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V: A letter rating for tires to indicate that they
are theoretically rated for speeds up to 240 kph (149 mph), as in P220VR15.
The next higher rating is W
and the one lower rating is H
v: A tire rating for speeds above 210 kph (130
mph) as in P185VR13.
VA: Value analysis.
vacuum: An enclosed area in which the
air pressure is below that of the surrounding atmospheric
pressure. Also see air-valve
carburetor and manifold
vacuum.
vacuum advance: A
mechanism on the side of the distributor
that automatically varies the instant at which the spark
occurs as a function of intake
manifold vacuum. Vacuum advance provides the additional advance that is
needed when the engine is operating at part throttle. At part throttle less air-fuel
mixture gets into the cylinders
and the mixture takes longer to burn after it is ignited. Because the mixture
burns more slowly, the piston
will be past top
dead center and moving down before the mixture has a chance to burn and
produce high power. As a result much of the power in the fuel will be lost. The
vacuum advance mechanism consists of a flexible spring-loaded diaphragm
connected by a linkage
to the breaker
plate on which the points are mounted. The sealed side of the diaphragm
is connected by a tube to the carburetor.
The throttle
valve is below the vacuum passage in the carburetor air horn
so there is no vacuum advance when the engine is idling because the throttle is
closed. However, when the throttle is partly open, intake
manifold vacuum pulls the diaphragm
in and this causes the breaker
plate to rotate a few degrees and advance the timing.
With wide-open throttle there is very little vacuum in the intake
manifold so there will be no vacuum advance. In most instances the vacuum
advance is disconnected before checking the timing and point
gap.
vacuum assisted
brake: See brake
booster.
vacuum assisted
brakes: See brake
booster.
vacuum booster: A small diaphragm
vacuum
pump, generally in combination with the fuel
pump, that is used to bolster engine vacuum
during acceleration
so that the vacuum operated devices will continue to operate.
vacuum gage: See vacuum
gauge.
vacuum gauge: A gauge used to
determine the amount of vacuum
existing in a chamber.
vacuum modulator: A
small unit attached to the automatic
transmission. If the vehicle tends to stay in low
gear, shifts with difficulty or produces whitish smoke, has an automatic
transmission, and is constantly low in transmission
fluid, try replacing the vacuum modulator before undertaking major repairs.
Most vacuum modulators simply screw into place. See modulator.
vacuum pump: A diaphragm
type of pump
used to produce a vacuum.
vacuum runout point:
This refers to the point reached when a vacuum brake power piston
has built up all the braking force it is capable of with the vacuum
available.
vacuum tank: A tank in which a vacuum
exists. It is generally used to provide vacuum to a power
brake installation in the event engine vacuum cannot be obtained. The tank
will supply several brake applications before the vacuum is exhausted.
value of shipment:
summation of value of shipments produced by establishment, receipts of custom
and repair revenue.
valve: A device used to either open or
close an opening to allow or prevent the flow of a liquid or gas from one place
to another. There are many different types. Also see air-valve
carburetor, anti-backfire
valve, anti-percolation
valve, blowoff
valve, brake
proportioning valve, butterfly
valve, bypass
valve, cam
follower, check
valve, compensator
valve, economizer
valve, exhaust
valve, expansion
valve, fuel
injector nozzle, heat
control valve, hydraulic
valve lifter, intake
valve, lightened
valves, manifold
heat control valve, overhead
valves, PCV
valve, petcock, poppet
valve, power
valve, pressure
relief valve, Presta
valve, RAVE
valve, reed
valve, relief
valve, safety
valve, Schrader
valve, sodium-cooled
valve, spool
balance valve, spool
valve, suction
throttling valve, throttle
valve, tire
valve, valve
clearance, valve
cover, valve
duration, valve
face, valve
float, valve
grinding, valve
guide, valve-in-head
engine, valve
keeper, valve
key, valve
lash, valve
lift, valve
lifter, valve
margin, valve
oil seal, valve
overlap, valve
port, valve
rotator, valve
seat, valve
seat grinding, valve
seat insert, valve
spring, valve
stem, valve
tappet, valve
timing, valvetrain, valve
umbrella, variable
valve actuation, and variable
valve actuation.
valve assembly: A device
through which a tire is inflated. It includes a valve stem, valve core, and
valve cap.
valve bounce: See bounce.
valve cap: A screw-on cap to seal
air in a tire valve.
valve clearance: The
distance between the small end of the valve
stem and the rocker
arm or valve
lifter. This gap is necessary to compensate for expansion
due to heat. Also called valve
lash.
valve core: A check valve within a
tire air valve which permits air pressure chucks without undue loss of air
pressure. The core should not be considered a valve seal.
valve cover: A long metal lid
located on the top of the cylinder
head on vehicles with overhead camshafts. The valve cover is removed when
the valves need adjusting.
valve duration: The length
of time, measured in degrees of engine crankshaft
rotation, that a valve remains open.
valve extension: Extra
length added to a tire valve stem for greater accessibility particularly on
inside duals.
valve face: The outer lower edge
of the valve
head. The face contacts the valve
seat when the valve is closed.
valve float: A condition where
the valves in the engine are forced back open before they have had a chance to
seat. Brought about (usually) by extremely high rpm. The valve
lifters lose contact with the cam lobes because the valve
springs are not strong enough to overcome the momentum
of the various valvetrain
components. The onset of valve float prevents higher-rpm operation. Extended
periods of valve float will damage the valvetrain.
valve follower: See valve
lifter.
valve grinding: Renewing
the valve
face area by grinding on a special grinding machine.
valve guide: The cylindrical
hole which is located in the cylinder
head or block
through which the stem of the poppet
valve passes. It is designed to keep the valve in proper alignment. It also
serves as a bearing surface. Some guides are pressed into place and others are
merely drilled in the block or in the head metal.
valve head: The top of the large
end of a valve.
valve in head engine:
See valve-in-head
engine.
valve-in-head
engine: An engine in which both intake
and exhaust
valves are mounted in the cylinder
head and are driven by pushrods or by an overhead camshaft. Also called
"I-head
engine" or "Overhead-valve engine."
valve keeper: A small unit
that snaps into a groove in the end of the valve
stem. It is designed to secure the valve
spring, valve spring retaining washer and valve stem together. Some are of a
split design, some of a horseshoe shape, etc. Also called "valve
key" or "valve retainer."
valve key: See valve
keeper.
valve lash: valve
tappet clearance
or total clearance
in the valve operating train with cam
follower on camshaft base
circle.
valve lift: Distance a valve moves
from the full closed to the full open position.
valve lifter: The
cylindrically shaped component that presses against the lobe of a camshaft and
moves up and down as the cam lobe rotates. Most valve lifters have an
oil-lubricated hardened face that slides on the cam lobe. So-called "roller
lifters," however, have a small roller
in contact with the cam lobe -- thereby reducing the friction between the cam
lobe and the lifter. Also called "valve follower" or cam
follower.
valve margin: The width of the
edge of the valve
head between the top of the valve and the edge of the face. Too narrow a
margin results in preignition
and valve damage through over-heating.
valve oil seal: A neoprene
rubber ring that is placed in a groove in the valve
stem to prevent excess oil entering the area between the stem and the guide.
There are other types of these seals.
valve overlap: A certain
period in which both the intake
and exhaust
valve are partially open. The intake is starting to open while the exhaust
is not yet closed.
valve port: The opening, through
the head
or block, from the intake
or exhaust
manifold to the valve seat.
valve retainer: See valve
keeper.
valve rotator: A unit that
is placed on the end of the valve
stem so that when the valve is opened and closed, the valve will rotate a
small amount with each opening and closing. This gives longer valve life.
valve seat: The area onto which
the face of the poppet
seats when closed. The two common angles for this seat are forty-five and thirty
degrees.
valve seat grinding:
Renewing the valve seat area by grinding with a stone mounted upon a special mandrel.
valve seat insert: A
hardened steel valve seat that may be removed and replaced. Also see insert.
valve spring: A small coil
spring that closes the valve after it has been opened by the cam, and
prevents the valve from bouncing on its seat. The action of the spring keeps the
lifter
in contact with the cam. If the spring is weak, noise will be generated and the
valve, spring, lifter and cam will be subjected to hammer-like blows that cause metal
fatigue.
valve stem: The long cylindrical
portion of the valve that moves up and down in the valve
guide.
valve stem cap: !!!
Definition under construction !!!.
valve tappet: An adjusting
screw to obtain the specified clearance
at the end of the valve
stem (tappet clearance). The screw may be in the top of the lifter,
in the rocker
arm, or in the case of the ball
joint rocker arm, the nut on the mounting stud
acts in place of a tappet screw.
valve timing: Adjusting the
position of the camshaft
to the crankshaft
so that the valves will open and close at the proper time.
valve train: See valvetrain.
valvetrain: The various parts
making up the valve and its operating mechanism which causes the valves to open
and close.
valve umbrella: A
washer-like unit that is placed over the end of the valve
stem to prevent the entry of excess oil between the stem and the guide. Used
in valve-in-head installations.
van camper: See type
B motorhome
vane: A thin plate that is affixed to a
rotatable unit to either throw off air or liquid, or to receive the thrust
imparted by moving air or liquid striking the vane. In the first case it would
be acting as a pump
and in the second case as a turbine.
vapor injection: See water
injection.
vapor lock: This is an unwanted
condition where bubbles of air form in the fuel line caused by boiling or
vaporizing of the fuel in the lines from excess heat. The boiling will interfere
with the movement of the fuel and the air bubbles which form will in some cases,
completely stop the flow. Sometimes it will cause the float
chamber to overflow which floods
the carburetor
and result in an over-rich mixture that can cause stalling of the engine when
the accelerator
is depressed. Fuels containing alcohol
have lower boiling
points and many old-car owners have installed more-powerful electric fuel
pumps which overcome vapor lock tendencies of these fuels by pushing them
through the air bubble. A wet rag will cool the line and get rid of the problem.
To prevent the problem in hot weather, some mechanics wrap tinfoil around the
fuel lines to reflect the heat away.
vapor recovery
system: A system that prevents the escape of gasoline
vapors from the fuel
system into the atmosphere. The basic system consists of a canister
filled with activated charcoal
and pipes connecting the canister
to the fuel
tank and carburetor.
Any vapor-filled air that leaves the fuel
tank because of expansion
passes through special emission
control pipes to the canister
where the vapors are "grabbed" and stored by the charcoal.
Then when the engine is started, intake
manifold vacuum
draws fresh outside air up through an opening in the canister.
This moving air pulls the fuel vapor out of the charcoal
and carries it to the carburetor
and into the engine. In the meantime any gasoline
that evaporates from the carburetor
collects in the carburetor
and air
cleaner. As soon as the engine starts this vapor is drawn down through the carburetor
and into the engine along with the entering fuel-air
mixture. Also called evaporative emission
control. Also see exhaust
emission controls.
vapor separator: A
device used on cars equipped with air conditioning to prevent vapor
lock by feeding vapors back to the fuel
tank via a separate line.
vaporize: The action of converting a
liquid into a mist or vapor by breaking it into small particles and mixing it
with air. The design of the carburetor
and fuel
injectors vaporizes gasoline
to produce a combustible fuel-air
mixture. If it is not vaporized, the liquid gasoline may not burn properly
and may even hydraulic.
vaporization: Breaking the gasoline
into fine particles and mixing it with the incoming air.
variable exhaust
port: See adjustable
variable exhaust port.
variable pitch
stator: A stator
that has vanes
that may be adjusted to various angles depending on load conditions. The vane
adjustment will increase or decrease the efficiency
of the stator.
variable spring: Spring
providing variable effective length through cam action to suit load.
variable
transmission: See infinitely
variable transmission.
variable
valve actuation: In older engines, the intake
and exhaust
valves operated in a fixed program of timed openings and closings. With
variable valve actuation, these actions are varied for a better balance of
low-speed, medium-speed, and high-speed operation.
variable valve
timing: Through the use of computers, the precise time when the valves open
and close can be altered. It may be better to change the timing slightly when
the engine is at a higher RPM than when it is slower.
variable-venturi: See air-valve
carburetor.
variable
volume induction system intake configuration: !!! Definition under
construction !!!.
Variomatic
transmission: A transmission which used rubber belts and expanding pulleys
to provide an infinitely variable belt drive
varnish: [1] A deposit on the interior
of the engine caused by the engine oil breaking down under prolonged heat and
use. Certain portions of the oil deposit themselves in hard coatings
of varnish. [2] Residue formed when gasoline
gets old and stale.
Vauxhall: Only the 25/70 and 30/98
models of 1925-1948 are classic
cars.
VDA: Acronym for "Verband
der Automobilindustrie" (i.e., German Automakers Association)
VE: Value engineering.
vector: A physical quantity which has
direction such as force and momentum.
vee engine: A type of engine with
two banks of cylinders,
each set at an angle to each other (in an end view) to form a "V".
vehicle: A conveyance on wheels or
runners used to carry people or goods over land (e.g., bicycle, motorcycle, car,
truck, sleigh, snowmobile).
vehicle
Identification Number: (VIN) Number assigned to a vehicle by the
manufacturer primarily for registration and identification purposes (consisting
of numerals and letters).
velocipede: An early form of
bicycle or tricycle propelled by thrusts of the feet against pedals.
velocity: The rate of motion in a
particular direction.
velocity joint: See constant
velocity joint.
v engine: See V-type
engine.
v-engine: See V-type
engine.
vent: A small aperture designed to provide
an outlet from a confined space or a inlet into it.
venting: The act of perforating a
textile bias ply tubeless tire above the beads during retreading. Thus air
bleeding through the calendering can escape without forming air pockets between
plies.
vent wing: A small triangular-shaped
side window which is located in front of the main front side windows. Vent wings
can be swung out into the air stream to improve ventilation
inside the car. Also called wind wings.
ventilated brakes: A
brake setup which allows air to enter to cool the rotor and caliper.
ventilation: See flow-through
ventilation.
venturi: That part of a tube, channel,
pipe, etc., so tapered as to form a smaller or constricted area. A liquid, or a
gas, moving through this constricted area will speed up and as it passes the
narrowest point, a partial vacuum
will be formed. The taper facing the flow of air is much steeper than the taper
facing away from the flow of air. The venturi principle is used in the air
horn throat of the carburetor.
Also see air-valve
carburetor and variable
venturi.
VER: Acronym for "Voluntary Export
Restraint."
vertical position:
Type of weld where the welding is done on a vertical seam and on a vertical
surface.
vertical tire
clearance: The distance between the top of the tread and some part of the
vehicle closest above it, after subtracting the axle stop clearance and any
increase in tread depth from me existing tire.
vibration damper: A
round weighted device attached to the front of the crankshaft
to minimize the torsional
vibration. Also see harmonic
balancer.
VICC: Acronym for "Vehicle Information
Centre of Canada."
VIN: Acronym for "Vehicle
Identification Number."
vis-a-vis: A four-seater in which
the two passengers faced the driver. Used around the turn of the century.
viscometer: See saybolt
viscometer.
viscosimeter: A device used
to determine the viscosity
of a given sample of oil. The oil is heated to a specific temperature and then
allowed to flow through a set orifice. The length of time required for a certain
amount to flow determine the oil's viscosity.
viscosity: A measure of an oil's
ability to pour or be thick. Every container of oil is marked with the viscosity
of the oil. Straight
weight (also called "single viscosity" or "single
weight") oil has a single number like 30 weight. A lower number means the
oil is thinner and is particularly good for lower temperatures. A higher number
is better for hotter temperatures. Multigrade (also called "multiviscosity"
or "multiweight") oil has two numbers like 10W40. When the temperature
is low, a multigrade oil like 10W40 will act like a 10 weight oil; but when the
temperature increases, it will act like a 40 weight. In this way, a multigrade
oil is excellent for all-around driving.
viscosity index: A
measure of an oil's ability to resist changes in viscosity
when heated.
viscous coupling: A
particular kind of fluid coupling in which the input and output
shafts mate with thin, alternately spaced discs in a cylindrical chamber.
The chamber is filled with a viscous fluid that tends to cling to the discs,
thereby resisting speed differences between the two shafts. Viscous couplings
are used to limit the speed difference between the two outputs of a
differential, or between the two axles of a car.
visibility: Good visibility
means that there are no blind spots for the driver in being able to see the
traffic around him and that he is able to see the road in dark or adverse
conditions.
visor: [1] A movable, perforated part of a
helmet, covering the face but permitting sight and speech through the
perforations. [2] The peak of a cap to shade the eyes from direct sunlight.
Visors were also used above the windshield
for the same purpose.
Voisin: The 1925-1948 models are classic
cars.
voiture Legere: A light
car, especially a racing car falling between the heavy cars and the voiturette.
Term seldom used to describe production cars. Not used after 1914.
voiturette: Early two-seater touring
car. Name first used by Leon Bollee and then applied to any small car.
volatile: Easily evaporated.
volatility: The property of gasoline,
alcohol,
etc., to evaporate quickly and at relatively low temperatures. For instance, gasoline
is more volatile
(has higher volatility) than kerosene because it evaporates at a lower
temperature.
volt: A unit of electrical pressure or force
that will move a current
of one ampere
through a resistance
of one ohm.
voltage: A difference in electrical potential
between one end of a circuit and the other. Also called "electromotive
force (EMF)." Voltage causes current
to flow.
voltage drop: The lowering of voltage
due to excess length of wire, undersize wire, etc.
voltage regulator: A
device which maintains the correct voltage
level in a vehicle's electrical
system by preventing the circuit voltage from exceeding a predetermined safe
value. When the battery
needs charging the regulator cuts resistance
out of the generator field
circuit, thus increasing the flow of current
in that circuit, with the further result that output is increased. When the
battery becomes fully charged, the resistance is cut back into the field circuit
so that the charging rate is decreased. As the engine speed increases, the alternator
increases and generates more voltage. Unchecked, the alternator might put out so
much voltage that bulbs
and other electrical components
might burn out. To a certain extent, the battery
acts as a voltage regulator, but it too can be damaged by an electrical
system which does not have an operating voltage regulator.
voltmeter: An instrument used to
measure the voltage
in a given circuit, in volts.
volume: The measurement, in cubic
inches, cubic feet, etc., of the amount of space within a certain object or
area. Also see displacement.
volumetric
efficiency: A comparison between the actual volume
of fuel mixture drawn in on the intake
stroke and what would be drawn in if the cylinder
were to be completely filled. Also see breathing
capacity.
voluntary
Export Restraint: (VER) In relation to Japanese manufacturers exporting to
Canada (no longer in effect).
voluntary
Restraint Agreement: In relation to Japanese manufacturers exporting to the
United States (no longer in effect).
volute: A spiral-shaped case in which an
impeller
forces liquid in the direction it should go. Often used in pumps.
Also see impeller.
vortex flow: The whirling motion
of the oil in a torque
converter as it moves around and around from the pump,
through the turbine,
through the stator
and back into the pump and so on.
Volvo: The 1961-67 P.1800S, 2-door Coupe
models are milestone
cars.
VRA: Acronym for "Voluntary restraint
agreement."
V type engine: See V-type
engine.
V-type engine: An engine in
which the cylinders
occur in two rows set at an angle to each other with the crankshaft
running through the point of the V. The single crankshaft
is turned by both banks of cylinders. The angle of displacement
is generally between 60 and 90 degrees. Although the most common engines are V-8
and V-6, manufacturers have used V-4 and V-12.
vulcanize: Process rubber by
chemical means, usually in combination with heat, to improve its strength,
hardness, elasticity, and to effect bonding to other rubber compounds. Used in
the manufacture, repair, and retreading of tires.
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Mobile: 79693511