed to resemble a castle battlement: e.g., a castellated nut
castellated:
See castellated nut.
castellated nut:
A nut with several lugs protruding
from one end making it look like the
turrets on the top of the wall of a
castle. This nut is used on a shaft
with a hole drilled in it. It is secured
to the shaft by passing a cotter pin
through an opening in the nut and
through the shaft hole.

caster:
A wheel alignment adjustment that positions
the wheels like the casters on a chair or
shopping cart, so the tires follow naturally in
a forward straight line. In a truck or older car,
the top of the kingpin is either forward
(negative) or toward the rear of the vehicle
(positive). On a turn, the wheels will tend to
straighten out when the steering wheel is
released. If the car has independent front
suspension, the upper ball joint is set forward
or rearward in relation to the lower ball joint.
Caster is measured in degrees.
Also see
trail distance
caster action:
The self-centering action which causes a caster wheel to move into a
straight-ahead position.
caster angle:
The inclination or angle that a wheel makes when measuring the distance
between the vertical post and the offset of the wheel placement.
caster offset:
The distance on the ground between where the vertical post would touch
the ground if it were extended and the point where the wheel touches the
ground. Also called caster trail
caster trail:
The distance on the ground between where the vertical post would touch
the ground if it were extended and the point where the wheel touches the
ground. Also called caster offset
caster wobble:
A condition generally produced in the front wheels when they are attached
to the ends of a beam axle. It is particularly noticeable on rough roads and
the shimmy at the steering wheel makes it difficult to control the vehicle.

You have probably seen this condition in a shopping cart that has caster
wheels that wiggle or fluctuate back and forth and will not roll in a straight
line.
cast holes:
Holes made in cast objects by the use of cores, in order to reduce the time
necessary for machining, and to avoid metal wastage.
casting:
[1] A process technology that delivers a liquid molten metal into a
purpose-built mold. After cooling, the solid metal surface has the shape of
the mold cavity.
[2] Pouring metal into a mold to form an object.
[3] A metallic article cast in the shape required, as distinct from one
shaped by working.
Also see
die casting
lost-foam casting process
malleable castings
monobloc casting
sand casting
thin-wall casting
casting copper:
Metal of lower purity than best selected copper. Generally contains about
99.4% of copper.
casting ladle:
A steel ladle, lined with refractory material, in which molten metal is
carried from the furnace to the mold in which the casting is to be made.
casting number:
The number cast into a block, head, or other component when the part is
cast. Casting numbers can be helpful when identifying an engine or its
parts, but they are not completely accurate, because castings are
sometimes machined differently
casting process:

See lost-foam casting process
castings:
Metallic forms which are produced by pouring molten metal into a shaped
container or mold.
Also see
malleable castings
casting wheel:
Large wheel on which ingot molds are arranged peripherally and filled
from stream of molten metal issuing from furnace or pouring ladle.
cast-in-situ concrete piles:
A type of pile formed by driving a steel pipe into the ground and filling it
with concrete, using the pipe as a mold, or by a similar method.
cast iron:
[1] An alloy of iron and more than 2% carbon. It is used for engine blocks
and transmission and differential cases because it is relatively cheap and
easy to mold into complex shapes.
[2] Any iron-carbon alloy in which the carbon content exceeds the
solubility of carbon in austenite at the eutectic temperature. Widely used in
engineering on account of their high fluidity and excellent casting
characteristics. Carbon content usually in the range of 2-2.3%. Some kinds
are brittle and others difficult to machine. See ductile cast-iron, grey iron,
spherulitic graphite cast-iron.
cast-iron:
See cast iron
castle:
See castellated nut.
castle nut:
British term for castellated nut -- a six-sided nut in the top of which six
radial slots are cut. Two of these line up with a hole drilled in the bolt or
screw, a split pin can be inserted to prevent turning.

castle section:
A panel with humps or ribs which strengthen the panel. They are called
"castle" because from the end they look like the turrets of a castle
castor:
British spelling of caster.
cast spoke assembly:
That part of the vehicle consisting of the brake drum and wheel spider,
having 3, 5 or 6 spokes.
cast spoke type:
A type of dual mounting wheels where two demountable rims are mounted
directly on the spoke wheel and drum assembly held apart by a spacer
band and locked in place by clamps and nuts which attach to studs in the
spoke face.
cast steel:
Shapes that have been formed directly from liquid by casting into a mold.
Formerly applied to wrought objects produced by working steel made by
the crucible process to distinguish from that made by cementation of
wrought-iron, but both of these methods are long obsolete.
cast welded rail joint:
A joint between the ends of two adjacent rails made in position using the
thermite process.
cat:
An abbreviation for catalytic converter
catadioptric:
An optical system using a combination of refracting and reflecting
surfaces designed to reduce aberrations in a telescope.

catalan process:
Reduction of haematite to wrought-iron by smelting with charcoal.
catalog:
See parts catalog
catalyst:
[1] A substance that changes the rate of a chemical reaction without itself
being used up.
[2] A special agent which is added to a plastic body filler or resin or paint
to speed up the hardening process.
Also see
aged catalyst
fresh catalyst
metal catalyst
oxidizing catalyst
particulate catalyst
pellet catalyst
reducing catalyst
three-way catalyst
two-way catalyst
catalyst bed:
A layer of catalyst-coated material such as pellets or ceramic in a catalytic
converter through which the gases pass.
catalyst charge:
A catalyst-coated material such as pellets or ceramic in a catalytic
converter.
catalyst coating:
A catalytic layer
catalyst container:
A housing of a catalytic converter. Also called a "converter shell"
catalyst contamination:

A reduction of efficiency because of impurity deposits
catalyst degradation:
A reduction of efficiency because of impurities or overheating. Also called
catalyst deterioration
catalyst deterioration:
A reduction of efficiency because of impurities or overheating. Also called
catalyst degradation
catalyst efficiency:
See catalytic efficiency
catalyst indicator:
A light on the instrument panel which glows when a prescribed distance
has passed in order to remind the driver to have the catalytic converter
replaced.
catalyst substrate:
A base material which carries the catalytic layer or coating. Also called
catalyst support
catalyst support:
A base material which carries the catalytic layer or coating. Also called
catalyst substrate
catalytic:
See
catalytic converter
dual-bed catalytic converter
mini catalytic converter
open-loop catalytic converter
pellet-type catalytic converter
primary catalytic converter
three-way catalytic converter
catalytic activity:

The rate a catalytic converter purifies the exhaust system
catalytic converter:
A pollution-control device found on the exhaust system of all cars since its
introduction in 1974 which acts like an afterburner to reburn unburned gas
in the tail pipe. It looks like a small muffler and is usually made of
stainless steel. It contains platinum, rhodium, or palladium which is a
catalyst for the chemical reaction needed to burn off any unburned
hydrocarbons and carbon monoxide by turning them into water vapor,
carbon dioxide and other less toxic gases.
Also see
dual-bed catalytic converter
lean burn engine
mini catalytic converter
open-loop catalytic converter
pellet-type catalytic converter
primary catalytic converter
single-bed 3-way catalytic converter
two-way catalytic converter
catalytic efficiency:
The effectiveness of a catalyst in purifying exhaust gases
catalytic layer:
A thin layer of catalyst such as platinum and supported by a ceramic or
metal carrier material
catamaran:
A double hulled vessel
cataphoretic painting:
A process of applying the first coat of paint to the body of a car by
positively charging the paint particles and then dunking the metal into the
paint. A current is turned on so that the positively charged paint is attracted
to the negative metal panel. Also called cathodic electropainting
catapult:

an accelerating device for launching an aircraft in a short distance. It may
be fixed or rotatable to face the wind. It is usually used on ships which
have no landing deck, having been superseded on aircraft carriers by the
accelerator. During World War II, fighters were carried on (catapult armed
merchant ships) for defence against long-range bombers. Land catapults
hae been tried but have been superseded by RATOG and STOL aircraft.
catback:
A performance exhaust system upgrade which consists of new pipes from
the catalytic converter to the tail pipe which increases horsepower. These
new pipes are larger, thus, more exhaust can exit the system. The faster the
exhaust can exit, the more horsepower you gain.
catch:
See safety catch
catch basin:
See catch pit
catcher:
The element in a velocity-modulated ultrahigh frequency or microwave
beam tube which abstracts, or catches, the energy in a bunced electron
stream as it passes through it. See buncher
catcher foil:
Aluminum sheet used for measuring power levels in nuclear reactor by
absorption of fission fragments.
catching diode:
Diode used to clamp a voltage or current at a predetermined value. When
it becomes forward-biased it prevents the applied potential from increasing
any further.
catchment area:
The area from which water runs off to any given river valley or collecting
reservoir. Also called catchment basin

catchment basin:
The area from which water runs off to any given river valley or collecting
reservoir. Also called catchment area
catch net:
See cradle
catch pit:
A small pit constructed at the entrance to a length of sewer or drain pipe to
catch and retain matter which would not easily pass through the pipes.
Also called catch basin. See sump
catch plate:
A disk on the spindle nose of a lathe, driving a carrier locked to the work.
catch points:
Trailing points placed on an up-gradient for the perpose of derailing
rolling stock accidentally descending the gradient. See spring points
catch-water drain:
A drain to catch water on a hillside, with open joints or multiple
perforations to take in water in as many places as possible.
cat E:
Category E damage to an aircraft; equivalent to a total loss or "write off."
category:
See speed category
catenary construction:
A method of construction used for overhead contact wires of traction
systems. A wire is suspended, in the form of catenary, between two
supports, and the contact wire is supported from this by droppers of
different lengths, arranged so that the contact wire is horizontal. See

compound catenary construction
cathead:
[1] The sheave assembly on the top of crane jib.
[2] A lathe accessory consisting of a turned sleeve having four or more
radial screws at each end; used for clamping on to rough work of small
diameter and running in the steady while centering. Also called spider
cathetometer:
An optical instrument for measuring vertical distances not exceeding a few
decimeters. A small telescope, held horizontally can move up and down a
vertical pillar. The difference in position of the telescope when the images
of the two points whose separation is being measured are lined up with the
cross-wires of the telescope, is obtained from the difference in vernier
readings on a scale marked on the pillar. Also called reading microscope
and reading telescope
cathode:
[1] In an electric circuit, the negative terminal. Electrons leave at this
terminal.
[2] In an electronic tube or valve, an electrode through which a primary
stream of electrons enters the inter-electrode space. During conduction, the
cathode is negative with respect to the anode. Such a cathode may be cold,
electron emission being due to electric fields, photo-emission, or impact
by other particles, or thermionic, where the cathode is heated by some
means.
[3] In a semiconductor diode, the electrode to which the forward current
flows.
[4] In a thyristor, the electrode by which current leaves the thyristor when
it is in the ON state.
[5] In a light-emitting diode, the electrode to which forward current flows
within the devie.
[6] In electrolytic applications, the electrode at which positive ions are
discharged, or negative ions formed.
cathode coating:
A low-work function surface layer applied to a thermionic or photocathode
in order to enhance electron emission or to control spectral characteristics.
The cathode coating impedance is between the base metal and this layer.

cathode copper:
The product of electrolytic refining, after which the cathodes are melted,
oxidized, poled, and cast into wire-bars, cakes, billets, etc.
cathode efficiency:
Ratio of emission current to energy supplied to cathode. Also called
emission efficiency
cathode follower:
A valve circuit in which the input is connected between the grid and
ground, and the output is taken from between the cathode and ground, the
anode being grounded to signal frequencies. It has a high input impedance,
low output impedance, and unity voltage gain. See common-collector
connection
cahode glow:
Glow near the surface of a cathode, its color depending on the gas or vapor
is the tukbe. If an arc takes place in a partial vacuum, it may fill the greater
part of the discharge tube.
cathode luminous sensitivity:
Ratio of cathode current of photoelectric cell to luminous intensity.
cathode modulation:
Modulation produced by signal applied to cathode of valve through which
carrier wave passes.
cathode poisoning:
Reduction of thermionic emission from a cathode as a result of minute
traces of adsorbed impurities.
cathode ray:
A stream of negatively charged particles (electrons) emitted normally from
the surface of a cathode in a vacuum or low-pressure gas. The velocity of
the electrons is proportional to the square root of the accelerating potential,

being 6x105
ms-1
for one volt. They can be deflected and formed into beams
by the application of electric or magnetic fields, or a combination of both,
and are widely used in oscilloscopes and TV (in cathode-ray tubes),
electron microscopes and electron-beam welding, and electron-beam tubes
for high frequency amplifiers and oscillators.
cathode-ray oscillograph:
An oscillograph in which a permanent (photographic or other) record of a
transient or time-varying phenomenon is produced by means of an electron
beam in a cathode-ray tube. Deprecated term for cathode-ray oscilloscope
cathode oscilloscope:
(CRT) Device for displaying electronic signals by modulating a beam of
electrons before it impinges on a fluorescent screen
cathode ray tube:
A sealed tube on which graphs or pictures are displayed like a TV screen
cathodic electropainting:
A process of applying the first coat of paint to the body of a car by
positively charging the paint particles and then dunking the metal into the
paint. A current is turned on so that the positively charged paint is attracted
to the negative metal panel. Also called cataphoretic painting
cathode spot:
Area on a cathode where electrons are emitted into an arc, the current
density being much higher than with simple thermionic emision
cathodic chalk:
A coating of magnesium and calcium compounds formed on a steel
surface during cathodic protection in sea water
cathodic etching:
Erosion of a cathode by a glow discharge through positive-ion
bombardment, in order to show microstructure

cathodic protection:
[1] The action of protecting metal from electrochemical corrosion by using
it as the cathode of a cell with a sacrificial anode.
[2] In ships and offshore structures, corrosion can be prevented by passing
sufficient direct current through the sea water to make the metal hull a
cathode. See sacrificial anode
cathodoluminescence:
The emission of light, with a possible afterglow, from a material when
irradiated by an electron beam, such as occurs in the phosphor of a cathod-
ray tube
cathodophone:
Microphone utilizing the silent discharge between a heated oxide-coated
filament in air and another electrode. The discharge is modulated directly
by the motion of the air particles in a passing sound wave. Also called
ionophone
catholyte:
See catolyt
cation:
Ion in an electrolyte which carries a positive charge and which migrates
toward the cathode under the influence of a potential gradient in
electrolysis. It is the deposition of the cation in a primary cell which
determines the positive terminal. Compare anion
catolyte:
That portion of the electrolyte of an electrolytic cell which is in the
immediate neighborhood of the cathode. Also called catholyte
cation:
Ion in an electrolyte which carries a positive charge and which migrates
toward the cathode under the influence of a potential gradient in
electrolysis. It is the deposition of the cation in a primary cell which
determines the positive terminal. Compare anion

catolyte:
That portion of the electrolyte of an electrolytic cell which is in the
immediate neighborhood of the cathode. Also called catholyte
catoptric element:
A component of an optical system that uses reflection, not refraction, in
the formation of an image
cauchy's dispersion formula:
μ= A + (B/λ2
) + (C/λ21
) + ...
An empirical expression for the relation between the refractive index μ of
a medium and the wavelength λ of light; A, B, and C are the constants for
a given medium.
catwalk:
[1] A raised walkway running fore
and aft from the midship.
[2] An obsolete term for the section
between the fender and the hood. On
modern cars, this section does not
exist at all. But on older cars (like
the 1937 Cadillac), the fender was
spaced a little way apart from the
hood. The headlights were mounted
toward the front of the catwalk or
above it.
caulk:
To fill seams in a wood deck with oakum or hammer the adjoining edges
of metal together to stop leaks. Also spelled "calk"
caulking:
The process of closing the spaces between overlapping riveted plates or
other joints by hammering the exposed edge of one plate into intimate
contact with the other. A filler material is also used esp. for clsing (e.g.,
deck planking). Also called calking

caulking tool:
A tool, similar in form to a cold chisel but having a blunt edge, for
deforming the metal rather than cutting it.
causality:
[1] The principle that an event cannot precede its cause.
[2] See determinism
caustic curve:
A curve to which rays of light are tangential after reflection or refraction at
another curve
caustic embrittlement:
The intergranular corrosion of steel in hot alkaline solutions, e.g., in
boilers
caustic etching:
The removal of metal by dipping aluminum parts in caustic soda
caution:
A period in racing in which track conditions are too hazardous for racing
due to an accident or debris on the racing surface. The cars remain in their
racing positions behind the pace car until it is determined that it is safe to
resume the race.
caved:
Dented inward as in When the car hit me, it caved in the door.
cavitation:
A condition in which a partial vacuum forms around the blades or impeller
wheels of a pump, reducing the pump's output because part of the pump
blades lose contact with the liquid. It can be a problem in fuel and water
pump, fluid couplings, torque converters. When severe, it can result in the
erosion of the pump blades and other internal surfaces.
cavity:

[1] An empty space in a body structure, either in a box section or a double-
skinned area.
[2] A holder and contact for fuses
cavity sealant:
A product made of oil, wax, and rust inhibitors which is painted or sprayed
into a cavity to prevent rust and corrosion.
CB:
[1] diesel engine oil introduced in 1949.
[2] An acronym for Contact Breaker.
[3] An acronym for Citizens' Band.
Also see
CB radio
CB radio:
A two-way radio which is limited to specific frequencies. Initially used by
truck drivers and later by both mobile vehicles and stationary sites; but
more recently it has declined in use with the advent of cell phones.
CBR process:
Acronym for Controlled Burn Rate process. It is a method of improving
fuel economy by increasing or decreasing the rate which the fuel burns
CBU:
Acronym for "Completely Built-Up."
CC:
[1] Cruise control.
[2] A type of diesel engine oil introduced in 1961.
[3] (cc) Cubic centimeter.
CCC:
Acronym for computer command control
CCCA:

Acronym for "Classic Car Club of America."
CCEC:
Acronym for "constant current electronic circuit"
CCEGR:
Acronym for coolant controlled exhaust gas recirculation
CCFA:
Acronym for "Comité Des Constructeurs Français d'Automobiles"
C-clamp:
A tool which is in the shape of the letter "C". A screw at one end
of the clamp forces the end of the screw against the object to be
secured.
Also see
long-reach C-clamp
CCOT:
Acronym for "cycling clutch orifice tube system" or "Cycling clutch
orifice tube air conditioning system"
CCP:
Acronym for controlled canister purge
CCS:
Acronym for "controlled combustion system" of reducing unburned
hydrocarbon emission from the engine exhaust.
CCT:
Acronym for computer controlled timing
Cd:

Abbreviation for "Drag Coefficient," a measurement of air resistance
(drag). The lower the number, the less drag that a vehicle or shape has.
CD:
[1] Diesel engine oil introduced in 1955.
[2] See capacitive discharge.
[3] (Cd) A measurement of drag coefficient.
CD changer:
A device which is connected to a stereo system and allows several music
CDs to be played.
CDI:
Acronym for "Capacitor discharge ignition";
Also see
CDI box
CDI box:
Acronym for "capacitive discharge Ignition" device sometimes controlled
by a computer. It is designed to help the spark plug fire at a rate consistent
with the rpms of the engine.
CD player:
A device which plays music compact discs. Usually combined with a
stereo radio receiver and sometimes with a CD changer.
CDR:
Acronym for crankcase depression regulator
CDV:
Acronym for "Car-Derived Van" (e.g., Renault Kangoo).
Cd value:
a number representing the coefficient of drag which is the amount of
resistance that a moving vehicle makes in a wind tunnel

CEC:
Acronym for "combination emission control"
ceiling:
See
absolute ceiling
hold ceiling
joiner work ceiling
Celebrity:
A model of small car produced by Chevrolet
Click for books on Celebrity
Celica:
Click for books on Celica
cell:
[1] A compartment or chamber in a battery which contain positive and
negative plates suspended in electrolyte. A six-volt battery has three cells,
a twelve-volt battery six cells.
[2] The combustion chamber in a rotary engine.
Also see
battery cell
dry cell
electrolytic cell
fuel cell
galvanic cell
local cell
microgalvanic cell
passenger cell
primary cell
roller cell pump
seam sealing cell
secondary cell
storage cell
cell battery:
See gel cell battery

cell connector:
The lead bar or strap connecting battery cell groups.
cell phone:
See cellular phone
cell pump:
See roller cell pump
cellular phone:
A portable, wireless telephone which was first introduced in 1983 in the
US. Currently it is used both as a car phone and a personal phone.
Commonly called "cell phone."
cellular telephone:
A portable, wireless telephone which was first introduced in 1983 in the
US. Currently it is used both as a car phone and a personal phone.
Commonly called "cell phone."
cellulose:
A popular term for nitrocellulose -- a universal automotive finish, which is
thin and therefore suitable for spraying, fast drying, and gives a hard and
brilliant finish
cellulose putty:
A filler used to cover minor body imperfections.
Celsius:
Thermometer on which the boiling point of water is 100 deg and the
freezing point is 0 deg. The term replaces the word "centigrade." To
convert from Fahrenheit to Celsius, subtract 32 then multiply the result by
5 and divide by 9. To convert from Celsius to Fahrenheit, multiply by 9,
then divide by 5. Now add 32 to the result.
CEMA:

Acronym for "Consumer Electronics Manufacturers Association."
cement:
An adhesive rubber compound dissolved in solvent used to provide
building tack and cured adhesion for tires. May be brushed or sprayed on
the buffed surface. Also called contact cement
cementite:
FE3C Iron carbide. A hard substance found in cast iron.
census value added:
residual representing the difference between the value of goods and
industrial services produced and the direct material costs associated with
the production of goods.
center:
To place something in a central place in relation to other items.
Also see
after bottom dead
center
after top dead center
before bottom dead
center
before top dead
center
before upper dead
center
bottom dead center
dead center
diagnostic center
Driver and Vehicle Licensing
Center
drop center rim taper
drop center rim
gravity, center
high center rim
inner dead
center
lower dead
center
message center
outer dead
center
roll center
top dead center
upper dead
center
center bore:
See wheel center bore.
center console:
A section of the dash which is mounted between the driver
and passenger sections. It often houses the shifter, cup
holders, storage space, and possibly the stereo.
center differential:
A differential which is used in a four-wheel-drive vehicle to distribute the
power to both the front and rear differentials.

Also see
variable limited-slip axle/center differential
center drive:
Most engines have the power take-off at the end of the crankshaft. A center
drive has the power take-off between the cylinders.
center drive plate:
The disc between the driven plates in a twin plate clutch.
centered:
See high-centered
center electrode:
[1] Electrode which protrudes out of the insulator nose of a spark plug.
[2] A center terminal.
Also see
compound center electrode
center gear:
The sun gear of a planetary gearset.
center girder:
A vertical plate on the ship's centerline between the flat keel and inner
bottom extending the length of the ship. Also called center vertical keel.
center-hung float:
This type of carburetor float pivots on an axis that's parallel with the
vehicle axles. It's a better float design than a side-hung float during high
speed cornering because the float isn't affected by centrifugal force, so it
won't pull the inlet valve open in the middle of a corner
centering:
See
self-centering
steering wheel centering

center keelson:
See center girder
centerline:
[1] An imaginary line which passes from the front to the rear of a vehicle,
half way between the distance between the left and right side of the
vehicle.
[2] The middle line of the ship, extending from stem to stern at any level.
center locking disc:
A hub cap which is secured in place with a bolt or other locking device.
center lock nut:
A spinner which secures the wheel to the hub.
center median:
On a divided highway, the area between the two directions of traffic. The
British call it the "central reserve."
center of buoyancy:
The position in a floating object where the upthrust appears to act.
center of gravity:
(CG) That point in an object, if through which an imaginary pivot line
were drawn, would leave the object in balance. In the vehicle, the closer
the weight to the ground, the lower the center of gravity. Cornering,
acceleration, and other forces act upon the vehicle's center of gravity, thus
affecting body roll and other handling characteristics.
center of pressure:
An aerodynamically determined point at which wind force on the side of a
vehicle is assumed to be concentrated for analytical purposes. It is a
function of the shape and aerodynamic drag (resistance) of an automobile's
body shell, determines the effect of side winds on a vehicle's direction of
travel, and is a concept similar to the center of gravity.

center pillar:
The supporting post which is located in the middle of the car and holds up
the roof. It is also called the "B-post" or "B-pillar"
center point steering:
A steering geometry where the steering axis cuts the wheel axis in the
wheel center plane, with no offset at the road surface.
center punch:
A metal tool that is shaped like a pencil where you can hit the blunt end
with a hammer so that the sharp point makes an indentation in some metal.
In this way the drill-bit can fit into the indentation when you want to make
a hole.
center rim:
See
drop center rim
high center rim
semi-drop center rim
center rim taper:
See
semi-drop center rim taper
center section damage:
A description of a vehicle after it is involved in an accident when it has
been hit on the side somewhere between the front and rear wheels. The
frame and body are bashed in at the center, but the front and rear of the
vehicle may not have sustained any damage.
centerstand:
A stand that supports the motorcycle in an upright position
centerstand tang:

A small lever attached to the centerstand
center steering linkage:
A steering system using two tie rods connected to the steering arms and to
a central idler arm, the idler arm is operated by a drag link that connects
the idler arm to the pitman arm.
center terminal:
A high tension distributor has a rotor which spins around a center post and
transfers electrical energy from the center post or terminal to each of the
surrounding terminals located in the distributor cap. In this way the energy
from the coil is transferred to the high tension leads going to each spark
plug.
center the clutch:
To align the center holes in the clutch plates so that they fit easily on the
splines of the crankshaft.
center tunnel:
The hump which runs from front to rear between the left and right
passenger (i.e., driver and passenger). It often accommodates the
transmission and/or drive shaft. In front wheel drive vehicles it covers the
wiring leading to the rear of the vehicle.
Also see
transmission tunnel
center vertical keel:
See center girder
centigrade:
Thermometer on which the boiling point of water is 100° and the freezing
point is 0°. The term is no longer in use and is replaced by the word
Celsius.
centimeter:

See cubic centimeter
central fuel injection:
(CFI) a computer-controlled fuel metering system which sprays atomized
fuel into a throttle body mounted on the intake manifold
central chassis lubrication:
A configuration of the engine and chassis where an oil change and the
greasing of grease (zerk) fittings can be made from one spot -- generally
underneath the vehicle.
central gearchange:
The usual arrangement with the gear lever in the center of the floor.
centralized computerized controller:
Energy control device, centrally located, which makes control decisions
based on operating data, programmed information, and stored data. Can be
used to optimize energy consumption of many devices throughout a
building.
central locking:
The locking or unlocking of all the doors by locking from one location.
This may be done by turning a key in a door lock or using an electronic
device.
Also see
central locking hub
central locking hub:
A wheel with splines in the center which match up with the splines on the
outside of the hub. This system is usually found on wheels that are
attached to the hub with a center attaching nut on older cars -- especially
sports cars -- rather than the type that is attached with several studs or
bolts in a circular pattern.
central reservation:
A British term for the median which divides the north and southbound
lanes (or east and westbound lanes) of a divided highway.

central reserve:
A British term for the median which divides the north and southbound
lanes (or east and westbound lanes) of a divided highway.
central station:
Central location of condensing unit with either wet or air-cooled
condenser. Evaporator located as needed and connected to the central
condensing unit.
central warm air furnace:
Self-contained appliance designed to supply heated air through ducts to
spaces remote from or adjacent to the appliance location.
centre:
See center.
centrifugal advance:
A device found on the distributor which,
through the action of centrifugal force on two
weights, advances or retards the ignitionspark
to correspond with changes in engine speed
and load.
Also see
vacuum advance
centrifugal clutch:
A clutch that uses centrifugal force to expand a friction device on the
driving shaft until it is locked to a drum on the driven shaft.

centrifugal compressor:
Pump which compresses gaseous refrigerants by centrifugal force.
centrifugal force:
That force which tends to keep moving objects travelling in a straight line,
when a moving vehicle is forced to make a turn, centrifugal force attempts
to keep it moving in a straight line, if the vehicle is turning at too high a
speed, centrifugal force will be greater than the frictional force between
the tires and the road and the vehicle will slide off the road.
centrifugal force air filter:
A type of canister air filter used on the engines of semi-tractor-trailer units
which removes the dust before it reaches the filter element.
centrifugal governor:
A device which controls the speed by using centrifugal force. As the speed
of a shaft increases, weights are moved outward. When the weights reach a
predetermined place, the shaft can no longer increase in speed. This
governor may be found in automatic transmissions
centrifugal oil filter:
A filter in the lubrication system which pushes any impurities to the
outside of the filter as it rapidly rotates.
centrifugal pump:
[1] A pump which forces liquid from one location to another by the
rotation of an impeller.
[2] A pump which produces fluid velocity and converts it to pressure head.
centrifugal weight:
The movable part in a centrifugal clutch or centrifugal advance. The
weight (sometimes called a "finger") moves outward as a result of
centrifugal force. Changing the mass of the weight will cause the weight to
move outward sooner or later. The heavier the weight the later the
movement.

centrifuge brake drums:
To combine the strength of steel with the desirable friction characteristics
of cast iron, a lining of cast iron is sprayed on the inside of a steel drum.
Both metals are handled while hot to encourage the fusion of the two
metals
centripetal force:
A force which acts towards a central point, such as Earth's gravity. In a
sense it is the opposite of centrifugal force.
century:
A bicycle ride of 100 miles (160.9 km).
Also see
metric century
Buick Century
CEPA:
Acronym for "Canadian Environmental Protection Act."
ceramic:
A non-organic and non-metallic product made from clay or glass.
Currently some manufacturers are trying to develop ceramic cylinders
because of its ability to retain its shape when heated in contrast with metal
which expands when heated.
Also see
ceramic filter
ceramic brake pad:
A brake pad constructed with ceramics to reduce wear and heat.
ceramic capacitor:
Capacitor using a high-permittivity dielectric such as barium titanate to
provide a high capacitance per unit volume.
ceramic filter:

A filtering device using a porous ceramic as the filtering agent.
ceramic fuel:
Nuclear fuel with high resistance for temperature, e.g., uranium dioxide,
uranium carbide.
ceramic honeycomb:
The interior of a monolithic converter which supports the catalyst.
ceramic ignitor:
Electric ignition system used in a water glycol solution, forced-air furnace.
Electrically heated to create ignition of the gas-air mixture in the
combustion chamber.
ceramic insulator:
An insulator made of ceramic material, e.g., porcelain; generally used for
outdoor installations.
ceramics:
The art and science of non-organic non-metallic materials. See ceramic.
ceramics processing:
The methods of making ceramic products before final sintering.
ceramic transducer:
Transducer based on the electrical properties of ceramics such as
piezoelectricity.
Cerenkov counter:
Radiation counter which operates through the detection of Cerenkov
radiation.
Cerenkov detector:
Device which detects and measures the Cerenkov radiation produced as a
result of the incidence of high-energy charged particles; from this the

speed and charge of the particles may be calculated.
Cerenkov radiation:
Radiation emitted when a charged particle travels through a medium at a
speed greater than the speed of light in the medium. This occurs when the
refractive index of the medium is high, i.e., much greater than unity, as for
water.
cermet:
Ceramic articles bonded with metal. Composite materials combining the
hardness and high temperature characteristics of ceramics with the
mechanical properties of metal, e.g., cemented carbides and certain reactor
fuels.
CERN:
Byname for Organisation européene pour la Recherche Nucléaire
originally Conseil Europé pour la Recherche Nucléaire; the principal
European center in theoretical and experimental research in particle
physics, supported by most European countries; located in Geneva. Its
facilities include high-energy and low-energy proton and antiproton
accelerators, and an electron-positron collider. See Large Hadron Collider
certificate:
See
international load line certificate
international tonnage certificate
mot certificate
seaworthiness certificate
type approval certificate
certificate of registry:
A document specifying the country the vessel is registered.
Certification Label:
See safety Compliance Certification Label
cesium cell:

Celling having a cathode consisting of a thin layer of cesium deposited on
minute globules of silver; particularly sensitive to infrared radiation, but
generally approximating to that of the eye. British spelling caesium cell.
cesium clock:
Frequency-determining apparatus used on cesium-ion resonance of
9,192,631,770 Hz.
cesium-oxygen cell:
Cell in which the vacuum is replaced by an atmosphere of oxygen at very
low pressure. It is more sensitive to red light than the cesium cell.
cetane number:
A method of rating diesel oil or fuel by measuring the time lapse between
fuel injection and ignition to determine how easy it is to ignite and how
fast it will burn. The lower the cetane number, the higher the temperature
required to burn the oil.
cetane rating:
A method of rating diesel oil or fuel by measuring the time lapse between
fuel injection and ignition to determine how easy it is to ignite and how
fast it will burn. The lower the cetane number, the higher the temperature
required to burn the oil.
ceton filter:
A sock-type filter in the fuel tank capable of wicking diesel fuel, but not
water; keeps water from the rest of the fuel system until the sock is 90%
submerged in water
CFC:
Acronym for chlorofluorocarbon.
CFC gases:
Chlorofluorocarbon gases.
CFI:

Acronym for central fuel injection. A Ford fuel injection system that uses
an injector mounted throttle body assembly
CFM:
Acronym for "Cubic Feet per Minute." This is the rating of the volume of
air moved.
CG:
Acronym for center of gravity.
chafer:
The area between the bead and sidewall of a tire.
chafer strip:
The area between the bead and sidewall of a tire.
chafing plate:
A bent plate for minimizing chafing of ropes
chain:
Linked, flexible metal "rope" that connects two sprockets
(e.g., the chainwheel to the back wheel cogs, sized differently
for different types of bikes.) The teeth of the sprockets fit
inside the spaces between the links. Also called a roller chain.
Also see
cam chain
derailleur chain, narrow
width
derailleur chains
double roller chain
drive chain
duplex chain
O-ring
chains
primary
chain
safety chains
silent chain
simplex chain
single roller
chain
snow chains
timing chain
tire chains
triplex chain

chain breaker:
A tool for removing the pins in a roller chain
so that the links can be removed.
chaincase:
An enclosed metal covering which encircles the drive and driven sprockets
as well as the chain.
chain case:
See chaincase.
chain drive:
A system of transferring power from one shaft to another by means of
sprockets and an endless chain. This is the system used on a bicycle; but it
is also used on an engine to control the timing of valve opening (called
"timing chain" or "cam chain").
chain filter wrench:
A chain wrench which encircles the oil filter to assist in its removal.
chain guard:
A metal or plastic covering for the top run of a chain. It is most often
found on bicycle chains where the guard keeps your clothing from being
caught in the chain or even from getting greasy.
chain hoist:
A lifting device which uses a chain and block and tackle to lift large
objects like engines.
chain locker:
A compartment for the stowage of anchor chain
chain pipe:

A pipe for passage of chain from windlass to chain locker
chain pipe wrench:
A chain wrench which circles around a pipe and grips it
so that the pipe can be tightened or removed.
chainring:
One of the sprockets attached to the right
crankarm of a bicycle to drive the chain. Also
called "chainwheel."
chainring bolt:
The 4 or 5 bolts that attach the chainrings to the crankarm of a bicycle
chainring bolt circle diameter:
The configuration of the bolt pattern on a chainring. Draw a circle through
the center of all the bolt holes used to connect the chainring to the
crankarm and measure the diameter of the circle (in millimeters). On a
road crankset with two chainrings, they will both use the same bolt circle
diameter. Typical bolt circle diameters are 130 or 135 mm on road bikes.
chainring nut spanner:

A special bicycle tool used to loosen the slotted nuts that fasten a chainring
to a crankarm.
chainring teeth:
The number and type of teeth (i.e., pointed projections which are forced
between the rollers of a chain) in a chainring sprocket. A typical large road
bike chainring has 53 teeth cut into its surface and it is referred to as a size
53.
chain run:
The distance between the front and rear sprockets.
chains:
See chain
chain scrubber:
A device attached to a chain which rubs away the grime while the chain is
moving.
chainstay:
One of the two tubes of a bicycle frame that run horizontally from the
bottom bracket shell back to the rear dropouts.
chainstays:
The two tubes of a bicycleframe that run from the bottom bracket back to
the rear dropouts.
chain stopper:
A device used to secure the chain cable when riding at anchor, thereby
relieving the strain on the windlass
chain switch:
See snow chain switch
chain tensioner:

A device which takes up the slack in a chain. Some use an idler wheel
which can be adjusted (manually or automatically), others use a flat slide
which pushes against the chain to keep it from bouncing around. Most
modern units are spring loaded so that the tensioner automatically takes up
the slack. Some require that you need to undo a locking nut to allow the
spring to push against the chain. Afterward the lock nut needs to be
secured again.
chainwheel:
One of the sprockets attached to the right
crankarm of a bicycle to drive the chain. Also
called "chainring."
chain whip:
A tool consisting of a metal bar and two sections of chain, used in
changing cogs on a freewheel. Sometimes called "chain wrench."
chain wrench:
A locking pliers which employs a chain to wrap
around an object such as a pipe to secure or remove
it.
Also see

chain whip
chair:
Motorcycle sidecar
chalking:
The appearance of a white powder on a paint surface as it weathers and
ages.
chamber:
[1] A pressure chamber used to vulcanize pre-cured tread stock to the
buffed casing.
[2] A compartment which is basically empty or hollow.
Also see
climatic chamber
combustion
chamber
exhaust chamber
fireball
combustion
chamber
float chamber
gas chamber
hemispherical
combustion chamber
humidity chamber
main combustion
chamber
mixing chamber
pent-roof combustion
chamber
plenum chamber
pre-chamber
pre-combustion
chamber
pre-compression
chamber
pumping chamber
salt spray chamber
spherical
combustion
chamber
suction chamber
swirl chamber
twin swirl combustion
chamber
vacuum chamber
wedge
combustionchamber
chamber recess:
See combustion chamber recess
chamber volume:
See combustion chamber volume
chamfer:
To bevel or taper the edge of an object especially the sides of a hole or a
sharp corner
chamfered:
a chamfered object is one that has a symmetrically bevelled edge.

chamois:
Pronounced SHAM-mee. A soft piece of animal skin (from a deer, sheep,
goat, etc.) used to absorb water after washing the surface of a vehicle. Also
called a chamois leather or shammy leather.
chamois leather:
See chamois.
champ car:
When Championship Auto Racing Teams (CART) was co-sponsored by
FedEx, the series became known as the FedEx Championship Series for
the PPG Cup. The cars in this series, previously known as Indy Cars, are
called Champ Cars.
change:
To remove something and replace it with something else.
Also see
climate change
downward change
floor change
oil change
range-change
upward change
change down:
A British expression meaning to shift to a lower gear.
change gear:
The action of selecting a different gear. This expression is used more in
Britain than in North America where the expression is "shift gear."
change into:
A British term for the action of shifting into another gear, such as "change
into second" (shift into second gear) or "change into top" (shift into high
gear)
change of state:

[1] Rearrangement of the molecular structure of matter as it changes
between any two of the three physical states: solid, liquid, or gas
[2] Condition in which a substance changes from a solid to a liquid or a
liquid to a gas due to addition of heat. Or, the reverse, in which a substance
changes from a gas to a liquid, or a liquid to a solid, due to removal of
heat.
changeover:
[1] The refitting of equipment to either neutralize the effects of the just
completed production or to prepare equipment for production of the next
scheduled item, or both.
[2] The removing of new original equipment tires in exchange for a
different make, size, or type.
changer:
See
CD changer
column changer
column gear changer
change-speed gearbox:
A transmission which houses a set of gears which move into various
configurations of engagement in order to produce different output ratios.
change the oil:
The act of draining out the old or dirty oil from an engine and replacing it
with fresh oil.
change up:
A British term meaning to shift up to another gear
change valve:
A British term for a valve in an automatic transmission which raises the oil
pressure as the vehicle speed increases. In North America it is called the
shift valve.
changing:

See
charge changing
wheel changing
channel:
[1] To lower the vehicle body around the frame.
[2] A route or groove through which anything passes.
[3] The hydraulic routing used by the anti-lock brake system to control the
brake pressure at each wheel. A system may have one, three, or four
channels
Also see
chassis channel
distribution channel
glass channel
grip channel
runabout run channel
run channel
window channel
channelled:
Vehicle body lowered down around the frame.
channel section:
A long metal U-shaped member used in the chassis.
chap:
See tank chap
Chapman:
Anthony Colin Bruce Chapman (1928-1982), the founder of Lotus. One of
the most innovative engineer in automotive racing history.

Chapman strut:
A type of rear suspension
using a lower lateral link and
a long spring-shock strut to
determine wheel geometry.
The basic principle is the
same as that of the front
MacPherson strut and it is so
named because Colin
Chapman first used it on the
original Elite; it is also used
on the Elan models, the new
Elite, and the Datsun (Nissan)
Z-car.
characteristic map:
A three-dimensional picture showing the relationship between various
components of a vehicle. With the help of a computer, engineers can
modify one component to see the effect it has on the whole operation of
the vehicle.
characteristics of materials:
See performance characteristics of materials
character line:
The design line or bend in the side of the vehicle that separates the upper
and lower sections of the fenders and doors
charcoal:
The amorphous form of carbon obtained by the destructive distillation of
animal or vegetable matter in a limited supply of air. In automotive use, it
is used to purify air or exhaust gases.
Also see
activated carbon
activated charcoal
charcoal canister:
Another name for activated carbon canister

charcoal filter:
A filtration system using activated carbon to remove impurities.
charcoal trap:
See activated charcoal trap
charge:
[1] The action of passing an electric current through a battery to restore it
to the active (charged) state. Normally the vehicle's generator or alternator
takes care of this. If the vehicle is not used much, an external charger is
needed to charge the battery.
[2] The definite quantity of electricity usually found in a storage battery.
[3] Refers to the mass of air and fuel that enters a cylinder during the
intake stroke.
[4] A refund amount of money. See core charge.
[5] Amount of refrigerant placed in a refrigerating unit.
[6] A specific amount of refrigerant by volume or weight
Also see
air charge temperature
battery charge
catalyst charge
core charge
cylinder charge
electric charge
fuel charge
intake charge
state of charge
stratified charge
trickle charge
charge air:
The air/fuel mixture.
charge air cooling:
An intercooler
charge-air recycling:
A device on a turbocharger which maintains the speed of the compressor
when there is no boost so that the boost is more instantly available on
demand.

charge changing:
In a two-stroke engine, the removal of exhaust gases through the exhaust
port in order to introduce a new load of fuel-air into the transfer port. Also
called "charge exchange process."
chargecooler:
A radiator that cools and therefore recondenses the intake air that has been
compressed and heated by the turbocharger thus allowing a greater amount
of air into the engine. With more air in the combustion chamber, the ECM
can deliver more fuel and make more power. This radiator can be either
cooled by air or by water. Also called intercooler
charged:
See dry charged battery
charged battery:
See dry charged battery
charge engine:
See stratified charge engine
charge exchange process:
Another name for charge changing
charge indicator:
See battery charge indicator
charge losses:
In a two-stroke engine, the exhaust gases are expelled out the exhaust port
and the fresh charge is brought in through the transfer port. Sometimes
some of the fresh charge is also forced out with the exhaust gases. There is
therefore a loss of some of the fresh air-fuel charge.
Also see
scavenging losses

charger:
Common name for a battery charger.
Also see
fast charger
trickle charger
turbo charger
charges:
See on-the-road charges
charge temperature:
See air charge temperature
charging:
See
battery charging
piston charging pump
slow charging
charging board:
Specially designed panel or cabinet fitted with gauges, valves, and
refrigerant cylinders used for charging refrigerant and oil into refrigerating
mechanisms.
charging characteristic:
When a battery is being charged, the charger will reveal how much voltage
and/or amperage is being required to bring the battery up to full charge.
charging circuit:
See charging system.
charging current:
The amount of electric current being supplied to the battery from the
alternator or from a battery charger.
charging efficiency:

[1] In a vehicle's electrical charging system, its efficiency is the ratio of
energy output to energy input, i.e., how well does the alternator work to
supply voltage to the electrical components and still charge the battery.
[2] In a two-stroke engine, it is the ratio of the amount of the fresh charge
that remains in the cylinder after the two ports are closed and the actual
volume.
charging hose:
A small diameter hose constructed to withstand high pressures. It is
connected between the air conditioning system and the manifold set
charging piston:
In a two-stroke engine, this is a secondary piston which precompresses the
fresh charge and sends it into the cylinders
charging point:
A place where a battery can be charged -- especially for battery-powered
electrical vehicles. Also called battery charging station
charging pressure:
See boost pressure.
charging pump:
See piston charging pump
charging rate:
The amount of electrical current which is delivered by the charging
system. It is usually measured in amperes.
charging station:
A usually portable unit equipped with a manifold gauge set, charging
cylinder, vacuum pump, refrigerant supply, auxiliary gauges, various
valves and the plumbing necessary to hook everything together. Used for
servicing air conditioning systems.Also see battery charging station
charging stroke:

See induction stroke.
charging system:
A system that, using a fan belt driven by the engine, enables the alternator
(or generator) to generate electrical current, which is stored in the battery
and delivered to the electrically operated pars of the vehicle chassis: The
parts of the vehicle which are left when the body and fenders are removed.
charles's law:
Volume of a given mass of gas at a constant pressure varies according to
its temperature.
Charpy test:
An impact resistance test in which the specimen is supported as a
horizontal beam and broken by a single swing of a pendulum with the
impact line midway between the supports and directly opposite the notch
for notched specimens.
chart:
See color chart
chase:
To repair damaged threads on a bolt or nut with a tap or die
chassis:
Generally, chassis refers to the frame, engine, front and rear axles, springs,
steering system, fuel tank. In short, everything but the body or cab and
fenders. Because most modern automobiles (apart from trucks) do not
have a separate chassis, the body is sometimes called the chassis.
Also see
backbone chassis
cab chassis
cowl chassis
ladder chassis
mid-engine chassis configuration
punt chassis
separate chassis

chassis bracket set:
when the sill panel does not have a jointing flange, a set of securing pieces
are welded under the sill before straightening a bent or damaged sill.
chassis cab:
A truck with a cab but no bed. To this system various bodies (ambulance,
moving van, flat beds, etc.) can be added by aftermarket suppliers.
chassis channel:
A channel section which makes up a member of the chassis.
chassis configuration:
See mid-engine chassis configuration
chassis dynamometer:
A test stand for a vehicle to determine its power output or emission levels,
etc. when the vehicle is placed under a variety of driving conditions.
Also see
dynamometer
chassis frame:
A frame (found on large trucks) which is made up of two long side
members which are joined by several crossmembers. The suspension and
axles are attached to this frame.
chassis leg:
The short channel or box section which runs along the vehicle's main axle.
It is an auxiliary member, not the main side member.
chassis lubrication:
See central chassis lubrication
chassis number:
The serial number of an older vehicle which was originally stamped on a
chassis member. Later it became known as a vehicle identification number
(VIN)

chassis section:
One of the chassis channels or boxes, whether bolted or welded to the
whole.
chatter:
[1] A noise which is caused by an irregular movement of rattling parts.
[2] The jerky movement of two components which may have moved in a
systematic way under low speed; but as the speed increases, the
components make irregular contact.
Also see
contact bounce
contact chatter
check:
[1] An inspection to determine if everything is functional.
[2] A slight slash or marking which may appear in a tire or upholstery.
Also see
checking
compression check
door check arm
door check strap
optical check
check arm:
See door check arm
check ball:
A small ball (like a ball bearing) often made of metal or plastic, found in a
check valve to halt the progress of fluid in a certain direction.
check engine light:
A light on the instrument panel that lets the driver know of any detectable
engine management system malfunctions. Also used as an emission
maintenance reminder light on some vehicles. Often when this light is on,
a trouble code is stored in the computer
check engine warning light:

An light on the dash which is illuminated when one of the engine sensors
or components does not function properly.
checkered flag:
A flag with alternating black and white squares to signal the end of the
race.
checking:
[1] Short, very fine crack lines that appear in the paint film.
[2] Small cracks in the surface of rubber (e.g., tires) caused by aging and
oxidation.
Also see
ozone checking
check point:
[1] A designated spot on a component where it is possible to determine if
there is a malfunction.
[2] A place on the road where vehicles are stopped during a rally.
check routine:
A series items in an inspection which traces a fault or problem or which
determines if all the components of a new vehicle meets the required
specifications.
check stop:
An action taken by the police to stop vehicles in order to determine if the
drivers have been drinking, wearing seat belts, and conforming to the other
requirements of operating a vehicle.
check strap:
See door check strap
check the battery:
Determine if the electrolyte is at the correct level and add distilled water to
bring it up if necessary

check the oil:
Using a dipstick, determine if there is sufficient oil in the crankcase
checkup:
The process of discovering the reliability of a vehicle or its components.
"Give my engine a checkup." Sometimes it means "tune-up."
check valve:
A one-way, in-line valve that permits flow of liquids or gases in one
direction only and closes to prevent passage in the opposite direction.
Used to control flow of vacuum, refrigerant, coolant, etc.
Also see
residual check valve
cheese head:
A cylindrical head for a screw with a straight slot and straight sides.
chemical brightening:
The improvement of the smoothness of the surface of metal by immersing
it into a solution designed to remove any roughness. Also called "chemical
polishing."
chemical cure:
Vulcanization at room temperature or above, activated by chemical agents
without the application of heat from an outside source.
chemical curing:
The setting or curing of an adhesive, coating or sealer, brought about by
the addition of heat, a catalyst, or an accelerator
chemical polishing:
See chemical brightening.
chemical refrigeration:
System of cooling using a disposable refrigerant. Also called an
expendable refrigerant system.

chemical staining:
Spotty discoloration of the paint caused by air pollution in industrial areas
chemical toilet:
A portable toilet which is used in campers and motorhomes. They contain
chemicals to deal with the feces and its smell until the contents are
dumped.
Chenard-Walcker:
are classic cars.
cherry:
A colloquial term for a vehicle that has been kept in, or restored to, perfect
condition. Also called "mint" or "like new."
cherry condition:
A colloquial term for a vehicle that has been kept in, or restored to, perfect
condition. Also called "mint condition."
chest:
See sea chest
Chevelle:
An intermediate model automobile produced by
Chevrolet
Click for books on
Chevelle

Chevrolet:
A vehicle brand of which the 1955-57 Bel Air V-8
Hardtop and Convertible are milestone cars.
Click for books on
Chevrolet
Chevrolet Camaro:
A vehicle brand of which the 1967-69 SS/RS V-8
and Z-28 models are milestone cars.
Click for books on
Chevrolet Camaro
Chevrolet Celebrity:
See Celebrity
Chevrolet Chevelle:
See Chevelle
Chevrolet Corvair:
A vehicle brand of which the 1960-64 Monza models are
milestone cars. The 1962-64 Monza Spyder models are
milestone cars. The 1965-69 Monza/Corsa models are
milestone cars.
Click for books on
Corvair
Chevrolet Corvette:
milestone cars. See also a history of the Corvette

Click for books on
Corvette
Chevrolet Monte Carlo:
See Monte Carlo
Chevrolet Nomad:
Chevrolet Nova:
See Nova
Chevrolet type:
A dual mounting wheel type consists of one cone locking nut on each stud
that holds both wheels in place against the hub.
chicken coop:
Trucker slang for Truck weigh station as in "Are the chicken coops open
this morning?"
chicken lights:
Trucker slang for Extra lights on a truck as in "Look at all those chicken
lights on that northbound bulldog."
child bike seat:
An accessory which mounts behind the saddle
of a bicycle and is designed to hold a small
child.
childproof lock:

On the rear doors of a car, a specially designed locking device can be set to
normal or to childproof. When set to childproof, the door cannot be
opened from the inside.
child restraint system:
A term for a number of items which are designed to protect children from
injury during an accident (such as child seats).
child safety:
See integrated child safety seat
child safety seat:
See integrated child safety seat
child seat:
A small safety seat which is mounted on a regular car seat and is held in
place by the seat belt.
Also see
integrated child seat
child step running board:
An external step which allows a child to be
able to enter or leave a vehicle with a high
ground clearance (a van, SUV, truck, etc.)
chilled iron:
cast iron possessing a hardened outer skin.
chiller:
Air conditioning system which circulates chilled water to various cooling
coils in an installation.
chill factor:

Calculated number based on temperature and wind velocity.
chimney:
Vertical shaft enclosing one or more flues for carrying flue gases to the
outside atmosphere.
See
coil tower
coil chimney
chimney connector:
Conduit (pipe) connecting the heating appliance (furnace) with the vertical
flue.
chimney effect:
Tendency of air or gas to rise when heated.
chimney flue:
Flue gas passageway in a chimney.
chip:
[1] Small pits in the glass (windshield or headlight) or in the paint caused
by small flying stones.
[2] To cut with a chisel.
[3] A collection of sample paint.
Also see
paint chip book
chip book:
See paint chip book
chip damage:
See stone chip damage

chip hammer:
A hammer used to remove slag, etc. from metal
because it has a chisel-like end on one side
chipping:
The action of tearing away small bits or flakes of paint or of rubber from
the tread of a tire. When larger pieces of rubber tear away, it is called
chunking.
chipping hammer:
A hammer used to remove the slag from weld
seams.

chisel:
A thick pencil shaped tool with a sharp flat end like a blade
screwdriver. When you hit the blunt end with a hammer, it
forces the blade end into metal to mark it or even cut through it.
Also see
splitting chisel
chloride:
See
calcium chloride
polyvinyl chloride
chlorofluorocarbons:
(CFCs) A gas compound which was used as a propellant in aerosol cans
and in refrigerants.
chmsl:
(pronounced CHIM-sel) An acronym for "center high mounted stop light"
an additional brake light as required by federal law whose mounting
position is determined by the manufacturer using federal guidelines
chock:
[1] A wedge used to prevent a wheel from rolling -- especially when
replacing a tire/wheel. Also called a "wheel chock."
[2] A heavy smooth-surfaced fitting usually located near the edge of the
weather deck through which wire ropes or fiber hawsers may be led,
usually to piers.
Also see
boat chock
choke:
A butterfly valve or plate located near the top of the carburetor that limits
or restricts the amount of air allowed to enter the carburetor, thus

enriching the fuel-air mixture and enabling the vehicle to start and run
more easily when cold. Automatic chokes have a thermostatic coil or
thermostatic spring that activates a butterfly valve at the top of the
carburetor barrel. Older cars have manually operated chokes. Some
vehicles use an enrichner instead of a choke.
Also see
manual choke
radio choke
choke stove:
A flapper near the top of the carburetor which regulates the amount of air
entering the carburetor.
Also see
choke
choke control:
A device or system for operating a non-automatic choke. It is usually a
cable attached at one end to the choke butterfly and a knob on the dash at
the other end.
choke index:
Automatic chokes have index marks. The factory setting closes the choke
when the bimetal is about 70° F. If you want less or more choke at this
temperature, move the choke index one mark in the direction indicated by
the arrows designating a leaner or richer mixture. You will seldom need to
move the choke more than one mark
choke kick:
A preset position for the choke valve set by manifold vacuum that is
routed through a carburetor body passage to the choke diaphragm
choke knob:
A knob on the dash fascia which is part of the choke control system.
choke stove:
A heating compartment in or on the exhaust manifold from which hot air is
drawn to the automatic choke device.

choke thermal vacuum switch:
(CTVS) a switch used on some GM vehicle to deny vacuum to either the
front or the auxiliary choke vacuum breaks. Its purpose is to slow the
opening of the choke and to provide better driveability when the engine is
cold
choke tube:
[1] The part of the carburetor air horn where the choke butterfly is
positioned. Also called a carburetor venturi.
[2] Throttling device used to maintain correct pressure difference between
high-side and low-side in refrigerating mechanism. Capillary tubes are
sometimes called choke tubes.
choke valve:
In a carburetor, it is the choke butterfly.
chop:
Lowering the height of some area of the vehicle roof, hood, top, etc.
chopped wheel:
Lightened flywheel.
chopper:
[1] Once used to describe a custom motorcycle that had all superfluous
parts "chopped" off in order to make the bike faster. A chopper today is a
type of custom bike that usually has an extended fork, no rear suspension,
high handlebars and a lowered seat. Often the original fuel tank is changed
to a smaller size.
[2] To travel by motorcycle.
chop shop:
[1] A garage which specializes in turning a two-door car into a convertible
by removing the steel top.
[2] An illegal garage which processes stolen cars by removing valued parts
and selling them privately or by changing the serial numbers for illegal
resale.

Christmas tree:
A device, using a series of lights, to start cars on the timed 1/4 mile drag
run.
chromate:
[1] A salt or ester of chromic acid which is often used as a paint pigment.
[2] The action of treating metal with a solution of chromium compound to
produce a protective metal chromate coating. Also called "chromatize."
chromate coating:
A conversion coating produced by chromating.
chromate treatment:
A solution of chromium compound is applied to metal to produce a
protective coating of metal chromate.
chromatic aberration:
[1] An enlargement of the focal spot caused in a cathode tube, by the
differences in the electron velocity distribution through the beam.
[2] An enlargement of the focal spot caused in an optical lens system using
white light, by the refractive index of the glass varying with the
wavelength of the light, resulting in colored fringes surrounding the image.
chromatize:
The action of treating metal with a solution of chromium compound to
produce a protective metal chromate coating. Also called "chromate."
chrome:
[1] A short form for chromium.
[2] The chromium plating of metal on a vehicle.
[3] To plate with chromium.
Also see
piston ring, chrome
ring, chrome
chrome-hardened:

Steel that has been made harder by adding chromium.
chrome-plated:
In order to prevent iron from rusting and showing bright and shiny, the
iron is coated with a layer of chromium by process of electroplating (or
electrodeposition).
chrome ring:
A piston ring with a chrome face.
Also see
piston ring, chrome
chrome steel:
in order to improve rust resistance and increase hardness, chrome is added
to steel. Also called "chromium steel."
chrome work:
All the metal on a vehicle which has been plated with chrome.
chromic acid:
electrolyte which is used in anodizing processes for producing non-
transparent, non-metallic oxide layers.
chromium:
A very hard grey metal used in electroplating and the production of very
hard steel compounds that are also resistant to rust.
Also see
hard chromium plating
chromium-plated:
A coating of metal with chromium to protect the metal from rust.
chromium plating:
The process of coating metal with a layer of chromium to prevent rust.
Also see
black chromium plating
hard chromium plating

chromium steel:
In order to improve rust resistance and increase hardness, chrome is added
to steel. Also called "chrome steel."
Chrysler:
A vehicle brand of which the 1926-30 Imperial 80,
1931 Imperial 8 Series CG, 1932 CG and CH, 1933
CL, 1934-6 CW with required application are
classic cars. The 1970 300 Hurst is a milestone car.
The 1955-65 300 Letter Series are milestone cars.
The 1946-50 Town and Country models are
milestone cars. Click for books on
Chrysler
chubby screwdriver:
A British term for a screwdriver with a short handle and blade for reaching
into confined spaces. In North America it is called a "stubby screwdriver."
chug:
[1] The short explosive sound of an engine going steadily and rather
slowly.
[2] To make the sound of chug.
[3] To drive slowly and steadily.
chunking:
The action which occurs when large pieces of rubber from the tread of tire
breaks away. When small pieces break away, it is called chipping.
CI:
[1] Acronym for "compression ignition."
[2] Acronym for "coil ignition."

Ciera:
Motors' Oldsmobile division
Click for books on
Ciera
CIH:
Acronym for "camshaft in head"
CIH engine:
A type of overhead valve engine (OHV) where the camshaft is enclosed
within the cylinder head not placed on top of it. It is not the same as an
overhead camshaft (OHC).
CID:
Acronym for "cubic inch displacement."
cigar lighter:
A device which heats up an element when engaged. In turn, the lighter can
ignite something flammable like a cigarette. The socket can also be used to
power other electrical components requiring 12 volts.
cigar lighter:
A device which heats up an element when engaged. In turn, the lighter can
ignite something flammable like a cigarette. The socket can also be used to
power other electrical components requiring 12 volts.
CIM:
Acronym for "computer-integrated manufacturing."
circle:
See
base circle

bolt hole circle
cam heel
hole circle
pitch circle diameter
pitch circle
traffic circle
turning circle
wheel bolt hole circle
circle diameter:
See pitch circle diameter
circlip:
A flat retaining ring in the shape of an incomplete circle where the ends at
the gap may have small holes for inserting special pliers to spread the
circlip apart. Also called a snap ring.
Also see
internal circlip pliers
piston pin circlip
wrist pin circlip
circlip pliers:
See internal circlip pliers
circuit:
[1] A source of electricity (battery), a resistance unit (headlight, etc.) and
wires that form a path for the flow of electricity from the source through
the unit and back to the source. The path of electrical current through an
electrical system. See starting system.
[2] The path of the fuel in the carburetor. See carburetor circuits.
[3] The course over which vehicles are raced particularly if it is somewhat
circular.
[4] Tubing, piping, or electrical wire installation which permits flow to and
from the energy source
Also see
carburetor circuitcharging
circuit
cranking circuit
high-tension circuit
HT circuit
idle circuit
idling circuit
ignition circuits
low-speed
circuit
low speed
circuit
low voltage
open circuit
parallel circuit
primary circuit
printed circuit
board
printed circuit
secondary circuit
series-parallel
circuit
series circuit
series parallel
circuit
short circuit

circuit
LT circuit
circuit board:
See printed circuit board
circuit breaker:
A protective device that will make and break the flow of current when
current draw becomes excessive or overloaded. Unlike the fuse, it does not
blow out but vibrates on and off thus giving the driver some light to stop
by.
Also see
cutout
circuit diagram:
A wiring diagram showing the path of the electrical connections and the
various colors of the wires.
circuiting:
See short circuiting
circuit, parallel:
Arrangement of electrical devices in which the current divides and travels
through two or more paths and then returns through a common path.
circuit, pilot:
Secondary circuit used to control a main circuit or a device in the main
circuit.
circuit protector:
Electrical device which will open an electrical circuit if excessive
electrical conditions occur.
circuitry:
See
phase-locked loop circuitry
pll circuitry
circuit, series:

Electrical wiring; electrical path (circuit) in which electricity to operate
second lamp or device must pass through first; current flow travels, in
turn. through all devices connected together.
circuit tester:
A tool which looks like a screwdriver with a light at the end of the handle
as well as a long wire with an allegator clip. The pointed end touches the
hot wire while the allegator end touches or clips to the ground. If there is
continuity and power, the light in the handle will glow.
circular headlamp:
The older type of headlight which may be the larger one (7 inch) with both
high and low beam or the smaller one (5.75 inch) dedicated to either low
or high beam.
circular mil:
Unit of area equal to the area of a circle one mil in diameter
circulating pump:
A centrifugal pump, like an automotive water pump, which moves the
liquid in a closed system.
circulation:
See
forced circulation
oil circulation
circumference:
See rolling circumference
circumferential break:
An injury to the tread or sidewall of a tire which encircles the tire.
circumferential crack:
A crack in the grooves of the tread which may be evident around the whole
tire.

CIS:
Acronym for "continuous injection system." A Bosch fuel injection system
which injects a steady stream of pressurized fuel into each intake port. CIS
was once widely used throughout the industry
CIS-E:
A CIS system with electronic controls
CIS-Lambda:
A CIS system with an oxygen sensor
CIS with Lambda:
See K-Jetronic with Lambda
Cisitalia:
A vehicle brand of which the 1946-49 GT (Pininfarina) models are
milestone cars.
citizens band radio:
A CB radio which is used to communicate over a specified frequency. It
was particular the domain of truck drivers.
Citroen:
A vehicle brand of which the 1955-64 models D8 and
ID 19 are milestone cars.
Click for books on
Citroen
city car:
A compact vehicle used for driving within a city rather than on the
highway. It is usually only 10 to 12 feet (300 to 360 cm) long.

city cycle:
An adult bicycle or tricycle used for riding within the city. Also called an
urban cycle.
city kitty:
Trucker slang for Woman city police officer as in "You got a city kitty at
the next corner up here."
Civic:
Honda
Civic
CKD:
Acronym for "Completely-Knocked Down."
CL:
Acronym for "Comfort Luxe" as a designation for a vehicle which is more
luxurious than an "L" but not quite as luxurious as a "GL"
cladding:
[1] a process of covering one material with another and gluing them
together under high pressure and temperature.
[2] The outer body panels which are attached to the vehicle's frame.
[3] Excessive decorative elements applied to a vehicle.
Claire:
See Wills Sainte Claire
clamp:

A fastening device which secures something within its jaws without
constant human pressure.
Also see
bar clamp
battery clamp
battery hold down
clamp
C-clamp
cable clamp
distributor clamp
distributor hold-down
clamp
G-clamp
hold-down clamp
hose clamp
hose clamp installer
hose clamp pliers
hose clamps
locking bar clamp
locking clamp
long-reach C-
clamp
piston ring clamp
sheet metal clamp
triple clamp
v-band clamp
welding clamp
wheel clamp
clamping load:
In a clutch, the amount of pressure on the plates.
clamp installer:
See hose clamp installer
clamp pliers:
See hose clamp pliers
clamshell:
A shape which has a bottom and top but is hinged at one end so that it can
be opened to expose its interior.
clapboard:
A narrow board which is thicker at one edge than the other edge and used
to protect from the weather.
Clark:
Clark, Jim -- Winner of 3 Formula One Championships, 25 Grand Prix
races and of the 1965 Indianapolis 500
class A thread:
A British term for external thread.
class B thread:

A British term for internal thread.
classic car:
A vehicle that is generally considered to be one of the finest models ever
built. Unlike antique cars, classic cars do not have to be extremely old.
Mustangs and VW bugs built in the late 1960s are considered to be
classics by many people; however, they are really milestone cars. Classic
cars are defined by the Classic Car Club of America and are considered to
be certain models during the years 1925-1948. They include the following
built during those years:
• A.C.
• Adler*
• Alfa-Romeo
• Alvis Speed 20, 25, and 4.3 litre
• Amilcar*
• Armstrong-Siddeley*
• Aston-Martin*
• Auburn
• Austro-Daimler
• Ballot*
• Bentley
• Benz*
• Blackhawk
• BMW (327, 328, 327/328, 335)
• Brewster*
• Brough Superior*
• Bucciali*
• Bugatti
• Buick (1931-32 series 90)*
• Cadillac (1925-35, all 12-cyl and 16-cyl, 1938-41 60 Special, 1936-
48 all series 67, 70, 72, 75, 80, 85, 90)
• Chenard-Walcker*
• Chrysler (1926-30 Imperial 80, 1931 Imperial 8 Series CG, 1932
CG and CH, 1933 CL, 1934-6 CW)*
• Cord
• Cunningham
• Dagmar (25-70 model only)
• Daimler*
• Darracq (8-cyl. cars and 4-litre, 6-cyl. cars only)
• Delage (Model D-8, not 4-cyl.)*
• Delahaye (Series 135, 145, 165 not 4-cyl.)*

• Delaunay Belleville (6-cyl. cars only)
• Doble
• Dorris
• Duesenberg
• DuPont
• Excelsior*
• Farman*
• Fiat*
• FN*
• Franklin (All models except 1933-34 Olympic Six)
• Frazer Nash*
• Graham-Paige (Custom body only)*
• Hispano Suiza
• Horch
• Hotchkiss*
• Hudson (1929 Series L)
• Humber*
• Invicta
• Isotta-Fraschini
• Itala
• Jaguar (1946-48 2.5 Litre, 3.5 Litre Mark IV, not 4-cyl.)
• Jensen*
• Jordan (Speedway Series 'Z' only)
• Julian*
• Kissel (1925-26 all models, 1927 8-75, 1928 8-90 and 8-90 White
Eagle, 1929 8-125 and 8-90 White Eagle, 1930 8-125)
• Lagonda (all except Rapier)
• Lanchester*
• Lancia*
• LaSalle (1927-1933)
• Lincoln (All L, K, KA, and KB,1941 168H, 1942 268H)
• Lincoln Continental
• Locomobile (All models 48 and 90; 1927 8-80; 1928 8-80; 1929 8-
80)
• Marmon (All 16-cyl.; 1925 74; 1926 74; 1927 75; 1928 E75; 1930
Big 8; 1931 88 and Big 8)
• Maserati*
• Maybach
• McFarlan
• Mercedes*
• Mercedes-Benz (All 230 and up, and K, S, SS, SSK, SSKL, Grosser
and Mannheim)*
• Mercer

• MG (1935-39 SA, 1938-39 WA)*
• Minerva (All except 4-cyl)
• Moon (Custom bodies only)*
• N.A.G.*
• Nash (1930 Twin Ignition 8, 1931 Series 900, 1932 Series 990,
Advanced 8, Ambassador 8)*
• Packard (All sixes and eights 1925-34, all 12-cyl. models, 1935
Models 1200-1208, 1936 Models 1400-1408, 1937 Models 1500-
1508, 1938 Models 1603-1608, 1939 Models 1703-1708, 1940
Models 1803-1808, 1941 Models 1903-1908, 1942 Models 2004-
2008 plus 2023, 1946-47 Models 2106 and 2126, all Darrin-
bodied)*
• Peerless (1926-28 Series 69
• 1930-31 Custom 8
• 1932 Deluxe Custom 8)
• Peugeot*
• Pierce-Arrow
• Railton*
• Raymond-Mays*
• Renault (45 HP)*
• Reo (1931-33 Royale 8-31, Royale 8-35, Royale 8-52, and Royale
Custom 8 and 1934 N1, N2, and 8-52)
• ReVere
• Riley*
• Roamer (1925 8-88, 6-54e, 4-75; 1926 4-75e and 8-88; 1927; 1928;
1929 8-88; 1929 8-125; 1930 8:125)
• Rochet-Schneider*
• Rohr
• Rolls-Royce
• Ruxton
• Squire
• SS and SS Jaguar (1932-1940 except 4-cyl.)
• Stearns-Knight
• Stevens Duryea
• Steyr*
• Studebaker (1929-33 President)
• Stutz
• Sunbeam (8-cyl. and 3-litre twin-cam only)
• Talbot (all 105C and 110C)
• Talbot Lago (all 150C)
• Tatra*
• Triumph (Dolomite 8 and Gloria 6 models only)
• Vauxhall (25/70 and 30/98 only)

• Voisin
• Wills Sainte Claire
• Willys-Knight (Series 66)*.
The items marked with an asterisk (*) indicate that these models require
application to be a classic car.
Classic Car Club of America:
P.O. Box 443, Madison, NJ 07940. Organization which defines which cars
are true classics.
Classification:
See American Industrial Classification
classification society:
Independent and reputable organizations which verifies and inspects
vessels for seaworthiness. As technical experts, they serve to provide the
necessary basis for adjusting insurance rates for the vessel.
Classification System:
claw hammer:
a hammer with a forked end on the head which is used for
removing nails.
Claxton horn:

A horn which makes a particular sound "Ah-oo-gah."
Also see
horn
clay model:
When the design department is creating a new model, it will be built in
clay to full size to determine its looks etc.
clean:
See steam clean
cleaner:
A product to purify or remove unwanted substances.
Also see
abrasive cleaner
air cleaner horn
air cleaner
air filter
bath air cleaner
low-profile air cleaner
paper air cleaner
piston ring groove cleaner
thermostatic air cleaner
cleaner element:
See air cleaner element
cleaner horn:
See air cleaner horn
cleaning:
See
blast cleaning
self-cleaning
cleaning unit:

See spray gun nozzle cleaning unit
clean oil:
Fresh oil that has not been used in a vehicle before.
clean oil lubrication:
A lubrication system where fresh oil is supplied to the engine as needed --
such as in a two-stroke engine.
clean shot:
Trucker slang for "No highway patrol around" as in "Large Car you got a
clean shot all the way to the state line."
clearance:
A given amount of space between two parts such as between piston and
cylinder, bearing and journal , etc.
Also see
bearing clearance
front wheel tire clearance
ground clearance control
ground clearance
lateral clearance
lateral tire clearance
longitudinal tire clearance
pedal clearance
piston clearance
piston ring side clearance
radial clearance
ring side clearance
tire clearance
valve clearance
vertical tire clearance
clearance control:
See ground clearance control
clearance depression:
See valve clearance depression

clearance fit:
Parts that are assembled so that there is clearance between them so that
one part can slide in or on the other. Also called "sliding fit"
clearance height:
[1] The distance between the ground and the lowest portion of the bottom
of a vehicle (not counting the wheels). Also called ground clearance.
[2] The distance between the top of a vehicle and the bottom of a bridge or
tunnel which determines whether the vehicle can pass under it.
clearance lamp:
A light which is mounted on the extreme edges of the roof of a truck to
show the maximum height and width of a vehicle. Also called "marker
lamp."
clearance pocket compressor:
Small space in a cylinder from which compressed gas is not completely
expelled. This space is called the compressor clearance space or pocket.
For effective operation, compressors are designed to have as small a
clearance space as possible.
clearance sensor:
See ground clearance sensor
clearance volume:
The space above a piston when it is at the top dead center.
clear coat:
A clear paint covering used on modern vehicle bodies. It is the top coat.
clear system:
See base and clear system
clearwater stern:

A stern with a "shoeless" stern frame
cleat:
[1] An attaching bracket
[2] Clips at intervals on the horizontal stiffeners of hatch coamings to
secure the hatch covers
CLEPA:
Acronym for "Comité de Liaison de la Construction d'Equipements et de
Pièces d'Automobiles" (i.e., European Association of Automotive
Suppliers).
clevis:
A U-shaped metal piece with holes in each end through which a pin or bolt
is run, used for attaching the brake pedal to the power brake booster
pushrod, the clutch pedal to the clutch cable or master cylinder pushrod
and for various other connections on an automobile.Clevises are
sometimes used in other parts of the brake system, like attaching the
parking brake cable to the parking brake lever at the rear brakes
click:
[1] The action of inserting a bicycle shoe's bracket into the receiving part
of a click-in pedal (formerly known as a clipless pedal).
[2] A colloquial term for a kilometer
click-in pedals:
A term for road bike pedals that use a
releasable mechanism like that of a ski binding
to lock onto cleated shoes and do not use toe
clips or straps. Replaces the term clipless
pedals Some brands are: SPD, Look, Time,
and Speedplay.
click-type torque wrench:
A torque wrench which gives out an audible click when the preset torque
is reached.
climate change:

the international concern that increasing concentrations of greenhouse
gases (GHGs) in the atmosphere are changing the climate in ways
detrimental to our social and economic well-being.
climate control:
[1] A lever or button which you can move to change the temperature in the
passenger compartment of a vehicle. It controls the heater, vent, and/or air
conditioner.
[2] A space in which an ideal climate is maintained by some devices.
climatic chamber:
A test area into which an automobile can be placed to see if it will meet the
extremes of temperature and humidity.
climbing ability:
While some vehicles may have a high top end speed on a road with no
incline, the real test of a vehicle in mountainous terrain is its ability to go
up a hill at an adequate speed (i.e., its climbing ability).
clincher:
A tire whose edges hook under the curved-in hooked edge of a special rim,
not commonly found anymore on bicycles and often confused with the
common wired-on tire.
clincher rims:
Type of wheel rim used with early beaded-edge tires
clincher tire:
A tire whose edges hook under the curved-in hooked edge of a special rim,
not commonly found anymore on bicycles and often confused with the
common wired-on tire.
clinometer:
An instrument which measures the steepness of a hill.
clip:

See
alligator clip
crocodile clip
hose clip
hose clip installer
hose clip pliers
jubilee clip
rebound clip
spring clip
clip installer:
See hose clip installer
clipless pedal:
See clipless pedals.
clipless pedals:
An obsolete term for road bike pedals that use
a releasable mechanism like that of a ski
binding to lock onto cleated shoes and do not
use toe clips or straps. Preferred term is click-
in pedals Some brands are: SPD, Look, Time,
and Speedplay.
clip-on engine:
An engine that is attached to a conventional bicycle frame
clip-ons:
[1] Low racing handlebars for a motorcycle that clamp directly onto the
fork legs
[2] Handlebars that attach directly to the fork tubes, rather than to the top
yoke, that hold the fork tubes together
clip-on weight:
A wheel weight that is clipped on the rim between the rim and the tire. It is
used to balance a wheel.
clip pliers:

See hose clip pliers
clock:
[1] An instrument showing the time.
[2] An odometer as in the statement I want to buy this car, but it has too
many miles on the clock.
[3] To record the speed or time that vehicle makes.
[4]To turn the odometer back (an illegal practice)
clocking:
[1] The action of recording the speed of a vehicle.
[2] In Britain, it is the action of turning the odometer back.
C/locking:
Abbreviation for "central locking."
clockwise:
Rotation to the right like the direction of clock hands. In most cases it is
the direction to secure a nut to a bolt. It is the opposite to
counterclockwise.
clog:
To obstruct a passageway or track so that the normal flow or operation of
something is hindered.
close call:
In driving it is the near possibility of an accident.
closed circuit:
Electrical circuit in which electrons are flowing.
close coils:
The coils or loops of a spring which are tightly together.
close coupled sedan:

See close-coupled sedan.
close-coupled sedan:
Similar to the sedan, this body style is shorter and thus usually
accommodates only five passengers. The rear quarter windows were
eliminated.
closed container:
Container sealed by means of a lid or other device so that neither liquid
nor vapor will escape from it at ordinary temperatures.
closed cooling system:
See coolant recovery system.
closed crankcase ventilation:
A system in which crankcase vapors are discharged into the engine intake
system (usually through the intake manifold) and pass through the engine
cylinders rather than being discharged into the atmosphere.
closed-end connector:
Solderless connector shaped like a hat. Used to join two, three, or more
wires together. Similar to wire connectors used in home wiring, but
installed by crimping instead of twisting
closed end lease:
Most leases offered today are close-end leases, meaning that the residual
value is fixed and stated in the lease contract. The lessee's financial
obligations are unaffected by what the vehicle is actually worth when the
lease ends. In other words, the lessee assumes no risk for the depreciation
of the vehicle.
closed loop:
An operating condition or mode which enables modification of
programmed instructions based on a feedback system
closed loop system:

A self-adjusting system which keeps conditions stable and is controlled by
negative feedback from a sensor.
closed system:
An anti-lock brake system with some means, generally a pump, to restore
hydraulic pressure that's bled off during an ABS stop
close-ratio gearbox:
A transmission in which there is very little difference between one gear
ratio and the next. This kind of transmission makes it easy for fast shifting.
closes:
See
exhaust valve closes
intake valve closes
closing:
See power closing
closing cam:
A cam or rocker which closes a valve in a mechanically operated valve
system. Other types close the valve through the operation of the valve
spring. Also called "closing rocker."
closing force:
The force needed for the spring to close a valve.
closing panel:
A panel which covers a hole in the body, interior panels, or frame.
closing rocker:
A cam or rocker which closes a valve in a mechanically operated valve
system. Other types close the valve through the operation of the valve
spring. Also called "closing cam."
closing system:

See automatic closing system
closure:
See road closure
cloth:
See
emery cloth
tack cloth
cloth upholstery:
The fabric of the seats made of cloth rather than leather or vinyl.
cloud point:
The temperature at which diesel oil tends to thicken and cloud up (i.e.,
become cloudy).
cloverleaf:
A highway overpass system which has four basic loops for getting on the
highway or leaving it.
club:
See
automobile club
club Cab:
A type of pickup
truck (by Dodge)
which has a second
row of seating; but
unlike a crew cab
(which has four
full size doors) it
has a "half-door"
that can be opened
only after the main
door is opened.

The seating is
usually a little
more cramped than
in a crew cab. Also
called Extended
Cab, King Cab,
XtraCab, Access
Cab, SuperCab, or
Cab Plus.
club coupe:
The club coupe designation seems to come from club car,
describing the lounge (or parlor car) in a railroad train. The early
postwar club coupe combined a shorter-than-sedan body structure
with the convenience of a full back seat, unlike the single-seat
business coupe. That name has been used less frequently in the
1976-86 period, as most notchback two-door models (with trunk
rather than hatch) have been referred to as just "coupes."
Moreover, the distinction between two-door coupes and two-door
sedans has grown fuzzy.
Also see
two-door club coupe
club hammer:
A hammer with a short handle but a large, heavy head. It is used to hit the
back end of a chisel or drift.
clunker:
A vehicle which might run but is rusty and in need of a lot of repair work.
cluster:
See
analog cluster
analogue cluster
electronic cluster
footpedal cluster
instrument cluster
lamp cluster
rear lamp cluster
seat cluster

cluster gear:
The cluster of gears that are all cut on one long gear blank. The cluster
gears ride in the bottom of the transmission. The cluster provides a
connection between the transmission input shaft and the output shaft. Also
called "counter gear."
cluster panel:
The reverse side of the instrument panel or dash where all the wiring or
circuit board is located.
clutch:
[1] An electrically operated
coupling device that connects
or disconnects the compressor
pulley and compressor shaft
[2] A device that disconnects
the engine from the
transmission, to allow the
vehicle to change gears, and
then allows the engine and
transmission to resume
contact and turn together at a
new speed.
Also see
center the clutch
centrifugal clutch
clutch diaphragm spring
clutch disc
clutch explosion
clutch housing
clutch lever
clutch pedal free travel
clutch pedal
clutch pilot bearing
clutch pressure plate
clutch release bearing
clutch semi-centrifugal
release fingers
clutch shaft
clutch solenoid
clutch throwout fork
coil spring clutch
cone clutch
diaphragm spring
clutch
diaphragm clutch
disengage the clutch
dog clutch
double clutch
double clutching
dry clutch
electromagnetic clutch
fan clutch
fluid clutch
freewheeling
friction clutch
heavy clutch
hydraulically-activated
hydraulically-assisted
clutch
hydrodynamic clutch
light clutch
lock-up clutch
magnetic clutch
multi-plate clutch
multiple-plate clutch
multiple disc clutch
oil-immersed clutch
one-way clutch
one way clutch
overrunning clutch
starter drive
overrunning clutch
starter
overrunning clutch
push-type clutch
reactor one-way
clutch
reverse clutch
riding the clutch
roller clutch
self-operating clutch
single-plate clutch
slip the clutch
sprag clutch
stator roller clutch
sticky clutch
torque converter
lock-up clutch
twin-plate clutch
wet clutch

clutch
positive clutch
pull-type clutch
clutch aligning set:
A group of tools used to align the clutch plates with the flywheel. Usually
there is a shaft, pilot bearing adapters, and tapered universal sleeves
clutch aligning tool:
A tool which looks like a bar or a disc which can be used to line up the
clutch plates with the flywheel.
clutch brake:
A device for slowing down the clutch discs (and thus the gears themselves)
so that shifting is smoother and quieter.
clutch cable:
A cable (usually a cluster of thin strands within a plastic sheath) which
operates the movement of the clutch plates. At the other end is a pedal (in
automobiles) or a handlebar lever (left side).
clutch cover:
A metal cover which encases the clutch plates.
clutch cycling switch:
A device that turns the compressor on and off in response to changes in
pressure or evaporator temp
clutch diaphragm spring:
A round dish-shaped piece of flat spring steel. It is used to force the
pressure plate against the clutch disc in some clutches.
clutch disc:
A spinning plate located at the end of the driveshaft facing the engine
flywheel and covered with a friction material such as asbestos. When the
clutch is engaged, the disc is squeezed between the flywheel and the clutch
pressure plate, causing the engine and the transmission to turn at the same
speed. British term is called "clutch plate."

clutch drag:
When the clutch discs do not disengage completely after the clutch pedal
is depressed or the clutch lever is pulled in, there is excessive friction so
that it is difficult to shift gears because both the driven discs and the input
shaft are both rotating.
clutch explosion:
clutches have literally flown apart (exploded) when subjected to high rpm,
a scatter shield is used on competition cars to protect the driver and
spectators from flying parts in the event the clutch explodes.
clutch facing:
The asbestos-type lining on a clutch plate.
clutch field:
A clutch part on an air condition compressor, consisting of hundreds of
windings of wire, that creates a magnetic field when current is applied,
pulling in the armature to engage the clutch
clutch fork:
When the clutch pedal (or lever) is depressed, it pulls on a cable which
moves the clutch fork which in turn pushes on the release bearing and
disengages the clutch discs.
clutch housing:
A cast iron or aluminumhousing that surrounds the flywheel and clutch
mechanism. Also called "bell housing."
clutching:
See double clutching
clutch interlock switch:
A switch that prevents the vehicle from starting unless the clutch
pedal/lever is pressed.

clutch judder:
A British term for "clutch shudder."
clutch lever:
A hand-operated blade located on the left side of the handlebar of a
motorcycle. When the clutch lever is pulled in, it disengages the clutch so
the engine and the crankshaft can turn independently of the transmission
and the rider can change gears.
Also see
clutch release finger
clutch lining:
The friction material on the face of the clutch discs.
clutch, magnetic:
Clutch built into automobile compressor flywheel. operated magnetically.
which allows pulley to revolve without driving compressor when
refrigerating effect is not required.
clutch pedal:
A foot-operated pedal located on the floor of the vehicle to the left of the
brake pedal on cars with manual transmission. When the clutch pedal is
depressed, it disengages the clutch so the engine and the crankshaft can
turn independently of the transmission and the driver can change gears.
clutch pedal free travel:
The specified distance that the clutch pedal may be depressed before the
throwout bearing actually contacts the clutch release fingers.
clutch pilot bearing:
A small bronzebushing, or in some cases a ball bearing, placed in the end
of the crankshaft or in the center of the flywheel depending on the vehicle,
that is used to support the outboard end of the transmissioninput shaft.
clutch plate:

The clutch discs.
clutch pressure plate:
That part of a clutch assembly
that through spring pressure,
squeezes the clutch disc
against the flywheel thereby
transmitting a driving force
through the assembly. To
disengage the clutch, the
pressure plate is drawn away
from the flywheel via linkage.
clutch pulley:
The clutch part turned by the drivebelt. The pulley or rotor "free-wheels"
until the clutch is engaged. On rotors which contain the field, the electrical
connection is made through brushes similar to alternator and starter motor
brushes
clutch release bearing:
See throwout bearing.
clutch release finger:
A flat piece of metal shaped like a curved finger. Through the movement
of the throwout fork, the throwout bearing pushes against the clutch
release fingers or levers to release pressure against the pressure plate. Also
called "clutch release lever."
clutch release lever:
See clutch release finger.
clutch rotor:
The clutch part turned by the drivebelt. The pulley or rotor "free-wheels"
until the clutch is engaged. On rotors which contain the field, the electrical
connection is made through brushes similar to alternator and starter motor
brushes
clutch semi-centrifugal release finger:

See clutch semi-centrifugal release fingers.
clutch semi-centrifugal release fingers:
Clutch release fingers that have a weight attached to them so that at high
rpm the release fingers place additional pressure on the clutch pressure
plate.
clutch shaft:
The shaft that takes power from the clutch into the gearbox. Also called
the "drive pinion."
clutch shudder:
When the clutch tries to engage (when the pedal or lever is released), but
the discs do not mate securely, the discs engage intermittently and slip past
each other making a noise like a shudder. In Britain, it is called "clutch
judder."
clutch slip:
Clutch slip occurs when the clutch tries to engage (when the pedal or lever
is released), but the discs do not mate securely.
clutch solenoid:
In some automotive air conditioners, a solenoid that operates a clutch on
the compressor drive pulley. When the clutch is engaged, the compressor
is driven and cooling takes place.
clutch spring:
The clutch cover will have several posts over which the clutch spring
(shaped like a cylinder) fits and pushes the pressure discs against the
driven clutch discs to transmit power.
clutch starter:
See
overrunning clutch starter
overrunning clutch starter drive
clutch starter drive:

See overrunning clutch starter drive
clutch starter interlock:
A device which disengages the starter once the engine has started.
clutch stop:
A clutch brake
clutch throwout bearing:
The clutch release bearing.
clutch throwout fork:
The device or fork that straddles the throwout bearing and that is used to
force the throwout bearing against the clutch release fingers.
clutch thrust bearing:
The clutch release bearing.
cluttered engine compartment:
An engine compartment or bay in which all the available space around the
engine is occupied by other objects (alternator, pumps, air intake system,
battery, wiper motor, heater motor, windshield washer motor, starter,
radiator, air conditioner, hoses, pipes, wiring, electronic boxes, etc.)
C-matic transmission:
Citroen's name for a semi-automatic transmission
C motorhome:
See type C motorhome
CNG:
Acronym for "Compressed Natural Gas"
CO:

Acronym for "carbon monoxide." A deadly, colorless, odorless, and
tasteless gas found in the engine exhaust. Toxic even in relatively small
concentrations. Formed by incomplete burning of hydrocarbons. Thus at
its greatest with a rich mixture.
CO2 indicator:
Instrument used to indicate the percentage of carbon dioxide in stack
gases.
coach:
[1] An enclosed two-door type body with permanent back panels and top,
it is similar to the coupe, but the seating is different. A full width cross seat
in the rear accommodates three passengers. Two separate seats in the front
fold out of the way to admit rear passengers. There is no trunk, but trunk
racks are frequently provided.
[2] A luxurious bus, a tour bus.
coach bolt:
A bolt with a mushroom head, but just below the head there is a square
neck and then the threads. The square neck fits into a matching square hole
to keep the bolt from moving.
coachbuilder:
A person or company which manufactures special bodies for automobiles.
coachbuilt body:
A separate body which is not integral with the chassis.
coachbuilt construction:
The process of building an automobile so that the body is separate from
the chassis. Often the bodies are built to customer specifications and may
differ from one another even though they are built upon the same chassis
design.
Also see
skeleton construction
unitary construction

coachlining:
Pinstriping along the side of a vehicle or along the side of the fuel tank of
a motorcycle.
coach paint:
A slow-drying, high-gloss paint used on cars in the early 1900s. It was
painted on car bodies with a brush.
coachwork:
Although it is strictly the body of an automobile, it is particularly the
comfort and luxury appointments as distinguished from the operational
chassis thus it would include the interior, seats, upholstery, dashes,
fenders, etc. -- everything but the mechanicals and the chassis. The French
call it Carrosserie, the Germans call it Karosserie, and the Italians call it
Carrozzeria. Also called "bodywork."
coal bucket:
Trucker slang for Dump Trailer as in "Goin' up Rte. 61 in PA, better watch
for them coal buckets."
coalescing action:
The process of smaller water droplets merging together into larger droplets
which takes place in a water separator
coaming:
See hatch coaming
coarse:
See national coarse thread
coarse-cut file:
A file with deep grooves for removing a lot of metal quickly. It leaves
rough edges which will need to be cleaned up with a smooth-cut file
coarse file:

A file with deep grooves for removing a lot of metal quickly. It leaves
rough edges which will need to be cleaned up with a smooth-cut file
coarsening:
See grain coarsening
coarse pitch:
Gears or screw threads which have wide gaps between each tooth or
thread.
coarse thread:
The threads of a screw are wider apart. Opposite to fine thread.
Also see
national coarse thread
coast:
[1] To proceed, usually downhill, on a bicycle without pedalling; or in a
motor vehicle without the aid of the engine.
Also see
freewheel.
[2] A designation on a cruise control switch which (when activated) will
cause the vehicle to slow down to a lower cruise controlled speed.
coastal:
Domestic shipping routes along the coast.
coaster:
A vehicle, usually a bicycle, which has no means of propulsion (you can't
pedal it and it is without any engine).
coaster brake:
A braking system on a bicycle in which the rider stops pedalling forward
(thus coasting) and pedals backward to engage the brake within the hub of
the rear wheel.
coat:

[1] A covering of paint or similar substance.
Also see
anodize
base coat
clear coat
color coat
cross-hatch coat
cross coat
finish coat
fog coat
gel coat
guide coat
intermediate coat
mist coat
prime coat
protective coat
single coat
tack coat
top coat
undercoat
[2] To apply a covering of paint, etc.
[3] Single coat means to apply one layer of material on a surface. Double
coat -- to apply two coats of adhesive, coating, or sealer to a surface. In
spaying, it means to spray first a single coat with vertical strokes and then
a second coat across with horizontal strokes, or vice versa
coat drier:
See top coat drier
coated abrasive:
Sandpaper or grinding wheel where an abrasive material such as sand or
diamond grit is glued to a backing material and used to reduce or smooth a
surface.
coated electrode:
See covered electrode
coating:
A protective covering usually of paint.
Also see
anodic coating
anti-chip
coating
catalytic layer
chromate
coating
coil-coating
conversion coating
electrostatic powder
coating
galvanized coating
hard anodic coating
manganese phosphate
coating
phosphate coating
polymer coating
protective coating
pvc underseal
coating
roll coating
spray coating
underbody coating
undercoating
zinc phosphate
coating
coat oven:
See top coat oven
cobble:

To put something together in a rough or clumsy manner. This is usually
done as a temporary measure until more permanent repairs can be made.
cobbled:
The action of putting something together in a rough or clumsy manner.
This is usually done as a temporary measure until more permanent repairs
can be made.
Cobra:
See AC Shelby Cobra
COC:
Acronym for conventional oxidation catalyst
cock:
A tap or shut-off valve which controls the flow of liquid.
Also see
fuel cock
radiator drain cock
cockpit:
The area, usually in racing cars, in which the driver sits and the
instruments in front of him.
code:
A system of symbols (as letters, numbers, or words) used to represent
meaning of information.
Also see
highway Code
Nordic Anti-Corrosion Code
coded:
See color-coded
code hopping:
A technology which prevents thieves with scanners from either picking up
your encoded remote-control signal or from randomly firing numerous

codes at your vehicle in order to stumble upon the one that will disarm
your security system.
code installation:
Refrigeration or air conditioning installation which conforms to the local
code and/or the national code for safe and efficient installations.
coefficient:
See
absorption coefficient
block coefficient
drag coefficient
coefficient of apparent expansion:
The coefficient of expansion when the expansion of e.g., a dilatometer is
neglected. See coefficient of expansion
coefficient of conductivity:
Measure of the relative rate at which different materials conduct heat.
Copper is a good conductor of heat and, therefore, has a high coefficient of
conductivity.
coefficient of drag:
See drag coefficient.
coefficient of expansion:
[1] Increase in unit length, area, or volume for one degree rise in
temperature.
[2] The fractional change in length, area or volume per unit change in tem
of a solid, liquid, or gas at a given constant pressure. e.g., an aluminum bar
stretches 12 millionths percent of its original length for each degree F rise
in temperature. Also referred to as "expansivity"
coefficient of friction:
A measurement of the amount of friction developed between two objects
or surfaces in physical contact when one of the objects is drawn across the
other. If a book were placed on a table and a measuring scale used to pull
the book, the amount of weight or pull registered on the scale would be the

coefficient of friction. This coefficient of friction is dependent upon both
surfaces in contact. It is large if the surfaces are rough and small if they are
smooth.
coefficient of performance:
(COP) Ratio of work performed or accomplished as compared to the
energy used.
cofferdam:
Narrow void space between two bulkheads or floors
cog:
Any toothed gear. A sprocket attached directly to the rear wheel hub on a
single-speed bike and mounted on a freewheel on a multi-speed bike.
cog belt:
A toothed belt normally of fibreglass-
reinforced rubber for driving the camshaft
from the crankshaft. In cars, cog belts are
primarily used with overhead camshafts but
are sometimes used to drive pumps.
cogeneration:
Primary source of energy that is also used to produce a secondary source
of energy. Example: The use of waste heat from an electrical energy
generation system to heat a building.
cogged belt:
See cog belt

coil:
[1] Metal bands or strands of wire wrapped in
a circular fashion.
[2] A pulse-type transformer for increasing the
voltage to fire the spark plugs.
Also see
booster coil
close coils
exciter coil
field coil
four-spark ignition
coil
glow coil
high energy coil
hold-in coil
holding coil
ignition coil
resistor
ignition coil
induction coil
multi-spark coil
multi-spark ignition coil
multiple-spark coil
multiple-spark ignition
coil
open coil glow plug
pick-up coil
pickup coil
pulser coil
single-spark ignition
coil
thermostatic coil choke
coil binding:
Compressing a valve spring to the point at which each coil touches the
adjacent coil
coil chimney:
The top of the ignition coil where the high tension leads are attached.
coil choke:
See thermostatic coil choke
coil glow plug:
See open coil glow plug
coil ignition:
The standard ignition system which uses an ignition coil which stores the
power from the battery and steps it up. Then the high voltage is sent to the
spark plugs.
Also see
transistorized coil ignition
coil ignition with Hall sensor:

See transistorized coil ignition with Hall sensor
coil lead:
A British term for the high tension wire going from the coil to the
distributor. In America, it is called the "coil wire."
coil resistor:
See ignition coil resistor
coils:
See close coils
coil spring:
[1] A section of spring steel
rod wound in a spiral pattern
or shape. Widely used in both
front and rear suspension
systems. Like large metal bed
springs, these coils cushion
and absorb the shocks and
bumps as the vehicle is
driven. They are usually
found near the front wheels,
but some cars have them in
the rear as well. Often the
shock absorbers run up the
center of the coil springs.
[2] A coiled metal spring used
in a suspension fork.
Generally considered to be
plusher, but heavier, than air
springs.
coil spring clutch:
A clutch which has a ring of coil springs which hold the pressure plate in
position.
coil spring compressor:

See spring compressor
coil tester:
See spark gap coil tester
coil tower:
The top of the ignition coil where the high tension leads are attached.
coil wire:
The high tension wire going from the coil to the distributor or spark plug.
coin holder:
A device which retains coins for easy access.
coked up:
A British term for "carboned up" to indicate something covered in carbon.
cold:
[1] The relative absence of heat
[2] A temperature considerably below normal.
cold air:
Air that is below the prevailing ambient temperature.
cold air induction:
The induction system forces cold air into the combustion chamber.
Because cold air is more dense than warm air, it contains more oxygen
molecules. With more oxygen, fuel will burn more effectively and thus
increase horsepower.
cold air intake:
The induction system forces cold air into the combustion chamber.
Because cold air is more dense than warm air, it contains more oxygen
molecules. With more oxygen, fuel will burn more effectively and thus
increase horsepower.

cold cap:
A process in retreading a tire where the tire is placed in a pressure chamber
in a temperature range of 195°-212° until bonding of the pre-cured tread
rubber is achieved.
Also see
hot cap
cold-condensate corrosion:
The corrosion of the inside of an exhaust system by direct chemical attack
resulting from an acidic, aqueous solution that condenses from the exhaust
gas at relatively low temperatures and collects at the cooler rear portions
of the exhaust system.
cold cranking ability:
A measurement in amps of a battery's ability to start a vehicle under cold
temperatures. A higher number is better than a lower one. Basic
automobile batteries begin around 400 cold-cranking amps (which is only
marginally acceptable in most vehicles). The best batteries are around
1000 cold-cranking amps.
cold cranking amps:
See cold cranking ability
cold-cranking rating:
The minimum number of amperes a fully charged 12-volt battery can
deliver for 30 seconds at 0° F without falling below 7.2 battery volts
cold galvanizing:
The application of zinc to prevent rusting. It can be applied by a paint with
lots of zinc or by electroplating with zinc.
cold junction:
That part of a thermoelectric system which absorbs heat as the system
operates.

cold lash:
The valve lash clearance, measured between the rocker arm and valve tip,
when the engine is cold.
cold manifold:
An intake manifold not heated by exhaust gas
cold plug:
A spark plug which has a short insulator nose which absorbs less heat and
dissipates heat quickly. A colder plug is used in a hot engine while a hot
plug is used in a cold engine. Thus if the plugs are fouling too much, try a
hotter plug. If the plugs are coming out white, try a colder plug. The ideal
color of the center insulator nose should be a light chocolate brown.
cold solder joint:
A poor soldering technique where the solder has not quite melted enough
to produce a good electrical contact.
cold spark plug:
See cold plug
cold spraying:
A method of paint spraying where the paint is excessively diluted with
solvent. This process makes spraying easy, but the coats are very light.
cold start:
Getting a vehicle started which has been sitting for some time and cooled
down to ambient temperature. When temperatures reach -40°, a vehicle
may require three or four times as much battery power as it would during
the summer. As well, the carburetor or fuel injection system needs to be
much richer (more gasoline than air). Because condensation has a
tendency to build up in the gas tank during the winter, the liquid going to
the carburetor or fuel injectors may be diluted with water -- thus making
starting more difficult. The application of isopropyl alcohol (marketed as
"gasline antifreeze") removes the water from the tank.
cold starting:

See cold start
cold start enrichment:
A method of providing a higher ratio of fuel to air for starting a cold
engine. In some cases, more fuel is fed into the engine with a cold start
injector; in other cases, the amount of air is restricted through the use of a
choke.
cold start injector:
A device in a fuel injection system which shoots an extra amount of fuel
into the cylinder to increase the ratio of fuel to air.
cold wall:
Refrigerator construction which has the inner lining of refrigerator serving
as the cooling surface.
cold weather modulator:
(CWM) a vacuum modulator located in the air cleaner on some models.
The modulator prevents the air cleaner duct door from opening to non-
heated intake air when outside air is below 55° F. Similar to a temperature
vacuum switch
collapse:
See piston collapse
collapsed piston:
A piston whose skirt diameter has been reduced due to heat and the forces
imposed upon it during service in the engine.
Also see
piston collapse
collapsible spare tire:
A space-saver spare wheel.
collapsible steering column:

When a vehicle is involved in an accident, the driver's chest is forced into
the steering wheel. In older cars, the immovable steering column meant
that the driver could sustain chest damage. The collapsible steering column
telescopes or folds (articulate) so that chest damage is reduced.
collar:
A sleeve that fits over a shaft.
Also see
hexagonal collar
split collar
underhead collar
valve spring collar
collector:
Semiconductor section of transistor, connected to the same polarity as the
base. See solar collector
collector car:
An older car which may not fit into the category of a classic car or a
milestone car, but it has nostalgic appeal.
collet:
A removable ring or collar which fits into a groove to hold something in
place.
collier:
Vessel used for transporting coal.
collision:
See head-on collision
collision avoidance system:
Electronic system used to prevent collisions in inland navigable
waterways.
collision bulkhead:

The foremost main transverse watertight bulkhead designed to keep water
out of the forward hold in case of bow collision damage. Also called
forepeak bulkhead
collision insurance:
Insurance coverage that pays to repair damages to your vehicle when it is
involved in an accident.
colloids:
Miniature cells peculiar to meats, fish, and poultry which, If disrupted,
cause food to become rancid. Low temperatures minimize this action.
colonnade hardtop:
In architecture, the term colonnade describes a series of columns,
set at regular intervals, usually supporting an entablature, roof, or
series of arches. To meet US federal rollover standards in 1974
(standards that never emerged), General Motors introduced two-
door and four-door pillared body types with arch-like quarter
windows and sandwich type roof construction. They looked like a
cross between true hardtops and miniature limousines. Both
styles proved popular (especially the coupe with louvered coach
windows and canopy top) and the term colonnade was applied.
As their "true" hardtops disappeared, other manufacturers
produced similar bodies with a variety of quarter-window shapes
and sizes. These were known by such terms as hardtop coupe,
pillared hardtop, or opera-window coupe.
color:
See
four color
identification color
integral color anodizing
off color
paint color matching
color anodizing:
See integral color anodizing
color chart:

A listing of paint samples of available exterior paint for a vehicle.
color coat:
A coat of paint with the final color. Sometimes a clear coat is applied over
it.
color-coded:
[1] Something that is colored the same as the main part of the bodywork.
Also called "color-keyed" or "color-matched."
[2] A series of similar things in which each one is a different color to
distinguish one from the other, such as the wiring (e.g., the red wire goes
from the battery to the fuse box, the blue wire goes from ... to the ...).
colored:
See body-colored
color-keyed:
See color-coded.
color-matched:
See color-coded.
color matching:
See paint color matching
color scheme:
The combination of exterior colors which harmonize, e.g., A maroon body
and a white roof.
Columbus:
Italian manufacturer of high quality bicycle frame tubes.
column:
See
absorbing steering column

adjustable steering column
collapsible steering column
energy absorbing steering column
height adjustable steering column
safety steering column
steering column
telescopic steering column
tilt column
column changer:
See column shifter
column controls:
See steering column controls
column gearchange:
See steering column gearchange
column gear changer:
See column shifter
column shifter:
A gear changer lever and mechanism which is located on the steering
column below the steering wheel. In Britain it is called a "column
changer" or "column gear changer."
combi:
Vessel designed for a combination of passengers, and different types of
cargo.
combination:
A vehicle like a motorcycle and sidecar or a tractor and trailer.
combination lamp:
A light or group of lights which serves two or more purposes. For
example, the rear combination lamp illumines the running lights (i.e., the
ones that are turned on when the headlight is turned on) and brake light

and/or the signal light
combination pliers:
A British term for a Lineman's pliers or slip-joint pliers
combination spanner:
A British term for combination wrench
combination valve:
[1] A brake system hydraulic control device includes a pressure differential
valve, metering valve, and proportioning valve
[2] A hydraulic valve usually incorporating a pressure differential warning
switch, a metering valve and a proportioning valve. Not all combination
valves contain all of these control valves
combination weight:
See gross combination weight
combination wrench:
A flat wrench with a hex ring at one
end and an open end at the other.
combination valve:
A pressure-regulating valve in braking systems incorporating a failure
warning switch and comprising two or more of the following valves:
pressure-differential valve, metering valve, and proportioning valve.
combined weight rating:
See gross Combined Weight Rating
combiner:
See holographic combiner
combustible liquids:
Liquid having a flash point at or above 1400F 1600C1; known as Class 3
liquids.

combustion:
The intense burning of the fuel-air mixture in the combustion chamber.
Some used to think that the fuel-air mixture exploded; but further
investigation has shown that it rapidly burns.
Also see
combustion chamber volume
combustion chamber
combustion space
compression ignition
controlled combustion system
external combustion engine
fireball combustion chamber
hemispherical combustion chamber
internal combustion engine
main combustion chamber
pent-roof combustion chamber
pre-combustion chamber
wedge combustion chamber
combustion
chamber:
The volume
of the space
in the
cylinder
above the
piston with
the piston at
top dead
center (TDC)
in the
compression
stroke. The
head of the
piston, the
cylinder
walls, and
the head
form the
chamber.
Combustion
of the fuel-

air mixture
begins here
when ignited
by a spark
plug. The
design and
shape of the
combustion
chamber can
affect power,
fuel
efficiency,
and
emissions of
an engine.
Also see
fireball combustion chamber
hemispherical combustion chamber
main combustion chamber
pent-roof combustion chamber
spherical combustion chamber
twin swirl combustion chamber
wedge combustion chamber
combustion chamber recess:
The area where combustion occurs in a rotary piston engine
combustion chamber volume:
volume of combustion chamber (space above piston with piston on TDC)
measured in cc (cubic centimetres).
combustion engine:
See
external combustion engine
internal combustion engine
combustion pressure:
The pressure created during the combustion of the air/fuel mixture in the
cylinder, measured in pounds per square inch.

combustion residue:
Carbon and other deposits resulting from combustion.
combustion space:
See combustion chamber.
combustion system:
See controlled combustion system
comeback:
[1] A repair job which has been returned to the dealer because of a repeat
problem. Usually the dealer is responsible to repair it properly at no charge
to the customer.
[2] Trucker slang for Return call or repeat as in "Can I get a come back on
that smokey report."
comedian:
Trucker slang for Median strip as in "You got a smokey in the comedian
taking pictures."
CO meter:
A device for checking exhaust gases for carbon monoxide, a high level
indicates an over-rich mixture as well as causing pollution.
Comet head:
A cylinder head with a swirl chamber for indirect injection diesel engines.
Comfort:
A designation of some automobiles as a basic or standard line usually
abbreviated as "C"
comfort chart:
Chart used in air conditioning to show the dry bulb temperature, humidity,
and air movement for human comfort conditions.

comfort cooler:
System used to reduce the temperature in the living space in homes. These
systems are not complete air conditioners as they do not provide complete
control of heating, humidifying, dehumidification, and air circulation.
Comfort Luxe:
An automobile designation (abbreviated as CL) which has more luxury
appointments than a "Comfort" but less than a Grand Luxe (GL).
comfort zone:
Area on psychrometric chart which shows conditions of temperature,
humidity, and sometimes air movement in which most people are
comfortable.
comic book:
Trucker slang for Truck driver's log book as in "The chicken coops
checking comic books this morning."
coming on the cam:
The term used when a four stroke reaches its powerband
coming on the pipe:
The term used when a two stroke reaches its powerband
commercial tire:
A tire which is designed for truck and industrial use.
commercial vehicle:
A vehicle (like a truck or bus) used for carrying goods or large numbers of
passengers for money.
commutator:
[1] A series or ring of copper bars that are connected to the armature
windings. The bars are insulated from each other and from the armature.

The brushes (as in the generator or starter) rub against the whirling
commutator.
[2] Part of rotor in electric motor which conveys electric current to rotor
windings.
compact:
See
compact car
sub-compact
compact car:
A designation no longer used because even "full-size cars" are now about
the size of what was the compact car. In 1970, for instance, a Chevrolet
Impala was a full-size car, a Chevelle was an intermediate, a Nova was a
compact. When cars smaller than the Nova came out (i.e., Chevette), they
were called sub-compacts.
companionway:
An access way in a deck, with a ladder leading below, for the use of the
crew
company logo:
An emblem which represents all or part of a company's trademark.
comparison and identification:
See program comparison and identification
compartment:
See
battery compartment
cassette compartment
cluttered engine compartment
crowded engine compartment
engine compartment
glove compartment
passenger compartment
compartmentation:

The subdividing of the hull by transverse watertight bulkheads so that the
ship may remain afloat under certain flooding conditions
compass:
An instrument with a magnetic needle which is mounted on the dash to
give the driver an idea of where magnetic north might be.
compass mirror:
An inside rear view mirror which incorporates
a compass in one corner
compensating bar:
See compensator
compensating
jet:
A fuel tube
or pipe in
the
carburetor,
into which
air is
admitted
through
one or
more holes
to
compensat
e for a
tendency
of the main
nozzle to
deliver too
rich a
mixture as
the air
velocity

through
the
carburetor
increases.
Also called
"air bleed."
compensating port:
A small hole in a brake master cylinder to permit fluid to return to the
reservoir.
compensator:
A horizontal bar which is pulled forward when the parkbrake is applied at
its central point, which is pivoted, while it is connected at each end to the
parkbrake cable, enabling equal force to be exerted on each rear brake.
Also see
temperature compensator
compensator valve:
A valve in automatic transmissions designed to increase the pressure on
the brake band during heavy acceleration.
competition:
See interchannel competition
competition car:
A vehicle which is designed to compete in races, hill climbs, and rallies.
compliance:
A slight resiliency, or "give," designed into suspensionbushings to help
absorb bumps. Good compliance allows the wheels to move toward the
rear a little as they hit bumps but does not allow them to move laterally
(sideways) during cornering.
Compliance Certification Label:
See safety Compliance Certification Label

component:
[1] One of the parts that make up the whole system or device, as in The
brake pad is a component of the brake system.
[2] A raw material, ingredient, part or subassembly that goes into a higher
level assembly, compound, or other item.
Also see
body component
primary structure component
shared component
component anti-lock brake system:
A type of anti-lock brake system in which the hydraulic control unit is not
a part of the master cylinder/power booster assembly.
component assembly:
A combination of two or more parts or sub-components to form an
assembly.
component design:
the activity for the design of specific components including responsibility
for material, cost, weight, reliability, durability, function, appearance, and
serviceability.
components:
The various parts that make up the whole system or device.
component sharing:
The use of the same basic parts used in different models -- even in models
from different manufacturers.
composite:
Any material that consists of two or more substances where one or more of
them are high strength fibers and another is an adhesive binder. The most
common composite is fiberglass, which consists of thin glass fibers
bonded together in a plastic matrix. The structural properties of composites
can be altered by controlling the orientation and configuration of the high-
strength components.

composite headlamps:
Reflector and lens system designed for specific vehicle model
composite headlight:
A headlight system which is unlike the sealed beam headlight. When the
bulb fails, you can replace just the bulb, not the whole unit. Because the
lens is contoured to the shape of the vehicle, there are many different
shapes. Thus each lens is low production and can be very costly to replace.
composite propeller shaft:
A single-piece propeller shaft made of fibre-reinforced epoxy in which the
fibres are usually glass and/or carbon.
compound:
[1] Two or more ingredients mixed together.
[2] An abrasive paste or liquid that smooths and polishes the painted
surface.
Also see
anti-drum compound
anti-ozone compound
cutting compound
intermetallic compound
ozone compound
rubbing compound
sealing compound
sheet molding compound
underbody sealing compound
valve grinding compound
valve lapping compound
compound carburetor:
A carburetor with more than one choke. Usually there are two: one for the
large throttle opening and one for the small throttle opening, but they fit to
a single port
compound center electrode:
Also called compound electrode
compound electrode:

A spark plug with a copper core and a jacket of a nickel-based alloy.
compound gauge:
[1] A gauge that can indicate both pressure and vacuum.
[2] Another name for the low side gauge, because it can indicate both
pressure and vacuum
compound glass:
See laminated glass
compounding:
See pre-compounding
compound motor:
A direct current electric motor with two separate field windings, one in
parallel and the other in series with the armature circuit; used as a starter
motor
compound refrigerating systems:
System which has several compressors or compressor cylinders in series.
The system is used to pump low-pressure vapors to condensing pressures.
comprehensive insurance:
Insurance coverage that pays for damages to your car, its accessories,
spare parts against loss or damage caused by an accidental collision, fire,
theft, vandalism, typhoon, earthquake, and flooding. It will also pay
expenses to have the disabled vehicle towed to the repair shop and
expenses to return the vehicle back to you when the repairs are completed.
It also covers for the death and bodily injury of the insured or driver; loss
or damage to someone else's property as a result of the accident; legal
liabilities to the death or bodily injury of the third party arising from the
accident; legal liabilities to the damage to property of the third party
arising from the accident; loss or damage to the property of the spouse(s)
or the child(ren) of the insured or driver; and medical expenses of the
insured or driver's injury caused by the accident.
compress:

To place under pressure or to squeeze into a small space.
Also see
pre-compress
compressed-air spray gun:
A paint gun which makes a fine spray of paint for coating the surface.
compressed natural gas:
Abbreviated CNG. See natural gas
compression:
[1] Applying pressure to a spring, or any springy substance, thus causing it
to reduce its length in the direction of the compressing force.
[2] Applying pressure to a gas, thus causing a reduction in volume.
[3] One of the essential factors in a internal combustion engine (fuel, air,
proper proportion of mixture, compression, timing, spark). It is the
squeezing of the fuel-air mixture in the cylinder of a spark-ignition engine
or the squeezing of the air in a diesel engine. Compression makes the
process of combustion more effective and increases engine efficiency.
[4] Term used to denote increase of pressure on a fluid by using
mechanical energy.
[5] Reduction in volume and increase in pressure and temperature of a gas
caused by squeezing it into a smaller space
Also see
crankcase compression
grooved compression ring
high compression head
piston ring, compression
primary compression ratio
primary compression
ring, compression
secondary compression
compression check:
Testing the compression in all the cylinders at crankingspeed. All plugs are
removed, the compression gauge placed in one plug hole, the
throttlecracked wide open and the engine cranked until the gauge no
longer climbs. The compression check is a good way in which to
determine the condition of the valves, rings, and cylinders.

compression damping:
The control of the movement as the shock compresses as it hits a bump.
Rebound damping refers to controlling the movement as the shock extends
back to its relaxed position.
compression gage:
See compression gauge.
compression gauge:
[1] A gauge used to test the compression in the cylinders. A poor
compression reading can indicate that there is leakage through the valves
or the piston rings. In two stroke engines, it could indicate that there is
poor primary compression because of a leak in the crankshaft seals.
[2] Instrument used to measure positive pressures (pressures above
atmospheric pressures) only. Gauge dial usually runs from 0 to 300 lb. per
sq. in. gauge, (psig) (101.3-2 170 kPa).
compression head:
See high compression head
compression ignition:
combustion of a fuel-air mixture without spark. In the diesel engine, air is
drawn into the cylinder and compressed to a temperature sufficiently high
that fuel oil injected at the end of the compression stroke burns in the
cylinder without a spark to initiate combustion. A prank played on new
employees is to send them on a search for the spark plugs for a diesel
engine -- they don't exist.
compression leakage:
In an engine, when some gases escape past the piston because the rings or
cylinder walls are worn, the compression is reduced so that there is less
efficiency.
compression molding:
The shaping of molding material by softening it under pressure and the
action of heat, and forcing it through a hole into a hollow space which it
completely fills.

Also see
molding
compression moulding:
British term for compression molding
compression ratio:
[1] When the piston is at the bottom of its travel (BDC), the volume of
cylinder is measured (suppose the volume is X). Then the piston is placed
at the top of its travel (TDC) and the volume of the cylinder is measured
(suppose this volume is Y). The compression ratio is a comparison of these
two values expressed as X:Y. Then the values are mathematically changed
so that the second number is always 1. Thus you hear of ratios like 10.5:1
or 9.5:1 or 8:1. The higher the compression ratio, the more mechanical
energy an engine can squeeze from its air-fuel mixture. Higher
compression ratios, however, also make detonation more likely.
[2] Ratio of the volume of the clearance space to the total volume of the
cylinder. In refrigeration it is also used as the ratio of the absolute low-side
pressure to the absolute high-side pressure.
Also see
primary compression ratio
compression ring:
A ring which surrounds the piston and fits in a grove in the piston. It is
designed to seal the burning fuel charge above the piston. Generally there
are two compression rings per piston and they are located in the two top
ring grooves. They also help to transfer heat from the piston into the
cylinder walls and subsequently to the water jacket surrounding the
cylinder.
Also see
grooved compression ring
stepped compression ring
tapered compression ring
compression spring:
An open-coil, helical spring that offers resistance to a compressive form.

compression stroke:
The second stroke of the four-stroke
cycle, in which the piston moves
upward from bottom dead center to
top dead center, compressing the fuel-
air mixture.
compression tester:
A device which is screwed or pushed into the spark plug hole so that when
the engine is turned over, it measures the amount of compression in that
cylinder.
compressor:
[1] A mechanism in a refrigerator or air conditioner that
pumpsvaporizedrefrigerant out of the evaporator, compresses it to a
relatively high pressure and then delivers it to the condenser.
[2] A tool for compressing a coil spring, such as a valve spring.
[3] Pump of a refrigerating mechanism which draws a low pressure on
cooling side of refrigerant cycle and squeezes or compresses the gas into
the high-pressure or condensing side of the cycle.
[4] An air conditioning component which pumps, circulates, and increases
the pressure of refrigerant vapor

Also see
air compressor
coil spring compressor
piston-type compressor
piston compressor
positive displacement compressor
reciprocating compressor
roots compressor
spring compressor
valve spring compressor
[3] A device which produces
pressurized air for filling tires
and running air-powered tools
compressor, centrifugal:
Pump which compresses gaseous refrigerants by centrifugal force.
compressor control:
See motor control
compressor cut-off switch:
A device used by some manufacturers to prevent compressor operation.
Such as the wide open throttle (WOT) cut-off switch, low pressure switch,
and high pressure switch
compressor discharge switch:
A device that shuts off the compressor when refrigerant pressure is low.
The switch is wired in series between the compressor clutch and the
control panel switch
compressor displacement:
Volume, in cubic inches, represented by the area of the compressor piston
head or heads multiplied by the length of the stroke.

compressor, external drive:
See compressor, open type
compressor, hermetic:
Compressor in which the driving motor is sealed in the same dome or
housing as the compressor.
compressor impeller:
An impeller of a turbocharger driven by the turbine at speeds up to
160,000 rpm, which accelerates by centrifugal force the charge air which
enter axially and leaves radially at a very high velocity.
compressor muffler:
Sound absorber chamber in refrigeration system. Used to reduce sound of
gas pulsations.
compressor, multiple stage:
Compressor having two or more compressive steps. Discharge from each
step is the intake pressure of the next in series.
compressor, open type:
Compressor in which the crankshaft extends through the crankcase and is
driven by an outside motor. Commonly called external drive compressor.
compressor pressure ratio:
In a turbocharger system, the ratio between the absolute pressure at the
compressor outlet and the compressor inlet
compressor ratio:
In a turbocharger system, the ratio between the volume in the cylinder
when the piston is at the bottom of its stroke and the volume in the
cylinder when the piston is at the top of its stroke
compressor, reciprocating:

Compressor which uses a piston and cylinder mechanism to provide
pumping action.
compressor, rotary:
Compressor which uses vanes, eccentric mechanisms, or other rotating
devices to provide pumping action.
compressor seal:
Leakproof seal between crankshaft and compressor body in open type
compressors.
compressor shaft seal:
A seal in an air conditioner compressor, surrounding the compressor shaft,
that permits the shaft to turn without the loss of refrigerant or oil
compressor, single-stage:
Compressor having only one compressive step between low-side pressure
and high-side pressure.
Comprex supercharger:
A supercharger using the pressure waves created by the expanding exhaust
gases to compress the inlet charge. Also called "pressure wave
supercharger."
computer:
[1] A device which calculates information and sends the results to a
specific destination. In automobiles, computers are used to regulate fuel
flow, control the air conditioner, display speed, time, ETA, etc.
[2] Series of electrical components which accept inputs from an operator
and controls outputs.
Also see
diagnostic computer
fuel computer
on-board computer
spark control computer
trip computer
computer-aided:

Something which has been helped or designed by a computer.
computer brake control:
See anti-skid.
computer command control:
(CCC) an electronically-controlled fuel metering system used on GM
vehicle. Uses an oxygen sensor, a throttle position sensor and other
information sensors to provide a computer with the data it needs to alter
the air/fuel ratio via mixture control solenoid in the carburetor
computer command control system:
(C-3) an earlier engine management system used on GM vehicles. (C-4) A
later engine management system used on GM vehicles
computer-controlled:
Something which is monitored by a computer
computer controlled coil ignition:
(C3I) GM's computerized ignition coil system, used on many different
engine applications
computer controlled timing:
(CCT) a system that feeds input from various engine sensors into a
computer. The computer then matches spark timing exactly to engine
requirements throughout its full range of operations
computer languages:
Specific wording or codes, such as BASIC, FORTRAN, and COBOL,
which direct a computer to accept and store information and control
outputs.
con:
See
forked con rod
master con rod

concave weld face:
A weld having the center of its face below the weld edges
concealed headlamps:
Headlamp doors close to resent a flush fitting sheet metal to reduce air
resistance in headlamp area
concealed headlights:
Headlight which (when not lit) is hidden
behind a panel. When the headlight switch is
turned on vacuum is applied to a controller
which opens the panel exposing the light. Also
called "hide-away headlights" or "pop-up
headlights."
concentration:
See stress concentration
concentric:
Two or more circles so placed as to share a common center but different
diameters.
concept car:
A vehicle that is not currently in production, but is still in the design stage.
Some are merely paper drawings, but others are clay mock-ups. The ideas
in the concept cars sometimes appears in production models.
Also see
prototype
concept vehicle:
a current production vehicle modified for installation of new design
concepts for evaluation of environmental functional feasibility.
concho:
A chrome trim disk for saddlebags and leathers.

concours:
Also called "concours d'elegance." This is the term used to describe a
show where cars in superb condition are judged against a standard of
excellence established by the sponsors, with awards given to winners.
Show cars compete in a concours.
concours d'elegance:
See concours.
cond:
Abbreviation for "condition," as in excellent cond.
condensate:
A fluid formed when a gas is cooled to its liquid state. See cold-condensate
corrosion
condensate corrosion:
See cold-condensate corrosion
condensate pump:
Device to remove water condensate that collects beneath an evaporator.
condensation:
[1] Moisture, from the air, deposited on a cool surface. The reverse of
evaporation.
[2] Liquid or droplets which form when a gas or vapor is cooled below its
dew point.
[3] The act or process of reducing a gas or vapor to a liquid or solid form
condense:
Turning a vapor back into a liquid.
condenser:
[1] A small metal cylinder which is usually located in the distributor.
It is installed between the breaker points and coil to prevent arcing at
the breaker points by absorbing or storing the excess current. A

condenser (also called a "capacitor") has the ability to absorb and
retain surges of electricity. It is constructed of two metal plates
separated by an insulator.
[2] The unit in an air conditioning system that cools the hot compressed
refrigerant and turns it from a vapor into a liquid. It is the opposite of an
evaporator.
[3] The part of refrigeration mechanism which receives hot, high-pressure
refrigerant gas from compressor and cools gaseous refrigerant until it
returns to its liquid state.
Also see
steam engine
condenser, air-cooled:
Heat exchanger which transfers heat to surrounding air.
condenser comb:
Comb-like device, metal or plastic, used to straighten the metal fins on
condensers or evaporators.
condenser fan:
Forced air device used to move air through air-cooled condenser.
condenser, water-cooled:
Heat exchanger designed to transfer heat from hot gaseous refrigerant to
water.
condensing furnace:
High efficiency, gas forced-air furnace that extracts the latent heat lost in
conventional gas forced-air furnaces.
condensing pressure:
Pressure inside a condenser at which refrigerant vapor gives up its latent
heat of vaporization and becomes a liquid. This varies with the
temperature.
condensing temperature:

Temperature inside a condenser at which refrigerant vapor gives up its
latent heat of vaporization and becomes a liquid. This varies with the
pressure.
condensing unit:
Part of a refrigerating mechanism which pumps vaporized refrigerant from
the evaporator, compresses it, liquefies it in the condenser, and returns it to
the refrigerant control.
condensing unit service valves:
Shutoff valves mounted on condensing unit to enable service technicians
to install and/or service unit.
condition:
See
air conditioner
battery charge
battery condition
cherry condition
conditioner
mint condition
original condition
spark plug condition
conditioned:
See air-conditioned
conditioner:
See air conditioner.
conditioning:
See air-conditioning
condition-latched soft code:
A type of trouble code that disengages the ABS and turns on the amber
light only as long as the condition, or problem, exists

conditions:
See driving conditions
conductance:
A measure of the ease with which a conductor allows electron flow. In DC
circuits, conductance is the reciprocal of resistance
conduction:
[1] The transfer of heat from one object to another by having the objects in
physical contact.
[2] The flow of heat between substances by molecular vibration.
[3] The transfer of heat between the closely packed molecules of a
substance or between two substances that are touching, caused by a
temperature differential between the 2 molecules or substances
Also see
thermal conduction
conductive:
The ability of something to conduct electricity.
conductivity:
The ability of something to conduct electricity. Opposite of resistivity.
Also see
electrical conductivity
heat conductivity
conductor:
[1] A material forming a path for the flow of current, such as silver,
copper, and carbon.
[2] Substance or body capable of transmitting electricity or heat.
Also see
semiconductor
cone:

[1] A bearing race that curves to the inside of a circle of ball bearings and
works in conjunction with a cup.
[2] In welding, it is the inner visible flame shape of a neutral or near
neutral flame.
Also see
bearing cone
inner cone
cone clutch:
A clutch using a cone-shaped member that is forced into a cone-shaped
depression in the flywheel, or other driving unit, thus locking the two
together, although no longer used on cars, the cone clutch finds some
applications in small riding tractors, heavy power mowers, etc.
configuration:
The particular arrangement of the parts in relation to each other.
Also see
chassis configuration
delta configuration
mid-engine chassis configuration
Y-configuration
conformation:
The ability of a precision insert bearing to match the shape and contour of
a shaft surface even after it has been in use for some time.
conical:
something in the shape of a cone. It is usually tapered.
conical seat:
A circular, tapered place that something rests. For instance, a spark plug
may fit into a tapered hole.

connecting rod:
The connecting link or arm between the
piston and the crankshaft. It converts the up-
and-down (reciprocating) motion of the
piston into the circular (rotary) motion of the
spinning crankshaft. Often called "con rod."
Also see
big-end bearing
boxed rod
forked con rod
master con rod
slave con rod
throwing a rod
connecting rod bearing:
A precision insert bearing. Also called "big end bearing"
connecting rod shank:
A longitudinal part of the connecting rod
connection:
the joining of two or more parts which generally conduct electricity.
Also see
axle connection
earth connection
ground connection
rigid axle connection
negative connections
positive connections
connections:
See
negative connections
positive connections
connector:

A device which joins two items.
Also see
adapter
battery connector
blade connector
cell connector
engine diagnostic connector
eyelet connector
helmet connector
multicon connector system
T-connector
Y-connector
connector system:
See multicon connector system
con rod:
See connecting rod.
con rod bearing:
See connecting rod bearing.
conscious:
See environment-conscious
consistency:
The stiffness, or fluid quality of an adhesive coating or sealer compound
console:
[1] A small storage space or fascia between the two front seats in a car
with bucket seats. Often it houses the shifter, some instruments, coffee
holders, coin holders, etc.
[2] A total unit or system of controls located in one area and enclosed. A
window air conditioner is a console air conditioner.
Also see
brake console
center console
parking brake console
seat rail console

constantan:
An alloy made of nickel and copper which is used in resistance wire and in
thermocouplers.
constant depression:
See air-valve carburetor.
constant-depression:
constant idle system:
An electronically-controlled air bypass around the throttle. Also called idle
speed actuator or idle-speed stabilizer
constant mesh gearbox:
A type of transmission in which all or most of the gears are always in
mesh with one another, as opposed to a sliding-gear transmission, in which
engagement is obtained by sliding some of the gears along a shaft into
mesh. In a constant-mesh manual gearbox, gear ratios are selected by
small clutches that connect the various gearsets to their shafts so that
power is transmitted through them.
Also see
sliding mesh gearbox
constant mesh gear:
One of the gears that is always in mesh with another -- whether it is
driving or not (i.e., just idling).
constant mesh gears:
Gears that are always in mesh with each other -- whether it is driving or
not (i.e., just idling).
constant-radius turn:
A turn with a steady, non-changing arc. In a decreasing-radius corner, the
arc gets sharper as you progress through the curve, while in an increasing
radius corner, the arc becomes less sharp

constant vacuum:
constant-vacuum:
constant-velocity:
A type of carburetor.
constant velocity joint:
(CV joint) A type of universal joint so
designed as to create a smooth transfer of
torque from the driven shaft to the driving
shaft without any fluctuations in the speed
of the driven shaft.
constant velocity universal joint:
See constant velocity joint.
constant voltage regulator:
(CVR) a device used to maintain a constant voltage level in a circuit,
despite fluctuations in system voltage. CVRs are wired into some gauge
circuits so voltage fluctuations won't affect accuracy of the gauge readings
constant volume sampling:
See constant-volume sampling.
constant-volume sampling:
An exhaust-emissions measuring technique in which the exhaust gases
produced by a vehicle's engine are collected as it is driven through a test
sequence of accelerations, decelerations, and cruise modes on a chassis
dynamometer. A quantity of air is added to the exhaust gases until a
specific volume (the same for all cars) is obtained. Concentrations of

pollutants in the total sample are then analyzed for determination of their
actual mass.
constricted tube:
Tubing reduced in diameter.
constrictor:
Tube or orifice used to restrict flow of a gas or a liquid.
construction:
See
body and frame construction
body construction
coachbuilt construction
frameless construction
integral body and frame construction
monobloc construction
palletized construction
sandwich construction
skeleton construction
unibody construction
unitary construction
unitized construction
consumer factors:
demographic characteristics of consumers including age, gender, income
and geographic location, affordability.
Consumer Products Safety Commission:
(CPSC) the certification agency for bicycle helmets.
consumption:
The act of using up an amount of fuel. Actually the fuel is joined with air
and merely changed into other substances (Carbon Dioxide, Carbon
Monoxide, etc. and energy).
Also see
fuel consumption indicator
fuel consumption
oil consumption

specific fuel consumption
consumption indicator:
See fuel consumption indicator
contact:
[1] The touching of two or more parts.
[2] The parts that actually touch each other when making electrical
connection whether permanently or intermittently.
Also see
fixed contact
ground contact area
moving contact
sliding contacts
contact area:
The part of the tire that actually touches the ground at any particular
moment.
Also see
ground contact area
tire contact area
contact arm:
The movable segment of the points which is moved by the lobe of the
distributor.
contact bounce:
The rapid movement of the breaker arm as it opens and closes
contact breaker:
See breaker points.
contact breaker gap:
The distance between the contact points at their furthest opening.
contact breaker plate:
The plate on which the breaker points are mounted. When adjusting the
points, the plate and the points are moved apart in relation to each other.

contact breaker point:
The individual contact of the breaker points.
contact cement:
See cement.
contact chatter:
The rapid movement of the breaker arm as it opens and closes
contact controlled electronic ignition:
See electronic ignition system.
contact gap:
See point gap.
contacting surfaces:
Any two surfaces to be brought together and bonded
contactless electronic ignition:
See breakerless transistorized ignition
contactless ignition:
See breakerless.
contact patch:
The area of a tire's tread that touches the ground.
contact pattern:
The visible wear pattern created by two parts which touch each other
contact point:

See contact points.
contact points:
Two movable points or areas that when pressed together, complete a
circuit. These points are usually made of tungsten, platinum, or silver.
Also see
breaker points
contact set:
Replacement parts consisting of breaker points and possibly breaker plate
and condenser.
contact spring:
A spring which pushes on a contact which holds something in place and
maintains contact.
contact zone:
See tire contact zone
container:
A strong steel box of standard dimensions of 8 feet square and length of 20
feet or 40 feet, in which cargo is preloaded.
Also see
catalyst container
reefer container
containerization:
A shipping system where cargo is loaded into a large container at the
factory and shipped from truck to train to ship, etc. without rehandling of
contents within the container.
container ship:
A ship designed to carry containers as cargo.
contaminant:
[1] Some impurity in gasoline or oil or anything else.

[2] Substance such as dirt, moisture, or other matter foreign to refrigerant
or refrigerant oil in system.
contamination:
See catalyst contamination
content:
See blood alcohol content
Continental:
A vehicle brand of Ford cars of which the 1956-57
Mark II models are milestone cars.
Click for books on
Continental
Also see
Lincoln Continental
continental tire:
The bulge in the rear portion of the trunk which resembles a tire or a rear
mounted tire
Continental-type fuse:
A ceramic fuse with conical end caps. They are color coded for different
values.
Continuous AC Ignition System:
Abbreviated CACIS. An ignition system where a high-energy alternating
current arc burns for the entire power stroke. In this system, the spark
plugs don't erode as quickly and the air/fuel mixture is more completely
burned. Thus there is no need for a catalytic converter.
continuous cycle absorption system:

System which has a continuous flow of energy input.
continuous injection system:
(CIS) A mechanical fuel injection system designed and manufactured by
Bosch, used on many German vehicles. In a CIS system, the fuel injectors
are always open (i.e., they emit a continuous spray of fuel into the intake
ports). The amount of fuel sprayed is determined by the fuel pressure in
the system, which in turn is determined by the position of the throttle.
Also see
K-jetronic
continuously variable transmission:
Abbreviated CVT. See infinitely variable transmission.
continuous weld:
Completing a weld in one operation
Conti tire system:
Abbreviated CTS. A run flat tire and wheel combination which allows the
tire to be run for up to 400 km (250 miles) at a speed of up to 80 kph (50
mph)
contour:
See
buff contour
panel contour
contract carrier:
A shipping company which is transporting goods because of a contract
with another shipping company.
contracting-band brake:
A brake in which a band is tightened around a rotating drum
contraction:

A thermal action where the size (mass or dimension) of an object is
reduced when cooled; the opposite of expansion.
contre:
See outboard contre pente
contre pente:
Abbreviated CP. A French designed wheel where the raised portion of one
of the rim bead seat is designed to hold the tire bead of a nearly flat tire
without breaking the bead (i.e., becoming unseated).
Also see
outboard contre pente
contre pente on both bead seats:
Abbreviated CP2. A safety rim contour with a contre pente on both rim
bead seats
control:
[1] A device or mechanism for adjusting a component. See cruise control.
[2] The ability of the driver to make a vehicle perform as required.
[3] To regulate.
[4] Automatic or manual device used to stop, start, and/or regulate flow of
gas, liquid, and/or electricity.
Also see
air control
automatic
frequency control
automatic level
control
automatic speed
control
automatic
temperature control
automatic volume
control
balance control
choke control
clearance control
climate control
computer brake
control
electronic control
module
electronic control unit
electronic engine
control
electronic ride control
electronic spark control
electronic
tractioncontrol
electronic transmission
control
emission control
engine control system
evaporation control
system
evaporative emission
control system
heat control valve
height hamper
pitch control
hydraulic control
block
ignition control
unit
illumination
control
inflation control
seam
infrared remote
control
intermittent wiper
control
IR remote control
knock control
manifold heat control
valve
mirrorcontrol
mixture control knob
mixture control screw
mixture control unit
multi-function
control stalk
oil control ring
overrun control valve
piston ring, oil
control
remote control
running-on control
valve
speed control
temperature control

corrosion control
cruise control
digital frequency
control
dimmer control
dwell-angle control
electric air control
valve
exhaust emission
control
feedback control
finance and control
flow control
ground clearance
control
headlight leveling
control
level control
limit cycle control
low-speed traction
control
low speed traction
control
vacuum control
vacuum ignition-
timing control
vacuum timing
control
control arm:
A metal strut on the suspension which is located at the top and bottom of
the wheel spindle. The upper and lower control arms allow the front
wheels to change direction. Also called a "wishbone" or "A-arm."
Also see
suspension system
track control arm
control arms:
See control arm.
control block:
See hydraulic control block
control box:
A container which houses electrical components which regulate the action
of something.
control cable:
A wire cable which runs from a knob or lever to a device which operates
or regulates. Also called a "control wire."
Also see
starter switch control cable
control, compressor:
See motor control
control computer:

See spark control computer
control, defrosting:
Device to automatically defrost evaporator. It may operate by means of a
clock, door cycling mechanism, or during "off" portion of refrigerating
cycle.
contrôle:
A checkpoint where randonneur bicycle riders must stop to have their
route cards signed and stamped to prove they have kept to the course
within the time limits.
control element:
See temperature control element
control head:
The dashboard mounted assembly which houses the mode selector, the
blower switch and the temperature control lever of the heating, air
conditioner, and ventilation system
Control Information:
See Vehicle Emission Control Information
control knob:
See mixture control knob
controlled burn rate:
See CBR process
controlled canister purge:
(CCP) ECM-controlled solenoid valve that permits manifold vacuum to
purge the evaporative emissions from the charcoal canister
controlled combustion system:

An emission control term used by General Motors to include the
following:
• modified combustion chamber design
• high-temperature coolant systems
• thermostatically controlled air cleaners
• very lean air/fuel mixtures
• high idle speeds
• severely retarded ignition timing
• TCS (transmission controlled spark) and TVS (thermal vacuum
switch)
controlled electronic:
See magnetically controlled electronic ignition
controlled electronic ignition:
See
contact controlled electronic ignition
magnetically controlled electronic ignition
capacitor controlled electronic ignition
controlled intersection:
A road junction which is controlled by traffic lights (signal lights)
controlled spark:
See transmission controlled spark
controlled vehicle:
A vehicle with a reduced emission system consisting of a catalytic
converter, EGR, air injection, fuel evaporative emission control, etc. Also
called a "detoxed vehicle."
controller:
A group of controls and circuits used to accurately and automatically
operate a device.
See

battery discharge controller
solid state controller
controller, anti-lock brake:
CAB Chrysler Corporation's term for the electronic control unit
control link:
See toe control link
control, low-pressure:
Cycling device connected to low-pressure side of system.
control module:
One of several names for a solid-state micro-computer which monitors
engine conditions and controls certain engine functions, i.e., air/fuel ratio,
injection and ignition timing, etc.
See
electronic control module
transmission control module
control, motor:
Temperature or pressure-operated device used to control running of motor.
control orifice valve:
See oil control orifice valve
control plunger:
[1] A device in a fuel injection system which moves up and down to
provide the correct amount of fuel to each cylinder.
[2] One of several names for a solid state device which monitors engine
conditions and controls certain engine functions, i.e., fuel injection,
ignition timing, glow plug system in a diesels engine, etc
control pressure:
[1] The pressure in a fuel injection system.
[2] the pressure coming from line pressure or throttle pressure in the
automatic transmission which pushes on the command valves.

[3] In a Bosch CIS, the pressurized fuel used as a hydraulic control fluid to
apply a counterforce to the control plunger in Bosch CIS. Control pressure
alters the air-fuel ratio through the operation of the control-pressure
regulator
control, pressure motor:
High- or low-pressure control connected into the electrical circuit and used
to start and stop motor. It is activated by demand for refrigeration or for
safety.
control, refrigerant:
Device used to regulate flow of liquid refrigerant into evaporator. Can be a
capillary tube, expansion valves, or high-side and low-side float valves.
control ring:
See oil control ring.
controls:
See
dual controls
emission controls
exhaust emission controls
instruments and controls
steering column controls
control screw:
See
mixture control screw
volume control screw
control seam:
See inflation control seam
control stalk:
A shaft which projects from the steering column just below the steering
wheel. It may control lights, cruise control, wipers, windshield washer,
signal lights, horn, etc.
Also see

multi-function control stalk
control switch:
See vacuum control switch
control system:
All of the components required for the automatic control of a process
variable.
See
active noise control system
anti-spin regulation traction control system
engine control system
evaporation control system
evaporative emission control system
exhaust emission control system
traction control system
transmission control system
control, temperature:
Temperature-operated thermostatic device which automatically opens or
closes a circuit.
control unit:
See
electronic control unit
ignition control unit
mixture control unit
vacuum control unit
warm-up control unit
control vacuum advance:
See speed control vacuum advance
control valve:
[1] A valve which regulates or operates a system, especially a hydraulic or
vacuum control system.
[2] Valve which regulates the flow or pressure of a medium which affects a
controlled process. Control valves are operated by remote signals from
independent devices using any of a number of control media such as
pneumatic, electric, or electrohydraulic.

Also see
air control valve
boost control valve
electric air control valve
heat control valve
manifold heat control valve
oil control orifice valve
overrun control valve
running-on control valve
control valve assembly:
A casting located in the sump of the automatic transmission. It contains
most of the valves for the hydraulic control system.
control wire:
A wire cable which runs from a knob or lever to a device which operates
or regulates. Also called a "control cable."
controlled combustion system:
(CCS) A system of reducing unburned hydrocarbon emission from the
engine exhaust.
conv:
Abbreviation for "convertible."
convection:
[1] The transfer of heat from one object to another when the hotter object
heats the surrounding air and the air in turn heats the other object.
[2] The transfer of heat by the circulation or movement of the heated, or
cooled, parts of a vapor or liquid
Also see
thermal convection
convection, forced:
Transfer of heat resulting from forced movement of liquid or gas by means
of a fan or pump.
convection, natural:

Circulation of a gas or liquid due to difference in density resulting from
temperature differences.
conventional oxidation catalyst:
(COC) a catalyst which acts on the two major pollutants: HC and CO
convenience:
See flags of convenience
conventional cross ply:
A tire having two or more carcass plies arranged in a criss-cross manner
and diagonally to the beads and travels approximately 1/3 the distance
around the circumference before attaching to the other bead. Each cord in
the next ply is arranged in the same manner, but in the opposite direction.
conventional ignition:
The transfer of heat from one object to another when the hotter object
heats the surrounding air and the air in turn heats the other object.
conventional ignition system:
An ignition system consisting of the battery, ignition switch, ballast
resistor, ignition coil, distributor, contact breaker points, condenser,
centrifugal or vacuum advance unit, spark plugs, and high tension wires.
conventional spare tire:
A spare tire & rim which is the same size as the other four wheels. Most
cars do not have them because they take up too much space in the trunk.
conventional theory:
The direction of current flow was arbitrarily chosen to be from the positive
terminal of the voltage source, through the external circuit, then back to
the negative terminal of the source
conventional tire:

A bias ply tire.
conversion:
[1] The change from one state to another, e.g., harmful gases into harmless
gases.
[2] altered state of a particular system, or set of parts needed to achieve it.
Also see
manual choke conversion
energy conversion
tractive conversion
conversion coating:
A coating of some metal which uses the same kind of metal in the coating
compound and improves paint adhesion and corrosion resistance
conversion factors:
Force and power may be expressed in more than one way. A horsepower is
equivalent to 33,000 ft. lb. of work per minute, 746 watts, or 2546 Btu per
hour. These values can be used for changing horsepower into foot pounds,
British thermal units, or watts.
conversion rate:
The rate at which a given catalytic converter purifies the exhaust gas
stream, governed by various parameters such as operating conditions and
converter design
converter:
[1] When used with LPG (propane), it is a device which turns LPG
(propane) from liquid to vapor for use in the engine.
[2] Referring to a transmission it is the device that transfers engine torque
to the transmission.
Also see
catalytic converter
dual-bed catalytic
converter
hydrodynamic torque
converter
lock-up torque
converter
lockup torque
mini catalytic
converter
monolithic
converter
open-loop catalytic
converter
oxidizing converter
pellet-type catalytic
primary catalytic
converter
rust converter
single-bed 3-way
catalytic converter
single-bed oxidizing
converter
three-way catalytic
three way catalytic
converter
torque converter
two-way catalytic
converter

converter converter converter
converter case:
An assembly in the automatic transmission encasing the impeller with the
converter cover welded to it. It contains the converter fluid and vane
wheels and connected to the crankshaft by means of the drive plate and
revolving at engine speed.
converter, catalytic:
See
catalytic converter
converter cover:
A part in the automatic transmission that is welded to the pump and makes
up the converter case
converter drive plate:
See torque converter drive plate
converter housing:
[1] A stationary outer part of the automatic transmission which encloses
the converter case.
Also see
torque converter housing
[2] The housing of a catalytic converter. Also called "converter shell."
converter lock-up clutch:
See torque converter lock-up clutch
converter preheating:
An emission control device which increases catalytic action in cold starts
when HC and CO are their highest. Although not in use in current cars, it
may become necessary in the future. Thus it may mean the following:
Take longer to start a vehicle in the morning, require a larger battery,
necessitate plugging a vehicle into household circuit, need for frequent
replacement of the catalytic converter.

Also see
preheating
converter shell:
See the second definition of converter housing
convertible:
Generally this is a two-door automobile without a fixed roof.
Instead, the roof folds up or is removed in some way so that the
passenger compartment is exposed to the open air. Some roofs are
made of flexible fabric or plastic which folds up behind the
passenger compartment. Other roofs are not flexible and retract
into the trunk. Some retract automatically while others must be
manually removed and placed in the trunk. The term was
introduced in the 1930s. In the 1950s, a hardtop convertible was
introduced to look like a convertible with its top up; but its fixed
roof did not fold or retract. It was also called a "drophead coupé"
or "open car."
Also see
hardtop convertible
convertible sedan:
This is similar to the sedan body type, but with provisions of lowering
both the all-weather side windows and the fabric top to create a four-door
convertible.
convertible top:
The soft foldable canvas or vinyl top of a convertible. It usually has a clear
plastic rear window.
convex weld:
A weld with the face above the old edges
coolant:
Liquid in the cooling system. Usually a mixture of water and antifreeze
(ethylene glycol). This mixture lowers the freezing point of the water in
the cooling system, prevents rust and corrosion, lubricates the water pump,

and picks up heat from the engine and transfers it to the air passing
through the radiator.
Also see
engine coolant
coolant controlled exhaust gas recirculation:
(CCEGR) a system that prevents exhaust gas recirculation until engine
coolant temperature reaches a specific value
coolant level warning light:
A small light on the dash which is illuminated when the radiator is low on
coolant
coolant pump:
See water pump
coolant recovery system:
A small bottle that acts as a reservoir for liquid expelled from the cooling
system through the overflow pipe and returns the liquid to the system
when it cools down. A special radiatorpressure cap is also part of the kit. It
is also called a "Closed Cooling System" when it is part of the original
equipment.
coolant temperature override switch:
CTO A switch that prevents vacuum from reaching a component until
coolant temperature reaches a certain value
coolant temperature sensor:
A sensor located at the bottom of the radiator which is connected to the
temperature gauge.
cooled:
See
air-cooled
air cooled
liquid-cooled
water-cooled

cooled engine:
cooled valve:
See sodium cooled valve
cooler:
[1] A device for cooling hot liquid or air by passing air through the vanes
of a heat sink.
[2] Heat exchanger which removes heat from a substance.
Also see
aftercooler
oil cooler
cooler bypass:
See oil cooler bypass valve
cooler bypass valve:
See oil cooler bypass valve
cooling:
See
charge air cooling
fan cooling
flushing the cooling system
intercooling
thermosyphon cooling
cooling fan:
[1] A large fan designed to suck relatively cool air and force it onto a warm
object like an engine.
[2] A large fan designed to pull away the radiant warm air surrounding a
hot object.
cooling fins:
The greater the surface area that needs to be cooled, the better you will be
able to cool off a hot object, like an engine. By putting a number of fins on

a surface, you increase the overall area. On air cooled engines, for
instance, you will see a series of closely formed ridges or fins in parallel.
As the air passes by them, the engine heat is dissipated.
cooling jacket:
See water jacket
cooling system:
The system that removes heat from the engine. In a water-cooled engine it
includes radiator, pressure cap, fan, water pump, thermostat, water jackets;
in an air-cooled engine it consists of a fan, cooling fins, and ducting.
Also see
closed cooling system
flushing the cooling system
water cooling system
cooling tower:
Device which cools by water evaporation in air. Water is cooled to wet
bulb temperature of air.
Coolmax:
A garment constructed of four channel polyester, naturally hydrophobic
fabric. Coolmax is designed to regulate body temperature during physical
exertion by increasing air flow and transporting moisture through the
fibers to the outside of the fabric where moisture evaporates.
copolymer:
A polymer produced from two different monomers.
Also see
graft copolymer
copper core:
The center electrode of a spark plug or the center wires of a high tension
wire which is made of copper.
copper-faced hammer:
A hammer with a round head made of copper or brass. It is used to hit
objects without damaging them where hitting them with a steel hammer

might.
copper plating:
[1] The application of a thin layer of copper by a process of electrolysis.
Primarily it is done to electrical contacts and terminals to give excellent
conduction of electricity.
[2] Abnormal condition developing in some units in which copper is
electrolytically deposited on some compressor surfaces.
copy:
Trucker slang for "understand" as in "Do you copy?"
Cord:
[1] A vehicle brand of which the 1925-1948 model cars are classic cars.
[2] A strand of fabric or steel cable used in the ply of a tire.
[3] A rope.
Also see
bungee cord
cordura:
The brand name for a heavy-duty, synthetic material made by DuPont that
feels like canvas. It is often used in the manufacture of lightweight
clothing, backpacks, and camping gear.
core:
[1] When referring to casting -- a sand unit placed inside of a mold so that
when the metal is poured, the core will leave a hollow shape.
[2] The magnetic center of a coil usually made of iron.
[3] The primary part (engine block, alternator, starter, radiator, etc.) which
has malfunctioned, but is still suitable for rebuilding or remanufacturing.
You can exchange it for a new or rebuilt part. Thus, instead of paying full
price for a new alternator, you can submit your old alternator as a core and
pay a lower amount for the new alternator. "CORE" is an acronym for
"cash on return."
Also see
bead core
copper core
laminated iron core
timer core

valve core
core, air:
Coil of wire not having a metal core.
core charge:
The word "core" is short for "cash on return." When you purchase a part
which is rebuildable, you can return your old part and receive a core
charge. Generally a core charge is collected for engines, crankshafts,
alternators, radiators, brake shoes. If the part is beyond repair, there may
be no core charge.
core hole plug:
See
core plug
freeze plug
core hole plugs:
See core plug.
core/insulator:
See projected core/insulator nose
core/insulator nose:
See projected core/insulator nose
core leads:
See carbon-core leads
core, magnetic:
Magnetic center of a magnetic field.
core plug:
A metal plug located in the sides of the engine block which can pop out
because of excessive pressure or freezing and prevent the engine block
from cracking. These plugs are located in the water jacket and can

sometimes leak and should then be replaced. Block heaters are installed by
removing a core plug and inserting a heating element. Core plugs are also
called "freeze plugs" or "expansion plugs."
core plugs:
See core plug.
core support:
The framework that supports the radiator and air conditioner condenser
assembly and also serves as the attaching point for the front fenders, grille
assembly, hood latch, etc.
corncob:
A bicycle term used to describe a cluster of cogs on a racing freewheel
because of the small variation in number of teeth on adjacent cogs.
corner:
See
inside corner weld
outside corner weld
rear corner valance
rear corner panel
cornering:
The negotiation of a curve, bend, or corner of a road. Good cornering
ability allows the vehicle to go around a curve at a reasonable speed
without body roll and breakaway.
cornering force:
The forces exerted on a tire by the slip angle when moving around a curve.
Also see
ultimate cornering force
cornering limit:
The maximum speed that a vehicle can travel around a particular curve.
cornering speed:

The speed that a vehicle makes when turning. It is relative to the sharpness
of the curve and the ability of the vehicle to stay on the road under control.
corner joint:
A junction formed by edges of two pieces of metal touching each other at
an angle of about 90°
corner panel:
A panel used to fill a gap between larger panels or frame members meeting
at an angle and to serve as a stiffener, such as those at the intersection of
sidemembers and crossmembers and the rear corner panels of rear fenders.
Also see
rear corner panel
windshield corner panel
corners:
See across corners
corner steady:
A British term for a jack stand used to support and level the corner of a
parked travel trailer.
corner valance:
See rear corner valance
corner weld:
See
inside corner weld
outside corner weld
corn flakes:
Trucker slang for A Consolidated Freightway truck as in "Can I get a
smokey report there corn flakes."

Corolla:
Click for books on Corolla
Corona:
Click for books on Corona
corporate Average Fuel Economy:
(CAFE) Regulation enacted in 1975 which requires a motor vehicle
manufacturer to classify its U.S. vehicle fleet sales as either domestic or
import for the purpose of fuel economy averaging.
corporation:
Business association endowed by law with the rights and liabilities of an
individual
correction jet:
See air correction jet
corrector:
See height corrector
corrode:
To eat away, gradually, the surface material from an object by chemical
action, such as rust.
corrosion:
[1] The chemical process in which a metal is eaten away (i.e., rusting).

[2] Deterioration of materials from chemical action.
[3] The eating or wearing away of a substance, such as metal, usually
caused by chemical decomposition brought about by an acid.
Also see
anti-corrosion
atmospheric corrosion
bimetallic corrosion
cold-condensate
corrosion
electrochemical
corrosion
electrolytic
corrosion
fretting corrosion
galvanic corrosion
general corrosion
graphitic corrosion
intercrystalline
corrosion
intergranular corrosion
localized corrosion
microbial corrosion
oxygen corrosion
pitting corrosion
scab corrosion
selective
corrosion
underfilm
corrosion
uniform corrosion
corrosion control:
The minimizing of corrosion by coating with a protective metal, an oxide,
or similar substance, or with protective paint, or by making the metal
passive.
corrosion cracking:
See stress corrosion cracking
corrosion inhibitor:
A substance which reduces or prevents corrosion in oils, anti-freeze,
paints, etc.
corrosion prevention:
passive.
corrosion product:
A substance formed as a result of corrosion (i.e., the rust itself)
corrosion protection:
passive.
corrosion resistance:

The ability of metal not to corrode. For example, nickel has a high
corrosion resistance while iron does not.
corrosion warranty:
See anti-corrosion warranty
corrosive:
Causing corrosion, e.g., acid is corrosive because it eats away the
substance on which it is applied. That's why acid rain is so harmful to the
surface of automobiles.
Also see
anti-corrosive
Ford Cortina:
A model of automobile manufactured by Ford of
England
Click for books on Ford
Cortina
Corvair:
A vehicle brand of which the 1960-64 Monza models are
milestone cars. The 1962-64 Monza Spyder models are
milestone cars. The 1965-69 Monza/Corsa models are
milestone cars.
Click for books on
Corvair
Corvette:
milestone cars. See also a history of the Corvette
Click for books on
Corvette

cost:
The price that a shop charges for a vehicle or one of its components. To the
shop, it is the price they pay for the component (i.e., the net price) to
which they add an amount or percentage to arrive at the selling price.
Also see
cap cost
capitalized cost
net cap cost
net capitalized cost
opportunity cost
total Out-Of-Pocket Cost
operating costs
cost-effective:
worthwhile. Usually a determination of whether repairing a vehicle is
worth the expense in comparison with junking or selling it in favor of
purchasing a newer vehicle. If you spend a
1000 to repair a vehicle worth $20,000, that is cost effective. If you spend a
$1000 to repair a vehicle worth $200, it probably is not. The exception would
be a vehicle which has nostalgic or historic value.
cost of production:
actual cost to the manufacturer of producing a vehicle (does not include
mark-up).
cost option:
An optional item for a new vehicle for which extra money must be paid to
obtain it.
cost per kilometer:
A ratio which is obtained by dividing the total cost of the tire by the
distance the tire has gone. The total cost involves adding up the initial
price of the tire, price of retreading, repairs, rotation of tires, balancing
tires, and other services. From this total any credits such as warranty,
rebates, and trade-in value is subtracted. It must be remembered that when
calculating the cost per kilometer of summer tires if winter tires were
installed for a few months that only the number of kilometers that the

summer tires were actually in use should be determined for this ratio.
When purchasing tires, it may be helpful to divide the retail cost by the
number of expected kilometers in order to compare one brand or one series
against another.
cost per mile:
A ratio which is obtained by dividing the total cost of the tire by the
distance the tire has gone. The total cost involves adding up the initial
price of the tire, price of retreading, repairs, rotation of tires, balancing
tires, and other services. From this total any credits such as warranty,
rebates, and trade-in value is subtracted. It must be remembered that when
calculating the cost per mile of summer tires if winter tires were installed
for a few months that only the number of miles that the summer tires were
actually in use should be determined for this ratio. When purchasing tires,
it may be helpful to divide the retail cost by the number of expected miles
in order to compare one brand or one series against another.
cost reduction:
See
cap cost reduction
capitalized cost reduction
cost reduction effort:
See supplier cost reduction effort
Cotal gearbox:
A semi-automatic electrically controlled transmission made in France just
after WWII
cotter:
A tapered pin or wedge which is inserted into holes in two parts to secure
them. Older bicycles used a cotter to secure the crank arm to the crank
spindle.
Also see
cottered crank
cotter pin:
A fastener shaped like a pin, but split up the center. After it is inserted, the
legs are bent around the item containing the hole. A length of wire which

is folded almost in half and the bend forms an eye. Also called a "split
pin."
cottered crank:
A bicyclecrankset in which the crankarms are fastened to the axle by
means of threaded cotter pins and nuts.
cotterless crank:
means of nuts or bolts instead of cotter pins.
cotterless crankset:
means of nuts or bolts instead of cotter pins.
coulomb:
Abbreviated: C. A unit of electric charge. It is the amount of electricity
conveyed in one second by a current of one ampere.
Council for Automotive Research:
See United States Council for Automotive Research
counter:
See
rev counter
revolution counter
trip mileage counter
counter balance:
A weight attached to some moving part so that the part will be in balance.
Also see
crankshaft counter-balance
counterbalancer:
A weight inside an engine that cancels out some of the engine's vibration

counterbore:
Enlarging a hole to a certain depth.
counterclockwise:
Rotation to the left as if the hands of a clock were going backwards. In
most cases it is the direction to remove a nut from a bolt. It is the opposite
to clockwise.
counter emf:
Tendency for reverse electrical flow as magnetic field changes in an
induction coil.
counterflow:
Flow in opposite direction.
counterforce:
In Bosch CIS, the force of the fuel-pressure applied to the top of the
control plunger to balance the force of the airflow pushing against the
sensor plate
counter gear:
See cluster gear.
countershaft:
The shaft in a manual gearbox that carries power by means of gears from
the clutch shaft to the driveshaft, turning opposite to them. The British
term is "layshaft"
countersink:
To make a counterbore so that the head of a screw may set flush, or below
the surface.
countersteering:
The way you use the handlebar to lean the bike into a turn. If you want to
turn right, you push the handlebar to the left, and vice versa

countersunk bolt:
A bolt with a special head. The underside of the head is tapered to fit into a
hole that has tapered sides (countersunk hole) so that when the bolt is
screwed in all the way, the top of the bolt is flush with the surface
countersunk hole:
A hole with sloping sides where the top of the hole is larger than the
bottom of the hole as in the shape of the letter "V"
countersunk screw:
A screw with a special head. The underside of the head is tapered to fit
into a hole that has tapered sides (countersunk hole) so that when the
screw is screwed in all the way, the top of the screw is flush with the
surface
counterweight:
[1] Weight added to a rotating
shaft or wheel to balance
normal loads on the part and
offset vibration.
Counterweights are used on
the crankshaft and are often
found on the flywheel and
driveshaft.
[2] A balance weight
county mounty:
Trucker slang for Highway patrol as in "You got a county mounty
advertising at the 34."
coupe:
An enclosed single-compartment body with two doors and varying
passenger capacity depending on seat arrangements. The SAE standard
J1100 defines it as having less than 33 cubic feet (934 liters) of interior
volume. Larger coupes have rear quarter windows. Coupes have fixed

permanent back panels and top, as well as a luggage compartment in the
rear deck. Originally it meant a vehicle which was "cut" (thus the French
"coupé") by a glass partition behind the front seats so that the driver was
exposed to the air while those in the back were enclosed.
Also see
club coupe
drophead coupé
hatchback coupe
sport coupe
three-door hatchback coupe
two-door club coupe
two-door coupe
two-door hatchback coupe
coupé:
See coupe
coupled sedan:
See close coupled sedan
coupler:
A device which links two other components.
coupling:
A connecting device used between two objects so motion of one will be
imparted to the other; it may be mechanical,
hydraulic, or electrical.
Also see
doughnut coupling
föttinger coupling
flexible coupling
fluid coupling
foettinger coupling
guibo coupling
layrub coupling
rotoflex coupling
rubber coupling
rubber doughnut coupling
shaft-to-cage coupling
shaft-to-shaft coupling
viscous coupling

coupling differential:
See viscous coupling differential
coupling point:
This refers to the point at which both the pump and the turbine in a torque
converter are travelling at the same speed, the drive is almost direct at this
point.
couplings:
Mechanical device joining refrigerant lines.
coupling sleeve:
A collar or sleeve which is moved along the main shaft of a transmission
by a selector fork engaging in a groove on its center and having dog
clutches at either end.
courier bag:
A flat rectangular-shaped bag with a long strap. They are slung over the
head and one shoulder. Called a courier bag because they were originally
made for motorcycle and bicycle couriers.
course:
See road course
courtesy light:
A light in the cab of a vehicle which is illuminated when the door is
opened.
cover:
[1] A protective panel designed to protect or hide components.
Also see
arm cover
battery cover
car cover
clutch cover
converter cover
dust cover
end cover plate
engine cover
headlight cover
nut cover
rocker arm cover
rocker cover gasket
sill cover
tonneau cover
transfer port cover
transmission cover
valve cover
wheel cover

end cover rocker cover
[2] The tire itself as opposed to the inner tube.
coverage:
The surface area that a given quantity of paint will cover adequately
coverage:
The area over which a quantity of adhesive, coating, or sealer can be
applied at a specific thickness, usually expressed in terms of square feet
per gallon
covered electrode:
A metal rod used in arc welding which has a covering of materials to aid in
the arc welding process
covered wagon:
Trucker slang for Gravel trailer covered with a tarp as in "There's a line of
sand truck in this destruction up ahead."
cover gasket:
See
rocker cover gasket
valve cover gasket
cover plate:
See end cover plate
cowboy:
Trucker slang for Truck driver who constantly changes lanes at high
speeds as in "We got a bunch of real cowboys out on the road tonight."
cowl:
[1] The part of the vehicle body between the engine firewall and the front
of the dashpanel. It usually houses the instruments and the plenumchamber
for the heater-ventilation system. The British term is "scuttle."

[2] The part of the bodywork which protects and/or provides streamlining
for a usually projecting component.
cowl chassis:
A truck chassis with front fenders and hood as well as the instrument
panel. It is used for companies want their own custom body and cab.
cowling:
[1] The part of the bodywork which protects and/or provides streamlining
for a usually projecting component.
[2] A piece of bodywork that covers the engine area
cowl panel:
A British term for cowl
cowl section:
A subassembly of the body shell that includes the bulkhead, cowl, and
windscreen pillars; it is preassembled in the factory and spot-welded with
the other subassemblies to form the body shell
cowl shake:
This is a vibration or shake of a vehicle, usually a convertible type, in the
cowl area due to lack of torsional rigidity of the frame and body. A certain
amount is almost unavoidable in convertibles unless frame-strengthening
weight penalties are of no concern.
cowl side panel:
A vertical panel at either end of the cowl
CP:
Acronym for contre pente
CP2:
Acronym for contre pente on both bead seats

cpe:
Abbreviation for "coupe."
CPI:
Central Point Injection. A GM fuel injection system that uses a centralized
fuel injector delivering fuel through lines to injector nozzles located at
each cylinder
C pillar:
See C-post.
C-pillar:
The body post that supports the rear of the roof and to which the left and
right sides of the back glass are attached. Also called "C-post."
C post:
See C-post.
C-post:
The body post that supports the rear of the roof and to which the left and
right sides of the back glass are attached. Also called "C-pillar."
CPSC:
Acronym for "Consumer Products Safety Commission," the certification
agency for bicycle helmets.
CPSOV:
Acronym for canister purge shut-off valve
CR:
Acronym for "compression ratio."
crab:
The action of a vehicle where the rear wheels are offset from the track of
the front wheels.

crab-tracked:
A situation where the front wheels are wider apart than the rear.
crack:
[1] To open something just a little.
[2] A fracture in something which does not split it open. A hairline crack is
a very narrow fracture which is often barely visible with the naked eye.
Also see
circumferential crack
groove cracks
incipient crack
crackage:
Joint in a structure which permits movement of a gas or vapor through it,
even under a small pressure difference.
cracker:
A non-American colloquial term for something that is very enjoyable, e.g.,
"My car's a cracker."
Also see
nut cracker
cracking:
[1] The action of opening a valve slightly and then closing the valve
immediately.
[2] forming of cracks for instance in the sidewalls of a tire because of the
hardening of the rubber or in paintwork because of weathering.
Also see
heat cracking
radial cracking
stress corrosion cracking
stress cracking
weather cracking
cracking a valve:
Opening a valve a small amount.
cracking groove:

A split in the grooves of the tread caused by excessive strain.
cracking tread:
A split in the grooves of the tread caused by excessive strain.
cradle frame:
A motorcycle frame with two tubes passing under the engine.
Also see
open cradle frame
crank:
[1] An arm set at right angles to a shaft or axle, used for converting
reciprocal (to-and-fro) motion into circular motion.
Also see
cottered crank
cotterless crank
flat crank
hand crank
[2] The action of trying to start a vehicle engine or an electrical motor by
means of a crank handle or by an electrical starter.
crankarm:
[1] A part on a bicycle, where one end is attached to the bottom bracket
axle and the other holds a pedal, whose forward rotation provides the
leverage needed to power the bicycle.
[2] An arm set at right angles to a shaft or axle, used for converting
reciprocal (to-and-fro) motion into circular motion.
crankarm fixing bolt:
The bolt that holds a crankarm on the end of the axle in a cotterless
crankset of a bicycle.
crank bolt:
A bolt that run through the end of the crankarm and into the bottom
bracket spindle.
crankcase:

The lower part of the engine that surrounds the crankshaft. It contains the
crankshaft, pistoncylinders, connecting rods and other moving parts of the
engine. As well, in non-air-cooled engines, it has a number of internal
passages for the coolant and oil transfer. In air-cooled engines, it has
internal passages for oil transfer; but usually it has fins on the exterior to
dissipate the heat. The crankcase is not to be confused with the pan which
is a thin steel cover that is bolted to the bottom of the crankcase.
Also see
positive crankcase ventilation system
positive crankcase ventilation
crankcase breather:
A vent which allows fumes and blow-by gases to escape. It reduces
condensation. This breather is usually connected to the air intake of the
carburetor so that the fumes can be burned in the combustion chamber
crankcase compression:
The primary compression in a two-stroke engine located below the pistons
and enables a more fresh charge to be fed into the cylinder. Also called
"crankcase pre-compression."
crankcase depression regulator:
(CDR) a device which aids in the control of crankcase gases by
maintaining a specific amount of vacuum in the crankcase
crankcase dilution:
An accumulation of unburned gasoline in the crankcase, an excessively
rich fuel mixture or poor combustion will allow a certain amount of
gasoline to pass down between the pistons and cylinder walls and dilute
the engine oil.
crankcase emissions:
Pollutants allowed to escape into the atmosphere from the crankcase
crankcase half:
One side of a crankcase usually split down the middle. Usually found in
motorcycle engine.

crankcase pre-compression:
See crankcase compression
crankcase scavenging:
A system in a two-stroke engine where the fresh charge is induced into the
cylinder by way of the crankcase and the transfer ports
crankcase ventilation:
circulation of air through the crankcase of a running engine to remove
water, blow-by, and other gases in order to prevent oil dilution and
contamination, sludge formation, and pressure build-up.
Also see
closed crankcase ventilation
positive crankcase ventilation
positive crankcase ventilation system
crankcase ventilation system:
See positive crankcase ventilation system
cranked:
something which has an elbow or right-angle shape.
cranking:
The act of engaging the starter by turning the key in the ignition switch
which makes the engine turn over. In the old days, a hand crank was used
to do this, thus the term "cranking."
Also see
cold cranking ability
cranking ability:
See cold cranking ability
cranking amps:
See cold cranking amps

cranking circuit:
See starting system.
cranking motor:
See starter.
cranking on the throttle:
The action of moving a twist grip so that more fuel enters the engine and
thus increases the speed of the vehicle.
cranking speed:
The speed at which the starter turns the engine.
crank kit:
A reground or reconditioned crankshaft and new main and connecting rod
bearings
crankpin:
The bearing surface on a crank of the crankshaft to which the connecting
rod is attached. Also called the "journal" or "crank throw."
Also see
splayed crankpins
crankset:
A group of components on a bicycle that includes the bottom bracket
removable parts, two crankarms, and one or more chainrings.
Also see
cotterless crankset
crankshaft:
A main rotating
shaft running
the length of
the engine. The
crankshaft is
supported by
main bearings.
Portions of the

shaft are offset
to form throws
to which the
connecting
rods are
attached. As
the pistons
move up and
down, the
connecting
rods move the
crankshaft
around. The
turning motion
of the
crankshaft is
transmitted to
the
transmission
and eventually
to the driving
wheels.
Also see
assembled crankshaft
balanced crankshaft
built-up crankshaft
offset crankshaft
stroked crankshaft
crankshaft counter-balance:
A series of weights attached to or forged integrally with the crankshaft so
placed as to offset the reciprocating weight of each piston and rod
assembly
crankshaft counterbalance:
Series of weights attached to or forged integrally with crankshaft & placed
to offset reciprocating weight of each piston and rod assembly
crankshaft gear:

A gear mounted on the front of the crankshaft. It is used to drive the
camshaft gear.
crankshaft journal:
[1] The journals running in the main bearings as opposed to those for the
big-end bearings.
[2] Part of shaft which contacts the bearing on the large end of the piston
rod.
crankshaft position sensor:
A sensor which sends information concerning the precise position of the
crankshaft so that accurate ignition timing can be achieved.
crankshaft pulley:
A wheel attached to the front end of the crankshaft which is connected by
fan belts to the fan, the alternator, and other devices so that the rotating
crankshaft can drive these other parts as well. The crankshaft pulley
usually has timing marks located on it, and these are necessary for
checking and adjusting timing with a timing light. Also called a "harmonic
balance wheel."
crankshaft runout:
A term used to describe how much a crankshaft is bent
crankshaft seal:
Leakproof joint between crankshaft and compressor body.
crankshaft sprocket:
A chain-sprocket mounted on the nose of the crankshaft which drives the
camshaft by means of a timing chain
crank throw:
[1] The part of the crankshaft that the connecting rod fastens to. See
crankpin.
[2] The distance between the crankpin and the axis of rotation or centerline
of the crankshaft, which is equal to half the stroke

crank web:
One of the pair of arms which carry the big-end journal
crash:
A vehicle collision with another vehicle or a stationary object.
Also see
car crash
frontal crash
head-on crash
oblique crash test
crash barrier:
A longitudinal railing usually found on the edge of the road especially
around a curve to help prevent vehicles from leaving the road.
crash box:
An informal term for a non-synchromesh transmission. Short term for
"crash gearbox."
crash gearbox:
An informal term for a non-synchromesh transmission.
crash recorder:
An electronic device which measures and records a number of
characteristics of a vehicle for 60 seconds before a crash: the speed,
direction, braking, etc. so that the cause of a crash can be determined.
crash sensor:
A sensor which deploys an air bag when a crash is determined -- usually
because of excessive deceleration
crash test:
A controlled test of a vehicle in which it is propelled into a wall or another
vehicle at a given speed in order to determine the effect on its structure
and the effectiveness of its safety devices.

Also see
oblique crash test
crash test dummy:
A specially designed manikin which records the effects in the event of a
crash
crate:
[1] A framework of wooden boards for protecting something during
transport.
[2] A vehicle which appears to be unreliable and ready to fall apart.
crater:
A depression in the face of a weld, usually at the termination of an arc
weld
cratering:
The formation of holes in the paint coat due to surface contaminants.
crawler:
A British term for a slow-moving vehicle
crawler gear:
A British term for a very low gear used especially in off-road application
crawler lane:
A British term for a truck lane for slow moving trucks, especially going up
a hill.
crazing:
Many fine cracks in the paint surface, resembling crow's feet. It is similar
to checking, but more sever, where fine lines or cracks appear in the paint
cream:
[1] To hit another vehicle.
[2] A soft paste.

Also see
barrier cream
crease:
A wrinkle or ridge in metal as a result of design or accident damage.
creep:
[1] The tendency of a vehicle with automatic transmission to edge forward
when idling when the transmission is in Drive and the brake is not
engaged. Also called "idling drag."
[2] When a crankshaft has slightly excessive runout (is slightly bent), it
can sometimes be corrected by laying the crank in its saddles, installing
the center main bearing cap (with its bearing insert) and leaving it for a
day or two. Sometimes the crank will creep or bend enough to put it within
the specified runout range
[3] The change of an adhesive or sealer under constant pressure or load,
following its first slip from its original position (elastic deformation).
Creep at room temperature is sometimes called cold flow
creepage:
The slow spreading of rust under the paint which usually first appears as a
blister and then flaking
creeper:
A platform on four small caster
wheels that allows you to move
around easily while lying on your
back under your vehicle.
Also see
mechanic's creeper
crescent:
The part between the inner and outer gears of an internal gear pump
crescent wrench:
An adjustable wrench with smooth jaws.

Cressida:
Click for books on Cressida
crest:
The highest point of a screw thread. The opposite is called a "root."
Also see
thread crest
Crew Cab:
A pickup truck with a large passenger
compartment with four full-size doors
which lead to two full rows of seating. The
doors are mounted so that they swing open
the same way as most four-door car doors
do. Toyota calls it a Double Cab, Dodge
calls it a Quad Cab, Ford calls it a
SuperCrew
crimper tool:
See wire stripper/crimper tool
crimping:
The creation of corrugations in two thin metal parts as they are pressed
tightly together in order to join them. This is often the method used to
attach fittings to the end of an electrical wire -- thus avoiding the necessity
of soldering
crimping pliers:
A tool which looks like pliers with
serrated jaws which are used to attach
fittings to the end of an electrical
wire.
crimping tool:

A tool which looks like pliers with serrated jaws which are used to attach
fittings to the end of an electrical wire.
crisper:
Drawer or compartment in refrigerator designed to provide high humidity
along with low temperature to keep vegetables-especially leafy vegetables-
cold and crisp.
critical pressure:
Compressed condition of refrigerant which gives liquid and gas the same
properties.
critical speed:
The top speed of an engine or shaft at which unwanted vibration begins.
critical temperature:
Temperature at which vapor and liquid have same properties.
critical vibration:
Vibration which is noticeable and harmful to structure.
crocodile clip:
British term for alligator clip
Crosley:
A vehicle brand of which the 1950-52 Hotshot/SS models are milestone
cars.
crossbar:
[1] any transverse bar, especially a tie rod across the chassis.
[2] The top tube of a bicycle or motorcycle frame.
[3] A short bar used to assist a combination wrench in providing extra
torque. The British term is "Tommy bar"
cross-bolt:

A system of securing the main bearing caps with four bolts per cap by
which two bolts support the bearing cap from below, in the conventional
manner, and two other bolts enter the bearing from the side, passing
through the sides of the engine block. The cross-bolts are visible from the
outside of the engine. This system of securing the main bearing caps
ensures good side-to-side, as well as up-and-down rigidity
cross border shopping:
See Canadian cross border shopping
cross bracing:
strengthening ribs or other members which connect two sides of a frame
cross charged:
Sealed container of two fluids which together create a desired pressure-
temperature curve.
cross coat:
Paint spraying technique in which consecutive coats are sprayed at right
angles to one another
cross-country vehicle:
An off road vehicle
cross-draught carburetor:
A sidedraft carburetor
crossflow cylinder head:
A cylinder head design (especially in an OHC engine) with the inlet
manifold on one side and the exhaust manifold on the other side of the
head, so that inlet and exhaust valves are arranged on opposite sides of the
combustion chamber, giving a wider engine but better gas flow.
crossflow head:
A cylinder head with the intake valves) on one side of the combustion
chamber and the exhaust valve(s) on the other. Also called T-head

crossflow radiator:
A radiator in which the water flows sideways instead of vertically, and
which is therefore wider than it is high, permitting a lower hood line
cross hatch:
See cross-hatch.
cross-hatch:
The desired checkerboard design of the inner surface of cylinder after it is
honed.
cross-hatch coat:
Checkerboard application of paint to be sure of a continuous paint film.
One medium coat is usually followed by a second medium coat in a
perpendicular direction.
cross-head screw:
A screw with a slot which looks like an X or + into which the tip of the
blade of a Phillips or Reed and Prince screwdriver can be inserted
cross-head screwdriver:
A Phillips or Reed and Prince screwdriver where the tip forms an X or +
cross-jetting:
Rejetting the carburetor jets from left-to-right to compensate for a left-to
right variation in performance. These tests are usually conducted using an
engine dynamometer
cross member:
A brace or strut which provides structural stability for the sides of a frame
-- often in the shape of an "X".
Also see
axle crossmember
rear axle crossmember
rubber-isolated crossmember

crossover:
See heat crossover.
crossover gearing:
A bicyclegearing system whose shift sequence involves moving from the
lowest to the midrange of gears on the smaller chainring, then crossing
over to the larger chainring for the remainder of the gears.
cross ply:
See conventional cross ply
cross-ply tire:
See bias ply tire
cross-point screwdriver:
A Phillips or Reed and Prince screwdriver where the tip forms an X or +
cross scavenging:
Scavenging in a two-stroke engine with flow across the cylinder assisted
by a wedge-shaped piston crown
cross section:
A view of an object when cut transversely at right angles across its center.
Also see
section width
cross-shaft:
[1] Any transverse shaft.
[2] The outgoing shaft of the steering gearbox, to which the pitman arm is
connected. The British term is "rocker shaft"
cross-shaft lug wrench:
See lug wrench.
cross-shaft lug wrench:

See lug wrench.
cross shaft:
The shaft in the steering gearbox that engages the steering shaft worm, the
cross shaft is splined to the pitman arm.
cross-spoke wheel:
Modern design of alloy wheel which imitates the appearance of the
classical wire wheel
cross-threaded:
The characteristic of a bolt or nut in which the bolt is inserted at an angle
so that the original threads are damaged
cross three:
A spoking pattern in which a spoke passes over two and under a third
spoke before being attached to the rim.
crosswind:
Wind blowing at the side of a vehicle
crotch rocket:
A term some people use to refer to sportbike.
crowbar:
A iron bar tool with a crook at one end with a forking device for removing
nails, etc. The other end has a wedge shape.
crowded engine compartment:
An engine compartment or bay in which all the available space around the
engine is occupied by other objects (alternator, pumps, air intake system,
battery, wiper motor, heater motor, windshield washer motor, starter,
radiator, air conditioner, hoses, pipes, wiring, electronic boxes, etc.)

crown:
[1] The tread area of a tire.
[2] The top part of the head of a piston.
[3] The outward curvature of an apparently flat
sheet metal panel.
[4] The curve or convex surface of a properly
finished weld.
[5] A model of automobile manufactured by
Toyota
Click for books on Toyota
Crown
Also see
fork crown
high crown spoon
low crown panel
pent crown piston
piston crown
valve crown
crown panel:
See
high crown panel
low crown panel
crown piston:
See pent crown piston
crown radius:
The measurement of the curvature of a tire tread between the shoulders of
the tire. Expressed as a percentage, it indicates the relative flatness of the
tire tread area.
crown spoon:
See high crown spoon
Crown Victoria:
Ford

Click for books on Ford Crown
Victoria
crown wheel:
The larger of two gears in a bevel gear drive with teeth around its
periphery facing sideways
crown wheel and pinion:
A pair of gears in the final drive of a vehicle, always found in the back
axle of a rear-wheel drive layout where the pinion is on the end of the
propeller shaft driving the crown wheel mounted on the differential at right
angles to it, and also in front-wheel drives where the engine is not
transversely mounted
crown width:
The distance of a tire tread shoulder to shoulder measured along the buffed
contour.
CRT:
Acronym for cathode ray tube
cruciform frame:
A frame with an X-shaped bracing either as a chassis frame, or in a
monocoque as strengthening for the floor
crude oil:
Unrefined petroleum as it comes out of the ground. It forms the basis of
gasoline, engine oil, diesel oil, kerosene, etc.
cruise:
To drive at a constant speed, often at highway speed.
cruise control:
A feature that keeps your vehicle moving at a set speed. Old cruise
controls were mere throttle control units which kept the engine speed the
same. When the vehicle approached a hill, the vehicle slowed down
noticeable going up and speeded up going down. Later models used

vacuum controls to push or pull on the accelerator rod. Newer models use
electronic controls to accomplish this task. It can be turned off by hitting
the off button or touching the brake pedal. The resume switch allows you
to return to the pre-set speed after brake disengagement. The coast switch
slows the speed down and the accelerate switch increases it.
cruiser:
[1] Any motorcycle designed to be ridden long distances.
[2] Motorcycle riders who ride long distances.
cruiser bag:
A leather bag which is mounted on the top surface of the fuel tank or
possibly other parts of a motorcycle. Although it can be filled with
anything for a trip, usually it contains items that you want to access
quickly (e.g., camera, road map).
cruiser stern:
A spoon-shaped stern used on most merchant ships designed to give
maximum immersed length
cruising circuit:
The main carburetor metering system
cruising speed:
constant speed at which a vehicle can be driven on the highway
crumple zone:
An area of a vehicle that is designed to compress during an accident to
absorb the energy from the impact.
crush:
A slight distortion of the bearing shell that holds it in place as the engine
operates
crusher:

A machine which crushes scrapped cars into small blocks.
crush height:
The precision insert bearing must fit the bottom end of the connecting rod
in order to transfer friction heat to the connecting rod. The insert will
protrude a small amount above the rod bore parting surface. This distance
is called the crush height. When the rod halves are drawn together, the
inserts touch before the halves, thus forcing the inserts tightly into place.
crush washer:
A disc with a hole in the center. It is placed around the threads of a bolt
and secured with a nut or screwed into a hole. When the head of the bolt is
forced against it, the washer is squashed. Crush washers are used on some
spark plugs to provide a better seal when installed.
CRX:
Honda
CRX
cryogenic fluid:
Substance which exists as a liquid or gas at ultra-low temperatures (-250°F
or lower).
cryogenics:
[1] The study of physical phenomena at a temperature below -50°F (46°C)
[2] Refrigeration which deals with producing temperatures of 250°F below
zero and lower.
c spanner:
See C-spanner.
c-spanner:

A wrench whose end is shaped like a C, used to loosen the lockring on a
bottom bracket of a bicycle.
CSSA:
Acronym for "Chambre Syndicale Suisse de L'Automobile et Branches
Annexes" (Switzerland).
CTC:
Acronym for "Chrysler Technology Centre."
CTO:
Acronym for coolant temperature override switch
CTS:
Acronym for Conti Tire System
CTVS:
Acronym for choke thermal vacuum switch
cubby hole:
A glove compartment on older cars, often without a lid.
cubes:
A colloquial term for cubic inches, or cubic inch displacement of an
engine.
cube van:
A truck with a large compartment behind the driver's cab and used for
moving various products.
cubic capacity:
See displacement.
cubic centimeter:

(cc) Metric measurement of engine displacement. 1000 cc = 1 liter (litre)
which is about 61 cubic inches (61.02374409). Thus a 428 cubic inch
engine is 7 liters (428/61) and a 2 liter engine is 122 cubic inches (2 x 61).
cubic inch:
a measurement of volume equal to 16.387 cc
cubic inch displacement:
See displacement.
cubic inch engine:
An engine which is measured in cubic inches rather than cubic
centimeters.
cub scouts:
Trucker slang for Sheriff's deputies as in "Cub Scouts at the 97 so you
better watch out."
cu. ft.:
Abbreviation for "cubic feet."
cu. in.:
Abbreviation for "cubic inch" (also C.I.).
cult car:
A car which has many enthusiastic owners, but may not necessarily be a
classic or milestone car.
Cunningham:
A vehicle brand of which the 1925-1948 models are classic cars. The
1951-55 models are milestone cars.
cuno filter:
A filter made up of a series of fine discs or plates pressed together in a
manner that leaves a very minute space between the discs. Liquid is forced

through these openings to produce a straining action.
cup:
A type of lip seal used on hydraulic pistons.
Also see
adjustable cup
agitation cup
bearing cup
bearing shell
cup washer
fixed cup
vacuum suction cup
viscosity cup
cup dent puller:
See suction cup dent puller
cup holder:
A device to hold a coffee cup or pop bottle. Also called beverage holder
cup seal:
Synthetic rubber seal with a single lip used for sealing hydraulic and
pneumatic pistons
cup-shaped wire brush:
circular wire brush on an arbor for use with an electric drill
cup washer:
A washer that is dished.
curb:
A stone or cement ridge between the road and the sidewalk. In Britain it is
called "kerb"
curber:
[1] A person who buys cars needing a lot of work and fixes them, then
sells them privately from his own residence.

[2] A person who steals a car, falsifies the registration information, and
sells it from a place not near his own home. You need to contact him on his
cell phone where he informs you that you need to meet him at some
parking lot or on the curb of a residential area.
curb idle:
Normal idle rpm. Computer controlled on many modern vehicle
curb-idle port:
See idle discharge hole
curb-idle stop screw:
A screw which provides an adjustable stop for the throttle lever
curb weight:
The weight of a vehicle without passengers or payload, but including all
fluids (oil, gas, coolant, etc.) and other equipment specified as standard.
cure:
[1] A process of vulcanizing raw rubber through the application of heat,
pressure, and time to permanently shape and set the rubber at the degree of
hardness desired to protect it from the effects of normal operating
temperatures and wear.
[2] To change the properties of an adhesive by chemical action. Usually
accomplished by the action of heat, pressure, and catalysts, alone or in
combination
Also see
chemical cure
cure time:
The time required at a reference temperature for a compound to reach
optimum physical properties.
curing:
[1] Process of heating or otherwise treating a rubber or plastic compound
to convert it from a thermoplastic or fluid material into the solid, relatively

heat-sensitive state desired in the commercial product. When heating is
employed, the process is called vulcanization.
[2] The final drying stage where the paint reaches maximum strength.
curing gum:
A soft, tacky rubber compound used in retreading and repair to facilitate
bonding between different rubber compounds and between plies, etc.
Also see
cushion gum
curing rim:
When retreading a tire, a special rim that supports the inflated tire during
the curing process.
curing time:
The length of time required for paint or plastic to harden.
curing tube:
In retreading a tire, a heavy tube within the tire that provides pressure to
force the casing against the matrix during the curing process.
current:
[1] The movement of free electrons through a conductor.
Also see
alternating current
charging current
direct current
discharging current
electric current
spark current
[2] The most recent model vehicle (i.e., made in the same year as the
present calendar).
current for low temperatures:
See test current for low temperatures
current regulator:

A device for controlling the current output of a generator (which increases
with engine speed) by opening a switch when the current exceeds a certain
value, thus protecting the generator from damage due to excess current.
current relay:
Device which opens or closes a circuit. It is made to act by a change of
current flow in that circuit.
curtain:
See side curtain
curve:
[1] A gradual bend in the road. A sharp bend is a corner.
Also see
advance curve and torque curve
cush drive:
A motorcycle transmission shock absorber, usually a rubber cushion in the
rear hub
cushion:
See
air bag
air cushion
impact cushion
seat cushion
cushion gum:
A soft, tacky rubber compound used in retreading and repair to facilitate
bonding between different rubber compounds and between plies, etc.
custom:
[1] A restyled or modified vehicle.
[2] A new body mounted on an existing chassis.

customer:
A person who is at least potentially able to purchase something. Good
customer service involves providing the customer with the best answers to
his questions and the best choices to meet his needs or wants.
customize:
[1] To restyle or modify a vehicle.
[2] To mount a new body on an existing chassis.
customs duties:
Customs duties levied on imported goods under the Customs Tariff.
custom wheel:
A special wheel with attractive styling, usually alloy, available as an
aftermarket accessory, designed to make a car look more sporty
cut:
See T-cut
cut-and-shut:
A British term for a process of shortening a vehicle by cutting out a section
of the chassis and/or bodywork.
cutaway:
A drawing which shows some of the exterior part and at the cutaway the
interior parts and their workings are shown.
cut gears:
See straight cut gears
cut-in:
The temperature value or the pressure value at which the control circuit
closes.
cut in front:

The action of an overtaking (passing) vehicle which pulls back into the
lane of the overtaken (passed) vehicle. Usually it is a derogatory
expression of a vehicle's action which does not allow for much distance
between the two vehicles. Also called, "cut off" as in "He cut me off so I
had to jam on the brakes to avoid hitting him." Proper driving etiquette
states that you should not pull in until you see the front of the overtaken
vehicle in your rear-view mirror.
cut-in speed:
The speed at which the generator has to rotate to produce a voltage which
is greater than that across the battery terminals
cut off:
See
cut in front
deceleration fuel cut-off
fuel cut-off switch
inertia fuel cut-off switch
power cut-off switch
power cut-off
cut-off/shut-off:
See overrun cut-off/shut-off
cut-off switch:
See
fuel cut-off switch
fuel cut-off switch
cutout:
[1] A form of bypass valve, located in the exhaust line, that can be used to
divert the flow of exhaust from one pipe to another. Often used to bypass
the muffler into a straight pipe. See exhaust cutout.
[2] A device to connect or disconnect the generator from the battery
circuit. When the generator is charging, cutout makes circuit, when
generator stops, cutout breaks circuit. Also referred to as "cutout relay,"
and "circuit breaker."

[3] A portion of a panel which has been removed so that a cover can be
inserted.
[4] A circuit-breaker, especially one in the charging circuit of a generator
output is less than the battery voltage, so that the battery does not drain
into the generator. Also called a "cutout relay."
[5] Temperature value or pressure value at which the control circuit opens.
Also see
exhaust cutout
low-pressure cut-out
valve cut-out
wheel cutout
cutout relay:
A device to connect or disconnect the generator from the battery circuit.
When the generator is charging, cutout makes circuit, when generator
stops, cutout breaks circuit. Also referred to as "circuit breaker."
Also see
cutout
cutter:
A small pincer with sharp jaws for cuning and stripping wires, etc. The
British term is "end cutters" or "end cutting pliers."
Also see
end cutters
manual panel cutter
metal cutter
milling cutter
mini tube cutter
monodex-type cutter
panel cutter
sheet metal cutter
side cutters
taper cutter
tube cutter
valve seat cutter
variable hole cutter
cutters:
See
end cutters
side cutters
cut thread:

A thread produced by removing material from the surface with a form
cutting tool. This method keeps the unthreaded portion of the shank equal
to the major diameter of the thread.
cutting:
See
acetylene cutting
arc cutting
end cutting pliers
flame cutting
heavy-duty diagonal cutting pliers
heavy-duty end cutting pliers
high leverage diagonal cutting pliers
high leverage end cutting pliers
hole cutting snips
oxygen acetylene cutting
cutting compound:
An abrasive paste which is used to remove oxidation in the surface of
paint in order to bring back the shine.
cutting disc:
An abrasive wheel of an angle grinder
cutting flame:
A process in welding where cutting takes place by a rapid oxidation at a
high temperature produced by a gas flame accompanied by a jet action
which blows the oxides away from the cut.
cutting line:
A line established by the factory along which welded-up assemblies must
be cut when replacing a sheet metal part, in order to maintain structural
strength in the finished repair
cutting pliers:
See
end cutting pliers

cutting snips:
See hole cutting snips
cutting torch:
An oxyacetylene torch for cutting through metal, used by welders.
CV:
Abbreviation for constant-velocity.
CV joint:
Abbreviation for "constant velocity joint."
CV joint boot:
A rubber cover over the CV joint. It usually has accordion folds.
CVK:
Acronym for center vertical keel.
Also see
center girder
CVMA:
Acronym for "Canadian Vehicle Manufacturer's Association"
CVR:
Acronym for constant voltage regulator
CVT:
Acronym for "Continuously Variable Transmission." See infinitely
variable transmission.
CWM:

Acronym for cold weather modulator
cwt:
Abbreviation for "hundredweight."
cycle:
[1] A vehicle with one or more wheels (usually spoked) where the
rider/driver straddles the vehicle as a bicycle, motorcycle, tricycle, etc. It
also includes other vehicles adapted from a traditional cycle where the
rider/driver no longer straddles the vehicle (recumbent cycle, four-wheel
side-by-side pedal powered vehicle). Obviously the distinction blurs with
automobiles -- are they a cycle?
[2] A sequence of changes of state after which the system is in its original
state again.
[3] Series of events or operations which have tendency to repeat in the
same order.
[4] A type of pressure modulation during an ABS stop. Cycles include
pressure hold, pressure release (decay) and pressure build
Also see
city cycle
diesel cycle
ece test cycle
four-stroke cycle engine
four-stroke power cycle
four cycle engine
four stroke power cycle
four stroke cycle engine
ftp test cycle
limit cycle control
miller cycle
otto cycle
refrigeration cycle
two-stroke cycle
two stroke cycle
urban test cycle
working cycle
cycle car:
A term used to describe the very light production automobile made prior to
1922. It was usually made from motorcycle parts and generally powered
by single-cylinder or twin-cylinder engine. They disappeared when
genuine light cars appeared.
cycle control:
See limit cycle control
cycle engine:
See
four-stroke cycle engine
four cycle engine

four stroke cycle engine
two-stroke cycle engine
two stroke cycle engine
cycling clutch orifice tube system:
(CCOT) the GM system that utilizes an accumulator (instead of a receiver-
drier). The system uses a fixed orifice tube located at the evaporator outlet,
instead of an expansion valve. A thermostatic switch or a pressure sensing
switch cycles compressor operation off and on in accordance with system
status.
cycling clutch system:
Any system that controls compressor clutch operation as a means of
temperature control
cyl:
Abbreviation for "cylinder," as in 12-cyl. engine.
cylinder:
[1] The round
chamber or hole in
the cylinder block
that houses the
pistons and where
combustion takes
place. Also called
"bore" or "barrel."
[2] Any tube-like
device.
[3] A device which
converts fluid
power into linear
mechanical force
and motion. This
usually consists of
movable elements
such as a piston and
piston rod, plunger
or ram, operating
within a cylindrical

bore.
[4] A closed
container for fluids.
Also see
acetylene cylinder
brake cylinder
brake master cylinder
cylinder bore
cylinder head
cylinder sequence
cylinder sleeve
dual-piston master cylinder
inner cylinder
lock cylinder
master brake cylinder
master cylinder
oxygen cylinder
slave cylinder
split-system master cylinder
tandem master cylinder
wheel cylinder
working cylinder
cylinder bank:
One half of a V-6, V-8, V-12, and V-16 engines along one side.
cylinder barrel:
An external casing of a cylinder forming a separate unit, especially of an
air-cooled engine
cylinder block:
The basic
framework of the
engine to which
other engine parts
are attached. It is
usually a casting
and includes the
engine cylinders
and the upper part
of the crankcase.
Also see
engine block
cylinder block heater:
An electric heater element in the water jacket connected at the other end to
house current. The element warms the coolant so that in very cold weather
the block will not crack and the car will start easier. Often just called

"block heater."
cylinder bore:
The cylinder holes.
cylinder charge:
A quantity of fresh mixture fed into the combustion chamber prior to
combustion
cylinder head:
The detachable
metal (aluminum or
iron) plate or cap
that is bolted to the
top of the cylinder
block. It is used to
cover the tops of the
cylinders, in many
cases the cylinder
head contains the
valves, it also forms
part of the
combustion
chamber. It has
water and oil
passages for cooling
and lubrication. It
also holds the spark
plugs. On most
engines a valve
cover or rocker arm
cover is located on
top of the cylinder
head. Some engines
have just one
cylinder head
covering several
cylinders, while
others have separate
heads for each

cylinder. In some
motorcycle engines
and small engines,
the cylinder head is
not detachable -- it
is cast with the
cylinder which
forms a blind hole.
Also see
crossflow cylinder head
x-flow cylinder head
cylinder head bolt:
One of several bolts which hold the cylinder head in place
cylinder head gasket:
See head gasket
cylinder head nut:
One of several nuts which hold the cylinder head in place.
cylinder head tester:
A device used to detect cylinder head leakages which cause combustion
gases to appear in the cooling system
cylinder hone:
A tool that uses an abrasive to smooth out (hone) and bring to exact
measurements such things as engine cylinders, wheel cylinders, bushings,
etc.
cylinder liner:
[1] A cylinder sleeve.
[2] A hard metal block forming the cylinder wall and in which the piston
runs
cylinder, refrigerant:

Cylinder in which refrigerant is stored and dispensed. Color code painted
on cylinder indicates kind of refrigerant.
cylinder sequence:
The order in which the cylinders are located on a vehicle. It is important to
locate the number one cylinder to check and adjust timing. In some cars it
may be at the front of an engine on U.S. built cars and at the rear of some
foreign cars.
Also see
firing order
cylinder sleeve:
A replaceable cylinder liner or tube, it is made of a pipe-like section that is
either pressed or pushed into the block. If the cylinder cannot be re-bored
to an oversize or if the liner has been damaged beyond repair, the cylinder
may be re-sleeved.
cylinder surfacing hone:
Puts a cross-hatch pattern on the cylinder walls, after they have been
bored, to help seat the new rings properly
cylinder wall:
The inner surface of a cylinder.
cylindrical commutator:
Commutator with contact surfaces parallel to the rotor shaft.

D:
[1] Abbreviation for "diesel."
[2] Abbreviation for "drive."
[3] A mark on the output (live) terminal on a generator (contrasts with "F")
dab:
A bicycle maneuver in which the rider puts a foot down in order to catch
his balance on a difficult section of trail as in, "You will be disqualified if
you dab on this course."
DAB:
Acronym for "Digital Audio Broadcast."

dagmar:
[1] Large bullet-shaped protrusion on
bumpers of cars in the 1950s. It was
named after the nickname of a buxom
television star, Virginia Ruth Egnor
(1921-2001).
[2] Dagmar is an automobile of
which only the 25-70 models of
1925-1948 are classic cars.
Daimler:
Also called Austro-Daimler. A vehicle brand of which the 1925-1948
models with required application are classic cars. The 1949-53 DE-36
Custom Built models are milestone cars. The 1949-53 2.5 Special Sport
Convertible models are milestone cars.
dalton's law:
Vapor pressure created in a container by a mixture of gases is equal to sum
of individual vapor pressures of the gases contained in mixture.
dam:
See
air dam
heat dam
damage:
See
accident damage
center section damage
direct damage
ecological damage
engine damage
frame damage
impact damage
indirect damage
internal damage
secondary damage
stone chip damage

damp:
[1] To reduce the oscillations of spring, carburetor piston, etc.
[2] To reduce the vibration in a crankshaft
damper:
[1] A friction device sometimes called a
"shock absorber." Used for controlling and
damping spring oscillations. The springs
actually absorb road shocks; the dampers
convert the energy imparted to the springs
into thermal energy (by friction), which is
dissipated to the atmosphere or the vehicle's
chassis. Dampers are distinguishable by the
type of friction involved, mechanical or
hydraulic but most modern cars used tubular-
shaped hydraulic shock absorbers. Because
they affect up and down wheel motions,
dampers are an important link in tuning a
vehicle's ride and handling.
[2] A movable plate which permits or
restricts the flow of liquids or gasses.
Also see
friction damper
gas damper
harmonic balancer
mass damper
monotube damper
piston damper
pulsation damper
steering damper
steering wheel damper
torsional vibration damper
torsion damper
twin-tube damper
vibration damper
damper piston:
A piston in a cylinder whose movement is restricted by a liquid or gas,
which thus also restricts the movement of another member to which it is
connected.

damper settings:
See spring and damper settings
damper springs:
Springs in a clutch plate providing a cushion against sudden loads due to
abrupt engagement
damper strut:
A suspension strut whose hub carrier is attached to the spring element
rather than to the damper tube. Compare Macpherson strut
damping:
[1] Cushioning of force.
[2] The action of suspension to control the speed of movement through its
travel, usually by a piston running through oil and thus gives a smoother
ride. It vastly improves that smoothness of ride offered. Also see
compression damping
damping force:
The amount of cushioning applied by a shock absorber
damping rate:
The amount of cushioning applied by a shock absorber
dark 30:
Trucker slang for nighttime as in "I am shutting this rig down right at
darktime."
darktime:
Trucker slang for nighttime as in "I am shutting this rig down right at
darktime."
Darracq:

A vehicle manufacturer in which only the 8-cyl. cars and 4-litre, 6-cyl. cars
of 1925-1948 are classic cars.
dash:
See dashboard.
dash board:
See dashboard
dashboard:
That part of the body containing the driving instruments, switches, etc.
Also called the "instrument panel" or "dash panel" or just "dash."
dashboard gearchange:
British term for dash shifter
dashboard plaque:
[1] A metal or plastic plate which is mounted to the dash to indicate the
brand, model, or series of vehicle.
[2] A metal plate which is mounted to the dash to indicate an award for
attending or winning a rally or other automotive event.
dash design:
See wrapround dash design
dash panel:
[1] A structural panel with bracing across the width of the car on the inside
of the bulkhead below the windshield that provides the mounting locations
of the dashboard.
[2] The bulkhead
dash plaque:
[1] A metal or plastic plate which is mounted to the dash to indicate the
brand, model, or series of vehicle.
[2] A metal plate which is mounted to the dash to indicate an award for
attending or winning a rally or other automotive event.

dashpot:
A unit using a cylinder and piston or a cylinder and diaphragm with a
small vent hole, to retard or slow down the movement of some part.
dash-pot:
(DP) a diaphragm that controls the rate at which the throttle closes
dash shifter:
A shift lever and indicator which is located on the instrument panel either
as a short lever or push buttons
Data:
See radio Data System
Data System:
See radio Data System
Datsun:
A model of automobile manufactured by Nissan
Click for books on Datsun
Datsun Truck:
A model of truck manufactured by Nissan
Click for books on Datsun Trucks

Datsun Z:
A model of automobile manufactured by Nissan
Click for books on Datsun Z
davit:
A crane arm for handling lifeboats, stores, etc.
day-night mirror:
A mirror which adjusts to prevent the glare from the headlights of
following cars. The British term is "dipping mirror."
days' supply:
number of days needed to sell all vehicles in inventory, based on the
previous month's sales rate.
daytime running lights:
A safety-oriented lighting system in which the headlights or other front
lights are constantly on even during the day. They help to prevent possible
accidents because oncoming traffic can be seen.
dazzle:
The glare from the headlights of oncoming traffic which can momentarily
blind a driver.
dazzle mirror:
See dimming mirror
dBA:
A unit of measure for decibels, the measure of sound intensity or pressure
named after Alexander Graham Bell. It is a logarithmic measurement;
every 3dB increase represents a doubling of the sound pressure. The "A"
in dBA indicates that the measurement was taken with an A-weighted

scale; sound pressure varies across the audible spectrum, and the A-
weighted scale approximates the human ear's sensitivity to various
frequencies.
DBI:
Acronym for "De Danske Bilimport rer" (Denmark)
dbl:
Abbreviation for "double," as in dbl.-wide rear wheels.
DC:
[1] As an electrical term, it is an acronym for "direct current."
[2] As a piston position, DC is an acronym for "dead center" where the
piston at the extreme top or bottom of its stroke.
DC generator:
See generator
DC rim:
Abbreviation for Drop-Center rim
dead:
See
inner dead center
lower dead center
outer dead center

dead axle:
An axle that
does not rotate
nor is driven
but merely
forms a base
upon which to
attach the
wheels. Also
see beam axle.
It contrasts
with a live
axle.
dead battery:
A battery that registers almost no electrical charge. Sometimes it can be
brought back to life with a charger. The British call it a "flat battery"
dead center:
The point at which the piston reaches its uppermost or lowermost position
in the cylinder the rod crankjournal would be at 11 o'clock UDC or 6
o'clock LDC.
Also see
after bottom dead center
after top dead center
before bottom dead center
before top dead center
before upper dead center
bottom dead center
inner dead center
lower dead center
outer dead center
top dead center
upper dead center

dead end:
A road which has no outlet
dead freight factor:
The amount of a ship's carrying capacity that is not utilized.
dead-head pressure:
A fuel pressure reading taken directly at the fuel pump outlet. Many
systems use a fuel pressure regulator; dead-head pressure is an unregulated
measurement
dead pedal:
A footrest located to the far left of the driver so that he can brace his left
leg during hard cornering or to balance the position of the right foot on the
throttle pedal during normal driving.
dead rear axle:
A rear axle that does not turn. E.g., rear axle of front wheel drive car
dead rise:
Athwartship vertical rise between the keel and the bilge
dead space:
The space below the piston availaable for pre-compression of the
incoming fresh charge of the two-stroke engine.
deadweight:
The total weight in tons (2240 lb.) that a ship carries on a specified draft
including fuel, water in tanks, cargo, stores, passengers, baggage, crew and
their effects, but excluding the water in the boilers. It is the difference in
weight between a vessel when it is fully loaded and when it is empty
measured by the water it displaces.
Also see
tonnage deadweight

dealer:
[1] a firm that buys and sells, adding some value for the consumer in the
process. Dealer often means a firm which operates closer in the
distribution channel to the consumer than a distributor or wholesaler and
may add more value for consumers than either of the above-mentioned
terms. Also called "dealership."
[2] A person whose business is buying and selling cars and trucks or
motorcycles.
Also see
authorized dealer
auto dealer
car dealer
franchised dealer
new car dealer
scrap dealer
used car dealer
dealer invoice:
The price the dealer pays for a vehicle.
dealer participation:
The amount contributed by the dealer to reduce the final purchase price in
the lease contract. Dealer participation can take the form of a rebate or
simply a discount. The dealer participation is reflected in the lease contract
as a capitalized cost reduction.
dealer principal:
The individual or corporation that owns and controls one or a number of
auto dealerships.
dealership:
A firm that buys and sells, adding some value for the consumer in the
process. A dealership often means a firm which operates closer in the
distribution channel to the consumer than a distributor or wholesaler and
may add more value for consumers than either of the above-mentioned
terms.
deaeration:

Act of separating air from substances.
death rattle:
An informal term for a noise from an engine which indicates that it is
likely to break down at any moment
debugging:
The process of locating and correcting faults in a system
deburr:
To remove burrs from a metal surface
deburring:
Removing burrs from a metal surface or bearing
decal:
A sticker or transfer which is applied to a smooth surface to identify a
particular product. Pronounced dee-KALL in the United States, but
DECK-ull in Canada.
decarbon:
The action of removing carbon buildup from the surface of the cylinder
head and the dome of the piston. The accumulation of carbon indicates
poor combustion and will result in loss of performance.
decarbonize:
See decarbon
decay:
A term for hydraulic pressure reduction that occurs during an ABS stop
decelerate:
The action of slowing down. The opposite of accelerate

deceleration:
Negative acceleration; the rate of change in velocity as a vehicle slows
down during braking.
deceleration fuel cut-off:
A device which stops the flow of fuel to the carburetor or injectors when
the vehicle rapidly decelerates in the event of a crash thus preventing the
possibility of a fire or explosion.
deceleration switch:
A device that signals the rate of vehicle deceleration to the ECU, allowing
it to adjust ABS operation accordingly
decelerometer:
An instrument for measuring deceleration.
decibel:
(dB) Unit used for measuring relative loudness of sounds. One decibel is
equal to approximate difference of loudness ordinarily detectable by
human ear, the range of which is about 130 decibels on scale beginning
with one for faintest audible sound.
deck:
[1] The bed of a half-ton truck.
[2] The floor of a commercial vehicle like a bus.
[3] The trunk lid of a car. Also called "rear deck."
[4] In an engine, top face of the cylinder block on which the cylinder head
mounts.
[5] A platform in a ship corresponding to a floor in a building.
Also see
bulkhead deck
freeboard deck
main deck
radio/cassette deck
rear deck
rear deck panel
shelter deck
strength deck
tween deck

weather deck
[6] Insulated horizontal partition between refrigerated space and
evaporator space. Also called coil deck
deck beam:
An athwartship horizontal structural member supporting a flat or deck
decker:
See double-decker
deck house:
Small superstructure on the top deck which contains the steering wheel
and other navigational instruments.
decking:
See shaving
deck lid:
The panel which covers the engine in a vehicle with the engine in the rear
of the car.
Also see
hood
deck panel:
The sheet metal panel extending from the bottom of the rear window to the
rear panel and enclosing the cutout for the trunk lid, extending sideways to
the top of both rear fenders. In some cases, this panel covers only the area
between the bottom of the rear window and the front edge of the trunk lid.
Also see
rear deck panel
deck ship:
See flush deck ship
deck stringer:
The strake of deck plating that runs along the outboard edge of a deck

declutch:
The action of disengaging the clutch (i.e. releasing the clutch pedal or
lever).
Also see
double-declutch
decoke:
To decarbon
decompressor:
A valve which is manually operated to release compression in a cylinder
by allowing air to escape in order to facilitate manual starting of an old
engine or a diesel engine. Some motorcycles also used a decompressor to
assist in kick-starting.
decreasing-radius corner:
A turn where the arc gets sharper as you progress through the curve
dedicated:
Something that is designed for a specific use or for a specific vehicle.
de Dion axle:
A rear axle setup developed by Count de
Dion in the 19th century in which the driving
wheels are attached to curved dead axle that
is attached to the frame by a central pivot,
the differential unit is bolted to the frame and
is connected to the driving wheels by drive
axles using universal joints. The De Dion
system keeps the wheels upright (the same as
a live axle does), but unsprung weight is
reduced because the differential is out of the
axle. De Dion suspension also leaves room
around the differential for inboard brakes,
which can further reduce unsprung weight.
deep cycling:

The process of discharging a battery almost completely before recharging
deep tank:
Tanks extending from the bottom or inner bottom up to or higher than the
lowest deck of a ship
deer alert:
A device which is mounted on the outside of a vehicle and which makes a
high-pitched sound to warn deer and other animals away. Whether it really
works or not is debatable.
defect:
A fault in a system or a flaw in materials or a finish
defective:
A description of a component which is faulty or flawed.
defensive driving:
A driving technique in which the driver prepares for and watches for the
mistakes of other drivers around him so that he can avoid an accident.
deflated:
An air chamber (like a tire or lumbar support chamber) which has lost all
its air.
deflation:
The loss of air from a tire or other air chamber
deflation warning system:
(DWS) developed by Dunlop for on-line detection of tire pressure loss.
When tire pressure is reduced, the tire circumference is also reduced
resulting in increased wheel rpm. The system uses the wheel speed sensors
of an existing ABS system to continuously monitor wheel speed and tire
condition, and triggers a warning signal upon detecting a problem.

deflection:
The movement of a suspension piece when subjected to a load.
Also see
effective deflection
deflection rate:
The distance that a spring squeezes together (deflects) in relation to the
pressure applied. E.g., 5 inches per 1000 lb load.
deflection under load:
See temperature of deflection under load
deflector:
[1] A device which causes bugs, tar, and grime from hitting other
components.
[2] A special piston profile used to achieve cross scavenging in earlier two-
stroke engines.
Also see
air deflector
air shield
bug deflector
stone deflector
wind deflector
deflector piston:
A piston design which had a crown designed to direct the incoming fresh
mixture upwards to expel the burnt exhaust gas from the cylinder. This
design is no longer used today.
deflector shield:
See sunroof deflector shield
defog:
The action of removing mist or condensation from the inside of a window
or the outside of a mirror by means of blowing air or heated wires
imbedded in the glass. The British term is "demist." See defogger.
defogger:

An electric or hot air device to remove the fog or ice from both the inside
and outside of the windshield, backlight (i.e., rear window) or even
mirrors. Some are designed to remove fog from the side windows.
defogging system:
See backlight defogging system
deformation:
An alteration of shape or dimension which is caused by stress, expansion,
or contraction because of temperature, humidity, or metallurgical changes.
Also see
plastic deformation
deformation zone:
A crumple zone
defrost:
The action of removing frost from the inside of a window or the outside of
a mirror by means of blowing air or heated wires imbedded in the glass.
defrost cycle:
Refrigerating cycle in which evaporator frost and ice accumulation is
melted.
defroster:
The apparatus (either a fan connected to the heating system or electrical
wires imbedded in the glass) which removes frost or fog from a window.
Also called a "demister."
defrosting:
Process of removing frost accumulation from evaporators.
defrosting control:
Device to automatically defrost evaporator. It may operate by means of a
clock, door cycling mechanism, or during "off" portion of refrigerating
cycle.

defrosting type evaporator:
Evaporator operating at such temperatures that ice and frost on surface
melts during off part of operating cycle.
defrost timer:
Device, connected into electrical circuit, which shuts unit off long enough
to permit ice and frost accumulation on evaporator to melt.
deglaze:
The action of removing the smooth finish on cylinder walls so that a new
set of rings will seat.
deglazer:
An abrasive tool used to remove the glaze from cylinder walls so that a
new set of rings will seat.
Also see
glaze breaker
degradable:
See bio-degradable
degradation:
The deterioration in the condition of something.
Also see
catalyst degradation
degrease:
[1] To remove oil and grease from the surface of a parat.
[2] Wiping the surface to be painted with a clean cloth saturated in a
solvent. This is essential to good paint adhesion.
degreaser:
A substance which removes dirt and grease from a mechanic's hands. Also
called "hand cleaner."

degreasing:
[1] The removing of grease or oil from a surface.
[2] Solution or solvent used to remove oil or grease from refrigerator parts.
Also see
alkaline degreasing and vapor degreasing
degreasing agent:
A solvent or alkaline solution which is used for removing oil and grease
degree:
1/360 part of a circle.
degree-day:
Unit that represents one degree of difference from inside temperature and
the average outdoor temperature for one day; often used in estimating fuel
requirements for a building.
degree wheel:
A wheel-like disc divided into 360 equal parts that is attached to the
engine crankshaft it is used to time the valves to a high degree of accuracy.
dehumidifier:
A device which absorbs moisture from the atmosphere. It can be a unit
dedicated for this purpose, or even an air conditioner.
dehumidify:
To remove water vapor from the air
dehydrated oil:
Lubricant which has had most of its water content removed (dry oil).
dehydrator-receiver:
Small tank which serves as liquid refrigerant reservoir and which also
contains a desiccant to remove moisture. Used on most automobile air
conditioning installations.

dehydrator:
See drier
de-ice:
To remove the ice from the outside of the windshield.
deice control:
Device for operating a refrigerating system in such a way as to provide
melting of the accumulated ice and frost.
de-icer:
A liquid or spray which is applied to the windshield to assist in removing
ice.
Also see
door lock de-icer
lock de-icer
de-ionized water:
Water from which impurities have been removed by a special process and
used for topping up batteries.
Delage:
An old brand of automobile of which the 1925-1948 Model D-8 (but not
the 4-cyl.) with required application is a classic car. The 1946-49 D-6
Sedans are milestone cars.
Delahaye:
An old brand of automobile of which the 1925-1948 Series 135, 145, 165
(but not the 4-cyl.) with required application are classic car. The Type 135,
175, 180 (1946-51) are milestone cars.
de-laminate:
To split a layered or laminated material into its separate layers. Sometimes
used to describe failure of an adhesive in bond strength testing
Delaunay:

An old brand of automobile of which the 1925-1948 6-cyl Belleville are
classic cars.
delay:
See
headlight on/off delay system
ignition delay
delay relay:
See time delay relay
delay system:
See headlight on/off delay system
delay vacuum bypass system:
(DVB) an optional system used by Ford that bypasses the spark delay
valve during cold operation to improve driveability
delay valve:
A valve used in a vacuum or hydraulic system in which the valve's
opening or closing is delayed. Also called vacuum delay valve
delay wiper:
A windshield scraper which can be set to activate at various times and
pauses between each swipe. It is useful when there is a mist or light rain.
Also called "intermittent wiper."
d'elegance:
See concours.
d'elegance:
See concours d'elegance

delineator post:
A barracade marking device placed
on a road to prevent travel in a
particular direction
deliver:
[1] To pump or discharge a liquid.
[2] To drive a new car from the factory to the distributor or dealer. Or to
drive it to the customer.
delivery:
[1] The discharging of a liquid from a pump.
[2] Driving a new car from the factory to the distributor or dealer
delivery lines:
Fuel lines used to carry fuel from the fuel injection pump to the injector
nozzles
delivery mileage only:
The odometer reading reflects only the distance from the factory to the
selling dealer.
delivery valve:
[1] The valve on the outlet side of a pump.
[2] A fuel injection pump valve that rapidly decreases injection line
pressure to achieve an abrupt fuel cutoff at the injector

Delorean:
A model of automobile manufactured by John Z.
DeLorean
Click for books on Delorean
Del Sol:
Honda
Click for books on Honda Del
Sol
delta configuration:
A triangular connection of the three stator windings of an alternator.
Also see
Y-configuration
delta transformer:
Three-phase electrical transformer which has ends of each of three
windings electrically connected to form a triangle.
deluxe:
Abbreviated (DL). A term used to indicate a series of vehicle which is just
above the basic version.
delugger:
A machine used to cut the lugs from tires prior to buffing.
demagnetize:
Removing residual magnetism from an object which had been previously
magnetized
demand meter:

Instrument which measures the kilowatt-hour usage of a circuit or group of
circuits.
demist:
A British term to clear fog or frost from the windshield or rear window. In
the US and Canada, the term is defog.
demister:
A British term for a defogger or defroster
demonstrator:
A vehicle used by a dealer for test drives and sold later at a reduced price.
Also see
ex-demonstrator
demountable flange:
A side ring or side and lock ring combination that retains the tire on the
rim. It is removable to permit tire mounting or removal.
demountable rim:
A two piece rim found on trucks. The main part of the rim remains on the
axle while a side piece and a locking ring is removable. In this way the
whole rim is not removed from the vehicle like a passenger car's rim and
wheel. Also called a "detachable rim"
denatured alcohol:
Ethyl alcohol to which a denaturant has been added
Denovo tire:
A special tire (fitted to a special rim) which used to be made by Dunlop,
and which can be run flat for up to 160 km (100 miles) at up to 80 kph (50
mph)
density:
[1] Compactness; relative mass of matter in a given volume.

[2] Closeness of texture or consistency of particles within a given
substance. The weight per unit volume.
[3] The weight or mass per unit volume of a gas, liquid, or solid
dent:
[1] A hollow or dip in a body panel caused by a sharp blow or impact.
[2] To cause a dent in a body panel
dent puller:
A tool with a strong suction cup to pull out dents in body panels.
Also see
panel puller
suction cup dent puller
Denver boot:
A locking device which wraps around the wheel of a vehicle to immobilize
its movement
deodorizer:
Device which absorbs or adsorbs various odors, usually by principle of
absorption. Activated charcoal is commonly used.
départ:
The starting line of a randonnée or brevet
departure angle:
The most sharply angled incline the vehicle can leave without its rear
hitting the ground. As with approach angles, it's formed on one side by the
horizontal axis, and on the other by a straight line connecting the rear edge
of the rear tire and the most prominent point at the rear of the vehicle,
usually the bumper or exhaust pipe.
depolarize:
Removal of residual magnetism thereby destroying or removing the
magnetic. To remove polarity
deposit:

A coating of unwanted mineral or layer of sediment at the bottom of a
tank.
[2] To apply a coating of something (often metal by electrolysis).
Also see
gum deposit
lead deposit
refundable deposit
deposition:
See
electrolytic deposition
vapor deposition
zinc vapor deposition
depreciation:
The loss of value of a vehicle because of age or deterioration
depression:
[1] An indentation or dent in the surface of a sheet of metal whether
through deliberate design or accident.
[2] A restriction of airflow which causes low pressure and a partial
vacuum.
Also see
constant-depression
constant depression
engine depression
valve clearance depression
depressor:
See valve spring depressor
depress the accelerator:
The action of pressing down on the gas pedal (accelerator) to cause more
fuel to enter the engine thus making the vehicle go faster. Opposite to
"ease up on the accelerator."
depress the gas pedal:
The action of pressing down on the gas pedal (accelerator) to cause more
fuel to enter the engine thus making the vehicle go faster. Opposite to
"ease up on the gas pedal."

depress the throttle pedal:
The action of pressing down on the throttle pedal (accelerator) to cause
more fuel to enter the engine thus making the vehicle go faster. Opposite
to "ease up on the throttle pedal."
depth:
See
molded depth
profile depth
skid depth
throat depth
tread depth
well depth
depth gauge:
A measuring tool for determining the depth of something.
Also see
tread depth gauge
depth micrometer:
A measuring device (micrometer) used for precise measurement of a hole
depth, recesses, keyways, etc.
depth of thread:
The distance from the thread crest to root measured perpendicular to the
axis of the thread
derailleur:
A lever-activated mechanism that pushes the chain off one sprocket of
a bicycle and onto another, thus changing the gear ratio. See front
derailleur and rear derailleur.
derailleur cable:
A wound steel cable running from the shift lever to the derailleur on a
bicycle.
derailleur cable housing:

The outer casing into which the inner wire is inserted. The inner wire of a
brake cable and matching housing is thicker than those of a derailleur and
thus are not compatible.
derailleur chain, narrow width:
A bicycle chain made especially for use on an "ultra" or narrow freewheel
often recognized by bulging inner link plates and flushchain pins.
derailleur chain, standard width:
A bicycle chain designed to fit a freewheel of standard width, usually
characterized by straight-edged plates and chain pins that protrude slightly
beyond the outer link plates.
derailleur hanger:
the part of a rear dropout to which the rear derailleur attaches
derailleur pulleys:
One of two guide wheels of the rear derailleur which directs the path of the
chain.
derrick:
A device for hoisting and lowering heavy weights, cargo, stores, etc
derust:
To remove rust from a metal part
derv:
Diesel oil when used as a fuel for road vehicles. Acronym for "diesel-
engined road vehicle"
descaling:
The removal of scale or metallic oxide from metallic surfaces by pickling
desiccant:

[1] A drying agent (silica gel or a similar substance) used in refrigeration
or air conditioning systems to remove excess moisture from refrigerant
vapour
[2] Substance used to collect and hold moisture in refrigerating system. A
drying agent. Common desiccants are activated alumina and silica gel.
design:
[1] The arrangement of parts or the form of construction.
[2] To arrange parts or construction of a vehicle or major component.
Also see
cab-forward design
cabin-forward design
cam design
cam profile
component design
open-deck design
product design
wrapround dash design
designation:
See
model designation
one-piece rim designation
rim designation
type designation
design pressure:
Highest or most severe pressure expected during operation. Sometimes
used as the calculated operating pressure plus an allowance for safety.
desmodromic:
something (like valves) which is opened and closed by a mechanical
device. In most 4-stroke engines the valves are opened by the cam, but
closed by the action of the valve springs. In a desmodromic system, the
valves are opened by a cam and closed by a cam or a cable. A
desmodromic system is more costly and more difficult to manufacture, but
the advantage is more precise control of the valves and less valve bounce
which is seen in a normal engine at high speed.
desorption:

The removal of material which has been adsorbed. It is the opposite of
adsorption.
DeSoto:
A vehicle brand of which the 1956-58 Adventurer
models are milestone cars.
Click for books on
DeSoto
destruction:
Trucker slang for Road construction as in "Seem's like all the roads in
pennsylvania are always under destruction."
detachable rim:
A wheel rim which is bolted to the wheel center or spider and can be
disassembled for replacing the rubber tire. It is found on trucks and some
quads. It is also called a demountable rim
detachment:
See flow detachment
detail:
The action of correcting all appearance flaws in a vehicle.
detailitis:
A term coined by Art Treta to indicate a compulsive disorder which
compels a vehicle owner to correct its every flaw to the extent that he
searches for even the most hidden flaw.
Also see
restorationitis
detector:
See
glass tampering detector

radar detector
detector, leak:
Device used to detect and locate refrigerant leaks.
detent ball and spring:
A spring loaded ball that snaps into a groove or notch to hold some sliding
object in position.
detergent:
A soap-like chemical added to the engine oil (particularly MS oil) or
gasoline to improve its characteristics and keep the engine clean by
controlling the formation of sludge and gum as well as controlling
foaming.
detergent oil:
An MS oil which keeps the engine clean by preventing the formation of
sludge and gum.
deterioration:
See
catalyst deterioration
thermal deterioration
DeTomasoPantera:
A model of automobile manufactured in Italy
Click for books on Pantera
detonation:
The action of the fuel charge firing or burning too violently, almost
exploding. It sometimes results in a noise called "pinging." Detonation is
caused by autoignition of the "end gas" i.e., that part of the charge not yet
consumed in the normal flame-front reaction. Detonation occurs because
piston motion and compression of the end gas raise its temperature and
pressure to the point where the end gas autoignites. The pinging or
knocking noise is the result of intense pressure waves in the charge which
cause the cylinder walls to vibrate. Also called "fuel knock."

detonation-activated ignition retard:
A system which retards the ignition timing when the detonation sensor
picks up vibration at frequencies typical of denotation
detonation sensor:
A sensor, , usually piezoelectric, mounted near the cylinders which can
detect engine knocking or frequencies of detonation so that it will send a
message to retard the ignition timing to prevent damage to the engine.
detour:
An alternative route which traffic has to follow due to closure of a stretch
of road for repairs, etc. A diversion.
detoxed vehicle:
A vehicle with a reduced emission system consisting of a catalytic
converter, EGR, air injection, fuel evaporative emission control, etc. Also
called a "controlled vehicle"
detuned:
The intentional adjustment of an engine to reduce its power in an attempt
to reduce emissions, reduce top-end speed, increase fuel economy, or meet
specific governmental standards.
deuce:
Hot rod built around a 1932 Ford coupe body.
deutsche Industrie Normen:
See DIN.
development:
See research & development
deviation angle:
See tire deviation angle

device:
A piece of equipment or a mechanism designed for a specific purpose or
function.
See
anti-roll device
antiroll device
economy device
electronic sensing device
enrichment device
sensing device
triggering device
DeVille:
Click for books on
DeVille
Devon:
A vehicle brand of which the 1958-62 S/S models are milestone cars.
dew:
Condensed atmospheric moisture deposited in small drops on cool
surfaces.
dewax:
To remove a coating of wax from the body of a vehicle usually in
preparation for painting.
dew point:
Temperature at which vapor (at 100 percent humidity) begins to condense
and deposit as liquid.
DFC:

Acronym for digital frequency control
dhc:
Acronym for drophead coupe
DG:
Acronym for "Diesel General" oil for use under ordinary conditions in
diesel engines.
diac:
A two-lead alternating current semiconductor that allows current to flow in
both directions at a preset voltage.
diagnosis:
Refers to use of instruments to determine cause of improper function of
parts or system of a vehicle
See
fault diagnosis
self-diagnosis
diagnostic:
See
engine diagnostic connector
on-board diagnostic system
diagnostic center:
A garage or part of a garage where problems with a vehicle or part of a
vehicle are determined.
diagnostic code:
[1] Code displayed on instrument panel which can be used to determine
area in system where malfunction may be located.
[2] Code numbers obtained by accessing the diagnostic mode of the engine
management computer. This code can be used to determine the area in the
system where a malfunction may be located
diagnostic computer:

A computer terminal or engine analyzer which is hooked up to the car's
electronic box and reveals the condition of the engine and various sensors.
diagnostic connector:
See engine diagnostic connector
diagnostic link:
The electric cord which connects the computer terminal to the socket on
the vehicle.
diagnostics:
The process of identifying the cause or nature of a condition, situation, or
problem to determine the appropriate corrective action to take in the repair
of an automotive system. See on board diagnostics
diagnostic socket:
A socket on the vehicle (usually found in the engine compartment) which
is part of the onboard electronic sensor system.
diagnostic system:
The various sensors and electronic devices which record the operation of a
number of functions within the vehicle.
Also see
on-board diagnostic system
diagnostic testing:
The analysis of the various functions of the components of a vehicle to
determine if they are operating properly or have recorded faults which
need to be corrected.
diagonal:
See
diagonal belt:

Another term for shoulder belt
diagonal cutting:
See
diagonal cutting pliers:
See
diagonal split braking system:
A dual-circuit braking system in which each circuit brakes one front wheel
and the diagonally opposite rear wheel, so that in the case of failure of one
circuit reasonably balanced braking can be achieved. See dual brakes --
especially the picture.
diagonally split system:
A dual-circuit braking system in which each circuit brakes one front wheel
and the diagonally opposite rear wheel, so that in the case of failure of one
circuit reasonably balanced braking can be achieved. See dual brakes --
especially the picture.
diagram:
See
circuit diagram
indicator diagram
timing diagram
wiring diagram
dial:
The face (usually circular) of an instrument like a speedometer,
tachometer, vacuum gauge, etc.

dial caliper:
A slide-type caliper which registers
on a dial the distance between two
points
dialed in:
[1] The action of fine tuning an engine or component to its peak capacity.
[2] The ideal set up of a bicycle when everything works just right
dial gage:
See dial gauge.
dial gauge:
A precision micrometer type instrument that indicates the reading via a
needle moving across a dial face.
dial indicator:
A precision measuring instrument that indicates movement to a thousandth
of an inch with a needle sweeping around a dial face. See dial gauge.
dial torque wrench:
A wrench usually with a socket end
and which measures the torque of a
nut-bolt fastener. It registers the value
on a dial.
diameter:
The distance between one edge of a circular object to the other edge and
passing through the center.
Also see
bead seat diameter
bore diameter
circle diameter

external diameter
inside diameter
internal diameter
major diameter
minor diameter
nominal diameter
nominal rim diameter
nominal thread diameter
outer diameter
outside diameter
overall rim diameter
pitch circle diameter
pitch diameter
rim diameter
thread diameter
valve diameter
diamond frame:
[1] The traditional men's bicycleframe the principal parts of which form a
diamond shape.
[2] Tubular-frame design for motorcycles common until WW II and
derived from the bicycle layout. The engine cases often form part of the
structure. In profile it resembles a diamond shape
diamond star:
The name of Chrysler Corporation which comes from the pattern of its
emblem.
diaphragm:
[1] A flexible cloth-rubber sheet that is stretched across an area thereby
separating two different compartments. A diaphragm is used in pumps to
create a pressure differential that causes a fluid to be pushed or pulled
from one point to another. Some carburetors have no float bowl (i.e.,
Tillotsen), but use a series of diaphragms to pump gasoline into the engine.
[2] A flexible partition used to separate two chambers or elements.
[3] In air-conditioning system, a rubber-like piston or bellows assembly
which divides the inner and outer chambers of backpressure regulated air
conditioning devices.
[4] In fuel system, a thin dividing sheet or partition which separates a
housing into two chambers, one of which is usually vented to vacuum
while the other is not; used in vacuum-controlled secondaries, anti-stall
dashpots, and other carburetor control devices. Also see piston diaphragm

[5] A rubber-like piston or bellows assembly which divides the inner and
outer chambers of back-pressure regulated air conditioning devices
diaphram clutch:
Another term for a diaphragm spring clutch
diaphram link:
The arm which transmits the movement of the diaphram and the
distributor baseplate in a vacuum advance mechanism.
diaphragm pump:
A device which has a flexible diaphragm which moves forward and
backward by a solenoid or other mechanical device to transfer fluid.
Also see
twin diaphragm pump
diaphragm spring:
A type of spring shaped like a
disc with tapering fingers
pointed inward or like a wavy
disc, used in some clutches. In
an automotive clutch the
diaphragm spring is part of
the clutch pressure plate.
When the clutch is engaged,
this spring forces the pressure
plate against the clutch disc;
driver effort through the
clutch linkage overcomes the
spring pressure to disengage
it. A type of spring, shaped
like a disc with tapering
fingers pointed inward or like
a wavy disc, used in some
clutches. In auto application,
the diaphragm spring is part
of the clutch pressure plate.
When the clutch is engaged

this spring forces the pressure
plate against the clutch disc.
Also see
clutch diaphragm spring
diaphragm spring clutch:
A common clutch used in most vehicles with manual transmission where a
diaphragm spring keeps the pressure plate in contact with the friction plate
dichlorodifluoromethane:
The chemical substance (CCl2F2) used in automotive air conditioning
systems to absorb, carry, and release heat. A member of the fluorocarbon
family. Usually referred to as refrigerant or R-12
dickey:
British term for rumble seat.
die:
[1] One of a matched pair of hardened steel blocks that are used to form
(by stamping, pressing, extruding, drawing or threading) metal into a
desired shape.
Also see
bending die
lower bending die
[2] A tool for cutting threads. See tap and die set.
die back:
See die-back.
die-back:
In a lacquerfinish the loss of gloss after compounding, caused by
continued evaporation of thinner.
die cast:
Manufactured by forcing molten metal into a die. Especially used of
aluminum or an alloy.

die casting:
[1] Formation of an accurate and smooth object by forcing molten metal,
plastic, etc., into a die under pressure. See cast.
[2] Process of molding low-melting-temperature metals in accurately
shaped metal molds.
dielectric:
A material which is an electrical insulator or in which an electric field can
be sustained with a minimum loss of power.
dielectric fluid:
Fluid with high electrical resistance.
dielectric grease:
A special grease which is applied to the ends of electric terminals to inhibit
corrosion between the terminals or to be sure that there is good electrical
contact between the terminals.
diesel:
A type of engine or fuel or oil used for that engine.
Also see
diesel engine
dieselFuel
diesel oil
turbo-diesel
diesel cycle:
A four-stroke cycle where the air is sucked into the cylinder and
compressed at a ratio of up to 24:1. At the end of the compression stroke
the fuel is injected. Because of the high compression and resulting increase
in temperature, the fuel is ignited leading to the power stroke and followed
by the exhaust stroke where the combustion products are removed.
diesel engine:
An internal combustion engine that uses diesel oil for fuel. The true diesel
does not use a carburetor or an ignition system (i.e., spark plugs) but
injects diesel oil into the cylinders when the piston has compressed the air
so tightly that it is hot enough to ignite the diesel fuel without a spark.
Because a cold engine cannot ignite the diesel fuel, glow plugs are used to

heat the mixture, but they do not provide a spark. Named after Rudolf
Diesel (1858-1913), the inventor.
Also see
compression ignition
diesel fuel:
A light oil fuel which has a relatively low ignition temperature
dieseling:
A form of autoignition in which a gasoline engine continues to fire after
the ignition has been shut off. In late-model emission-controlled engines,
dieseling or run-on is caused by heat and the unusually high manifold
pressure that result from retarding the spark at idle.
diesel knock:
The noise caused by the rapid rise in pressure in a diesel engine especially
when the engine is cold or running at a low speed. Also called "diesel
rattle."
dieselling:
See dieseling
diesel oil:
Fuel for cars with diesel engines. This is not a form of lubricating oil. See
cetane rating.
diesel particulate filter:
A filter which removes small particles from a diesel exhaust. It looks like a
honeycomb catalytic converter but acts as a mechanical separator.
diesel rattle:
Another term for diesel knock
die set:
See tap and die set

die stock:
A tool used to hold and operate dies when cutting outside threads.
die size:
Retread rubber is designated by its crescent shaped dimensions in inches
and eighths, and its thickness in 32nds of an inch; (e.g., 66-72-16; the
crown would measure 6 and 6 eighths, the base 7 and 2 eighths wide; and
the thickness 16/32 of an inch, or gauge of the stock rubber.)
diff:
A colloquial term for a differential
differential:
[1]
The
tempe
rature
or
pressu
re
differ
ence
betwe
en
cut-in
and
cut-
out
tempe
rature
or
pressu
re of a
contro
l.
[2] A
unit
that
takes
the

power
of the
rotati
ng
drives
haft at
right
angles
to the
rear
axle
and
passes
it to
the
axle.
It will
not
only
drive
both
rear
axles
at the
same
time,
but
will
also
allow
them
to
turn
at
differ
ent
speed
s
when
negoti
ating
turns.
In this

way
the
tires
do not
scuff
or
skid.
Also see
automatic slip-control differential
axle differential
bevel differential
center differential
front differential
helical differential
inter-axle differential
limited-slip differential
limited slip differential
lockable differential
locking differential
lockup differential
multiple-disc limited-slip differential
no-spin differential
open differential
planetary gear differential
pressure differential switch
rear axle differential
rear differential
spur differential
torque sensitive limited slip differential
torsen differential
traction differential
variable limited-slip axle/center differential
visco-differential
differential cage:
The rotating metal fram which encloses the differential side gears and
pinion gears inside the axle casing. Also called the "differential carrier"
differential carrier:
See differential cage
differential case:

The steel unit to which the ring gear is attached. The case drives the spider
gears and forms an inner bearing surface for the axle and gears.
differential casing:
The differential housing
differential gear:
See differential gears.
differential gears:
The gears that transmit engine power to the driving axles and are arranged
so as to permit the rear wheels to turn at different speeds as required when
the vehicle is negotiating a turn.
differential grease:
See gear grease.
differential housing:
The enclosure which contains the differential gears.
differential lock:
A mechanism which eliminates the action of the differential so that both
wheels can be driven for better adhesion on slippery surfaces.
differentially:
See galvanize differentially
differential pinion:
The bevel pinion in the differential.
differential pressure:
The pressure difference between two regions, such as between the intake
manifold and the atmospheric pressures. In Bosch KE-Jetronic systems,
the difference between actuator fuel pressure in the lower chambers of the

differential-pressure valves and the system pressure entering the pressure
actuator.
Also see
pressure drop
differential-pressure regulator:
A pressure actuator
differential-pressure valve:
Inside the Bosch CIS fuel distributor, these valves (there is one for each
cylinder) maintain a constant pressure drop at each of the control-plunger
slits, regardless of changes in the quantity of fuel flow
differential side gear:
The bevel gear on either side of the differential into the center of which the
axle shaft fits
differential switch:
See pressure differential switch
diffusing lens:
The lens in the headlight glass which helps to focus the beam
diffusion:
[1] The way in which innovations spread through market or non-market
channels.
[2] Mixing the molecules of two gases by thermal agitation
digifant:
VW collaborated with Bosch to develop this electronic injection system.
Digifant is similar to a Motronic system, except that its timing control map
is less complicated than the Motronic map. And it does not have a knock
sensor
digifant II:

A refined version of VW 's digifant. This system has some control
improvements and uses a knock sensor for improved timing control
digital caliper:
A slide-type caliper which gives a digital readout.
digital frequency control:
(DFC) A system which automatically stabilizes or tunes the frequency of a
selected radio station.
digital fuel injection:
(DFI) a GM system, similar to earlier electronic fuel injection system, but
with digital microprocessors. Analog inputs from various engine sensors
are converted to digital signals before processing. The system is self-
monitoring and self-diagnosing. It also has the capabilities of
compensating for failed components and remembering intermittent failures
digital ratio adapter controller module:
(DRAC) a device used on GM vehicles to convert the analog signal from
the speed sensor into a digital signal that the EBCm can use
digital speedometer:
A speedometer which shows the speed in digital numbers rather than a
needle on a dial gauge (which is called an analog speedometer).
digital volt-ohm multimeter:
(DVOM) a digital electronic meter that displays voltage and resistance
dig out:
To accelerate at top power.
diluent:
A fluid which thins or weakens another fluid.
dilution:

See crankcase dilution.
dimmer:
A switch used to lower or dip the headlights from high beam to low beam
and back again.
Also see
headlight dimmer switch
dimmer control:
A rotary control switch which will increase or decrease the intensity of the
instrument lights. Also called interior dimmer light switch.
dimmer switch:
A device used to lower or increase the brightness and focus of the
headlights (i.e., from high-beam to low-beam). The British term is
"dipswitch." Also called headlight dimmer switch
DIN:
Acronym for "Deutsche Industrie Normen" (German industrial standards).
DIN horsepower is similar to the SAE net horsepower. It is measured at
the output shaft of an engine fully equipped with normal accessories.
dinging:
The action of straightening a damaged panel by using a hammer and dolly
to bring it back into shape.
DIN mounting:
The standard hole in the dash through which a DIN radio can be installed
Dino:
Ferrari
Click for books on Ferrari Dino
DIN radio:

An aftermarket radio which fits into a thinner hole than most American
radios. When installing a repacement radio, special faceplates are
necessary
diode:
[1] Two-element electron tube which will allow more electron flow in one
direction in a circuit than in the other direction; tube which serves as a
rectifier.
[2] An electrical component having the ability to pass electric current
readily in one direction but resisting current flow in the other. When four
diodes are connected in a certain way (i.e., "bridged") they will convert
AC to DC, thus becoming a rectifier.
Also see
rectifier diode
zener diode
Dion axle:
See de Dion axle
dioxide:
See carbon dioxide
dip:
[1] A British term for dimming the headlights.
[2] A low horizontal indentation of the pavement which may cause a
speeding vehicle to lose control.
[3] To immerse.
See
full dip treatment
hot dip
dipped beam:
A British term for low beam
dipper:
A British term for the dimmer switch
dipper switch:

dipping mirror:
A British term for day-night mirror
dipstick:
The metal rod that passes into the oil sump it is used to determine the
quantity of oil in the engine. The oil level is marked on the rod and
matches level indicators on the rod. Dipsticks are used to check engine oil
and transmission fluid. In most instances, the dipstick is inserted as far as
it will go and then removed to check the level. In motorcycle engines, the
dipstick is placed on the top of the threads (i.e., not screwed down) to
check the level. oil dipstick
dipswitch:
dip treatment:
See full dip treatment
direct-acting shock absorber:
A telescopic shock absorber.
direct current:
(DC) An electric current that flows steadily in one direction only. This is
the type of current found in a battery and throughout the lighting and
accessory system of a vehicle. Contrasts with alternating current (AC).
direct damage:
A vehicle damage caused directly by an impact with an object. In contrast
with an indirect damage.
direct digital control:
(DDC) Use of digital computer to perform required automatic control
operations in a total energy management system.

direct drive:
When the gearing is such that the crankshaft and driveshaft revolve at the
same speed, the vehicle is in direct drive. Usually this occurs in high gear
(except for those with overdrive). It is represented as 1.00:1 ratio.
direct drive powertrain:
A system of propulsion where the speed of the engine, transmission, and
propeller shaft rotate the same.
direct expansion evaporator:
Evaporator using either an automatic expansion valve (AEV) or a
thermostatic expansion valve (TEV) refrigerant control.
direct ignition system:
(DIS) An ignition system which does not used a distributor but carries high
voltage from the ignition coils directly to the spark plugs.
Also see
integrated Direct Ignition System
direct injection:
A fuel injection system which is generally used in diesel engines and
forces fuel directly into the combustion chamber. It requires very high
injection system pressure to overcome the pressure within the combustion
chamber.
Also see
high speed direct injection
directional baffle plate:
Installed in a Quadrajet carburetor's secondary bores to help direct the
airflow for improved distribution in the intake manifold
directional stability:
Ability of a vehicle to move forward in a straight line with a minimum of
driver control. A vehicle with good directional stability will not be unduly
affected by side wind, road irregularities, etc.

directional tire:
Directional designs are recognized by the grooves in the tread that swipe
away in a backward angle from the center of the tread face and rotate in
only one direction. A direction of rotation arrow is located on both
sidewalls of the tire. Directional tires enhance straight-line acceleration,
provide maximum dry traction, better wet performance which helps to
reduce rolling resistance as well as providing shorter stopping distances.
See
asymmetrical tread
directional tread
Symmetrical
directional tread:
An arrangement of bars, grooves, and ribs on a tire's tread in any manner
that gives most effective traction when the tire revolves in only one
direction.
Also see
directional tire
direction indicator:
The signal lights which blink on either side of the front of the vehicle and
either side of the rear of the vehicle. Some early cars (like the Austin and
Flying Standard) had small illuminated arms that flipped out from the B-
post instead. The purpose of signal lights is to warn other drivers of a
change in direction when turning a corner or changing lanes.
direction indicator warning light:
A light on the instrument panel which flashes when the signal lights are
operating. Usually this light is in the shape of a green arrow. On some cars,
like Cadillac, a secondary light is mounted in a pod on the upper edge of
each front fender and in a pod inside the cab above the backlight (i.e., back
window)
direction of rotation:
The direction in which a wheel or shaft turns or is supposed to turn.
direction of travel:
The direction in which an object (e.g., a vehicle) is moving.

direct polarity:
Direct current flowing from anode (base metal) to cathode (electrode). The
electrode is negative and the base metal is positive.
dirtbike:
Bikes intended for off-road use that are not legal to ride on public roads.
Sometimes the term pure-dirt is used to distinguish a dirtbike from a dual-
sport motorcycle
dirty town:
Trucker slang for New York City as in "I got a load of garbage going to
dirty town."
DIS:
An acronym for direct ignition system or a distributorless ignition system
similar to the C3I system, using two coils on four-cylinder engines
disabled:
[1] the condition of a vehicle which is not able to be driven because of a
failure of some component (e.g., bad battery, flat tire, engine seized) or
because of an accident.
[2] A driver who lacks the use of a limb.
disabler:
See ignition disabler
disassemble:
To take a vehicle or major component (e.g., the engine) apart in order to
repair or restore the vehicle or component or to sell or recycle them. Also
called "dismantle."
disc:
May be spelled "disk." A flat dish-shaped item which may or may not have
a center hole.
Also see
abrasive disc
balance disc

brake disc
brake disc type
caliper disc
center locking disc
clutch disc
cutting disc
disc brake
fixed-caliper disc brake
four wheel disc brakes
friction disc
grinding disc
hardy disc
hinged-caliper disc brake
multi-disc
multiple disc clutch
multiple disc
padding disc
parking disc
plain disc wheel
rotary disc valve
tax disc
ventilated discs
wheel disc
discard diameter:
The diameter at which a worn brake drum should be replaced
discard thickness:
The thickness at which a brake disc should be replaced
disc brake:
A type of brake that has two basic components: a flat rotor (disc) that turns
with the wheel and a caliper that is stationary. When the brake pedal is
depressed, linkage (mechanical or hydraulic) causes the caliper to force its
heat-resistant brake pads against both sides of the rotating disc thus
slowing or stopping the wheel. Almost all new cars have disc brakes on the
front wheels with drum brakes on the rear. More expensive cars have four
wheel disc brakes. Because of the need for greater pressure to activate disc
brakes, most cars so equipped also have a power booster. Wear takes place
in the pads and the rotors. The pads are usually replaced while the rotors
can sometimes be reground else they too must be replaced. If the rotors are

not tightened correctly when installed, they can warp and cause a jerking
motion when stopping.
Also see
brake, disc type
caliper disc brake
fixed-caliper disc brake
four wheel disc brakes
hinged-caliper disc brake
sliding-caliper disc brake
disc brake gauge:
A tool for measuring the thickness, wear, and score depth on brake discs
disc brake rotor:
See brake rotor
disc brakes:
See disc brake.
disc clutch:
See multiple disc clutch
discharge:
[1] The action of drawing electric current from the battery. The opposite
action to charging.
[2] to pour out liquid from a pump.
[3] the product (e.g., the liquid) that is poured out of a pump.
[4] To bleed some or all of the refrigerant from a system by opening a
valve or connection to permit refrigerant to escape slowly
Also see
battery discharge controller
capacitive discharge
gas discharge headlight
gas discharge lamp
gas discharge light
gaseous discharge headlight
gaseous discharge lamp
main mixture discharge nozzle

discharge air:
Air conditioning air forced through the vents (ducts) into the passenger
compartment
discharge check ball:
In a carburetor, a small check ball that lifts off its seat when the pump well
is pressurized by the accelerator pump, which allows fuel to be discharged
into the venturi through the shooter nozzle
discharge controller:
See battery discharge controller
discharged battery:
A battery that cannot produce sufficient power.
discharge headlight:
See
gas discharge headlight
gaseous discharge headlight
discharge ignition:
See capacitor discharge ignition system
discharge indicator:
See battery discharge indicator
discharge lamp:
See
gas discharge lamp
gaseous discharge lamp
discharge light:
See gas discharge light
discharge line:

[1] In an air conditioning system, the line which connects the compressor
outlet to the condenser inlet
[2] The line which connects the compressor outlet to the condenser inlet
discharge nozzle:
In a carburetor, the end of the main delivery tube that discharges fuel into
the venturi area. See main mixture discharge nozzle
discharge pipe:
The outlet pipe from a pump
discharge plug:
See surface discharge plug
discharge pressure:
[1] The pressure exerted in a liquid pumped, expressed in psi.
[2] The (high side) pressure of the refrigerant being discharged from the
air conditioner compressor
discharge rate:
Amount of current discharged from a battery, expressed in amps
discharge side:
[1] Outlet side.
[2] The part of the air conditioner system under high pressure, extending
from the compressor outlet to the thermostatic expansion valve/tube inlet
discharge valve:
[1] Valve on the outlet side of a reciprocating pump. The opposite is
suction valve.
[2] In an air conditioner system, a device used to check high side
pressures, usually referred to as the high side service valve
[3] A device used to check high side pressures. Usually referred to as the
high side service valve
discharge voltage:

See spark discharge voltage
discharging current:
Current supplied by a storage cell or battery, whose direction is opposite to
that of the charging current
discolor:
To alter the color of (a finish, metal, etc.) to a color which is not wanted.
This fading may be caused by sitting in the sun, drops of contaminants
(tree sap, bird dropping, spilled gasoline), poor paintwork, etc.
disconnect:
To remove the terminal from a mechanical or electrical device or from the
other side of the terminal. While some may be simply pulled apart, others
have catches which must first be released.
disconnect terminal:
Solderless connectors in male and female forms, intended to be easily
disconnected and connected. Typically, a blade or pin (male connector) fits
into a matching receptacle or socket (female connector). Many
components have built-in (blade) terminals that require a specialized
female connector
disconnect the battery:
The action of removing the high tension electrical cables from the battery
terminals. Also called "isolate the battery"
discount:
See
residual discount
manufacturer discounts
disc sander:
A round, rubber disc powered by an electric drill and covered with
abrasive paper for rough sanding work.
also see
orbital sander

disc type:
See brake disc type
disc valve:
A type of rotary valve that allows the passage of fluid through an arc-
shaped slot.
Also see
rotary disc valve
disc wheel:
[1] A wheel constructed of stamped steel.
[2] A rim and metal disc that have been welded together. The disc is
usually offset from the centerline of the rim to allow for dual tire mounting
and to provide sufficient clearance between the duals. Disc wheels are
attached to the hub with either single nuts or double cap nuts.
Also see
plain disc wheel
solid disc wheel
disc wheel type:
A type of dual mounting wheels where the discs are offset from the
centerline of the rim to provide clearance between the tires. They are held
in place by double cap nuts, inner cap nuts, and outer cap nuts.
disengage:
To move (a gear, dog clutch, etc.) so that it no longer meshes with another
matching part
disengage the clutch:
During normal driving, the power of the engine is being transferred to the
gears of a manual transmission because the clutch plates are pressed
together. When you press down on the clutch pedal (or pull in the clutch
lever on a motorcycle), you are releasing that contact (i.e., disengaging the
clutch) so that there is no connection between the engine and the
transmission. You engage the clutch when you release the pedal or lever.
dish:
[1] A depression in the top of a piston.

[2] Offsetting of the hub on a rear wheel on a derailleur bike to make room
for the freewheel and still allow the wheel to be centered within the frame.
Also see
negative wheel dish
offset dish
dished:
A plate, washer, or disc is dished when the center is recessed from the rim
like a shallow bowl.
dished brake disc:
A disc that has worn thinner at the inner part of its friction surface. This is
an abnormal form of wear
dishing:
See negative wheel dishing
dish washer:
A washer is a flat disc with a hole in the center. The disc in a dish washer
is dished or bent in a concave fashion.
disk:
More commonly spelled "disc."
dismantle:
To take a vehicle or major component (e.g., the engine) apart in order to
repair or restore the vehicle or component or to sell or recycle them. Also
called "disassemble."
dispersant:
Dispersing or scattering in various directions; a state of matter in which
finely divided particles of one substance (disperse phase) are suspended in
another (dispersion medium) substance
displacement:

The total volume of air displaced by all the pistons in travelling from BDC
to TDC, i.e., the total volume of air and fuel the cylinder can hold before
compression occurs. Also called "piston displacement."
Also see
cubic inch displacement
engine displacement
light displacement
loaded displacement
piston displacement
positive displacement compressor
displacement compressor:
See positive displacement compressor
displacement, piston:
Volume obtained by multiplying area of cylinder bore by length of piston
stroke.
displacement taxes:
A vehicle taxation system which determines the amount of taxes based on
the engine displacement of the vehicle.
displacement volume:
That part of the cylinder capacity that is swept by the pistons on their up
and down strokes (i.e., the volume through which a piston moves in one
stroke) formed by the bore diameter and the piston stroke. Also called
"swept volume."
display:
Any device that conveys information. In a vehicle, displays are either
lights, gauges, or buzzers. Gauges may be analog or digita
also l.
See compass display
graphic display unit
heads up display
display unit:
See graphic display unit

disposition fee:
A fee you pay at the end of the lease, to the lessor, that covers the lessor's
cost of getting the vehicle ready for sale after you have returned the
vehicle. It is often applied against any deposit you made at lease inception.
dissipate:
Scattered in various directions
dissolve:
Transition from one scene to another in which the whole image of the first
gradually disappears as it is replaced by the second
distance:
See
braking distance
reaction distance
stopping distance
trail distance
distance piece:
A collar or spacer which is placed between two parts to keep them the
correct distance apart.
distance to the sun:
See mean distance to the sun
distilling apparatus:
Fluid-reclaiming device used to reclaim used refrigerants. Reclaiming is
usually done by vaporizing and then recondensing refrigerant.
distillation:
Heating a liquid and then catching and condensing the vapors given off by
the heating process.
distilled water:
Pure water that through distillation has had all other chemicals (salts,
suspended solids, and organisms) removed. It is recommended for topping

up batteries and radiators.
distortion:
A warpage, bendng, twisting, or change in form from the original shape.
distribution:
See
asymmetic power distribution
asymmetrical power distribution
constant power distribution
equal power distribution
load-controlled power distribution
load distribution calculation
load distribution
power distribution
static high-voltage distribution
distribution calculation:
See load distribution calculation
distribution channel:
The path goods take as their title transfers from producer to consumer. The
title transfer for consumer goods is usually accompanied by transfer of the
physical goods, as well.
distribution controls:
Systems which help evenly and efficiently transfer the heating or cooling
medium to the area where it is needed.
distribution tube:
See distribution tubes.
distribution tubes:
Tubes used in the engine cooling area to guide and direct the flow of
coolant to vital areas.

distributor:
[1] A unit in
the ignition
system
designed to
make and
break the
ignition
primary circuit
and to
distribute the
resultant high
voltage to the
proper cylinder
at the correct
time. The high
voltage comes
from the coil to
the center
terminal of the
distributor cap
and passes
down the rotor.
As the rotor
turns, contact is
made with each
successive
terminal on the
circumference
of the
distributor cap.
From there, the
voltage goes
into the spark
plug wires and
to the spark
plug. Generally
when your
vehicle has its
timing
adjusted, it is
the distributor
that is adjusted.

Also called
"ignition
distributor."
[2] A
distributor
performs many
of the same
functions as
wholesalers
such as selling,
physical
distribution,
credit, etc.; but
is between the
dealer and the
wholesaler.
Some
industries use
the term
distributor
instead of
wholesaler.
Also see
breakerless distributor
fuel distributor
high-tension distributor
HT distributor
ignition distributor
shaft distributor
short-type distributor
distributor baseplate:
The fixed plate in the body of the distributor on which the contact breaker
or triggering device is mounted, and through the centre of which the
distributor shaft passes
distributor body:
The bowl-like part containing the distributor shaft with the rotor arm at its
top end, and, in the conventional version, the centrifugal advance
mechanism and the contact breaker
distributor cam:

The cam at the top of the distributor shaft with as many lobes as there are
cylinders, acting on the heel of the contact breaker arm
distributor cap:
An insulated cover containing a central terminal or tower with a series
(one per cylinder) of terminals or towers that are evenly spaced in a
circular pattern around the central terminal or tower, the secondary voltage
travels to the central terminal or tower where it is then channelled to one
of the outer terminals or towers by the rotor. The cap also keeps dirt and
moisture out of the distributor.
distributor clamp:
See distributor hold-down clamp
distributor hold-down clamp:
A metal bracket at the base of the distributor that has a nut or bolt which
can be loosened to allow the distributor to be moved on its shaft to readjust
ignition timing or to open the points for gapping.
distributor injection pump:
A fuel injection pump using pistons which pressurizes fuel for injection in
the proper cylinder based on the relative port position of the rotating shaft
in the hydraulic head
distributorless ignition system:
(DIS or DLS) An electronic ignition system that does not have a
conventional rotating distributor. Instead, it uses multi-spark ignition coils
or one ignition coil for each spark plug.
distributor pipe:
A pipe or tube through which the fuel travels from the fuel distributor to
the injection nozzle
distributor rotor:
A rotating part of the distributor which transfers high voltage to each spark
plug. In a distributors with points, it is oblong-shaped; but in a distributors
without points, it is usually a disc. Also called a "rotor" or "rotor arm."

distributor shaft:
The metal shaft inside the distributor that has
a cam wheel which revolves with the shaft
and forces the points to open. A spring causes
the points to close. The distributor rotor is
mounted on the top of this shaft.
distributor tower:
The terminals at the top of the distributor cap into which the spark plug
wires fit. Also called "terminal tower"
distributor weight:
One of two flat pieces of metal found inside the distributor's centrifugal
advance mechanism on the baseplate. They swing out as speed increases
and consequently advances the timing of the spark.
distributor wrench:
A special tool used to tighten or loosen the distributor hold down clamp
when installing or removing a distributor
district heating and cooling:
Use of a central utility system designed to provide heating and cooling to
large residential and industrial areas.
dive:
The action of the front of the vehicle to point downward (or dip) during
braking. The opposite is squat.

Also see
anti-dive system
anti-lift
anti-squat system
anti-dive
brake dive
nose dive
diversification:
In today's market, especially in smaller centers, a dealership cannot make a
profit on just one brand of vehicle -- especially foreign imports. Thus the
dealership will diversify by having several brands (e.g., Mercedes-Benz,
BMW, and Mazda). A car manufacturer diversifies by making several
different kinds of vehicles (trucks, vans, luxury cars, family-size cars,
commuter cars, compacts, convertibles, sports cars, etc.) in an attempt to
reach every segment of the population. Some dealers or manufacturers
may diversify by offering lawnmowers, boat motors, and motorcycles as
well as automobiles (e.g., Honda) or even musical instruments (e.g.,
Yamaha).
diversion:
An alternative route which traffic has to follow due to closure of a stretch
of road for repairs, etc. A detour.
divert:
To cause (air, a liquid, traffic, etc.) to follow a different course. For
example, air is diverted to the air cleaner; traffic has been diverted around
the accident site.
diverter valve:
[1] A valve which adds an amount of air to the rich air-fuel mixture
entering the intake manifold during deceleration.
[2] Used in air injection system to channel airflow to either the exhaust
manifold or oxidation catalyst under different operating conditions.
See
air gulp valve
air bypass valve
divided propeller shaft:

A propeller shaft, usually in long chassis rear-wheel drive vehicles, which
is divided into two sections with a bearing and CV joint mounted on a
chassis crossmember at the central point. Also called "divided propshaft"
divided propshaft:
A propeller shaft, usually in long chassis rear-wheel drive vehicles, which
is divided into two sections with a bearing and CV joint mounted on a
chassis crossmember at the central point. Also called "divided propeller
shaft"
divider:
A measuring tool with two straight pointed arms used to mark off and
transfer measurements, e.g., on sheet metal or other metal components.
Also see
spring divider
divorced choke:
Vacuum diaphragm is mounted on the carburetor, but the bimetal spring is
mounted either on a pad on the intake manifold or in a heat well in the
exhaust man. Choke lever is operated by a mechanical linkage rod from
the bimetal spring. Also called a remote choke
DIY:
An acronym for "Do-it-yourself."
Also see
do-it-yourself market
DIY mechanic:
A person, whether qualified or not, who does his own repairs on his own
vehicle.
D-Jetronic:
Term used by Bosch to describe a fuel injection system controlled by
manifold pressure. The D is short for "druck," the German word for
"pressure." Manifold pressure is measured to indicate engine load (how
much air the engine is using.) This pressure is an input signal to the control
unit (ECU) for calculation of the correct amount of fuel delivery

DKW:
In 1904 Jörgen Skafte Rasmussen set up on his own as a manufacturer of
boiler fittings. In 1906 he purchased a textile mill in Zschopau, Saxony.
Production started there in 1907. During the First World War Rasmussen
worked on a steam-driven vehicle (Dampfkraftwagen), from which the
three letters DKW were derived. In 1922 the company Zschopauer
Motorenwerke started manufacturing its own motorcycles. The sporting
successes of the lightweight motorcycles with 2.25 hp two-stroke engine
were remarkable. Victories in the Berlin Avus race in 1922 and the triple
victory by the DKW team in the ADAC Reichsfahrt the same year made
people sit up and take notice. The first DKW motorcycle was consequently
called the Reichsfahrt. Over the next six years Zschopauer
Motorenwerke/DKW established itself as the world's biggest motorcycle
manufacturer. Rasmussen finally had access to a powerful engine for the
DKW car (600 cc, 15 hp) in the form of the two-cylinder motorcycle unit
(1927). The vehicle, which had a load-bearing body covered in imitation
leather, had rear-wheel drive. It was produced in the Spandau district of
Berlin from 1928.
DL:
An abbreviation for deluxe which is usually applied to a series of vehicles
which is one step up from "custom"
DLI:
Acronym for "distributorless ignition"
dlr:
Abbreviation for "dealer"
dnf:
A racing term for "Did not finish"
Doble:
DOC:

Acronym for "double overhead camshafts"
dock:
See dry dock
document:
See
registration document
vehicle registration document
Dodge:
A vehicle brand of which the 1967-70 Coronet R/T
models are milestone
Click for books on
Dodge
dog:
[1] Man's best friend.
[2] A vehicle in very bad shape, which may not be man's best friend.
[3] A lug or protrusion on an object.
dog clutch:
[1] A simple coupling with two halves called "dogs," with square
projections in one that engage in square slots in the other to transmit drive,
but can also be disengaged to break the drive.
[2] Mating collars, flanges, or lugs which can be moved as desired to
engage or disengage similar collars, flanges, or lugs in order to transmit
rotary motion
dog guard:
A grid made of tubular bars or wire mesh to keep a dog in the back part of
a vehicle
dogleg pillar:

The C-post or C-pillar.
dogleg section:
An irregular shaped part of the leading edge of the rear quarter panel of a
four-door sedan along the wheel cutout and up to the waistline
DOHC:
Acronym for
"double-
overhead
camshaft."
Refers to an
engine with
two overhead
camshafts.
Also see
double overhead cam
engine type
do it to it:
Trucker slang for Speed up as in "Now that we're on the boulevard lets do
it to it."

do-it-yourself market:
(DIY) The vehicle maintenance and repairs conducted by the vehicle
owner or friend/relative who purchase auto parts from a retail outlet.
do-it-yourself mechanic:
A person, whether qualified or not, who does his own repairs on his own
vehicle.
dolly:
[1] A metalworking tool, available in a variety of shapes and sizes,
comprising a curved polished block of cast iron or forged steel, used to
assist in forming three-dimensional shapes and in straightening dented
panels, usually by holding the dolly behind the metal to be shaped and
hammering the metal. See heel dolly.
[2] A small two-wheeled trolley for moving heavy objects.
[3] A trolley that supports the front wheels or back wheels of a disabled
vehicle for towing it.
Also see
grid dolly
heel dolly
kidney dolly
mushroom-shaped dolly
shrinking dolly
toe dolly
wheel dolly
domains:
Groups of atoms that have same magnetic polarity
dome:
See
pop-up
piston dome
dome-hat:
Sealed metal container for the motor compressor of a refrigerating unit.
dome lamp:

A dome-shaped interior light. Also called a "dome light."
dome light:
A dome-shaped interior light. Also called a "dome light."
domestic:
A vehicle produced in Canada, United States, or Mexico. The opposite is
"foreign."
donor car:
A car from which parts are used to repair another one of the same type or
to build a special or kit car
do not enter:
A sign indicating that travel is not permitted
down a certain road or in that direction
door:
The hinged side panels of a vehicle which permit the occupants to enter or
leave the passenger compartment. In most cases the doors open so that the
hinge is toward the front of the vehicle. When the hinge is toward the back
of the vehicle, they are called "suicide doors."
Also see
filler door
five-door
four-door
gull-wing door
pull-out door handle
rear-hinged door
sagging door
suicide door
three-door
two-door

door alignment:
Accuracy or fitting of the door in the door aperture
door aperture:
opening into which the door fits
door beam:
A longitudinal reinforcing bar which fits between the inner and outer shell
of the door. It is designed to withstand side impacts. Also called a side
impact bar.
door bottom:
The lower door area, both of the door skin and of the door frame, also the
narrow horizontal lower panel of the door frame that has the drain holes
door capping:
the molding between the door trim panel and the window glass
door check arm:
A metal part near the hinge which has several notches which allows the
door to remain partially or fully open
door check strap:
A leather strap near the hinge which prevents the door from opening too
far.
door face:
The edges of a door which are not visible from the outside or inside when
the door is shut. Also called "door shut."
door frame:
[1] the bare skeleton of the door to which the door skin and door trim are
added.

[2] the door aperture.
door gap:
The distance around the door between the edge of the door and the
aperture
door glass:
The glass pane filling the top half of a door, which can usually be lowered
or raised
door handle:
The interior or exterior handle for opening a door.
Also see
pull-out door handle
door hinge:
The pivoting part which is attached to the door fram and the door pillar. It
allows the door to swing open or shut.
door hold-open spring:
A spring attached to the door hinge to provide a spring load to keep the
door in an open position
door latch:
That part of the door lock which contacts the striker plate as the door is
closed, and springs back when the door is fully shut to hold it in the closed
position
door lock:
A mechanism for allowing a door to be opened either by the operation of a
key on the outside of the door or by releasing a mechanical switch on the
inside of the door.
door lock de-icer:
A fluid which is inserted into the key-hole to melt the ice which has bound
the tumblers in a door lock.

door mirror:
An exterior, door mounted, rear-view mirror. On trucks and older vehicles
the mirror is manually adjusted; but on many cars they are adjuste either
by a cable inside the cab or by an electric motor with the switch inside the
cab. The control device is located on the door, on the dash, or on the
console between the driver and passenger.
door pad:
The door inner trim panel
door panel:
A panel covered in vinyl or other material and mounted to the inside of the
door
door pillar:
One of the vertical members of the body shell ahead of and behind the
doors, which also support the roof structure and reinforce the body as a
whole
door pillar switch:
A small switch, typically in the lower portion of the A-pillar, whose main
function is to turn on the courtesy lights when the door is opened and to
indicate that the door is open especially if the key is left in the door.
door pocket:
A container or pouch located on the lower inside portion of the door. It can
be used to store maps and other small items
door post:
One of the vertical members of the body shell ahead of and behind the
doors, which also support the roof structure and reinforce the body as a
whole
door protector:

A strip of rubber, plastic, or chrome which fits over the edge of the door to
protect it from damage when opened carelessly
door pull:
A handle on the inside of a vehicle door which allows the driver/passenger
to pull his door shut
door rates:
The hourly rates charged by dealers on standardized units of service work.
Hourly rates may or may not correspond to an actual hour of work.
door seal:
A weatherstrip surrounding the door to form a seal when the door is closed
door shut:
The edges of a door which are not visible from the outside or inside when
the door is shut. Also called "door face."
door sill:
The bottom part of the door frame (i.e., the pat under the door when it is
closed).
door skin:
The large sheet metal panel of the door visible from the outside. Available
to body shops as a replacement panel for most cars
door speaker:
Radio/stereo speakers mounted in the door panel
door stay:
A device incorporated in door hinges that keeps the door in an open
position and prevents it from closing under its own weight
door step:

Top part of the outer sill, visible when the door is opened
door surround:
The faces of the door step, door pillars, and roof section which makes up
the door aperture
door trim:
A panel covered in vinyl or other material and mounted to the inside of the
door
door well:
A cavity enclosed by the door frame, door skin, and trim panel containing
the window winding mechanism and into which the window glass is
lowered
doosy:
See Duesy.
dope:
Highly combustible alcohol/methanol-based fuel mixture
Dorris:
dos-a-dos:
Back to back seating on older cars where the driver and front passenger
faced forward; but the two rear passengers faced rearward.
DOT:
Acronym for "Department of Transportation" -- an American federal
agency or "Department of Transport" -- a British agency
DOT 3:
This brake fluid has a glycol base. It is clear or light amber in color. Its dry
boiling point is 401° minimum and wet boiling point of 284° minimum. It

will absorb 1 to 2 percent of water per year depending on climate and
operating conditions. It is used in most domestic cars and light trucks in
normal driving. It does not require cleaning the system and it can be mixed
with DOT 4 and DOT 5.1 without damage to the system. The problem
with it is that it absorbs moisture out of the air and thereby reduces its
boiling point. It can also damage the paint on a vehicle.
DOT 4:
This brake fluid has a borate ester base. It is clear or light amber in color.
Its dry boiling point is 446° minimum and wet boiling point of 311°
minimum. It is used in many European cars; also for vehicles in high-
altitude, towing, or high-speed braking situations, or ABS systems. It does
not require cleaning the system and it can be mixed with DOT 3 without
damage to the system. The problem with it is that it absorbs moisture out
of the air and thereby reduces its boiling point. It can also damage the
paint on a vehicle.
DOT 5:
This brake fluid generally has a silicone base. It is violet in color. Its dry
boiling point is 500° minimum and has no wet boiling point in federal
DOT 5 specifications. It is used in heavy brake applications, and good for
weekend, antique, or collector cars that sit for long periods and are never
driven far. It does not mix with DOT 3, DOT 4, or DOT 5.1. It will not
absorb water and will not damage the paint on a vehicle. It is also
compatible with most rubber formulations. The problem with it is that it
may easily get air bubbles into the system which are nearly impossible to
remove, giving poor pedal feel. It is unsuitable for racing due to
compressibility under high temperatures. If as little as one drop of water
enters the fluid, severe localized corrosion, freezing, or gassing may occur.
This can happen because water is heavier and not mixable with silicone
fluids. It is unsuitable for ABS.
DOT 5.1:
This brake fluid has a borate ester base. It is clear or light amber in color.
Its dry boiling point is 500° minimum and wet boiling point of 356°
minimum. It is used in severe-duty vehicles such as fleets and delivery
trucks; towing vehicles, and race cars. It can be mixed with DOT 3 or
DOT 4 without damage to the system. It maintains higher boiling point
than DOT 3 or DOT 4 fluids due to its higher borate ester content. It is
excellent for severe duty applications. The problem with it is that it costs

more than other fluids and there is limited availability. It also absorbs
moisture out of the air and thereby reduces its boiling point. It can also
damage the paint on a vehicle.
DOT number:
The symbol DOT on a tire means it meets or exceeds Department of
Transportation safety standards. Following DOT are a maximum of eleven
numbers. E.g., "DOT FT TW A2NX 092." ("DOT" = meets or exceeds
federal standards; "FT" = identifies manufacturing plant; "TW" = the code
for tire size; "A2N" or "A2NX-3" or optional 4 digits = manufacturer's
code to identify the characteristics of the tire; "092" = Week of mfg., in
this case, 9th week of 1972. Prior to May 22, 1971 the manufacturer's
plant was identified by only three numbers (Example DOT 129).
Retreaded tires must also have a new serial number and can be determined
by the letter "R" following DOT letters.
double-acting:
(of a shock absorber or pump) having a piston with fluid on both sides so
that in a pump one piston end performs the suction stroke while the other
discharges the liquid, and in a shock absorber both upward and downward
movements are damped
double anchor drum brake:
See leading/trailing drum brake
double-barrel carburetor:
Two throttle openings or barrels from the carburetor to the intake
manifold. Also called "twin-choke carburetor."
Also see
four-barrel carburetor
single-barrel carburetor
double bottom:
Compartments at the bottom of a ship between inner bottom and the shell
plating, used for fresh water, ballast water, fuel oil, etc
double cap nut:

(Budd mounting) A type of securing device which consists of an inner cap
nut (sleeve nut) and an outer cap nut. It is the most common method for
mounting disc wheels in dual.
double century:
A bicycle ride of 200 miles.
double clutch:
See double clutching.
double clutching:
Vehicles with manual transmission and no synchromesh have difficulty
shifting from one gear to another. With synchromesh, shifting is
accomplished by depressing the clutch pedal and moving the gearshift
selector from one gear to the next. Without synchromesh, shifting is not
smooth unless you double clutch. Here you depress the clutch pedal shift
to neutral lift up on the clutch pedal blip the throttle (accelerator), then
depress the clutch pedal again and shift to the next gear. While this action
seems complicated, you can get used to doing it to avoid the grinding
noise heard in non-synchromesh transmissions.
double coat:
Two single coats of primer or paint applied with little or no flash time
between them.
Also see
single coat
double-cradle frame:
A bike frame with two steel tubes circling the engine from the front and
"cradling" it
double-decker:
A passenger bus with a set of seats on a floor above a lower set.
double-decker bus:

A passenger bus with a set of seats on a floor above a lower set.
double-declutch:
A British term for double clutch
double duty case:
Commercial refrigerator in which a part of space is for refrigerated storage
and part is equipped with glass windows for display purposes.
double-ended spanner:
British term for double-ended wrench
double-ended wrench:
A tool which has a hexagon ring at each end.
double filament bulb:
A light bulb with two filaments. For example a headlamp bulb with one for
the high beam and another for the low beam; or a bulb with one filament
for the stop light and another for the taillight.
double flare:
The end of the tubing, especially brake tubing, has a flare made so that the
flare area uses two wall thicknesses. This makes a much stronger and safer
joint in bicycle tubing.
double harley:
Trucker slang for Putting the CB on channel 11 as in "Anyone looking to
buy a good C.B. take it to the double harley."
double helical gear:
A gear with two rows of inclined teeth, each forming an open "V" or
chevron. Also called "herringbone gear"
double hexagon socket:

A socket with 12 points rather than the normal 6 points.
double leading brake shoe:
A system of braking where two hydraulic plungers and separate pivots
create better braking when the vehicle is going forward; however it is not
very effective when the vehicle goes in reverse.
Also see
single leading brake shoe
double nickel:
Trucker slang for Traveling at 55 MPH as in "I sure got tired of running
the double nickle."
double overhead
cam:
(DOHC) An
engine with
two camshafts
located above
the cylinders.
One drives the
intake valves
and the other
operates the
exhaust valve.
In a single
overhead cam
engine
(SOHC), one
cam has
enough lobes
to drive both
the intake and
exhaust valves.
The DOHC
engine is
considered to
be a very
sophisticated
and more
efficient

engine; but is
sometimes
more difficult
to adjust the
valves. Also
called "twin
overhead
camshaft." See
engine type.
double overhead camshaft:
See double overhead cam
double-pivot steering:
Steering in which the steered wheels are pivoted on kingpins, which is the
usual arrangement on motor vehicles.
Also see
ackermann steering
single-pivot steering
double reduction axle:
A drive axle construction in which two sets of reduction gears are used for
extreme reduction of gear ratio
double reduction gearing:
Gearing in which the ratio is reduced in two stages, used especially in
heavy trucks
double roller chain:
See duplex chain
double thickness flare:
Copper, aluminum, or steel tubing end which has been formed into two-
wall thickness, 37 to 45 deg. bell mouth or flare.
double-throw switch single-pole:

(SPDT) Electric switch with one blade and two contact points.
double-tube shock absorber:
An older design of hydraulic shock absorber using two concentric tubes,
one serving as the working cylinder, the other as the reservoir.
Also see
single-tube shock absorber
double wishbone:
A form of independent suspension used on the front of a vehicle where
both the upper and lower wishbones are of equal length.
double wishbone suspension:
See double wishbone
doughnut:
See rubber doughnut coupling
doughnut coupling:
A flexible joint made of rubber and shaped like a ring doughnut. It is used,
for example, between the front of the propeller shaft and the gearbox. Also
called "doughnut joint."
Also see
rubber doughnut coupling
doughnut joint:
A flexible coupling made of rubber and shaped like a ring doughnut. It is
used, for example, between the front of the propeller shaft and the
gearbox. Also called "doughnut coupling."
dowel:
A pin projecting from one of two mating surfaces which fits into a
correspondng hole in the other thus lining up the two pieces accurately
during assembly.
Also see
locating dowel

dowel pin:
[1] A pin (steel or wood), passed through or partly through, two parts to
provide proper alignment and to prevent movement between them.
Sometimes called "locating pin."
[2] Accurately dimensioned pin pressed into one assembly part and slipped
into another assembly part to insure accurate alignment.
downdraft carburetor:
A carburetor in which the air passes downward through the carburetor into
the intake manifold. Contrasts with sidedraft carburetor.
downdraught carburetor:
British spelling for downdraft carburetor
downflow radiator:
A traditional type of vertical radiator, with header tank and bottom tank
and a system of small tubes and cooling fins in-between, the hot water
entering at the top and exiting at the bottom. This type of radiator has been
replaced by a crossflow radiator.
downforce:
A vertical force directed downward, produced by airflow around an object
such as the body of a vehicle.
downgearing:
See downshifting.
downhand welding:
See flat position welding
downpipe:
The pipe that joins the entire exhaust system to the exhaust manifold.
downshift:
The act of selecting a lower gear. In Britain it is called "downward
change."

Also see
forced downshift
downshifting:
Manually shifting to a lower gear in order to use the engine compression
to assist in reducing the vehicle's speed. Also called "downgearing."
downstroke:
[1] The downward movement of the piston, either the intake stroke or the
power stroke in a four-cycle engine.
[2] Trucker slang for A hill going down as in "You can put her in georgia
overdrive on the downstroke."
downtime:
Downtime occurs when a vehicle is being repaired (esp. a commercial
vehicle), it cannot fulfil its function. There is a loss in both potential
proceeds from its use as well as the salary of its operators.
down tube:
The bicycle frame tube running from the headset to the bottom bracket one
part of the main triangle on a bicycleframe.
down tube shifter:
One of the gear shift levers that are mounted to
the down tube of a bicycle frame.
downward change:
A British expression of shifting the transmission to a lower gear. The
North American term is downshift.

dozer:
A portable frame straightening machine
DP:
Acronym for "dash-pot"
D-pillar:
The fourth vertical post in a van or station wagon. Also called D-post
D-post:
The fourth vertical pillar in a van or station wagon. Also called D-pillar
dr:
Abbreviation for "door," as in 2-dr. Sedan."
draft:
[1] An unpleasant current of air intruding into the interior of a car.
[2] The depth of the ship below the waterline measured vertically to the
lowest part of the hull.
[3] To follow behind a faster vehicle to take advantage of its air currents.
Also see
horizontal draft carburetor
draft gauge:
Instrument used to measure air movement by measuring air pressure
differences.
draft indicator:
Instrument used to indicate or measure chimney draft or combustion gas
movement. Draft is measured in units of .1 in. of water column.
drafting:
The action of following closely behind a faster vehicle so as to take
advantage of the aerodynamic effect which causes both the vehicles
behind and the one in front to move faster. See slip stream.

draft marks:
The numbers which are placed on each side of a ship at the bow and stern
from the lower edge of the number to the bottom of the keel
draft regulator:
Device which maintains a desired draft in a combustion-heated appliance
by automatically controlling the chimney draft to the desired value.
drag:
[1] To accelerate a vehicle from a standing start, over a course one-fourth
mile in length. Also called "drag racing."
[2] Used by some drivers when referring to challenging another driver to
an acceleration race.
[3] Air resistance. See aerodynamic drag.
[4] The condition of a clutch when it fails to fully disengage. The plates
still rub against each other and causes intermittent contact between the
engine output and the transmission gears. Called "clutch drag."
[5] The condition of brakes when the pads or shoes still rub the disc or
drum. Called "brake drag."
Also see
aerodynamic drag
clutch drag
coefficient of drag
idling drag
wind drag
drag coefficient:
(Cd) A number used in calculating the aerodynamic drag acting on a
vehicle. The drag coefficient is a function of factors like the shape of the
vehicle, airflow through the vehicle for ventilation and cooling. The
number is determined in a wind-tunnel or by coasting tests performed on
the vehicle. The lower the drag coefficient the less drag on the vehicle and
the more aerodynamic is the vehicle. A sleek vehicle has a drag
coefficient, or "Cd," of about 0.30; a square, flat plate's is 1.98. Also
signified by Cx.
drag link:
A steel rod connecting the pitman arm to one of the steering knuckles. On
some installations the drag link connects the pitman arm to a center idler

arm.
dragon fly:
Trucker slang for A truck with no power as in "Drag 'er up one side of the
hill, let 'er fly down the other"
dragon wagon:
Trucker slang for Tow truck as in "Looks like that bulldog is gonna need a
dragon wagon."
drag race:
A competitive match between two vehicles in which they race over a 1/4
mile course.
dragster:
A specially constructed car for drag racing, typically with a huge
supercharged V-8 engine mounted well back in the chassis and extremely
wide rear tires
dragstrip:
A quarter-mile stretch of track for drag racing
drag wheel:
Special steering wheel used on some dragsters. Often consists of a
crossbar spoke and a portion of rim on each end.
drain:
[1] To empty a container usually from the bottom.
[2] A tube or channel which allows water to run to another place.
Also see
magnetic drain plug
oil drain plug
oil drain valve
radiator drain cock
radiator drain plug
draincock:

A petcock or drain tap.
Also see
radiator drain cock
drain hole:
A hole drilled in the bottom of a box section or a door, to allow water that
has accumulated to escape so as to prevent or delay rusting
draining tray:
A container used to catch oil when draining the sump, transmission, etc.
drain plug:
Usually a threaded plug at the lowest point of the sump, gearbox, cooling
system, etc., which is removed in order to drain the oil or coolant, and
typically has a recessed hexagon head.
Also see
magnetic drain plug
oil drain plug
oil pan drain plug
radiator drain plug
sump drain plug
drain plug key:
A tool for removing and tightening drain plugs, e.g., on transmissions and
engine sumps, either as a multi-purpose tool with a number of different
drives in the form of hexagonal or square projections at either end for
different drain plugs, or as a special tool for one specific size of drain plug.
Also called a "drain plug wrench."
drain plug spanner:
A British term for a drain plug wrench
drain tap:
A device which controls the flow of fluid (oil or coolant) out of the bottom
of the cylinder block or the bottom of the radiator.
drain plug wrench:

A tool for removing and tightening drain plugs, e.g., on transmissions and
engine sumps, either as a multi-purpose tool with a number of different
drives in the form of hexagonal or square projections at either end for
different drain plugs, or as a special tool for one specific size of drain plug.
Also called a "drain plug key."
drain valve:
See oil drain valve
draught:
British spelling for "draft"
draught excluder:
A British term for "weatherstrip"
draw:
[1] To form wires by pulling the wire stock through a series of hardened
dies.
[2] The process of removing the hardness from a piece of metal.
[3] The amount of electrical load or electrical requirement.
drawback:
See duty drawback
drawbar:
Two converging bars forming a V-frame or an A-frame at the front of a
trailer or motorhome, which carry the coupling for attaching to the towing
vehicle
draw filing:
A file is drawn across work at right angles. See draw-filing.
draw-filing:
Filing by passing the file, at right angles, up and down the length of the
work.

draw-through:
A tubocharger system in which the turbocharger sucks the air/fuel mixture
through the carburetor or fuel in, i.e., the air and fuel mixing occurs
upstream from the turbocharger
dream car:
A one-of-a-kind futuristic, experimental automobile usually appearing at
auto shows to stimulate interest in the manufacturer's products. Much
design benefit spurs from dream cars and many reach the production stage.
dress:
[1] to give (a rough surface, flanges, etc.) the right shape by grinding or a
similar process.
[2] To prepare ore for smelting by removing impurities.
dresser:
A motorcycle set up for long-distance touring
dressing:
See tire dressing
dribble:
Insufficiently atomized fuel issuing from the fuel injection nozzle at or
immediately following the end of the main injection phase
drier:
[1] A dehumidifier.
[2] A drying oven.
[3] Substance or device used to remove moisture from a refrigeration
system.
[4] A device located in the liquid line, contains desiccant to absorb
moisture from the system. Usually combined with the receiver
Also see
A-drier
accumulator-drier
accumulator drier

gelling drier
infrared radiant drier
receiver-drier
top coat drier
tunnel drier
drift:
[1] A short bar or punch used with a hammer to drive a component in or
out of place for removal or installation.
[2] To deviate from the normal direction.
See
four-wheel Drift
tire deviation angle
drift punch:
A tapered tool which is hit with a hammer and used to remove or install
pins, shafts, rivets, etc. or to align holes when inserting screws and bolts.
drill:
[1] A tool used to bore holes.
[2] The action of using a drill to make a hole.
Also see
hammer drill
hand drill
letter drills
number drills
press, drill
spot-weld drill
twist drill
drill bit:
A piece of rod with spiral recesses cut in it and a hardened steel tip, made
in different sizes for drilling different sized holes, and inserted in the
chuck of a drill
drilled:
An expression used to describe a hole which has been cut into a crankshaft
to allow oil to be fed to the main bearings on the connecting rod throws.

drill press:
A nonportable machine used for drilling.
d ring:
See D-ring.
d-ring:
A D-shaped ring found on many models of bicycle shift levers, used to
adjust the level of tension on the inner parts of the lever.
drip molding:
The curved metal molding around the edge of the roof that directs water
away from the side windows. Also called "drip rail"
drip moulding:
British term for "drip rail"
drip pan:
Pan-shaped panel or trough used to collect condensate from evaporator.
drip rail:
A gutter running along either side of the roof to take water to the front or
rear of the car, and prevent it from dripping into the car when the door is
opened. The British term is "drip moulding"
drivable:

The condition of a vehicle which may have many mechanical and
appearance problems, but it has an engine which runs and wheels that turn,
etc. so that it can be operated and driven.
drivability:
The general qualitative evaluation of a powertrain's operating qualities,
including idle smoothness, cold and hot starting, throttle response, power
delivery, and tolerance for altitude changes.
drive:
[1] to travel in a car as in the expression, "We drove to Chicago."
[2] to operate a vehicle as in the expression, "Martha drove to New York
by herself."
[3] to cause a wheel, shaft, etc. to turn or rotate.
[4] to propel a vehicle.
[5] a journey in a car as in "The drive to Chicago was uneventful."
[6] to go for a drive as in, "We went for a drive last Sunday."
[7] A stretch of private road leading to a house (i.e., driveway).
[8] A means of transmitting power or motion as in "The drive is controlled
by a servo switch."
[9] A tool which has a square end (1/4 inch, 3/8 inch, or 1/2 inch) which
fits into a recess in a corresponding socket for the installation or removal
of nuts and bolts.
[10] a die position.
[11] One of the forward gears marked on the gear selector of an automatic
transmission.
Also see
all-wheel drive
all wheel drive
automatic four-wheel drive
axle drive
belt drive
bendix drive
bendix type starter drive
bevel gear drive
camshaft drive
center drive
chain drive
clutch starter drive
direct drive powertrain
direct drive
dual drive

eccentric drive
Ferguson four-wheel drive
final drive gear
final drive ratio
final drive
fixed drive
flexible drive handle
flexible drive
four-wheel drive
friction drive
front-wheel drive
front wheel drive
full-time four-wheel drive
hotchkiss drive
hydrostatic drive
inertia drive
intermediate drive plate
left-hand drive
meshing drive
metallic drive screw
overrunning clutch starter drive
part-time four-wheel drive
permanent four-wheel drive
real-time four-wheel drive
rear-wheel drive
rear-wheel drive transaxle
right-hand drive
shaft drive
starter drive
strap drive
tandem drive
test-drive
test drive
torque tube drive
torsen four-wheel drive
tri-drive
two-wheel drive
v-belt drive
drive belt:
A flat belt which connects two or more pulleys so as to transmit motion
from one pulley to the other.
Also see
camshaft drive belt
drive cable:

See speedometer drive cable
drive chain:
An endless chain which encircles two or more sprockets so as to transmit
motion from one sprocket to the other
drive end:
The end of an alternator, generator, etc., where the drive pulley or gear is
located.
drive end bracket:
The cover which houses the drive end of an alternator or generator
drive fit:
A condition of fit (contact) between two parts that requires pressure to
force the parts together. Usually the shaft is slightly larger than the hole so
that they must be pounded or forced or driven together. Also called "force
fit," "press fit," or "interference fit."
drive gear:
The gear which transmits the power to a driven gear.
Also see
final drive gear
drive handle:
A tool, typically in the form of a bar, for turning sockets to loosen and
tighten nuts and bolts, with a male square drive to be inserted into the
female square drive of sockets for the turning operation. They include
ratchets, jointed handles, speed brace, T-handles, torque wrenches,
speeeder handle, and breaker bar.
Also see
flexible drive handle
drive layout:
The arrangement of the order of the engine, transmission, and driven axles,
e.g., Front-wheel drive, rear-wheel drive, mid-engine drive, four-wheel
drive, two-wheel drive

drive line:
See driveline
driveline:
All the individual components beyond the engine up to the wheels (e.g.,
clutch, drive shaft, differential, driven axles); but not the engine or
transmission. Also called "drivetrain" or "powertrain"
drive module:
interchangeable unit providing motive power, either in the form of an
electric motor and ancillaries, or an internal combustion engine with all
necessary components, for alternative use in the same vehicle according to
needs and conditions
drive motor:
electric motor providing motive power in an electric vehicle
driven:
Something made to rotate by the engine or some other source of motive
power.
Also see
two-wheel driven
driven axle:
The axle to which power is transmitted to drive the vehicle
driven gear:
An engine needs to transmit power to the wheels by the use of sprockets
and chain (as in a motorcycle) or by a drive gear which meshes with a
driven gear to propel the vehicle.
driven plate:
The central clutch plate carrying clutch linings and held under pressure
between the flywheel and the pressure plate when the clutch pedal is
released, and transmitting power to the gearbox input shaft via splines

driven pulley:
A pulley which is surrounded by a belt to receive power from the drive
pulley
driven sprocket:
On a vehicle which uses a chain (like a bicycle and some motorcycles),
there are two important sprockets: the drive sprocket is connected to the
power source (the engine or your pedals) and the driven sprocket is usually
connected to your rear wheel.
driven wheel:
The wheel (or wheels) to which power is transmitted to drive the vehicle
drive pinion:
The shaft that takes power from the clutch
into the gearbox.
Also see
clutch shaft
hypoid gear
drive plate:
A light plate bolted to the crankshaft to which the torque converter is
attached in a vehicle with automatic transmission.
Also see
center drive plate
intermediate drive plate
torque converter drive plate
drive powertrain:
See direct drive powertrain

drive pulley:
[1] A pulley which is surrounded by a belt to transmit power to the driven
pulley
[2] The pulley attached to the nose of the engine crankshaft. It drives the
compressor clutch pulley, usually with a V-type drivebelt
driver:
[1] A collectible vehicle which is too good to treat as a beater and not quite
good enough to show. It is a presentable old car or truck that is used for
everyday purposes. It is maintained as though it were a late-model vehicle.
With care, it could be easily restored to show car condition.
[2] A person who operates the controls of a vehicle to regulate its speed
and direction.
[3] A tool used to insert something like a fastening device (e.g.,
screwdriver).
[4]
Also see
drivers
impact driver
nut driver
rim drivers
socket driver
tubular nut driver
valve guide driver
driver air bag:
original type of air bag, designed to protect the driver from being hurled
into the steering wheel and instrument panel
Driver and Vehicle Licensing Agency:
(DVLA) A section of the British Department of Transport which is
responsible for keeping records of all registered vehicles and issuing
registrations and licences for vehicles as well as licences for drivers. The
center is located in Swansea.
Driver and Vehicle Licensing Center:
The location for the British Driver and Vehicle Licensing Agency located
in Swansea.
drive ratio:

See final drive ratio
driver error:
A mistake made by the operator of a vehicle particularly when there is an
accident. An accident may be caused by a vehicle failure (e.g., a tire
blowout), unsafe road conditions (e.g., snow, ice, fallen rock or tree), the
inattention of a pedestrian, or the fault of a driver (e.g., drunkenness,
inattention, intentional damage, disobedience to rules of the road).
driver evaluation:
A test of a driver's ability to handle a vehicle. May be used to grant a
driver's licence for a particular type of vehicle (i.e., motorcycle, passenger
car, truck, bus, taxi)
drivers:
Colloquial term for "drive axle tires."
Also see
rim drivers
drive screw:
See metallic drive screw
driveshaft:
The shaft
connecting
the
transmission
output shaft
to the
differentialp
inion shaft.
It transmits
power from
the
transmission
to the
differential.
It is found
primarily on

rear-drive
vehicles.
There is
usually a
universal
joint on
either end.
Also called
"propeller
shaft."
Also see
auxilliar drive shaft
bevel drive shaft
drive shaft:
See driveshaft
driveshaft safety strap:
A metal strap or straps, surrounding the driveshaft to prevent the shaft
from falling to the ground in the event of a universal joint or shaft failure.
drive sprocket:
On a vehicle which uses a chain (like a bicycle and some motorcycles),
there are two important sprockets: the drive sprocket is connected to the
power source (the engine or your pedals) and the driven sprocket is usually
connected to your rear wheel.
Also see
drive tool:
Any accessory for use with a socket wrench, including the drive handle
drive train:
[1] This term refers to the entire moving part of the car: Engine, clutch,
transmission, driveshaft, differential, axles, and sometimes the wheels.
Also see
strain in the drive train
[2] The derailleurs, chain, freewheel, and crankset of a bicycle.

drivetrain:
[1] This term refers to the entire moving part of the car: Engine, clutch,
transmission, driveshaft, differential, axles, and sometimes the wheels.
[2] The derailleurs, chain, freewheel, and crankset of a bicycle.
drive transaxle:
See rear-wheel drive transaxle
driveway:
A short drive, often leading to a garage
driving:
[1] providing motive power, making a gear, shaft, etc. rotate.
[2] Controlling the movement and direction of a vehicle.
Also see
al fresco driving
defensive driving
metro driving
urban driving
driving axle:
The axle which is driven by the engine through the drivetrain. Used to
hold, align, and drive rear wheels and support weight of vehicle on rear
wheel drive cars, or half shafts on front wheel drive cars that provide
torque force to front wheels. Also called the "drive axle" or "driven axle"
driving conditions:
The situation created by the amount of traffic, the weather, and state of the
roads
driving gear:
The gear which is driven by the engine. Also called the "driven gear"
driving habits:
The personal behaviour of the driver when controlling the vehicle,
including the speeds he travels, how and when he shifts gears, how he uses
the brakes, when and if he uses his signal lights, how he changes lanes,
how he turns corners, etc.

driving lamp:
A British term for "driving light" or "spot light."
Also see
auxilliar driving lamp
driving licence:
A British term for "driver's licence" or "operator's licence." A document
which allows the holder to drive a certain type or types of vehicle, and is
the only document required to be carried by the driver in Britain
driving light:
An auxiliary light used at night to illuminate the side of the road and
increase the viewing distance.
Also see
auxiliary driving light
driving mirror:
A British term for either the interior rear-view mirror or the mirrors
mounted on the outside of the front doors or the front fenders
driving position:
The position in which the driver grasps the steering wheel and adjusts the
location of the seat in relation to the pedals.
driving style:
The manner in which the driver handles a vehicle. See sporty driving style
driving wheel:
The wheel(s) which is driven by the engine through the drivetrain. Also
called the "driven wheel"
drop:
[1] A sudden reduction of pressure or voltage, etc. See voltage drop.
[2] The vertical distance from the horizontal line connecting the two wheel
axles and the bottom bracket, one way of determining the location of the
bottom bracket in relation to the rest of the bicycleframe.

Also see
drops
drop arm:
A British term for the pitman arm
drop-center axle:
A beam axle in which the main central portion of the beam is lower than
the wheel centers, which was the usual layout for front axles until
independent front suspension became almost universal
drop-center rim:
See drop center rim
drop center rim:
A one-piece rim with a deep center section which is lower than the two
outer edges, this allows the bead of the tire to be pushed into the low area
on one side while the other side is pulled over and off the flange. The
British term is "well-base rim"
drop center rim taper:
A passenger rim where both bead seats are tapered 5° or a tubeless truck
rim where both bead seats are tapered 15°.
drop-centre rim:
See drop center rim
drop centre rim:
See drop center rim
drop forged:
A part that has been formed by heating the steel blank red hot and
pounding it into shape with a powerful drop hammer.
drop forging:

A piece of steel shaped between dies while hot
drophead:
[1] A British term for a convertible. The word "head" refers to the roof.
[2] Having a folding top which can be raised or lowered over the
passenger compartment.
See
drophead coupé
Jaguar Drophead
Lagonda Drophead
drophead coupe:
(DHC) This is a two-door automobile which has the appearance of a
convertible, but the roof is fixed in place. Abbreviated: dhc. In Europe, it
is called a "cabriolet."
drophead coupé:
This is a two-door automobile which has the appearance of a convertible,
but the roof is fixed in place. Abbreviated: dhc. In Europe, it is called a
"cabriolet."
dropout:
One of two slots in the frame into which the rear wheel axle fits.
Also see
fork tips
dropout hanger:
A threaded metal piece that extends below the right rear dropout of a
bicycle used as a mount for the rear derailleur.
dropped axle:
A front axle that has been altered so as to lower the frame of the vehicle,
consists of bending the axle downward at the outer ends.
dropped valve:
A situation where the rising piston hits a valve which has become
dislodged or open at the wrong time.

drops:
The lower, straight portion of a turned-down-type handlebar set.
droptop:
A colloquial term for "convertible."
Druid forks:
Side-sprung girder forks on a motorcycle. Druid was the original maker
drum:
[1] A cylindrical container.
[2] A housing for transmission gears where the bands are located.
[3] To make a "whump, whump" sound.
Also see
brake drum
brake drum lathe
drum brake
drum brake:
A type of brake using a shallow drum-shaped metal cylinder that attaches
to the inner surface of the wheel and rotates with it. When you press down
on the brake pedal, curved brake shoes with friction linings press against
the inner circumference of the drum to slow or stop the vehicle.
Also see
brake drum
drum brakes:
See drum brake.
drum compound:
See anti-drum compound
drum lathe:
See brake drum lathe

dry:
[1] For paint, to lose its wetness often to the place where the surface is not
even tacky.
[2] For bearings, to lack grease or other lubricant.
Also see
air-dry
air dry
hard-dry
surface dry
touch-dry
dry ballast:
A form of ballasting where a fine powder of barium sulphate is inserted
inside the tire. It is sometimes referred to incorrectly as "Lead" ballast
because of one brand name, "Ledballast."
dry battery:
See dry cell.
dry boiling point:
The temperature at which fresh brake fluid from a new container will boil.
See wet boiling point, and DOT 3.
dry box:
Trucker slang for Freight trailer as in "I pulled both skateboards and dry
boxes."
dry bulb:
An instrument with a sensitive element to measure ambient air
temperature.
dry bulb temperature:
Air temperature as indicated by an ordinary thermometer.
dry capacitor condenser:
Electrical device made of dry metal and dry insulation; used to store
electrons.

dry cargo ship:
Vessel which carries all dry cargo
dry cell:
A battery (like a flashlight battery) that uses no liquid electrolyte.
dry cell battery:
Electrical device used to provide dc electricity, having no liquid in the
cells.
dry charged battery:
A battery with the plates charged but lacking electrolyte
when ready to be placed in service, the electrolyte is added.
dry clutch:
A clutch with only one plate.
dry dock:
An enclosed basin used to place a ship on dry land so that all the
submerged parts and fittings can be repaired.
dryer:
See a-dryer
dry friction:
Dry friction exists when the rubbing parts have no other substance
between them and are clean of other materials (i.e., no grease or oil).
Opposite to wet friction.
dry galvanizing:
A hot-dip galvanizing method in which the metal components are first
immersed in a solution of flux and then dried, so that they become pre-
coated with a thin film of flux, which melts in the zinc bath, to which
certain metals, such as tin and aluminum, may be added to give fluidity,

and in the case of tin, brightness. The opposite is wet galvanizing
dry ice:
Refrigerating substance made of solid carbon dioxide which changes
directly from a solid to a gas (sublimates). Its subliming temperature is -
109 0F I - 79 0C1.
drying agent:
See desiccant
drying oil:
Any oil that hardens in the presence of air and sunlight
drying oven:
An enclosure where painted vehicle bodies are subjected to heat in order to
dry and/or bake on the paint
drying time:
The time required for a solvent to evaporate after an adhesive film has
been spread over the two surfaces to be bonded
dry joint:
A faulty electrical joint which does not give proper contact
dry liner:
When a cylinder sleeve is pressed into a bore and the cooling fluid does
not contact the outside of the sleeve, the engine has a dry liner.
Also see
liner
dry manifold:
An intake manifold with no integral coolant passages cast into it
dry setting:
The adjustment of the float with a graduated rule or drill bit while the
carburetor is disassembled on the bench. Usually consists of setting a

prescribed clearance between the top of the float and the air horn
dry sleeve:
A cylinder sleeve application in which the sleeve is supported in the block
metal over its entire length, the coolant does not touch the sleeve itself.
Also see
wet sleeve
dry spray:
See dry-spray.
dry-spray:
A paint fault where the paint pigment is not being held properly by the
binder, or where the binder evaporates before the paint reaches the surface.
Atomized paint that does not dissolve into the material being sprayed. It is
caused by holding the gun too far from the work, too much air pressure or
a solvent that evaporates too fast.
dry sump:
A lubrication system in which the engine's supply of oil is not contained in
the crankcase (sump) but is pumped to the engine from an external
container. This system allows the crankcase to be reduced in size and the
engine to be installed lower in the chassis, and eliminates the oil starvation
most conventional oiling systems suffer when subjected to the
accelerative, braking, and cornering forces generated by a racing car.
dry sump lubrication:
See dry sump
dry system:
Refrigeration system which has the evaporator liquid refrigerant mainly in
the atomized or droplet condition.
dry type evaporator:
Evaporator in which the refrigerant is in the liquid droplet form.

dry weight:
The weight of a vehicle without any fuel, oil, or coolant.
Also see
curb weight
gross vehicle weight
DS:
Acronym for "Diesel Severe" oil for use in under adverse conditions in
diesel engines.
dual:
[1] a combination of two nearly identical parts (e.g., a truck with dual tires
has two tires at each end of the axle).
[2] In Britain, dual is a verb meaning to twin a highway or railroad.
dual-acting:
See double-acting
dual axles:
See tandem axles.
dual bead tire:
Heavy service and large truck tires using two or more sets of bead wires in
each bead rather than one.
dual-bed catalytic converter:
A catalytic converter which combines two converters (with different
catalysts) in a single housing
dual brake:
See dual brakes.

dual brakes:
A brake system that uses a tandem or dual
master cylinder to provide separate brake
system for both front and rear of vehicle. In
the event of a loss of hydraulic fluid, one
system may still work because it is
independent of the other system. Often the
front left brake is linked with the right rear
brake. Likewise the right front brake is linked
with the left rear brake. Some cars like the
Rolls-Royce, link the two front brakes with
the right rear brake, and the two front brakes
with the left rear brake. Also called "dual-
circuit braking system."
dual braking system:
See dual brakes.
dual breaker points:
A distributor, using two sets of breaker points, to increase the cam angle so
that at high engine speeds, sufficient spark will be produced to fire the
plugs.
dual carbs:
Two carburetors on the same engine.
dual carburetors:
Two carburetors on the same engine.
dual carriageway:
A British term for a divided highway (i.e., a road that has four lanes -- two
in one direction and two in the other -- separated by a median).
dual-circuit braking system:
A brake hydraulic system composed of two separate hydraulic circuits. See
dual brakes
dual controls:

A second set of controls for use by a driving instructor when teaching
someone to drive
dual drive:
[1] Tandem axles, both powered directly by the engine.
[2] Colloquial term for twin screw.
dual exhaust system:
See twin exhausts
dual fuel engine:
An engine equipped to operate on two different fuels such as gasoline and
LP-Gas
Dual Ghia:
dual ignition system:
See twin ignition system
dual-line braking system:
A braking system in which a towing vehicle and trailer are connected by
two or more brake lines
dual mounting:
Two tires mounted together on each side of an axle of several types: cast
spoke type, disc wheel type (held on by double cap nuts or inner cap nuts
and outer cap nuts), Chevrolet type, and motor wheel type
dual overhead cam engine:
See double overhead cam engine.
dual-piston engine:

See twin-piston engine
dual-piston master cylinder:
See tandem master cylinder
dual-purpose motorcycle:
Street-legal motorcycles with varying degrees of off-road capabilities.
Also called dual-sport
dual purpose ship:
Specially designed ship for carrying different types of cargoes such as ore
and/or oil.
dual-range gearbox:
See dual-range transmission
dual-range transmission:
A transmission in a four-wheel drive vehicle and some motorcycles with
two sets of ratios, usually a higher set for road use and a lower set for off-
road use.
dual reduction axle:
A drive axle construction with two sets of pinions and gears, either of
which can be used
duals:
[1] Two sets of exhaust pipes and mufflers -- one for each bank of
cylinders.
[2] Two tires on each end of an axle.
Also see
between duals
kissing between duals
dual spacing:
A measurement in inches (or millimeters) from the center of the tread of
one tire, to the center tread of the other tire in dual, which provides
clearance between duals for air circulation.

dual sport:
Street-legal motorcycles with varying degrees of off-road capabilities.
Also called dual-purpose motorcycles
dual-tone horn:
See two-tone horn
Dubonnet suspension:
An independent front suspension and steering arrangement used in the
1930s and '40s, in which the axle beam is rigidly attached to the vehicle
frame, and the kingpins carry sprung steering and suspension arms, from
which the wheels are mounted on stub axles
duct:
A tube or channel through which air, gas, or liquid is conducted, conveyed,
or moved.
Also see
air duct
NACA duct
oil duct
ductile:
Metal which can be bent, hammered, or drawn out into wire or sheet
without fracturing
ductility:
The ability of a material to undergo stretching or bending without
fracturing
Duesenberg:
A vehicle brand of which the 1925-1948 models
are classic cars. Click for books on
Duesenberg
duesy:

Expression to indicate quality, as "It's a duesy." The word is derived from
the high quality Duesenberg automobiles.
dull:
[1] A finish that is not shiny.
[2] A blade, saw, or drill bit that is not sharp.
Also see
go dull
dumbirons:
The front extensions of the side members of a chassis frarne in older
designs, to which were fitted the front ends of the leaf springs carrying the
front axle.
dummy:
A stuffed figure made to look like a human being, used, for instance, when
crash testing cars. Also called a crash test dummy.
Also see
crash test dummy
side impact dummy
dummy lights:
[1] Exterior lights which do not work, but may enhance the appearance of
a vehicle.
[2] The idiot lights that indicate a condition, but does not give details as a
gauge would do, e.g., an oil light that indicates low pressure. By the time it
comes on, you may have damaged your engine.
dump:
See end dump
dump body:
A large truck's metal body which is generally hinged at rear and dumped
by hydraulic means. The size is generally given in cubic yard water level
capacity.
dumps:

See bottom dumps
dump truck:
[1] A large truck with a bed designed to be tilted at its front to unload its
contents usually through a gate in the rear.
[2] In Britain it is a small truck with a tipping container in front of the
driver, used in construction, like a front-end loader
dump valve:
A valve for relieving pressure, such as that between the turbocharger and
the carburetor in some systems
dunnage:
Cushioning material placed among cargo to prevent their motion
duo-servo brake:
A servo brake with one double-end wheel cylinder and two linked self-
energizing brake shoes
duo-servo drum brake:
A type of self-energizing drum brake that has servo action in both forward
and reverse
duplex:
Double, having two parts. Applies to motorcycle frames with two
downtubes, and chains with double rows of rollers
duplex chain:
A chain with two rows of rollers, used especially for timing chains.
Also see
simplex chain
triplex chain
DuPont:

durability:
[1] The ability of a component or entire vehicle to last a long time.
[2] The expected lifespan of a paint film
durable:
The ability of something to be serviceable for a long time before being
replaced
Duraspark system:
Ford electronic ignitions system
duration:
The length of time that an action is allowed to operate or that something is
supposed to last.
Also see
spark duration
valve duration
durometer:
A device to indicate the hardness of rubber.
Duryea:
See Stevens Duryea
dust boot:
[1] A covering (often shaped like an accordian) usually made of rubber or
plastic to cover over a shaft, CV joint, etc.
[2] A rubber diaphragm-like seal that fits over the end of a hydraulic
component and around a pushrod or end of a piston, not used for sealing
fluid in but keeping dust out
dust cap:
[1] A metal or plastic covering that fits into a hub shell to keep
contaminants out of hub bearings.
[2] A metal or plastic end cover for a spindle in a pedal or a cotterless
crankset.

dust cover:
A soft, flexible valve cap to protect the valve assembly from dust while in
shipment and storage. It is not capable of sealing the air pressure and
should not be used in service.
dust-free paint:
A condition of paint which has hardened beyond being tacky so that any
air-borne dust particles will not be imbedded in the paint.
dust sheet:
A sheet for covering a car when in a garage and not in use.
Also see
car cover
dust shield:
Sheet metal disc or plate placed on the brake assembly to keep debris from
brake assembly. Also called "splash shield."
duties:
See customs duties
duty:
See
heavy-duty
light-duty
duty cycle:
Many solenoid-operated metering devices cycle on and off. The duty cycle
is a measurement of the amount of time a device is energized, or turned
on, expressed as a percentage of the complete on-off cycle of that device,
in other words, the duty cycle is the ratio of the pulse width to the
complete cycle width
duty-cycle solenoid:
The duty-cycle solenoid is a computer-controlled device in a feedback
carburetor that alters the mixture adjustment. Also called a mixture control
solenoid

duty drawback:
Import duties or taxes repaid by a government in whole or in part, when
the imported goods are re-exported or used in the manufacture of exported
goods.
duty paid value:
In respect to imported goods, is the aggregate value for duty on imported
goods.
duty waiver:
forgiveness, in whole or in part, of import duties when certain conditions
are met.
DVB:
Acronym for delay vacuum bypass system
DVLA:
Acronym for Driver and Vehicle Licensing Agency
DVLC:
Acronym for Driver and Vehicle Licensing Center
DVOM:
Acronym for digital volt-ohm multimeter
dwell:
[1] In a contact breaker ignition system, the number of degrees the breaker
cam rotates from the time the breaker points close until they open again.
Also called the "dwell angle" or "dwell period."
[2] In a breakerless ignition system, the time during which the electronic
control unit allows current to flow through the primary winding of the coil,
which in ignition systems with a Hall generator is determined by the width
of the vanes.
Also see
variable dwell

dwell angle:
See dwell.
dwell-angle control:
A system which makes sure that the dwell is sufficient for all engine
conditions
dwell-angle map:
The pattern described by the electronic dwell-angle control, dependent on
engine speed and battery voltage
dwell meter:
An instrument which determines the number of degrees the breaker cam
rotates while the breaker points are closed. Changing the point gap affects
the dwell angle. When the breaker points are correctly gapped, the
distributor can give the proper amount and duration of spark to the spark
plugs.
dwell period:
The time during which the primary circuit is closed and primary current
flows through the ignition coil, given in crankshaft or distributor shaft
degrees and therefore also called dwell angle. See dwell.
DWS:
Acronym for deflation warning system
dwt:
Deadweight ton(s)
Dykem-type metal bluing:
A special blue dye used to check a valve job. When applied to the valve set
to show up as a dark ring contrasted against the brightly finished top &
bottom cuts, making the seat easier to see and measure

dykes ring:
A compressionpiston ring which is L-shaped when
viewed from the end. When installed in the piston
the horizontal part fits more deeply in the piston
groove while the vertical side rubs against the
cylinder wall. This style of ring gives good sealing
and prevents piston-ring flutter during acceleration
and deceleration of the piston.
dynamic balance:
When the center line of the weight mass of a revolving object is in the
same plane as the center line of the object, that object would be in
dynamic balance. For example, the weight mass of the tire must be in the
same plane as the center line of the wheel. Static balance is made off the
vehicle and determined with the tire stationary. Dynamic balance is made
with the tire in rotation.
dynamic ignition timing:
Before the introduction of a strobe light, ignition timing was done
statically in that the distributor was moved a certain measured amount.
With modern engines, a timing light or strobe light is used. It is connected,
generally, with the spark plug of the number one cylinder. As power is
provided to that cylinder from the coil, the timing light flashes. When the
light is projected to the flywheel, the timing marks are illuminated.
Moving the distributor will make the timing mark move closer to a fixed
mark (retarded) or further away (advanced). Also called stroboscopic
ignition timing. The opposite is static ignition timing
dynamic imbalance:
Lack of balance in a rotating part such as a wheel, which can cause
vibration and shudder
dynamic seal:
oil seal between a moving and a stationary part. Opposite to static seal
dynamic supercharging:
The pressurizing of the air/fuel mixture using the natural dynamic
behaviour of the aspirated air, and not some mechanical device to
compress it

dynamic timing meter:
A GM diesel tool used for measuring timing while the engine is running
by using a quartz sensor in the combustion chamber that measures the
point of combustion and converts this to timing in degrees of crankshaft
flotation through the use of a magnetic crankshaft pickup and
microprocessor
dynamo:
A British term for a generator producing direct current.
Also see
alternator
dynamometer:
[1] An electric or hydraulic machine used to measure the actual engine
horsepower output and torque. An engine dynamometer measures
horsepower at the crankshaft and a chassis dynamometer measures
horsepower output at the wheels.
[2] Device for measuring power output or power input of a mechanism.
Also see
roller dynamometer
dynastart:
A combined generator and starter used on some cars in the 1920s and '30s,
and more recently on two-stroke motorcycles
dynastarter:
A combined generator and starter used on some cars in the 1920s and '30s,
and more recently on two-stroke motorcycles

E:
Abbreviation for Economy Gear
EACV:
Acronym for "electronic air control valve." A valve used in fuel-injection
system, usually computer controlled, that controls the amount of air
bypassing the throttle during idle. The more air that bypasses the throttle,
the higher the idle speed
EAC Valve:
electric air control valve. This is the GM version of a diverter air gulp
valve, providing three functions in a single valve:
1. the normal diverter valve function, i.e., it diverts air on rapid
increase in manifold vacuum;
2. it relieves pressure by diverting air to the air cleaner when the air
injection system pressure exceeds a certain set level;
3. being solenoid-controlled, it allows air to be diverted under any
desired operating mode
Also see
EAS valve
EAMA:
Acronym for "Egyptian Automobile Manufacturers Association."
ear:
A projection in the shape of an ear, usually as a lug or support for other
components such as the brackets which are part of the fork cover and to
which the headlight is mounted on a motorcycle. It is also a spoiler behind
the rear windows to improve stability in side winds.

Also see
fork ear
Earles forks:
Long leading-link motorcycle forks, i.e., front suspension has a pivoting
fork controlled by twin shock absorbers. Designed by Ernie Earles, they
were used by many manufactures of motorcycles in the 1950s
early fuel evaporation system:
(EFE) A system that heats the inlet manifold to provide a warm air/fuel
mixture, reducing condensation and improving fuel evaporation, thus
improving cold engine operation and reducing exhaust emissions. An EFE
system operated by engine exhaust gas responds quicker to engine heat-up
than systems heated by engine coolant; some EFE systems use an electric
heater in the intake duct
early termination:
A vehicle's depreciation is highest in the first few months after it leaves the
dealer's lot. Since a lessee pays for depreciation in equal monthly
payments, lessees who end a lease early have almost always used up more
of a car's value than they've paid for. Therefore, lease contracts generally
include penalties for early termination. Be aware of these penalties before
you sign the lease contract and consider your ability to fulfill the contract.
earnings:
See average weekly earnings
ears on:
Trucker slang for CB is turned on as in "Any smokeys out there with their
ears on."
earth:
British term for ground
earth connection:

British term for ground connection
earth electrode:
British term for ground electrode
earthmover:
See A-2 tire.
earth return:
British term for ground return
earth strap:
British term for ground strap
earth wire:
British term for ground wire.
ease up on the accelerator:
The action of releasing the accelerator partially or completely in order to
reduce the amount of fuel entering the engine and thus slow down the
speed of the vehicle. Opposite of depress the accelerator or step on the
accelerator.
ease up on the gas pedal:
The action of releasing the gas pedal partially or completely in order to
speed of the vehicle. Opposite of depress the gas pedal or step on the gas
pedal..
ease up on the throttle:
The action of releasing the twist-grip or throttle lever partially or
completely in order to reduce the amount of fuel entering the engine and
thus slow down the speed of the vehicle. Opposite of engaging the throttle
or cranking on the throttle..

ease up on the throttle pedal:
The action of releasing the throttle pedal partially or completely in order to
speed of the vehicle. Opposite of depress the throttle pedal or step on the
throttle pedal..
easing fluid:
Penetrating oil
Easton:
American developer of high quality aluminum and carbon fiber bicycle
products.
east-west layout:
transverse positioning of the engine across the car from left to right, found
in many front-wheel drive designs. Also called transverse engine. The
opposite is north-south layout
EAS Valve:
The valve in an emission control system governing the airflow from the air
pump in connection with the EAC valve. When its solenoid is energized,
air is directed into the exhaust ports to increase oxidation and accelerate
catalytic converter heat-up to operating temperature, and when its solenoid
is de-energized, it switches airflow between the converter beds to help the
oxidizing catalyst to decrease the CO and HC levels

easy access cab:
A regular cab
pickup with an
extra fold-out
section behind the
door to allow you
to have access to
the things behind
the seat. Unlike an
extended cab, there
is no seating
behind the seat.
easy out:
A brand name for a screw extractor.
easy-out:
A brand name for a screw extractor.
eat:
to corrode and remove the metal from the front fender has been eaten away
by rust
eat away:
to corrode and remove the metal from the front fender has been eaten away
by rust
eat-em-up:
Trucker slang for Truck stop Cafe as in "It's been so long since I stopped at
the eat em up that my stomach thinks my throats been slashed."
eater:
See rust eater

ebonite:
hard black rubber compound especially one containing no filler
e box:
Any electronic box including capacitive discharge ignition and computer
controlled devices.
e-box:
Any electronic box including capacitive discharge ignition and computer
controlled devices.
E-brake :
See emergency brake
ECA:
Acronym for electronic control assembly
ECC:
Acronym for electronic climate control
eccentric:
[1] Two circles, one within the other, neither sharing the same center, i.e.,
they are off-center.
[2] A protrusion on a shaft that rubs against or is connected to another part,
such as a cam on a camshaft.
[3] A part transmitting an eccentric drive, such as a disc with a provision
for a drive from its outer part, or an eccentric shaft
eccentric bolt:
A bolt with centers of head and body on different axis so that one is off-
center in relation to the other.
eccentric drive:
A drive from a point not on the axis of the driving shaft, e.g., from the
outer part of a disc, so that a reciprocating or up and down motion is
transmitted; used in pumps or for a camshaft drive

eccentric journals:
These are used to attach the connecting rods to the crankshaft (also called
metal shafts)
eccentric rotor pump:
rotor-type pump
eccentric shaft:
A shaft transmitting eccentric motion
ECE test cycle:
A 13 minute, three-part test of automotive emissions for compliance with
emission standards, adopted by most European countries, simulating urban
driving conditions, i.e., involving relatively long idling periods and speeds
below 35 mph, emission characteristics at cruising speeds not being
considered
echelon parking:
A British term for angle parking
ECI:
Acronym for electronically controlled injection
Eclat:
A 2+2 Coupe produced by Lotus from 1975 to 1982. This vehicle was the
basis for the current Lotus Excel.
ECM:
Acronym for "electronic Control Module" which is the master computer
responsible for interpreting electrical signals sent by engine sensors and
for activating automated engine components and processes accordingly in
order to produce optimum performance.
ecological damage:

damage to the environment, usually in the form of pollution, such as that
caused by vehicle emissions
ecologically harmful:
damaging to the environment automotive exhaust gases are ecologically
harmful
ecology:
Science of life balance on earth.
economical:
The determination of how much money or fuel is required to cover a
particular distance. Good economy involves driving at a steady rate,
avoiding rapid starts and stops, driving in the highest possible gear,
avoiding using power- robbing components (e.g., air conditioning), proper
tire inflation, etc.
Economic Cooperation:
See Asia Pacific Economic Cooperation
economizer:
A device for making a vehicle use less fuel, either by regulating the flow
of fuel, or by admitting extra air to the air/fuel mixture -- especially when
cruising
economizer valve:
A fuel flow control device within the carburetor.
economy:
The ratio between a product or service and its value.
Also see
corporate Average Fuel Economy
epa fuel economy
fuel economy
tuned for economy
economy device:

See economizer
economy gear:
High gear designed for economical cruising often better than 1:1 ratio like
an overdrive.
economy jet:
An additional jet in a carburettor admitting extra air to the air/fuel mixture
-- especially when cruising
economy ratio:
An overdrive gear ratio better then 1:1 for economical cruising
ECS:
[1] Acronym for electronically controlled suspension.
[2] Acronym for evaporation control system
ECT:
Acronym for "engine coolant temperature sensor"
ECU:
Acronym for "electronic Control Unit"
eddy currents:
Induced currents flowing in a core.
edge:
See
*absorption edge
abutting edge
beaded edge
feather-edge
feather edge
leading edge
trailing edge
wiring an edge

edge binding:
tape for securing the edges of carpets
edge guard:
rubber or plastic, U-section strip fitted to panel edges to protect them
against chipping, etc.
edge joint:
A joint formed when two pieces of metal are lapped with at least one edge
of each at an edge of the other.
edge protection:
protection of edges against corrosion, e.g.. by weatherstrips
edge-ride:
The tendency of crankshaft main bearings to ride up the radius (rather than
seat on the journal) when the radius is too large
edge tire:
See beaded edge tire
edge trim:
rubber or plastic, U-section strip fitted to panel edges to protect them
against chipping, etc.
Edison base:
A light bulb base that is threaded.
Edison screw:
A light bulb base that is threaded

Edsel:
Click for books on Edsel
Edwardian car:
A car built in Great Britain between 1905 and 1918
EEC:
[1] Acronym for electronic engine control system.
[2] Acronym for evaporative emission control system
EECS:
Acronym for "evaporative emissions control system"
EER:
Acronym for energy efficiency ratio
EESS:
Acronym for evaporative emission shed system
EEVIR:
Acronym for evaporator equalized valve in receiver
EFE:
Acronym for early fuel evaporation system
EFE system:
Acronym for Early Fuel Evaporation System
effect:
See
alteration effect

barrier effect
braking effect
engine braking effect
ground effect
hall effect
kadenacy effect
liftoff effect
load alteration effect
roll steer effect
self-centering effect
synergetic effect
synergistic effect
effective:
[1] actual rather than theoretical or potential.
[2] producing an effect.
Also see
cost-effective
indicated mean effective pressure
mean effective pressure
effective area:
Actual flow area of an air inlet or outlet. Gross area minus area of vanes or
grille bars.
effective deflection:
deflection of a suspension system under a particular load
effective pressure:
See
brake mean effective pressure
indicated mean effective pressure
mean effective pressure
effective stroke:
working or power stroke in a two-stroke engine
effective temperature:
Overall effect on a human of air temperature, humidity, and air movement.

efficiency:
[1] The accomplishment of something with the least amount of effort,
energy, or fuel.
[2] Output of a device, system, or activity, divided by the input necessary
to create the output. In a compressor the efficiency would be the work
output, as measured by pressure change, divided by the energy input
(usually electrical).
See
braking efficiency
catalyst efficiency
catalytic efficiency
charging efficiency
fuel efficiency
mechanical efficiency
thermal efficiency
trapping efficiency
volumetric efficiency
effort:
The force which is doing work on an object.
Also see
braking effort
EFI:
(EFi) Acronym for electronic Fuel Injection
EGC:
Acronym for exhaust gas check valve
egg-crate grille:
A radiator grille with crisscrossing bars forming gaps which are more or
less square. One of the distinctive characteristics of Cadillac cars
EGI:
Acronym for electronic gasoline injection
EGO:
Acronym for exhaust gas oxygen sensor

EGR:
Acronym for "Exhaust-gas recirculation."
Also see
negative transducer EGR valve
vacuum modulated EGR
EGRC:
Acronym for EGR control solenoid
EGR control solenoid:
(EGRC) energizes to allow manifold vacuum to the EGR gas temperature
EGRV:
Acronym for EGR vent solenoid
EGR vacuum:
A vacuum source above the closed throttle plate; used for control of ported
EGR valves. Vacuum is zero at closed throttle
EGR valve:
[1] A part of an EGR system mounted on or near the inlet manifold and
controlled by inlet manifold vacuum, which is usually closed at idle and
low speeds, but opens during acceleration, admitting exhaust gas to the
inlet manifold. Most EGR valves are of the single diaphragm type, some
are dual diaphragm valves connected to two separate vacuum sources to
more closely match EGR function to engine loads; for the same purpose,
EGR valves are frequently governed by additional regulating devices.
[2] A valve used to introduce exhaust gases into the intake air stream.
There are several types.
Also see
integral backpressure transducer EGR valve
ported EGR valve
electronic EGR valve
valve and Transducer assembly
negative transducer EGR valve
EGR valve position sensor:
(EVP) A potentiometric sensor used in electronically controlled EGR
system. Sensor wiper position is proportional to EGR valve pintle position,

which allows electronic control assembly to determine actual EGR flow at
any point in time
EGR vent solenoid:
(EGRV) electrical solenoid that normally vents EGRC vacuum line. When
EGRV is energized, EGRC can open the EGR valve
EGR venturi vacuum amplifier:
A device that uses a relatively weak venturi vacuum to control a manifold
vacuum signal to operate the EGR valve. Contains a check valve and relief
valve that open whenever the venturi vacuum signal is equal to or greater
than manifold vacuum
EIA:
Acronym for "Electronics Industries Association."
eight:
eight-cylinder engine, or a vehicle fitted with one; the cylinders may be in-
line (a straight eight) or in a V-layout (a V-8).
Also see
flat eight straight eight
V-eight
8 trk:
Abbreviation for "eight-track" tape player found in many '60s and some
'70s cars.
8-trk:
Abbreviation for "eight-track" tape player found in many '60s and some
'70s cars.
eighteen wheeler:
Trucker slang for A truck with 18 wheels as in "If you got it an 18-wheeler
brought it."
eight track:

See eight-track.
eight-track:
An 8-track tape player found in many '60s and some '70s cars.
EIN:
Engine Identification Number
eject:
To push or throw out
eject button:
button on a cassette player or CD player for taking out the cassette or CD
ejector:
Device which uses high fluid velocity, such as a venturi, to create low
pressure or vacuum at its throat to draw in fluid from another source.
Elan:
A two-seater roadster produced by Lotus from 1964 to 1974.
elapsed time:
(ET) The length of time it takes a dragster to complete the one-fourth mile
run.
elasticity:
[1] The ability to recover the original size and shape after being deformed,
especially stretched, forces are released.
[2] The property of an adhesive or sealer which enables it to recover its
original shape and size when deforming forces are removed. It is the
ability to change size or shape repeatedly without breaking the molecular
bonds that cause an object to hold its shape.
elastomer:

[1] A term which includes natural rubber and the many synthetic materials
that possess rubber-like properties.
[2] An elastic macromolecular material that at room temperature returns
rapidly to approximately its initial dimensions and shape after substantial
deformation by a weak stress and release of the stress.
[3] A classification of rubber-like substances used in the formulation of
adhesives, coatings, and sealers without reference to their composition.
Also classed as an elastic material that can be stretched repeatedly to at
least twice its original length and, upon sudden release of stress, to return
with equal force to its approximate original length thermoplastic
elastomers
[4] An elastic polymer, a springy plastic used commonly as a spring or
shock absorber, particularly in suspension forks and similar mechanisms.
elbow:
A pipe or rod with a bend, usually at right angles.
Also see
mechanic's elbow
ELC:
Electronic level control
Eldorado:
A Cadillac vehicle brand of which the 1953-58, 67-
70 Eldorado models are milestone cars. Also see
the history of Cadillac Eldorado.
Click for books on
Cadillac Eldorado
Eldorado Brougham:
See Cadillac Eldorado Brougham
Electra:
Buick Click for books on Buick Electra

electric:
operated by or derived from electricity
electric air control valve:
The EAC valve
electric air switching valve:
EAS valve
electrical:
relating to electricity
electrical arcing:
Band of sparks formed when an electrical discharge from a conductor
jumps to another conductor
electrical balance:
An atom or an object in which positive and negative charges are equal
electrical conductivity:
The ability of a material to conduct electricity. The opposite is resistivity
or resistance.
electrical potential:
Electrical force which moves, or attempts to move, electrons along a
conductor or resistance.
electrical resistance:
The difficulty electrons have moving through a conductor or substance.
electrical screwdriver:
A British term for an electric screwdriver
electrical spanner:

A British term for an ignition wrench
electrical system:
The system that generates, stores, and distributes electrical current to crank
the engine for starting and to keep it running by providing high voltage to
the spark plugs; and to give power to the lights, the heater motor, radio,
and other accessories. It is made up of the ignition system starter motor,
battery alternator voltage regulator lights, electrical accessories and all the
wiring, switches, and relays.
electric car:
A car whose only power source is an electric motor and a number of
batteries.
electric charge:
A definite quantity of electricity, which-may be positive, as with protons,
or negative, as with electrons.
Also see
coulomb
electric current:
The flow of electricity passing through a conductor
electric defrosting:
Use of electric resistance heating coils to melt ice and frost off evaporators
during defrosting.
electric fuel pump:
electrically powered gasoline or diesel pump which draws fuel from the
tank and delivers it to the carburetor or fuel injection system
electric grid:
The electrical system
electric heating:

System in which heat from electrical resistance units is used to heat the
building.
electrician:
See automotive electrician
electric insulation:
Substance which has almost no free electrons.
electricity:
See static electricity
electric mirror:
An external door mirror which is controlled by an electric motor and
operated by a switch inside the car
electric motor:
A device which changes electrical energy into rotational motion. In
addition to the starter and windshield wiper motors, which were the first
electric motors to be added to the automotive electrical system, modern
cars include a large number of small motors for driving such items as the
electric windows, aerials, sunroofs, mirrors and seat adjustment, central
locking and power hoods; electric-powered cars use large motors for their
drive.
electric rectifier:
Electrical device for converting ac to dc.
electric screwdriver:
A tool which resembles a pistol which can accept screwdriver bits. It is
similar to an electric drill.
electric top:
A power convertible roof. The British term is "power hood"

electric vehicle:
Cars, buses, vans or trucks which use dedicated or hybrid electric systems
as their power source.
electric water valve:
Solenoid type (electrically operated) valve used to turn water flow on and
off.
electric welding:
Welding by using an electric current to melt both metal (work) and
welding rod, or electrode
electric windows:
Side windows which are raised and lowered by an electric motor which is
operated by a switch.
electrochemical:
Chemical (battery) production of electricity.
electrochemical corrosion:
corrosion involving at least one electrode reaction
electrocoating:
electrophoretic painting

electrode:
[1] In a spark plug one electrode (the center
electrode) is the center rod passing through
the insulator. The side electrode is a rod
welded to the shell of the spark plug. The
distance between them is the spark gap.
[2] In welding it is the metal rod that is used
in arc welding. A substance which brings
electricity up to the point where the arc is to
be formed; in other words it is the material
immediately adjacent to the arc proper and
the one which carries the current to this point.
In electric arc welding the electrode is usually
melted and becomes a part of the weld.
Also see
center electrode
coated electrode
compound center electrode
compound electrode
covered electrode
earth electrode
ground electrode
negative electrode
outer electrode
platinum electrode
positive electrode
side electrode
spark plug electrode
top electrode
triangular ground electrode
electrode adjusting tool:
A British term for a spark plug gap gauge
electrode gap:
Spark plug gap
electrodeposition:
A generic term for electrolytic processes in which a metal is deposited at
the cathode from a solution of its ions, such as electroplating, or in which
paint is deposited in an immersion process by means of electric current
electrodeposition process:

Process in which metallic particles are applied to another metal surface
through the use of an electric current.
electrode spark plug:
See split electrode spark plug
electrogalvanizing:
An electroplating coating of zinc on metal that will rust (i.e., iron or steel).
electro-hydraulic pressure actuator:
See pressure actuator
electro-hydraulic pump:
An electrically powered hydraulic pump used to create pressure in certain
portions of the brake system. Typically found in GM Powermaster brake
boosters and in ABS hydraulic control units
electrolysis:
[1] A method by which chemical reactions are carried out by passage of
electric current through a solution of an electrolyte or through a molten
salt.
[2] Movement of electricity through a substance which causes a chemical
change in the substance or its container.
electrolyte:
In automotive batteries, it is a sulphuric acid and water solution. It can be
any solution (usually an acid) that will conduct electric current. The acid
reacts with the battery plates (usually made of lead) to produce direct
current (DC) electricity.
electrolytic:
relating to electrolysis or an electrolyte
electrolytic cell:
A cell consisting of electrodes immersed in an electrolyte solution for
carrying out electrolysis

electrolytic condenser-capacitor:
Plate or surface capable of storing small electrical charges.
electrolytic corrosion:
electrochemical corrosion causing the electrolytic removal of metal
electrolytic deposition:
electroplating
electrolytic galvanizing:
electrogalvanizing
electrolytic protection:
cathodic protection
electromagnet:
A magnet produced by placing a coil of wire around a steel or iron bar.
When current flows through the coil the bar becomes magnetized and will
remain so as long as the current continues to flow.
electromagnetic:
Magnetic (generator) production of electricity.
electromagnetic clutch:
any clutch in which a magnetic force is used to hold the drive in
engagement, such as that in the compressor drive of an air-conditioning
system
electromagnetic energy:
Energy which has both electrical and magnetic characteristics. Solar
energy is electromagnetic.
electromagnetic induction:

Voltage is induced in a coil of wire by moving coil through a magnetic
field or by keeping coil stationary and moving magnetic field.
$electrometer: See *absolute electrometer
electromotive force:
(EMF) A source of electrical energy required to produce an electric
current, produced by devices such as batteries or generators and measured
in volts. See voltage.
electromotive force voltage:
(emf) Electrical force which causes current (free electrons) to flow or
move in an electrical circuit. Unit of measurement is the volt.
electron:
A negatively charged particle that makes up part of the atom.
Also see
bound electrons
free electrons
electron flow:
A current produced by the motion of free electrons towards a positive
terminal, whose direction is the opposite to that of the current
electronic:
Featuring semiconductors (usually transistors) as an operating medium.
Also see
fully electronic ignition
high energy ignition system with electronic spark timing
electronic air control valve:
(EACV) A valve used in fuel-injection system, usually computer
controlled, that controls the amount of air bypassing the throttle during
idle. The more air that bypasses the throttle, the higher the idle speed
electronically controlled:
Most items can be controlled by a mechanical means (squeeze a lever to
move something) or by hydraulics (a lever pushes fluid which applies
movement to something) or electronically (move a switch and a servo

motor moves something)
electronically controlled transmission:
A transmission that relies on sensors, an electronic control unit (ECU), and
solenoids to control torque convertor lockup and shift points
electronically-controlled wastegate:
A turbo-charger wastegate that is activated by an electric signal from a
computer
electronic brake control module:
(EBCM) GM's term for the electronic control unit
electronic climate control:
(ECC) An air conditioning system control which determines and maintains
the preset temperature in the passenger compartment.
electronic cluster:
A display showing various functions, including speedometer, tachometer,
gauges, etc., using LEDs or LCD technology displaying symbols and bar
graphs instead of numbers. The opposite is an analog cluster
Electronic control Assembly:
ECA: A Ford vehicle computer consisting of a calibration assembly
containing the computer memory, its control program, and processor
assembly (the computer hardware)
electronic control diagnostics:
Trouble codes which may be referenced on an automatic climate control
system to diagnose problems.
electronic control module:
(ECM)
[1] The master computer responsible for interpreting electrical signals sent
by engine sensors and for activating automated engine components and
processes accordingly in order to produce optimum performance.

[2] A GM term and also a generic term referring to the computer. The
ECM is the brain of the engine control system receiving information from
various sensors in the engine compartment. The ECM calculates what is
required for proper engine operation and controls the different actuators to
achieve it Also called "electronic control unit"
electronic control unit:
(ECU)
[1] A microprocessor and memory with electronic maps, forming the
central part of an engine management system or of subsystems such as a
fuel injection or ignition system.
[2] The "brain" of an ABS system. The ECU reads impulses from the
wheel speed sensors to determine if anti-lock braking needs to take place.
If so, the ECU controls the cycling of the solenoid valves in the hydraulic
control unit. Also called "Electronic Control Module"
electronic EGR valve:
The EGR valve used in engine management system in which the EGR
flow is controlled by the computer (usually by means of an EGR valve
position sensor attached to the EGR valve). Operating vacuum is supplied
by EGR solenoid valve(s)
electronic engine control:
(EEC)
[1] The engine management system which controls the ignition system and
various other systems, including the exhaust gas recirculation and air-
injection systems.
[2] Ford's computerized engine control system. There are four versions:
EEC-I controls engine timing. EEC-II controls engine timing and fuel (on
engines with an FBC system). EEC-III-FBC is a refined version of EEC-
II. EEC-III-CFI controls engine timing and fuel (on engine with an EFI
system). EEC-IV is a refined version of the EEC-III system
electronic fuel injection:
(EFI or EFi) A system that injects fuel into the engine and includes an
electronic control unit to time and meter the flow. Fuel is delivered in
intermittent pulses by the opening and closing of solenoid-controlled
injectors. Also called pulsed injection

electronic gasoline injection:
(EGI) Mazda's fuel injection system for the RX-7, RX-7 Turbo, 323, and
626
electronic ignition:
See
electronic ignition system
all electronic ignition
capacitor controlled electronic ignition
contact controlled electronic ignition
contactless electronic ignition
fully electronic ignition
electronic ignition system:
An ignition system using electronic switching devices to assist or
eliminate the mechanical breaker points. There are three basic electronic
ignitions: contact controlled (the breaker points are retained but merely
serve to trigger a transistor which switches the heavy primary current),
magnetically controlled (transistors are used as the switching device for
the primary current and the points are eliminated -- also called
"contactless" or "all-electronic"), and capacitor controlled (also called
"capacitive-discharge system" and can be either all-electronic or breaker-
point controlled).
electronic leak detector:
Electronic instrument which measures electronic flow across gas gap.
Electronic flow changes indicate presence of refrigerant gas molecules.
electronic navigator:
A trip computer which gives estimated time of arrival (ETA), amount of
fuel left, average fuel consumption, etc.
electronic relay:
Electronic switch, such as a triac, which controls a power consuming
device.
electronic ride control:

A suspension control system made up of a microprocessor-controlled,
electronically adjustable air shock absorbers for automatic selection of the
optimum damping characteristics depending on road surface and load
conditions
electronics:
Field of science dealing with electron devices and their uses. Also see
automotive electronics
electronic sensing device:
An electronic device for vehicles with fuel injection. It detects changes in
speed and driving conditions and determines the amount of fuel to be
injected into the combustion chamber thus eliminating the need for
carburetors.
electronic sight glass:
Device that sends an audible signal when system is low in refrigerant.
electronic spark:
See high energy ignition system with electronic spark timing
electronic spark advance:
(ESA) the part of an ECU that controls ignition timing and dwell angle
electronic spark control:
(ESC) The timing of the ignition by means of an ignition map, either
integrated into the mapped ignition systems or available as a separate
module to enhance transistorized ignition systems. Also called "electronic
spark timing."
electronic spark timing:
(EST) The timing of the ignition by means of an ignition map, either
integrated into the mapped ignition systems or available as a separate
module to enhance transistorized ignition systems. Also called "electronic
spark control."
Also see

electronic spark timing system:
(EST) An ECM-controlled timing of ignition spark. This replaces the
vacuum or centrifugal mechanism in the distributor and uses the computer
to advance or retard the spark timing
electronic thermistor:
Electrical device that senses temperature change to control an output
source; see thermistor
electronic thermostat:
Thermostat that uses electronic components to accomplish various
sensing, switching, timing, staging, and display functions.
electronic traction control:
(ETC) A system for reducing wheelspin, incorporating wheel sensors.
Also see
antispin regulation
electronic transmission:
A system of controlling the shifting of gears in the transmission by means
of electrical pulses sent to solenoids and relays. In mechanical
transmissions, the operator moves levers which makes the transmission
shift gears.
electronic transmission control:
A system or module for controlling an automatic transmission
electro vacuum relay:
(EVR) a combination solenoid vacuum valve and electrical relay which
locks out blower operation and closes the fresh air door in cold weather,
and switches the system to the recirculating air mode during maximum
system use
electronic voltage regulator:

(EVR) a type of regulator that uses all solid state devices to perform the
regulatory functions
electrons:
See bound electrons free electrons
electropainting:
Electrophoretic painting.
Also see
cathodic electropainting
electropaint tank:
A tank in which items are immersed for electrophoretic paint application
electrophoretic painting:
A process used to apply the first coat of paint (primer) to car bodies. The
process involves using negatively charged paint particles (anodic
electropainting) or positively charged paint particles (cathodic
electropainting). The cleaned metal parts to be coated are immersed in a
tank of electrodeposition paint, and the current is turned on, so that the
paint particles are attracted by the positively charged paint particles
electrophoretic primer:
Paint used to prime car bodies by the electrophoretic process
electro picker:
A device which is electrically operated and is used to open locked car
doors. It is available only to automotive locksmiths and the police. It
consists basically of a vibrator with an attached steel blade. When the
vibrating blade is inserted into a lock, it finds its way past the locating pins
which would normally block anything but the original key
electroplate:
The process of depositing gold, silver, chrome, nickel, etc., upon an object
by placing the object in a special solution and then passing an electric
current through the solution. The object forms one terminal, a special
electrode the other. Direct current is used.

electroplating:
The process of electrodeposition of metal or alloys from suitable
electrolyte solutions. The articles to be plated are connected to the cathode
in an electrolyte solution, and direct current is introduced through the
anode of the metal to be deposited.
Also see
zinc electroplating
electrostatic filter:
For cleaning air, a type of filter which gives dust particles an electric
charge. This causes particles to be attracted to a plate so they can be
removed from air.
electrostatic painting:
A painting method using the particle-attracting property of electrostatic
charges, in which a direct current of approximately 100,000 volts is
applied to a grid of wires through which the paint is sprayed to charge
each particle, and the metal objects to be sprayed are connected to the
opposite terminal of the high-voltage circuit, so as to attract the paint
particles. Also called "Electrostatic Spraying"
electrostatic powder coating:
(EPC) A painting process in which the outer parts of the body shell are
coated with a powder dispersion by means of cathodic immersion, and in
which the cavities are coated with cathodic electropaint
electrostatic spraying:
A painting method using the particle-attracting property of electrostatic
charges, in which a direct current of approximately 100,000 volts is
applied to a grid of wires through which the paint is sprayed to charge
each particle, and the metal objects to be sprayed are connected to the
opposite terminal of the high-voltage circuit, so as to attract the paint
particles. Also called "Electrostatic Painting"
electro vacuum relay:
(EVR)A combination solenoid vacuum valve and electrical relay which
locks out blower operation and closes the fresh air door in cold weather,

and switches the system to the recirculating air mode during maximum
system use
electrovalve:
A solenoid valve
element:
A group of plates in a battery. Three elements for a six volt and six
elements for the twelve volt battery. The elements are connected in series.
Also see
air cleaner element
air filter element
filter element
hall element
hot-wire element
open element glow plug
temperature control element
element glow:
See open element glow plug
element glow plug:
See open element glow plug
Elliot:
See Elliot axle reversed Elliot axle
Elliot axle:
A solid bar front axle on which the ends span or straddle the steering
knuckle.
Also see
reversed Elliot axle
Elliott steering knuckle:
Type of axle in which ends of axle beam straddle spindle
Elliot type axle:
See elliot axle

ellipsoidal headlight:
A headlight with a reflector which is wider than it is high, and not circular;
has replaced the parabolic reflector
elongation:
The percentage increase in the length of a specimen when stressed to its
yield strength.
ELV:
Acronym for "End-of-Life Vehicles."
emblem:
See wheel trim emblem
embrittlement:
A reduced toughness in plastic or metal caused by age, heat or rough use.
Also see
hydrogen embrittlement
emergency:
A sudden, unexpected occurrence, such as a breakdown or the failure of
some part, which may be dangerous and demands immediate action.
emergency brake:
A braking system which is independent of the main hydraulic system. It
can be used to slow or stop the vehicle if the primary brakes fail, or to hold
the vehicle stationary though the brake pedal is not depressed. It usually
consists of a foot pedal or hand lever that actuates either front or rear
brakes mechanically through a series of cables and linkages. It is also
called the "parking brake" or E-brake.
emergency inflator:
An aerosol can which inflates a punctured tire and injects sealing
compound to provide at least a temporary repair
emergency transmitter:

A transmitter no larger than a car radio, fitted inside the vehicle which
enables a driver to radio for help from the security of his own car
emergency windshield:
A sheet of clear plastic fitted in place of a broken windshield
emery cloth:
A cloth coated in emery crystals like fine sandpaper for use as an abrasive
on metals
EMF:
Acronym for "electromotive force" See voltage.
Emily:
An affectionate name for the RollsRoyce radiator mascot, the "Spirit of
Ecstasy"
emission:
The
passing of
gases and
other toxic
substances
into the
atmospher
e.
Also see
automotive emissions
crankcase emissions
evaporative emissions
exhaust emission controls

exhaust emissions
low-emission
low Emission Vehicle Standards
particulate emission limit
particulate emission
emission control:
A system for restricting the amount of noxious emissions. There are two
standards for emission controls: level E for Europe and the more stringent
level U for the United States. See exhaust emission control evaporative
emission control system
Emission Control Information:
See Vehicle Emission Control Information
emission controls:
See exhaust emission control.
emission control system:
See
exhaust emission control system
emission levels:
amounts of toxic substances passed into the atmosphere by motor vehicles
emission limit:
See particulate emission limit
emissions:
Gases and other pollutants coming from a vehicle with an internal
combustion engine. See emission
emission standards:
specified maximum emission levels permitted from different classes of
motor vehicle in different countries

Emission Vehicle:
See Low Emission Vehicle Standards
Emission Vehicle Standards:
See
Low Emission Vehicle Standards
ultra Low Emission Vehicle Standards
emitter:
The lead of a transistor shown using an arrow with a head on it.
employment:
total employment in each manufacturing facility, including total
manufacturing employees, total support staff, and total engineering/R&D
staff. Average number of workers employed by an establishment during
the year. Production workers relate to the average number actually
engaged in the manufacturing process. Administrative and non-
manufacturing includes employees at head offices and sales offices.
employee benefits:
the provision of direct (salary, bonuses, etc.) indirect (vacation leave,
medical and dental plans, etc.) and deferred employee compensation
(pensions, etc.).
EMS:
Acronym for Engine Management System
emulsification:
The process of making an emulsion
emulsion:
A mixture of two liquids which do not fully mix, such as oil and water, or
specifically of gasoline and air in a carburetor before it is discharged and
fully atomized
emulsion tube:

part of a fixed jet carburetor, in which air is introduced into the mixture
through holes to help atomize it and correct excessive richness at higher
engine speeds. A perforated tube which extends from an air bleed in the
top of the air horn down into the main well. Admits air from the air bleed
into the main well to emulsify the fuel in the main well. Improves idle
response and stability when the engine is hot and prevents fuel percolation
and general hot-starting problems. Also improves response in the main
metering circuit during part throttle conditions. Also called main-well tube
enable:
A microcomputer decision that results in an engine management system
being activated and permitted to operate
enamel:
Type of paint that dries to a smooth, glossy finish. It is easier to apply than
cellulose. If cellulose is applied over it, the cellulose will lift (i.e., peel
off).
Also see
finishing enamel porcelain enamel
vitreous enamel
enamelling:
See vitreous enamelling
EN block:
See EN-block.
EN-block:
One piece -- such as an engine cylinder block cast in one piece.
enclosure:
See speaker enclosure
end:
See
belt end
big end
firing end
front end
male end
nut end
ring end gap
small end

bitter end
bottom end
drive end
drive end bracket
female end
front end alignment
gudgeon pin end
little end
open end lease
piston pin end
piston ring end gap
rear end
rear end lift
stud end
tie rod end
top end
wedge end
end alignment:
See front end alignment
end bearing:
See small end bearing
end bell:
End structure of plate of electric motor which usually holds motor
bearings.
end bracket:
The cover containing a bearing at each end of a generator or alternator.
Also called "end cover" or "end cover plate."
Also see
drive end bracket
slip-ring end bracket
end cap:
The cap covering the end of a piece of trim or of a barrel fuse
end cover:
Also called "end bracket" or "end cover plate"
end cover plate:
Also called "end cover" or "end bracket"
end cutters:
British term for a "side cutter"

end cutting:
See
end cutting pliers:
British term for "side cutter"
Also see
end dump:
A term used to describe various dump trucks or trailers that tilt to unload at
the rear.
end float:
End play
end form:
Any type of connector at the end of a hose or pipe.
end gap:
See
piston ring end gap
ring end gap
end gas:
The last part of the fuel-air mixture that has been introduced into the
cylinder but has not yet been consumed in the normal flame-front reaction.
end gear:
See axle end gears.
end gears:
See axle end gears.
end hexagon screwdriver:

See ball end hexagon screwdriver
end lease:
See
closed end lease
open end lease
end lift:
See rear end lift
endo:
(Short form for "end-over-end"). The maneuver of flying unexpectedly
over the handlebars, thus being forcibly ejected from the bike as in "If you
hit that log you'll go endo."
end-of-lease purchase price:
If there is a purchase option in the lease contract or agreement, this will be
the agreed upon price for the purchase of the vehicle at the end of the
lease-the stated residual value. This price may also include additional fees.
end-of term interest rate:
See buy at end-of term interest rate
endoscope:
An instrument used to see into the interior of hollow cavities such as box
sections
endothermal:
Chemical reaction in which heat is absorbed.
end piece:
See sill end piece
end play:
[1] The looseness in bearing clearance in an axial direction.
[2] Slight movement of shaft along its center line.

Also see
camshaft end play
end speed:
See top end speed
endurance test:
A test of a material or system over a long period to determine when it will
fail
enduro:
Off-road competition against the clock and usually over long distances
energize:
To activate (a solenoid, relay, etc.) by providing sufficient energy
energizing:
See self-energizing
energy:
Capacity (actual or potential) for doing work. It is measured in joules or
kilowatt-hours.
See
high energy battery
high energy coil
high energy ignition system
kinetic energy
potential energy
energy-absorbing:
The ability to absorb impact forces
energy absorbing bumper:
See bumper system.
energy-absorbing bumper:

See bumper system.
energy absorbing steering column:
A steering column which collapses when the vehicle is involved in an
accident.
energy audit:
Process of accurately determining the current energy consumption for a
given area.
energy battery:
See high energy battery
energy coil:
See high energy coil
energy conservation:
Process, upon reviewing the calculations for determining head loads, of
instituting changes that will result in energy savings.
energy conversion:
The changing of one form of energy into another or into work, such as that
in the combustion process, the heat of which is used to turn the engine and
thus create motion
energy efficiency ratio:
(EER) The ratio of the rated cooling capacity in Btu per hour divided by
the amount of electrical power used in watts.
energy ignition:
See
energy ignition system:

See
energy ignition system with electronic spark timing:
See high energy ignition system with electronic spark timing
energy management control system:
Controllers used in a system which optimizes total energy usage in a
building or residence.
Energy Protection Agency:
See EPA estimates.
energy retarder:
See engine brake.
energy utilization index:
(EUI) A number which is used to compare energy usages for different
areas. It is calculated by dividing the energy consumption (in BTUs) by
the square footage of the conditioned area.
engage:
[1] to come into contact and be locked together (with another part).
[2] to bring (a part) into contact with another so that it is locked to it
engagement:
The result of bringing into locking contact (e.g. of the clutch), or selection
of a gear
engaging the throttle:
The action of causing the throttle linkage to move so that more fuel enters
the engine to increase the speed of the vehicle.
engine:

A device for changing fuel energy to mechanical energy. The term applies
to the primary source of power generation. In Britain there is a desire to
make a clear distinction between "engine" and "motor" so that "motor"
refers only to electric power units (i.e., starter motor) and "engine" for
gasoline or diesel powered units. However, in the U.S.A. the term "motor"
can apply to both types. Yet, even in Britain, combustion driven vehicles
are called "motor cars" and "motorcycles."
Also see
adiabatic engine
air cooled engine
all-alloy engine
alloy engine
aspirated engine
balanced engine
big-block engine
boxer engine
cam engine
carburetor engine
cih engine
combustion engine
cubic inch engine
diesel engine
dual-piston engine
dual overhead cam
engine
electronic engine
control
engine types
exchange engine
external combustion
engine
F-head engine
federal engine
F head engine
fire engine
flat engine
flooded engine
four-cycle engine
four-cylinder engine
four-stroke cycle
engine
four cycle engine
four stroke cycle
engine
front engine
fuel-injected engine
fuel injection engine
high-camshaft engine
horizontally opposed
engine
hydrocarbon engine
I-head engine
IC engine
I head engine
in-line engine
inclined engine
indirect injection
engine
injected engine
inlet over exhaust
engine
inline engine
intake over exhaust
engine
internal combustion
engine
ioe engine
L-head engine
lean-burn engine
L head engine
long block engine
longitudinal engine
long stroke engine
mid-engine
naturally aspirated
engine
nominal engine speed
normally aspirated
engine
OHV engine
opposed engine
over square engine
pancake engine
piston-valve engine
piston engine
plastic engine
quad-cam engine
radial engine
rear engine
rebuilt engine
reciprocating
engine
reconditioned
engine
rotary engine
short block engine
short engine
short stroke engine
side-valve engine
SI engine
single-cylinder
engine
six-cylinder engine
sixteen valve
engine
slant engine
small-block engine
spark ignition
engine
square-four engine
square engine
steam engine
stirling engine
straight engine
stratified charge
engine
supercharged
Engine
SV engine
T-head engine
T head engine
three-port engine
three-valve engine
traction engine
transverse engine
twelve-cylinder
engine
twelve-valve engine
twin-piston engine
twin cam engine
twin camshaft
engine
two-cycle engine
two-stroke cycle
engine
two-valve engine
two stroke cycle
engine
U-cylinder engine
under-square engine
undersquare engine
under square engine
unit engine
V-eight engine
V-engine
V-four engine
V-six engine
V-sixteen engine
V-ten engine
V-twelve engine
V-type engine
V-X engine
valve-in-head
engine
vee engine
V engine
VR engine
V type engine
W-engine
wankel engine
winding the engine
X-engine
X-type engine
x. Liter Engine

HC engine
pre-combustion
engine
pushrod engine
push rod engine
turbine engine
turbocharged
engine
X engine
engine adapter:
A unit that allows a different engine to be installed in a vehicle and still
bolt up to the original transmission.
engine analyzer:
An electronic engine testing device which (because of its size) used to be
placed in a cabinet or a movable stand. The modern units are often hand-
held and are connected to the vehicle's diagnostic socket (as in the case of
the diagnostic read-out box), which provides data on all aspects of the
engine's state of tune
engine bay:
The engine compartment.
engine block:
The cylinder block.
engine block heater:
See block heater
engine brake:
(Energy Retarder or jake brake) A system that allows for slowing of a
vehicle that is independent of the conventional braking systems. A driver
would normally down-shift to slow his descent of a hill, using engine
compression. The engine brake increases the effectiveness of this
regarding force.
engine braking effect:
A retarding effect of an engine when the vehicle is in gear with the throttle
closed. Also called a "jake brake"
engine calibration unit:

An electronic component which can be specifically programmed to the
design of each car model to control the M/C solenoid. Plugs into the
Electronic Control Module (ECM). Also called a programmable read only
memory (PROM)
engine capacity:
The swept volume of an engine
engine compartment:
The space where the engine is mounted. Also called the "engine bay."
Also see
cluttered engine compartment
crowded engine compartment
engine control:
See electronic engine control engine control module
engine control module:
(ECM) An advanced electronic computer which monitors engine
conditions and then controls engine settings to optimize the combustion of
the air/fuel mixture.
engine control system:
See engine-control system.
engine-control system:
A computer that regulates the operation of the engine by monitoring
certain engine characteristics (rpm, coolant temperature, intake airflow,
etc.) through a network of sensors and then controlling key variables (fuel
metering, spark timing EGR, etc.) according to pre-programmed
schedules.
engine coolant:
Antifreeze liquid used in the engine's cooling system
engine coolant temperature sensor:

(ECT) the thermistor sensor that provides coolant temperature information
to the computer. Used to alter spark advance and EGR flow during warm-
up or an overheating condition
engine cover:
The panel which conceals the engine in a mid-engine car. Also called
"access panel." Also see hood (British "bonnet") which covers the engine
only in a front-mounted engine.
engine damage:
Breakage, deformation, or scoring of the internal parts of an engine due to
running at very high rpms for an extended period of time or with
insufficient lubrication. A rod could break off and drive a hole into the
cases; a valve could break off or imbed itself into the top of a piston; the
piston could heat and expand and thus seize against the cylinder walls; or
other types of damage could occur.
engine depression:
Low pressure on the engine side of the throttle caused by piston suction in
the inlet manifold
engine diagnostic connector:
The electrical connector for plugging in the engine analyzer, forming an
interface between the engine electronic controls and diagnostic unit, and
used to read the engine data as well as any fault codes stored in the
memory of the engine controller
engine displacement:
To determine, multiply the volume of the space through which the head of
the piston moves in the full length of its stroke by the number of cylinders
in the engine. The result is given in cubic inches.
engineering:
See
automotive engineering
badge engineering
production engineering

engine flywheel:
A spinning plate located at the end of the crankshaft. See flywheel.
engine hoist:
small crane for lifting an engine out of a motor vehicle, formerly
incorporating a block and tackle, but now usually hydraulically operated.
Also see
gantry
engine identification number:
(EIN) A number stamped on the engine which may or may not match the
number on the vehicle identification plate. Also called "engine number"
engine knock:
When the engine is operating, an audible noise may be heard when the fuel
in the cylinders is ignited too early and/or spontaneously, resulting in
colliding flame fronts and shock waves which cause high thermal and
mechanical stress, and can severely damage the engine.
engine layout:
[1] The type of engine, with reference to the arrangement of its cylinders
and their number (as in a flat four, V-twin, or straight eight).
[2] The location of the engine in the vehicle (as in a front mount, mid-
mount, or rear engine.
[3] The placement of the engine in the engine compartment: e.g., a
transverse or in-line engine
engine management system:
(EMS) An electronic engine control system which covers at least the
functioning of the fuel injection and ignition, but may also include
emission controls and self-diagnostics
engine map:
See characteristic map. As an engine speeds up, the timing needs to be
advanced. On older vehicles, this is accomplished mechanically with a
counterweight advance in the distributor. In modern vehicles, the timing
can be advanced progressively by means of a computer chip which is
programmed to provide the ideal timing. It also provides other factors in

some engines such as the opening and closing of valves, etc.
engine misfire:
See misfire
engine modifications:
Alterations to the specification of the engine to increase power output,
improve economy, reduce emissions, etc.
engine mounting:
A flexible support for the engine in which an elastic medium, usually
rubber, is interposed between the lugs on the engine and the frame of the
vehicle
engine noise:
The amount of noise produced by the engine when it is running. Engine
noise is more noticeable with a diesel at lower speeds
engine number:
(EIN) A number stamped on the engine which may or may not match the
number on the vehicle identification plate. Also called "engine
identification number"
engine oil:
Oil within the engine used to lubricate the moving components. At one
time the oil was a single grade, but modern engines use a multigrade oil.
Also see
straight weight engine oil
synthetic engine oil
engine oil pan:
See oil pan.
engine oil level warning light:
A light on the instrument panel which comes on when the oil in the sump
falls below a certain level

engine overhaul:
When an old engine burns too much oil and loses power, it is dismantled
and restored to the manufacturer's original tolerances by replacement of
worn parts, reboring the cylinders, regrinding the crankshaft, etc.
engine parameters:
A term used in the context of emission controls for those engine
characteristics sensitive to engine performance, such as power/bhp,
general engine performance, and fuel economy
engine performance tester:
An engine analyzer
engine sequence test:
The test which determines how well oil will prevent engine rusting,
corrosion, scuffing, wear, and the formation of sludge and varnish.
engine size:
The engine displacement or capacity
engine speed:
The number of revolutions per minute (rpm) at which the engine
crankshaft turns. The vehicle itself may be stationary or in motion.
Also see
nominal engine speed
engine speed limiter:
A device which acts as a governor which cuts the power when a certain
number of rpm is reached
engine speed sensor:
In most cases, a magnetic pick-up that scans the flywheel teeth and
produces one output signal per scanned tooth, or a hall generator in the
distributor, whose signals are passed to the electronic control unit

engine subframe:
A separate frame in which the engine is mounted
engine temperature sensor:
A sensor used to monitor the temperature of the engine
engine timing:
[1] The point of time when the spark ignites the air/fuel mixture (ignition
timing)
[2] The setting of the valves when they open or close (valve timing)
engine type:
Over the years of engine development, several types or configurations
have been made. All of them relate to the position of the valves and the
camshaft (s) that operates them.
• air cooled engine -- An engine which is not cooled by antifreeze but
by passing air beside external fins.
• diesel engine -- An engine with high compression that pressurizes
the diesel oil fuel and fires the charge through compression not by a
spark plug.
• DOHC -- double overhead camshafts
• F-head -- Side exhaust valve and overhead intake valve.
• flat engine
• four-stroke cycle engine
• hemi or hemi-head -- Engine using hemispherical-shaped (half of a
globe or sphere) combustion chambers.
• horizontally opposed engine
• hydrocarbon engine
• I-head -- Both valves located directly over the piston. Also called
valve-in-head or overhead valve engine.
• in-line engine
• internal combustion engine
• L-head -- Both valves on one side of the cylinder
• oversquare engine
• pancake engine
• radial engine
• rotary engine
• slant engine
• SOHC -- Single overhead camshaft.
• square engine

• steam engine
• stirling engine
• stratified charge engine
• straight engine
• T-head -- exhaust valve on one side and intake valve on the other
side of the cylinder and found on twin-camshaft engines.
• traction engine
• transverse engine
• turbine engine
• two-stoke cycle engine
• undersquare engine
• V-type -- Two sets of cylinders set apart in a V-formation like a V-8
or V-6
• valve-in-head engine
• wankel engine
• X-type
engine warning light:
See check engine warning light
enrichment:
making the air/fuel mixture richer, i.e., increasing the fuel content.
Also see
acceleration enrichment
after-start enrichment
cold start enrichment
cranking enrichment
full load enrichment
full throttle enrichment
hot start enrichment
warm-up enrichment
enrichment device:
A circuit in a carburetor providing a richer mixture, operated by engine
vacuum
enrichment unit:
A circuit in a carburetor providing a richer mixture, operated by engine
vacuum

enrichner:
A fuel plunger which is used in a carburetor in place of a choke. By
activating the plunger more gas is permitted into the intake area to
enrichen the fuel-air mixture for easier starting.
Also see
choke
entertainment:
See in-car entertainment
enthalpy:
Total amount of heat in one pound of a substance calculated from accepted
temperature base. Temperature of 32 0F (0 0C1 is accepted base for water
vapor calculation. For refrigerator calculations, accepted base is -400F
(-400C).
entrain:
to add or suspend bubbles or particles in a moving fluid
entrepreneur:
One who undertakes ownership of a business or enterprise
entrepreneurship:
A person's ability to organize, manage, and assume risks of operating a
business
entropy:
Mathematical factor used in engineering calculations. Energy in a system.
entry:
See
illuminated entry system
keyless entry system
multi-entry
remote keyless entry

entry-level version:
basic model suitable as someone's first car
entry model:
basic model suitable as someone's first car
entry system:
See
illuminated entry system
keyless entry system
envelope:
[1] A thin rubber wrapper that surrounds the tread, sidewall and is tucked
inside the curing rim during the pre-cured cold process retreading. It
protects bonding materials from humidity within the chamber.
[2] A cover enclosing something entirely, such as the glass of a lamp bulb.
Also see
outer envelope
envelope separator:
A porous plastic separator used in maintenance-free batteries to enclose
the individual plates completely
enveloping body:
See all-enveloping body
environment:
The surrounding conditions.
environmentally aware:
An awareness of the dangers and threats to the environment caused by
vehicle use and the taking of appropriate action to avoid them
environmentally friendly:
Something that is harmless to the environment, or causing as little harm as
possible

Environmental Protection Act:
See canadian Environmental Protection Act
environment-conscious:
An awareness of the dangers and threats to the environment caused by
vehicle use and the taking of appropriate action to avoid them
enzyme:
Complex organic substance, originating from living cells, that speeds up
chemical changes in foods. Enzyme action is slowed by cooling.
EPA:
[1] Acronym for "Energy Protection Agency." Also see EPA fuel economy.
[2] Acronym for "Environmental Protection Agency" which is responsible
fol recommending environmental legislation and in the automotive sphere
produces test cycles and estimates fuel economy
EPA estimate:
An American organization (Energy Protection Agency) which determines
the fuel consumption of various vehicles. It takes into account city and
highway driving. These figures may be helpful in comparing one vehicle
against another. Your vehicle can greatly exceed these estimates with
sensible driving, the use of cruise control obeying the speed limits
avoiding rapid starts, coasting long before a stop light or sign.
Also see
EPA fuel economy
EPA estimates:
An American organization (Energy Protection Agency) which determines
the fuel consumption of various vehicles. It takes into account city and
highway driving. These figures may be helpful in comparing one vehicle
against another. Your vehicle can greatly exceed these estimates with
sensible driving, the use of cruise control obeying the speed limits
avoiding rapid starts, coasting long before a stop light or sign.
Also see
EPA fuel economy
EPA fuel economy:

Laboratory fuel economy tests administered by the Environmental
Protection Agency (EPA) using simulated weight and drag to re-create real
driving conditions. The city fuel-economy test, also used to test emissions
compliance is based on a drive through typical Los Angeles urban traffic
of about twenty years ago. Such conditions in LA are no longer present.
The highway test uses a higher, steadier speed averaging 79.5 kph (49.4
mph).
EPC:
Acronym for Electrostatic Powder Coating
EP gear oil:
An extreme pressure gear oil preventing metal-to-metal contact, used
mainly in gearboxes and final drive units. Also called "EP lubricant"
epicyclic:
See epicyclic gearbox.
epicyclic gear:
A gear that operates around the circumference of another
epicyclic gearbox:
A form of gear used by Benz in which small pinions revolve around a
central or sun gear and mesh with an outer ring gear called the annulus.
Type used in the Ford Model T. Also called planetary gearset "planetary
transmission" and "sun-and-planet gears."
epitrochoid:
A geometric path followed by a specific point located in a generating
circle which is rolled around the periphery of a base circle.
epitrochoidal:
A part of a circle which is not on the circumference of another circle
around which it turns
EP lubricant:

See extreme pressure lubricant.
epoxy:
Synthetic plastic adhesive.
epoxy adhesive:
Adhesives which offer a combination of high room temperature strength
with good load bearing properties. These adhesives have exceptional
adhesion to metal surfaces
epoxy resin:
A thermosetting resin based on ethylene oxide or similar materials or
derivatives, used in adhesives, fillers, and primers and other finishes
EPR:
[1] Acronym for evaporator pressure regulator valve.
[2] Acronym for exhaust pressure regulator
EPR system:
Acronym for evaporator pressure regulator
EPS:
Acronym for electronically controlled power steering. EPS is used in more
expensive models, such as the BMW Servotronic system where the
assistance provided alters according to the speed at which the car is
travelling
equalizer:
A bracket or cable connector which balances tension equally on the cables
to the parking brakes.
See
graphic equalizer
compensator
equalizer line:
In air conditioner system, a line or connection used to operate certain
control valves. Little or no refrigerant flows through the line

equal length header:
An exhaust manifold where the runners from each cylinder are of equal
length. Such a system allows exhaust pulses to meet at the collector or
single pipe in a controlled sequence, thus enhancing cylinder evacuation
and gas flow.
equal power distribution:
A system in four-wheel drive vehicles which ensures that an equal amount
of power is passed to the front and rear wheels
equal power split:
A system in four-wheel drive vehicles which ensures that an equal amount
of power is passed to the front and rear wheels
equation:
See nernst equation
equilibrium:
See thermal equilibrium
equipment:
devices and systems fitted to a vehicle which are either essential or
optional, and either fitted by the manufacturer (original equipment) or
subsequently by the owner (after market equipment).
Also see
aftermarket equipment
integral equipment
low-bake equipment
optional equipment
original equipment
standard equipment
equipment package:
A combination of equipment provided by the manufacturer
ergonomics:

[lit: The law of work] Technically, it means the biotechnology study of
how human beings relate to their surroundings and how efficiently they
perform in that environment. However, the meaning has also come to be
used in a qualitative sense so that a vehicle has good or bad ergonomics
meaning that the controls, switches, instruments, seats, pedals, and
steering wheel suit the human driver.
Ergopower shifter:
Campagnolo's integrated brake levers/shifter levers which provides the
ability to shift gears without taking your hands off of the handlebars.
erode:
to remove a surface layer (by chemical action or by rubbing)
erosion:
A reduction in size of an object because of a liquid or gas impact on the
object.
error:
See driver error
ESA:
Acronym for Electronic Spark Advance
ESC:
Acronym for Electronic Spark Control
escape trunk:
A vertical trunk fitted with a ladder to permit personnel to escape if
trapped

Escort:
Click for books on Ford Escort
escutcheon:
A panel or part used to hide another part
ESR:
Acronym for electric sunroof
EST:
Acronym for electronic spark timing system
establishment:
smallest operating entity producing a homogenous set of goods and
services and is capable of reporting full range of production account
variables to calculate "value added."
estate car:
A British term for a station wagon
estimate:
See estimates.
estimates:
A guess on the part of a service department with respect to the nature of a
vehicle's problem and cost of repairing it. Although most shops will stand
by their estimate, there is also the situation where the problem is caused by
something which will be more expensive to repair or may be less
expensive. In the case where other components are also faulty (but the
estimate did not include them), the shop may contact the customer with a
revised estimate saying, "We can repair what we thought was the faulty
part, but we found another defective part which also contributed to the

problem once we took things apart. Now the cost will be more. Do you
want us to go ahead and repair that component too?" In the case where a
lesser solution repaired the problem, good shops will give you a bill that is
much less than the estimate with an explanation like, "We thought we had
to replace the expensive control box, but we found that one of its plugs
had come loose."
Also see
EPA estimates
ESV:
Acronym for Experimental Safety Vehicle
ET:
Acronym for "elapsed time." The length of time it takes a dragster to
complete the one-fourth mile run.
ETA:
Acronym for "expected time of arrival."
ETC:
Acronym for Electronic Traction Control
etching:
[1] A roughening or disintegration of the paint surface, which can occur on
small patches or over a wide area, through attack from bird droppings,
soap deposits, industrial fallout, etc. Also called "lifting."
[2] The removal of soil or the natural oxide film from an aluminium
surface, giving a roughened surface which improves adhesion of the
subsequent paint layer, or removal of the actual metal.
[3] A system of marking car windows with the registration number so as to
deter thieves.
Also see
caustic etching
window etching
etching primer:
A primer for aluminum which has an etching effect to improve adhesion

etch primer:
A primer for aluminum which has an etching effect to improve adhesion
ethane:
(R-170) Refrigerant sometimes added to other refrigerants to improve oil
circulation.
ethanol:
ethyl alcohol which is added to gasoline, typically in a mixture of 10%
ethanol and 90% unleaded gasoline
ethyl acrylate:
A polymer used in toughening rubber
ethylene glycol:
A chemical solution added to the cooling system to protect against
freezing. See antifreeze.
ethyl gasoline:
Gasoline to which ethyl fluid (tetraethyl lead ethylene dibromide, ethylene
dichloride, or another octane improver) has been added to improve the
gasoline's resistance to knocking. It slows down the burning rate thereby
creating a smooth pressure curve that will allow the gasoline to be used in
high compression engines. It is a generic term describing premium or
high-octane fuel. It was first sold in 1924.
ETR:
Acronym for evaporator temperature regulator
ETRTO:
Acronym for "European Tyre and Rim Technical Organisation."
EUI:
Acronym for energy utilization index

Euromix formula:
The basis for a standard test cycle covering both town driving and driving
on the open road. In North America a similar is called the "Town and
Country Formula"
eutectic:
That certain mixture of two substances providing lowest melting
temperature of all the various mixes of the two substances.
eutectic alloy:
A mixture of metals which has a melting point lower than that of any of
the metals in the mixture, or of any other mixture of these metals.
eutectic point:
Freezing temperature for eutectic solutions.
evacuate:
[1] To remove by pushing out.
[2] To create a vacuum in an air conditioning system to remove all traces
of air and moisture.
[3] To pump the air, moisture and foreign material out of the system with a
vacuum pump. Also called pump down
evacuation:
Removal of air (gas) and moisture from a refrigeration or air conditioning
system.
evaluation:
See driver evaluation
EVAP:
Acronym for evaporative emission control system
evaporate:

to turn into a vapour
evaporation:
The process of changing from a liquid to a vapor, such as boiling water to
produce steam; evaporation is the opposite of condensation. Heat is
absorbed in this process of evaporation. Evaporation can occur at various
temps, depending on the liquid and the pressure. Also refers to solvents in
the paint escaping to the air.
Also see
early fuel evaporation system
evaporative condenser:
Device which uses open spray or spill water to cool a condenser.
Evaporation of some of the water cools the condenser water and reduces
water consumption.
evaporation control system:
(EVAP or ECS) A system for reducing evaporative emissions by means of
a sealed fuel tank, a vapour-liquid separator, a three-way valve, an
activated carbon filter, and a network of interconnecting hoses. A system
used to prevent the escape of gasoline vapors to the atmosphere from the
fuel tank and carburetor. Also called "evaporative Emission Control
system"
evaporation system:
See early fuel evaporation system
evaporative emission control system:
(EVAP pr EEC) A system for reducing evaporative emissions by means of
a sealed fuel tank, a vapour-liquid separator, a three-way valve, an
activated carbon filter, and a network of interconnecting hoses. Also called
"evaporation control system"
evaporative emissions:
Vapours or fumes not emitted by the exhaust system, but escaping from
the fuel tank, carburetor and crankcase, and accounting for about 40% of
hydrocarbon emissions released by a gasoline engine without emission
controls

evaporative emission shed system:
(EESS) a Ford evaporative emission control system introduced in 1978
evaporative losses:
Vapours or fumes not emitted by the exhaust system, but escaping from
the fuel tank, carburetor and crankcase, and accounting for about 40% of
hydrocarbon emissions released by a gasoline engine without emission
controls
evaporator:
The unit in an air conditioning system used to transform refrigerant from a
liquid to a gas. It is at this point that cooling takes place as heat is removed
from the air. An air conditioning system component through which cool,
liquid refrigerant is pumped at a reduced pressure. When heated by the
warm passenger compartment air being forced through the evaporator, the
refrigerant evaporates, drawing heat from the air as it passes over the
cooling fins. Opposite to "condenser."
evaporator, dry type:
Evaporator in which the refrigerant is in the liquid droplet form.
evaporator equalized valve in receiver:
(EEVIR) A unit similar in design to a valve-in-receiver type, except that it
has an equalizer port of the expansion valve that allows for faster reaction
time
evaporator fan:
Fan which increases airflow over the heat exchange surface of
evaporators.
evaporator, flooded:
Evaporator containing liquid refrigerant at all times.
evaporator pressure regulator:

Automatic pressure regulating valve mounted in suction line between
evaporator outlet and compressor inlet. Purpose is to maintain a
predetermined pressure and temperature in the evaporator.
evaporator pressure regulator valve:
(EPR) An evaporator temperature control device regulated by back
pressure. Used on an older Chrysler Corp. system. Located in the
compressor inlet. A system using this device is referred to as an EPR
system
Evaporator temperature regulator valve:
(ETR) A temperature-regulated evaporator temperature control device used
on some early model Chrysler Corp. systems
EVAP system:
Acronym for Evaporative Emission Control System
EVC:
Acronym for Exhaust Valve Closes
even keel:
A ship at even keel is when the keel is horizontal
evil kenivel:
Trucker slang for Motorcycle cop as in "Ther's an Evil Kenivel taking
pictures at the 38."
EVO:
Acronym for Exhaust Valve Opens
evolution:
[evo] When Harley-Davidson began using aluminum to build its cylinder
jugs, it called this new engine the Evolution
EVP:

Acronym for EGR valve position sensor
EVR:
Acronym for electronic voltage regulator
EVRV:
Electronic vacuum regulator valve
EVT:
Acronym for "Electromagnetic Valve Train."
EW:
acronym for "electric windows"
examination:
See metallographic examination
exc:
Abbreviation for "excellent," as in exc condition.
Excalibur:
A vehicle brand of which the 1965-69 model II Series I are milestone cars.
exchange engine:
A replacement engine which is provided in exchange for a worn engine
while the original engine is being rebuilt
exchange process:
See charge exchange process
exchanger:
See heat exchanger.

Excelsior:
The 1925-1948 models with required application are classic cars.
excitation winding:
Field winding
excite:
To pass an electric current through a unit such as the field coils in the
generator.
exciter coil:
A primary coil which provides stepped up voltage to a second coil.
exciter winding:
Field winding
excluder:
See draught excluder
ex-demonstrator:
A vehicle which had been used as a demonstrator and is now available for
sale
exducer:
The outermost section of a turbine wheel, used to purge the turbine of
exhaust gases
executive car:
A large, powerful luxury car considered suitable for a business executive
exfiltration:
Slow flow of air from the building to the outdoors.

exhaust:
[1] To expel spent fumes.
[2] The spent fuel after combustion takes place
in an internal combustion engine. Sometimes it
refers to the exhaust system.
Also see
dual exhaust system
intake over exhaust engine
raw exhaust gas
residual exhaust gases
tuned exhaust
tuning the exhaust
exhaust back pressure:
any pressure holding back the flow of the gases in an exhaust system.
Pressure exerted in exhaust system in reverse direction. Also called back
pressure
exhaust back pressure transducer valve:
(BPV or BPS) a device sued to sense exhaust pressure changes and control
vacuum to the EGR valve in response to these changes
exhaust cam:
A separate camshaft controlling the opening and closing of the exhaust
valves used in twin overhead camshaft engines
exhaust camshaft:
A separate camshaft controlling the opening and closing of the exhaust
valves used in twin overhead camshaft engines
exhaust chamber:
part of the two-stroke exhaust system designed to maintain a specified
back pressure
exhaust cutout:
A Y-shaped device that is placed in the exhaust pipe ahead of the muffler.
The driver may channel the exhaust through the muffler or out the other

leg of the "Y" where the exhaust passes out without going through the
muffler.
Also see
cutout
exhaust donuts:
The small rubber hangers used to suspend the exhaust system from the
chassis pan
exhaust emission:
See exhaust emissions.
exhaust emission control:
See exhaust emission controls
exhaust
emission
controls:
Systems
or
adjustment
s designed
to limit
noxious
gases in an
engine's
exhaust.
Such
controls
can be
grouped
into two
broad
categories:
those
designed
to reduce
or
eliminate
the

formation
of harmful
pollutants
in the
engine
itself (e.g.,
retarded
spark
setting)
and those
designed
to destroy
or
otherwise
alter the
pollutants
after they
have been
formed
(e.g., air
injection,
thermal
reactors,
and
catalytic
converters
).
Evaporativ
e emission
controls
prevent
gasoline
vapors
from
escaping
into the
atmospher
e from the
fuel tank
and
carburetor
and
crankcase

controls
recycle
fumes
from the
crankcase
through
the engine.
exhaust emission control system:
A general term for any system that reduces the harmful exhaust emissions
of a motor vehicle, including one or all of the following systems: catalytic
converter (with or without oxygen sensor air/fuel control), exhaust gas
recirculation, secondary air injection or induction, and positive crankcase
ventilation
exhaust emissions:
The unburned hydrocarbons, carbon monoxide, oxides of nitrogen, and
other noxious gases emitted when gasoline is burned in an engine.
exhaust engine:
See intake over exhaust engine
exhaust gas:
gas which is the product of the combustion process and which is passed
out of the cylinder through the exhaust valve or port into the exhaust
system.
Also see
raw exhaust gas
residual exhaust gases
exhaust gas analyzer:
An instrument for determining efficiency with which an engine is burning
fuel. See exhaust-gas analyzer.
exhaust-gas analyzer:
An instrument used to measure the exhaust gases (in parts per million,
percent, grams per kilometer, or grams per mile) to determine both
combustion efficiency and the amount of pollutants in the exhaust.

exhaust gas check valve:
(EGC) a device that allows air injection system air to enter the exhaust
manifold, but prevents a reverse flow in the event of improper operation of
other components
exhaust gas oxygen sensor:
(EGO) a device that changes its output voltage as the exhaust gas oxygen
content changes when compared to the oxygen content of the atmosphere.
This constantly changing voltage signal is sent to the processor for
analysis and adjustment to the air/fuel ratio
exhaust gas purification system:
An emission control system for diesel engines, which may consist of an
exhaust scrubber, a diesel exhaust filter, and/or a catalytic converter
exhaust gas recirculation:
See exhaust-gas recirculation.
exhaust-gas recirculation:
(EGR) An emission control system where some of the exhaust gases are
rerouted from the exhaust manifold into the combustion chamber to make
sure that all fuel is burned before entering the atmosphere. The process
lowers the combustion temperature and reduces the formation of oxides of
nitrogen (NOx) in the exhaust.
exhaust gas recirculation system:
(EGR) a system used to control oxides of nitrogen (NOx) the exhaust
gases are recirculated, lowering the engine combustion temperature,
thereby reducing engine pollutants
exhaust gas:
See exhaust gases.
exhaust gases:

The burned and unburned gases which are expelled out of the exhaust
system after combustion takes place.
Also see
exhaust emissions
exhaust header:
Steel tubing connecting pipes between the exhaust ports and the exhaust
pipe. Usually a header has been polished to allow for better flow of the
exhaust.
Also see
exhaust manifold
exhaust heat control valve:
(HCV) a valve which routes hot exhaust gases to the intake manifold heat
riser during cold engine operation. Valve can be thermostatically
controlled, vacuum operated or computer controlled
exhaust manifold:
The connecting pipes between the exhaust ports of each cylinder and the
exhaust pipe. It is usually made of cast iron. Sometimes called the
"exhaust header " but it is usually made of steel tubing.
exhaust note:
The sound coming from the end of the exhaust pipe. It is usually described
as pleasant, loud, throaty, or sporty.
exhaust oxygen sensor:
Device that detects the amount of oxygen in the exhaust stream and sends
that information the ECM. Also called an oxygen sensor or an O2 sensor

exhaust pipe:
Pipe
connectin
g exhaust
manifold
or header
to the
muffler.
exhaust pollutants:
Exhaust emissions
exhaust port:
[1] The
passage in the
cylinder head
which connects
the exhaust
valve and the
exhaust
manifold. The
exhaust gases
pass through
the port to the
exhaust
manifold or
header.
[2] On two-
stroke engines
the exhaust
port is cut into
the cylinder
wall because it
does not have
valves.
[3] That
opening which
carries the fluid
to the

downstream
pressure of a
fluid system.
Also see
adjustable variable exhaust port
variable exhaust port
exhaust pressure regulator:
(EPR) a device for increasing exhaust backpressure at specific times to
increase exhaust flow to the EGR valve
exhaust scrubber:
A diesel exhaust gas purification system which cools the exhaust and
separates nitrogen oxide and oil vapours from the gas stream
exhaust side:
The side of the engine where the exhaust valves and exhaust manifold are
located
exhaust stroke:
The fourth stroke of a four-stroke cycle where
the piston moves upward from bottom dead
center to top dead center and pushes the
burned exhaust gases out of the cylinder.

exhaust system:
The pipes, resonators and mufflers that carry
the exhaust gases from the exhaust manifold
out into the atmosphere.
Also see
dual exhaust system
stainless-steel exhaust system
twin exhaust system
exhaust timing:
exhaust control system developed especially for two-stroke motorcycle
engines in order to enhance low and mid-range power
exhaust treatment:
any measures taken to reduce the pollutant concentrations in the exhaust of
an internal combustion engine released into the atmosphere
exhaust tuning:
Cutting the exhaust pipe to a length that provides maximum efficiency.
exhaust turbocharging:
See turbocharging

exhaust valve:
[1] The valve
through which
the burned fuel
charge passes
on its way
from the
cylinder to the
exhaust
manifold. It is
driven by the
camshaft.
When
comparing an
exhaust valve
with an intake
valve in the
same engine,
the part of the
exhaust valve
that seats into
the head (i.e.,
not the stem)
will have a
smaller
diameter than
the intake
valve.
[2] A movable
port which
provides an
outlet for the
cylinder gases
in a
compressor or
engine.
Also see
sodium-cooled exhaust valve
exhaust valve closes:
(EVC) A mark on a valve-timing diagram
exhaust valve opens:

(EVO) A mark on a valve-timing diagram
exothermal:
Chemical reaction in which heat is released.
expander:
[1] A ring placed under a piston ring to increase ring pressure on the
cylinder walls. For instance an oil control ring may have an expander ring
to assist the oil-control ring to scrape oil off the cylinder wall and provide
further sealing. See piston ring expander.
[2] A device in a drum brake system (either hydraulic or mechanical)
which forces the shoes apart into contact with the drum.
Also see
bead expander
piston skirt expander
ring expander
skirt expander
tailpipe expander
wedge expander
expander spacer:
See expander ring
expanding:
See piston skirt expanding
expansion:
An increase in size, for example: when a metal rod is heated, it increases
in length and perhaps also in diameter. Expansion is the opposite of
contraction.
Also see
piston expansion
shell expansion
expansion joint:
Device in piping designed to allow movement of the pipe caused by the
pipe's expansion and contraction.

expansion plug:
A steel plug, slightly dished or cup-shaped. When driven into place it
flattens to fit tightly in its seat. In an engine block, expansion plugs (also
called freeze plugs or core-hole plugs) are inserted into the holes in the
casting through which core was removed when casting was formed. They
open into cooling passages and thus provide pressure relief should the
engine coolant freeze and expand. See core plugs.
expansion stroke:
See power stroke
expansion tank:
When the engine is heated, the coolant expands to fill any available space
(usually in the radiator). Before the introduction of coolant expansion
tanks, the excess coolant was forced out of a vent tube and on the ground.
The expansion tank collects the coolant so that when the engine cools off,
the resultant vacuum sucks the coolant from the tank back into the
radiator.
expansion tube:
A device that converts high pressure liquid refrigerant into low pressure
liquid refrigerant (thus lowering its boiling point) before it passes through
the evaporator. The expansion valve replaces the thermostatic expansion
valve. It is also referred to as a fixed orifice tube
expansion valve:
A part of an air-conditioning system, located between the condenser and
the evaporator that regulates the flow of liquid refrigerant to the vaporator.
If cooling needs are low, the valve is almost closed; as additional cooling
is required, the valve opens wider so that more liquid refrigerant flows to
the evaporator. It reduces the pressure from the high side to the low side
and is operated by pressure. Also called an automatic expansion valve
(AEV) or "thermostatic expansion valve."
expansivity:
See coefficent of expansion
expected residual value:

This is the projected or expected value of the vehicle at the end of the
lease. Residual value is a measure of the vehicle's expected depreciation.
expendable refrigerant system:
System which discards the refrigerant after it has evaporated.
expenditures:
See capital expenditures
experiment:
See windsor experiment
Experimental Development Program:
See scientific Research and Experimental Development Program
Experimental Safety Vehicle:
(ESV) A special vehicle built for research into and testing of safety
features; (compare SID)
exploded view:
A drawing of a mechanism or structure which shows the parts separately
but approximately in the position they occupy when assembled
explosion:
A rapid disintegration of an object. See clutch explosion.
Export Restraint:
See Voluntary Export Restraint
expressway:
A US multilane highway road with limited access to be used for rapid
travel with few interchanges.
ext:

Abbreviation for "exterior."
Extended Cab:
A type of pickup truck
(by GM) which has a
second row of seating;
but unlike a crew cab
(which has four full size
doors) it has a "half-
door" that can be opened
only after the main door
is opened. The seating is
usually a little more
cramped than in a crew
cab. Also called Club
Cab, King Cab, XtraCab,
Access Cab, SuperCab,
or Cab Plus.
extension:
A part which is inserted between a ratchet and a socket to provide access
to nuts or bolts which are deeply inset or hard to reach. Also called
"extension bar" or "extension piece."
Also see
brake extension
fender extension
load floor extension
park brake extension
piston extension screw
valve extension
wheel arch extension
wing extension
extension bar:
See
extension
wobble extension bar
extension housing:
See transmission extension housing

extension piece:
See extension
extension screw:
See piston extension screw
extension spring:
A closed-coiled helical spring that offers resistance to a pulling force.
exterior mirror:
The mirror that is usually mounted on the door. In Japan (and other
countries) it was mounted on the front fenders. Also called "external
mirror."
external combustion engine:
An engine that burns its fuel outside the engine. A steam engine is an
external combustion engine.
external diameter:
The outside diameter of a cylinder, tube, or washer
external drive:
Term used to indicate a compressor driven directly from the shaft or by a
belt using an external motor. Compressor and motor are serviceable
separately.
external drive compressor:
See compressor, open type
external equalizer:
Tube connected to low-pressure side of a thermostatic expansion valve
diaphragm and to exit end of evaporator. See equalizer line
externally-balanced crankshaft:

A crankshaft that requires external balancing weight, usually on the
vibration damper of the flywheel, for balance
external micrometer:
A micrometer for measuring external diameters
external mirror:
The mirror that is usually mounted on the door. In Japan (and other
countries) it was mounted on the front fenders. Also called "exterior
mirror."
external mix air cap:
A special type of air cap for spray guns. Air and fluid are mixed in the
space outside the air cap, directly in front of the nozzle: the most common
type of air cap.
Also see
external thread:
Thread consisting of projecting ridges on the outside of a part such as a
bolt or screw (which fits into the corresponding internal thread of a nut).
Also called male thread
external vane pump:
A pump with either an elliptic rotating piston or an eccentrically mounted
circular rotor
extinguisher:
See fire extinguisher
extractor:
A device for removing some object (e.g., bearing, bushing, sleeve, bolt,
stud, etc.).
See
oil and water extractor
screw extractor
stud extractor

extras:
Optional items either supplied by the manufacturer at the buyer's request,
or added later by the owner. Usually they are things like seat covers, floor
mats, additional lights, sunroof, glass tinting, CD changers, etc.
extreme-pressure lubricant:
(EP lubricant) A lubricant designed and compounded to withstand very
heavy loads imposed on gear teeth.
extruder:
A machine that shapes a rubber compound into a usable form. Uncured
rubber is heated to soften and forced through dies having the desired shape
and dimensions.
eye:
A circular opening or hole, such as that at the end of a leaf spring or that
formed at the end of a cable.
Also see
fish eye
impeller eye
spring eye
towing eye
eyebolt:
A bolt with an eye in place of a head, through which a cable can be passed,
e.g. for lifting purposes
eyelet:
A frame attachment that allows you to mount racks or fenders to the
bicycle.
eyelet connector:
A connector for electrical connections which is attached to a wire and has
its ring-shaped end pushed onto a round post or threaded terminal
eyelet pliers:

Pliers for punching small holes, with a round stud in one jaw and a hole in
the other

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