|
p: A tire designation for "Passenger,"
as used in rating tires such as P185R13.
PA: Acronym for "power
antenna."
pace car: A vehicle which leads the
pack of racers during the first part of the race (usually one lap) so that the
racers can warm up their engines, etc. The pace car never runs the actual race.
pace lap: The warm-up part of the race
before the actual race begins.
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 with required application are classic
cars. The 1953-56 Caribbean models are milestone
cars. The 1946-50 Clipper and Custom Eight are milestone
cars. The Pacific sedan and convertible for 1954 are milestone
cars. The 1954 Panther Daytona is a milestone
car. The Patrician 400 for 1951 to 56 are milestone
cars.
PAD: Acronym for "Program Associated
Data."
pad: See brake
pads.
paint: A liquid or paste consisting of a
suspension of a pigment
in oil or water, etc. When spread over a surface, it dries to form a hard, thin
covering colored by the pigment. The primary purpose of paint is to help in the
preventing of rusting. A secondary purpose is to provide a variety of color.
Also see metallic
paint and pyroxylin
paint.
paint film: The actual thickness
of the paint on a surface.
palletized
construction: The process of building a vehicle where the workers assemble a
complete chassis
at a comfortable workbench height, in a well-lighted area, away from the main
line -- not underneath a moving body. Working conditions and product quality are
vastly improved.
| palm spinner: A device which is attached to a
steering wheel to allow disabled people to insert a hand into its
bracket in order to steer a vehicle. |
|
pan: A thin stamped cover
that is bolted to the bottom of the crankcase,
it forms a sump
for the engine oil and keeps dirt, etc. from entering the engine. Also see oil
pan.
pancake engine: An engine
in which the cylinders
are on a horizontal plane, this reduces the overall height and enables them to
be used in spots where vertical height is restricted. Also see flat
engine.
panel: A flat piece of metal that is
stamped to create a body component
such as a door panel. Also see access
panel, cluster
panel, dashboard, header
panel, instrument
panel, and rocker
panel.
Panhard: The Dyna for 1946-67 models
are milestone
cars.
panhard rod: A rod or linkage
on the axle which runs from side to side. Usually one end is attached to the
body and the other end is connected to the axle. Also called a "track
bar."
pannier: A luggage bag used in pairs
and fastened alongside one or both wheels of a bike. Saddlebag.
panniers: Luggage bags used in pairs
and fastened alongside one or both wheels of a bike. Saddlebags.
p. ant: Abbreviation for "power
antenna."
paper air cleaner: An air
cleaner that makes use of special paper through which the air to the carburetor
is drawn.
parallel circuit: An
electrical circuit with two or more resistance
units so wired as to permit current
to flow through both units at the same time. Unlike the series
circuit, the current
in the parallel circuit does not have to pass through one unit to reach the
other.
parallelism: See axle
parallelism.
parallelogram
steering linkage: A steering
system using two short tie
rods connected to the steering
arms and to a long center link. The link is supported on one end on an idler
arm and the other end is attached directly to the pitman
arm. The arrangement forms a parallelogram shape.
parallel parking: The
action of bringing a vehicle to a stop behind another vehicle (or between two
vehicles) so that your front bumper is right behind the rear bumper of the
vehicle in front of you. The technique of parallel parking involves driving
beside the other vehicle and then backing up while turning the steering first to
the right and then at the correct time turning it to the left. It is one of the
testing requirements for obtaining a licence.
parking: The action of placing a
vehicle at a full stop out of the flow of traffic.
parking brake: Hand or foot
operated brake which prevents vehicle movement while parked by locking rear
wheels, or transmission output
shaft. One type applies the rear brake
shoes by mechanical means and the other type applies a brake
band to a brake
drum installed in the drivetrain.
Also see emergency
brake.
park light: A low intensity light
which is often incorporated into the front signal lights. The park lights are to
be illuminated when the vehicle is still running, but pulled off the road.
However, many people drive with them on -- an action which is illegal in some
parts of North America.
partnership
for a New Generation of Vehicles: (PNGV) established in 1993, this
partnership, between the United States Federal Government and the Automotive
industry, was founded to establish global technical leadership in the
development and production of affordable, fuel-efficient, low emission vehicles
that meet today's performance standards.
part out: To dismantle a vehicle and
sell the parts. British term is "break up"
parts car: A vehicle that has been
damaged beyond repair or restoration,
or that has deteriorated badly. It is useful only as a source of parts. It may
be drivable
though unsafe, but it usually is not in drivable condition.
pascal's law: A principle which
states that when pressure is exerted on a confined liquid, it is transmitted
undiminished. The law is particularly valid for hydraulic
systems.
pass: [1] The act of overtaking a vehicle
which is travelling in the same direction you are. [2] The act of going past a
vehicle which is travelling is the opposite direction from you. [3] Weld metal
created by one progression along the weld.
passenger capacity:
The maximum number of people that a vehicle can carry.
passenger vehicle:
four wheeled motor vehicle that also includes mini-vans and sport utility
vehicles.
passing: [1] The action of overtaking
another vehicle going in the same direction you are. [2] The action of going
past another vehicle which is going in the opposite direction you are.
passing gear: An automatic
transmission gear that shifts a vehicle into a lower gear for a short burst
of extra power to pass other cars on the highway. The gear is engaged by sharply
depressing the gas
pedal. When the pedal is released, the vehicle returns to normal to normal
driving gear.
passive
restraint system: See airbag
restraint system.
passive safety: Any device
which automatically provides safety for the occupants of a vehicle such as the
bumpers, seat
belt, padded dash, laminated
windshield, etc. In contrast with active
safety.
passive safety
features: Items in a vehicle which do not require action on the part of the
driver to avoid a hazard. See passive
safety.
patch: [1] To repair a component. [2] The
added part used to repair a component, e.g., a rubber disc glued to a tube to
cover a nail hole. [3] The footprint of a tire in its contact with the ground.
See contact
patch.
pawl: A bar, pin, or stud
that can be moved, pivoted, or slid into engagement with teeth cut on another
part, such as the parking pawl on the automatic
transmission that can be slid into contact with teeth on another part to
lock the rear wheels.
payload: The actual weight of cargo
being carried, including packaging, etc. (GVW -- Unladen weight = payload).
PB: Acronym for "power
brakes" or for "pushbutton"
as in PB radio.
| park brake extension: A device which is attached
to the parking brake to help disable people to operate the parking brake
more easily. |
|
PCV: Acronym for "positive
crankcase ventilation."
PCV system: Abbreviation for
"positive
crankcase ventilation system." A system which prevents crankcase
vapors from being discharged directly into the atmosphere. Also see closed
crankcase ventilation.
PCV valve: Part of the positive
crankcase ventilation system, which reroutes crankcase blowby
to the intake
manifold and back to the engine, where it is reburned in the cylinders
as part of the fuel-air
mixture. This cuts emission pollution and improve fuel
economy because unburned fuel in the blowby
is consumed the second time around. It also keeps the blowby
and water vapor from fouling the oil in the crankcase,
thus reducing the formation of engine sludge.
PDA: Acronym for "Personal Digital
Assistant."
PDB: Acronym for "power disc
brakes."
PDL: Acronym for "power door locks."
PDLR: Acronym for "power deck lid
release."
PDR: Acronym for "power deck
release."
peaking: A condition, usually in the
cushion rubber, resulting from local material starvation and excessive flow from
adjacent areas.
peanut: A small motorcycle fuel tank
which holds about five litres (one gallon). See chopper.
pedal: A lever operated by the foot. See accelerator,
brake
pedal, clipless
pedal, clutch
pedal, dead
pedal, low
brake pedal, spongy
pedal, and throttle
pedal.
pedal free travel: See
clutch
pedal free travel and free
pedal play.
pedal free play: See clutch
pedal free travel and free
pedal play.
pedal to the metal: To
fully apply the accelerator
for a fast take-off.
peel: [1] The action of rapid acceleration
so that the tires slip on the road surface (i.e., the wheels are turning, but
the vehicle is not moving very much) which may result in a strip of rubber on
the road surface. See peel
rubber. [2] The action of paint coming off. See orange
peel.
peel rubber: Rear wheels
slipping on the highway during acceleration.
Also called "burn
rubber."
peen: To flatten out the end of a rivet,
etc., by pounding with the round end of a hammer.
Peerless: The 1926-28 Series 69;
1930-31 Custom 8; and 1932 Deluxe Custom 8 are classic
cars.
pegs: Studs or nipples which may be used for
alignment of parts or the placement of a part.
Pegaso: All models from 1951-58 are milestone
cars.
penetrating oil: A
special oil with very thin viscosity
that is used to free rusted parts (esp. nuts and bolts) so that they can be
removed.
penetration: The extent that
the fusion goes into the base metal as measured from the surface of the base
metal.
penny-farthing: An early
bicycle which had a large front wheel (which was both the driving wheel and the steering
wheel) and a smaller rear wheel. Its name comes from two British coins --
the large penny and the small farthing.
pent-roof: A combustion chamber
whose upper surface resembles a shallow peaked roof. Usually used with four
valves per cylinder.
percolation: A condition in
which the fuel actually boils due to excess heat. Percolation prevents proper
atomization of the fuel causing rough running. Also see anti-percolation
valve.
percussion welding:
The type of resistance welding in which the heating comes from an arc produced
by an electrical discharge and instantaneous pressure applied during or
immediately following the heating.
perf: See hi Perf.
periphery: The outside edge or
circumference.
permanent magnet: The
permanent magnet does not need electricity to function and will retain its
magnetism over a period of years.
perpetual motion: A
situation where a device will turn forever because there is no friction between
the moving part and the stationary part. Although friction can be greatly
reduced, it can never be eliminated. Thus a perpetual motion machine is
impossible.
petcock: A small valve or tap which is
used to control the flow of liquid. You may find one at the bottom of a radiator
to permit draining the radiator. A petcock may also be found on the line coming
from the fuel
tank in small engines and motorcycles.
It allows you to cut the flow of gasoline
going to the carburetor.
On some motorcycles,
the position of the petcock lever may permit draining the last part of the fuel
tank as a reserve position. In units where the carburetor
is fed by gravity feed from a fuel
tank, turning off the petcock when the unit is not in operation may prevent
gasoline from leaking past the carburetor's needle
and seat and into the crankcase
to dilute the oil.
petrol: A British term for gasoline.
petroleum: Raw material from which
gasoline,
kerosene, lubricating oils, propane,
diesel fuel, etc. are refined. Consists primarily of hydrogen and carbon;
but also contains other elements. Its source is decomposed organic matter which
has been buried. Some used to think that the action of ice ages moved soil over
great forests of tropical vegetation. The current
suggestion is that great bodies of water flooded tropical vegetation in a
cataclysmic event.
Peugeot: With required application the
1925-1948 models are classic
cars.
PG: Acronym for "powerglide" automatic
transmission.
phaeton: An open-type body with two
cross seats, it usually accommodates five passengers. A folding windshield,
folding weatherproof fabric top and removable side curtains are usually standard
equipment. The four-seater was called a double phaeton, and the six-seater or
seven-seater was called a triple phaeton. Also see sport
and Imperial phaeton.
phillips head screw:
A screw having a fairly deep cross slot instead of the single slot as used in
conventional screws.
phillips
screwdriver: A screwdriver
with a pointed tip that is shaped to fit the crossed slots in the heads of
Phillips screws.
phosphor-bronze:
Bearing material composed of tin, lead,
and copper.
photochemical: Relates to
branch of chemistry where radiant energy (sunlight) produces various chemical
changes.
pickup: A utility truck with a closed
cab and an open box. Also see pick-up
coil and yoke.
pick-up: See yoke.
pickup coil: See pick-up
coil.
pick-up coil: The coil in
which voltage
is induced in an electronic
ignition.
Pierce-Arrow: The 1925-1948
models are classic
cars.
piezoelectric
ignition: A system of ignition
that employs the use of a small section of ceramic-like
material. When this material is compressed, even a very tiny amount it emits a
high voltage
that will fire the plugs this system does not need a coil,
points or condenser.
pigment: Finely ground powders in the
paint that give it its color.
pile: This is a steel or concrete bar which
is driven into the ground to form part of the foundations for a building.
pillar: A shaft or upright member
holding up the roof. Also see A-post, B-post,
and C-post.
pilot bearing: See clutch
pilot bearing.
pilot shaft: A dummy shaft that
is placed in a mechanism as a means of aligning the parts. It is then removed
and the regular shaft installed.
pin: A small cylinder used for fastening
something or as a pivot. Also see pawl piston
pin, cotter
pin, dowel
pin, floating
piston pin, hood
pins, shear
pin, spiral
wrapped pin, and worm
and taper pin.
pin spanner: A wrench with pins
on forked ends, used to turn an adjustable
cup on a bottom
bracket of a bicycle.
ping: See pinging.
pinging: A metallic rattling sound
produced by the engine during heavy acceleration
when the ignition
timing is too far advanced for the grade of fuel being burned. The noise is
caused by vibrations in the cylinder
walls, head,
and piston.
When an engine pings, the normal, controlled even spread of the flame
front is disrupted by the spontaneous combustion
of pockets of fuel. Their collision sets off the pressure waves that result in
the pinging sound. Pinging can be caused by bad timing,
inadequate octane rating, incorrect fuel-air
mixture, a hot
spot in the combustion
chamber caused by a glowing piece of carbon,
or an overheat condition. Also called "knocking."
Also see detonation.
pinion: A small, tapered gear which
meshes with a larger gear or rack. It is found in two primary places in an
automobile: the differential ring
and pinion and the steering's rack
and pinion. Also see drive
pinion.
pinion carrier: That part
of the rear axle assembly that supports and contains the pinion
gear shaft.
pinion gear: Pinion Gear: The
smaller of two meshing gears. A pinion gear is used in a starter
motor to engage the flywheel
ring gear and also rides along the surface of the steering
rack (a rod with grooves cut in it to mesh with the gear) See rack
and pinion gearbox.
pinned piston ring:
A steel pin, set into the piston,
is placed in the space between the ends of the ring. The ring is thus kept from
moving around in the groove.
pinned ring: A steel pin, set
into the piston,
is placed in the space between the ends of the ring. The ring is thus kept from
moving around in the groove.
pipe: A tube used to transfer liquid or gas.
Also see breather
pipe, downpipe, exhaust
pipe, inlet
pipe overflow
pipe, and tail
pipe.
pipes: exhaust
system.
pipe wrench: An adjustable
wrench with serrated jaws. Also called a "monkey wrench."
piston: A round or cylindrical plug,
which closed at one end and open at the other. It slides up and down in the cylinder.
It is attached to the connecting
rod and when the fuel charge is fired, will transfer the force of the explosion
to the connecting
rod then to the crankshaft.
Also see accumulator
piston, autothermic
piston, belted
piston, cam-ground
piston, and slipper
piston.
piston boss: The built-up area
around the piston
pin hole. Also see boss.
piston collapse: A
reduction in the diameter of the piston
skirt caused by heat and constant impact stresses. Also see collapsed
piston.
piston crown: The very top of
the piston. Also called piston
dome.
piston displacement:
Amount (volume)
of air displaced by a piston
when moved through the full length of its stroke. Also see displacement.
piston dome: The top surface of
a piston.
It is often shaped for better combustion and to prevent a valve from contacting
the surface. Also called piston
crown. See piston
head.
piston expansion:
Because pistons are usually made of aluminum and the cylinder walls are made of
iron, the piston will expand more rapidly than the cylinder when they get hot.
Some type of compensation needs to be made for this expansion or the piston will
seize in the cylinder. Also see split
skirt, T-slot, steel
strut, and cam-ground
piston.
piston head: That portion of the
piston
above the top ring. See piston
dome.
piston land: That portion of the
piston
which is between the ring
grooves.
piston lands: That portion of
the piston
which is between the ring
grooves.
piston pin: A steel pin that is
passed through the piston,
it is used as a base upon which to fasten the upper end of the connecting
rod. It is round and may be hollow. Also called "wrist pin" or
"gudgeon pin." See floating
piston pin.
piston pin boss: See piston
boss.
piston ring: A metal, split ring
installed in the groove
on the outside wall of the piston.
The ring contacts the sides of the ring
groove and also rubs against the cylinder
wall thus sealing the space between the piston and the wall. Poor rings can
cause poor compression
and severe blowby.
Often seen as blue smoke out the exhaust
pipe. See compression
ring, dykes
ring, and oil
control ring.
piston ring, chrome:
A piston
ring which has a thin layer of chrome plate on the outer edge.
piston ring,
compression: See compression
ring.
piston ring end gap:
The distance left between the ends of the ring when installed in the cylinder.
piston ring expander:
A spring device placed under a piston
ring to hold it snugly against the cylinder
wall. Also see expander.
piston ring gap: See piston
ring end gap.
piston ring groove:
The channels into which the piston rings reside.
piston ring job:
Reconditioning the cylinder
and installing new rings.
piston ring, oil
control: See oil
control ring.
piston ring, pinned:
A steel pin, set into the piston,
is placed in the space between the ends of the ring. The ring is thus kept from
moving around in the groove.
piston ring ridge:
That portion of the cylinder
above the top limit of ring travel. In a worn cylinder, this area is of a
smaller diameter than the remainder of the cylinder and will leave a ledge or ridge
that must be removed.
piston
ring side clearance: The space between the sides of the ring and the ring lands.
piston skirt: That portion of
the piston
below the rings and bosses.
(Some engines have an oil
ring in the skirt area.).
piston skirt
expander: A spring device placed inside the piston
skirt to produce an outward pressure which increases the diameter of the
skirt.
piston skirt
expanding: Enlarging the diameter of the piston
skirt by inserting an expander,
by knurling
the outer skirt surface, or by peening
the inside of the piston.
piston slap: The condition
caused by too much clearance
between the piston
and the cylinder
walls. The piston rattles or slaps against the wall of the cylinder. It
makes a hollow, muffled, bell-like sound.
piston thrust: The pushing
action of the piston which occurs at the sides of the piston 90° away from the
piston pin as it pushes against the cylinder wall.
pitch: [1] The back and forth rocking
motion of a vehicle which compresses the front springs and extends the rear
springs so that the nose of the vehicle is down while the tail is up. Then the
action reverses so that the nose is up and the tail is down (i.e., dive and squat).
[2] The distance between two threads on a bolt or screw. [3] The distance
between a point on one gear tooth and the same point on the next gear tooth. [4]
The quality of sound with respect to the frequency of vibration of the sound
waves. [5] The angle at which something is tilted. See variable
pitch stator. .
pitman arm: A short lever arm splined
to the steering
gear cross
shaft, the pitman arm transmits the steering force from the cross
shaft to the steering
linkage system. In this way rotary motion of the steering
wheel is turned to lateral movement of the arm. The British term is
"drop arm." Also see idler
arm.
pit: [1] Area at a race track for fuelling,
tire changing, making mechanical repairs, etc. [2] Small craters in the surface
of metal.
pit road: !!! Definition under
construction !!!.
pits: Area at a race track for fuelling,
tire changing, making mechanical repairs, etc.
pit stop: [1] A stop at the pits by
racer, for fuel, tires, repairs, etc. [2] Colloquial term for going to the
toilet.
pivot: A pin or shaft about which a part
moves. The place at which a lever swivels. A lever cannot work without a pivot.
pivot bolt: A bolt on which the
arms of caliper
brakes pivot and which also serves as the means for mounting the brakes on the
bike frame.
Also called "mounting
bolt."
PL&PD: Acronym for
"Public Liability and Property Damage" as a form of basic car
insurance
plain gage tubing: See
plain
gauge tubing.
plain gauge tubing:
Tubing whose thickness remains constant over its entire length.
plane: A flat surface. See inclined
plane.
plane sailing: A method of
navigation which ignores the earth's curvature, treating its surface as a plane.
Colloquially it indicates travel or procedure without difficulty or obstruction.
planet carrier: That part
of a planetary
gearset upon which the planet
gears are affixed. The planet gears are free to turn on hardened pins set
into the carrier.
planet gear: See planet
gears.
planet gears: Those gears in a
planetary
gearset that are in mesh with both the ring and the sun
gear. They are referred to as planet gears in that they orbit or move around
the central or sun
gear.
planetary gears: See planetary
gearset.
planetary gearset: A
gearing
unit consisting of a ring
gear with internal teeth, a sun or central pinion
gear with external teeth, and a series of planet
gears that mesh with both the ring and the sun
gear. Frequently used in overdrives and automatic
transmission. Also called epicyclic
gearbox.
planned
obsolescence: A policy of manufacturers that encourages motorists to become
dissatisfied with their cars so that they are eager to buy the latest model.
plasma: Temporary physical condition of
a gas after it has been exposed to and has reacted to an electric arc.
plastic moulding: a
process that converts organic-based materials, by means of a general-purpose
press and purpose-built tooling
under controlled heat and pressure, and injects the hot material into a die
cavity shaped in the final form of the intended part.
plate: [1] The action of coating
a material with some metal. Also called "electroplate"
or anodize.
[2] A flat piece of material. Also see plates.
plates: [1] Thin sections of lead
peroxide or porous lead in a battery.
There are two kinds of plates -- positive and negative. The plates are arranged
in groups, in an alternate fashion, called "elements," they are
completely submerged in the electrolyte.
[2] Any basically flat surface often used to mount another device. Also see baffle
plate, brake
backing plate, breaker
plate, and clutch
pressure plate.
platform: primary load-bearing
structural assembly of a motor vehicle determining the basic size of the motor
vehicle, and is the structural base that supports the driveline and links the suspension
components of the motor vehicle.
platinum: A precious metal sometimes
used in the construction of breaker
points. It conducts well and is highly resistant to burning.
play: Movement between two parts. See free
pedal play.
plenum: A chamber, located between the throttle
body and the runners of an intake
manifold, used to distribute the intake charge evenly and to enhance engine
breathing.
plexiglas: A trade name for an acrylic
plastic, made by the Rhom and Haas Co.
plexiglass: See plexiglas.
plies: See ply.
plug: A removable "cork" which
fills a hole. See core
hole plug, core
plugs, drain
plug, expansion
plug, freeze
plug, glow
plug, oil
drain plug, spark
plug gap, and spark
plug, welch
plug.
plug gap: See spark
plug gap.
plug gapping: Adjusting the
side electrode
on a spark
plug to provide the proper air
gap between it and the center electrode.
plug Patch: A tire repair material
which is forced into a nail hole to fill it. Although a common procedure, it is
not the most satisfactory method of repair
plug repair: The filling of a
nail hole by forcing repair material into the damaged area, often while the tire
is mounted and containing air. It is not a satisfactory method of repair.
plug weld: A weld which holds two
pieces of metal together and made in a hole in one of metal which is lapped over
the other pieces. Also called "rosette weld."
ply: A layer of rubber-coated parallel cords
which forms a unit of a tire carcass. The plies are made of cord, fiberglass,
steel, or structural fabric. See bias
tire and tire
plies.
Plymouth: The Fury for 1956-58 are milestone
cars. The Satellite SS and GTX for 1965-70 are milestone
cars. The Barracuda Formula S for 1965-69 are milestone
cars. The Roadrunner and Superbird for 1968-70 are milestone
cars.
ply rating: An indication of tire
strength load carrying capacity, does not necessarily indicate actual number of plies.
A two-ply four-ply rating tire would have the load
capacity of a four-ply tire of the same size but would have only two actual
plies. This system of measurement has been replaced by the term "load
range."
ply separation: A
breakdown of the bonding compounds resulting in the plies detaching from each
other. Usually as a result of excessive heat.
ply turnup: The extension of a
carcass ply to its end after wrapping around the bead. Also called "flipper
strip"
pneumatic
suspension: See air
suspension.
pneumatic tire: A
flexible, hollow rubber forming the outer part of the vehicle wheel and inflated
by air pressure. Originally rubber tires were solid core. Dunlop was the first
to invent a tire with an air-filled tube for bicycles. Later, tubeless
tires were invented. The tire is filled with enough compressed air to
support the weight of the vehicle and cushion road impacts.
pneumatic trail: See self-aligning
torque.
pneumatics: The study of
pressure and flow in gases. A pneumatic drill
is operated by compressed air; a pneumatic
tire contains compressed air.
PNGV: Acronym for "Partnership for a
New Generation of Vehicles."
point: See boiling
point, breaker
points, cloud
point, contact
points, coupling
point, dry
boiling point, dual
breaker points, fire
point, flash
point, ignition
points, point
gap, pour
point, shift
point, vacuum
runout point, and wet
boiling point.
point gap: The space between the contact
points when they are fully open. The distance of the gap will determine the
effectiveness of the points.
points: See boiling
point, breaker
points, and contact
points.
polar moment of
inertia: The resistance
of an object to rotational acceleration. When the mass of an object is
distributed far from its axis of rotation, the object is said to have a high
polar moment of inertia. When the mass distribution is close to the axis of
rotation, it has a low polar moment of inertia. A mid-engined
car has most of its mass within its wheelbase,
contributing to a low polar moment of inertia, which, in turn, improves
cornering turn-in. See moment
of inertia.
polarity: [1] Indicates if the pole
shoes are so magnetized as to make current
low in a direction compatible with the direction of flow as set by the battery.
[2] Indicates if the end of a magnet
is the North or South pole (N or S). [3] Indicates if the battery
terminal (either one) is positive or negative (plus or minus) (+ or -).
polarizing: The process of
sending a quick surge of current
through the field
windings of the generator
in a direction that will cause the pole
shoes to assume the correct polarity.
This will insure that the generator will cause current
to flow in the same direction as normal.
pole: [1] One end, either North or South, of
a magnet.
Also see negative
pole, and north
pole. [2] A post.
pole shoe: See pole
shoes.
pole shoes: Metal pieces about
which the field
coil windings are placed, when current
passes through the windings, the pole shoes become powerful magnets,
example: Pole shoes in a generator
or starter
motor.
polish: [1] A substance like wax used to
make the exterior paint shine or gloss. [2] The act of making the paint shine.
[3] To remove the minor obstructions in the exhaust flow. A term sometimes
coupled with porting,
as in porting and polishing or "port and polish." This is
generally a process of blueprinting
a two-stroke
engine so that the intake
and exhaust
ports are polished and have no obstructions in the flow of fuel-air
mixture or exhaust
gases. In this way the engine generally has more performance. A problem may
arise when an individual ports and polishes too much.
pollutant: See exhaust
emissions.
pollution: See air
pollution.
polyester: A synthetic fiber.
poly-glycotes: See glycote.
polymer: A material consisting of
large units (molecules) made by joining many smaller building blocks (simple
molecules). Usually used to describe synthetic rubber.
polymer coating: A coating
that prevents paint from oxidizing and so protects a vehicle from premature
fading and rusting. Professionally applied, it will last up to three years.
Pontiac: The Safari for 1955-57 are milestone
cars. The GTO for 1964-69 are milestone
cars.
pony car: Small, sporty car along the
lines of the Mustang, Firebird, Camaro, etc.
poppet valve: A valve
structure consisting of a circular head with an elongated stem attached in the
center, very much like the shape of a mushroom with a flat top. It is designed
to open and close a circular hole or port.
Its name comes from the fact that it pops up and down. In engines, it is the
valve used to open and close the valve
port entrances to the engine cylinders.
pop-up headlights:
See concealed
headlights
porcelain: The material used to
insulate the center electrode
of a spark
plug, it is hard and resistant to damage by heat.
porosity: Presence of gas pockets or
voids in the metal.
Porsche: The Series 356 for 1949-64
are milestone
cars. The 356C for 1965 is a milestone
car.
port: [1] Openings in engine cylinder
blocks for exhaust
and intake
valves and water connections. Also see adjustable
variable exhaust port, exhaust
port, intake
port, transfer
port, and valve
port. [2] To smooth out, align, and somewhat enlarge the intake
passageway to the valves or intake chambers (especially in two-stroke
engines). [3] A small hole in the master
brake cylinder to permit fluid to return to the reservoir. See compensating
port and intake
port.
port fuel injection:
A type of fuel injection with at least one injector mounted in the intake port(s) of each cylinder. Usually the injector is mounted on the air
intake
manifold close to the port. Port fuel injection improves fuel distribution
and allows greater flexibility in intake-manifold design, which can contribute
to improved engine breathing.
pos: Abbreviation for "positive
ground."
positive camber: See camber.
positive caster: See caster.
positive
connections: Connections in an electric circuit out of which electricity
constantly flows. The positive connections out of which electricity flows may
also be termed that into which electrons flow; and the negative connection into
which electrons flow; and the negative connection into which the electricity
flows may be considered that pole out of which the electrons flow.
positive
crankcase ventilation: (PCV) A process for preventing the buildup of harmful
acid-producing combustion gases within the crankcase. See closed
crankcase ventilation.
positive
crankcase ventilation system: (PCV) A process for preventing the buildup of
harmful acid-producing combustion gases within the crankcase. See closed
crankcase ventilation.
positive ground: An
automotive electrical system where the negative post of the battery was the hot
wire and the positive post was connected to the frame of the vehicle. Opposite
to negative
ground.
positive pole: The point
away from which an electrical current
flows through the circuit. It is designated by a plus sign (+).
positive terminal:
The terminal (such as that on the battery),
to which the current
flows. It is usually marked with the letters "pos" or a plus sign (+).
post: [1] The round, tapered lead posts
protruding above the top of the battery
to which the battery cables are attached. See terminal.
[2] The pillars which support the roof on a car. See A-post, B-post, C-post,
and hardtop.
The insert tube to which the seat of a bicycle is attached. See seatpost.
postheating: Temperature to
which a metal is heated after an operation has been performed on the metal
(welding, cutting, forming, etc.).
pot: [1] A colloquial term for "carburetor"
or for a "cylinder." [2] An abbreviation for a
"potentiometer."
pot metal: An alloy
that is cast
as a unit. It is relatively inexpensive to make, but is easily subject to
breakage.
potential: An indication of the
amount of available energy.
potential energy: The
mechanical energy possessed by a body due to its position. For example, water in
a reservoir above a hydro-electric power station has high potential energy which
is converted to work when it drives the turbines
of the power station.
pound foot: The unit of
measurement for torque.
One pound-foot is equal to the twisting force produced when a one-pound force is
applied to the end of a one-foot-long lever.
pour point: The lowest temperature
at which oil will pour, a test of its ability to flow and lubricate in cold
weather.
power: The rate of doing work. It is
expressed in mass times distance over a period of time. Also see candle
power and horsepower.
power antenna: (PA) or
(P.Ant) A radio antenna which automatically moves up and down whenever the radio
is turned on or off. It is a telescoping antenna driven by an electric motor.
See antenna.
power assisted brake:
See power
brakes.
power assisted
brakes: See power
brakes.
power band: The subjectively
defined rpm range over which an engine delivers a substantial fraction of its
peak power. The power band usually extends from slightly below the engine's torque
peak to slightly above its power peak.
power booster: A device that
uses engine vacuum
to assist you in braking the vehicle. Helps the brake
pedal to activate the hydraulic pistons
in the master
cylinder.
power brake: See power
brakes.
power brakes: (PB) A
conventional hydraulic
brake system that uses engine vacuum
to operate a vacuum power piston,
the power piston applies pressure to the brake
pedal, or in some cases, directly to the master cylinder piston. This system
reduces the amount of pedal pressure that the driver
must exert to stop the vehicle. Also called "vacuum-assisted brakes"
or "hydraulic-assisted brakes." Also see brake
booster.
powerglide: (PG) A two-speed automatic
transmission offered by General Motors.
power oversteer: In a
rear-wheel-drive vehicle, power oversteer
creates a skid
when too much power is applied and the rear wheels spin.
powerplant: The automobile
engine regardless of its type.
power seat: (P.seat) The cushions
upon which the driver
and or passengers sit which is adjusted by a control switch connected to a small
electric motor. See also seat.
power steering: (PS) A steering
system using hydraulic
pressure to increase the driver's
turning effort. As the driver turns the steering
wheel, steering effort is reduced. The pressure is used either in the gearbox
itself or in a hydraulic cylinder attached to the steering
linkage. Also called power-assisted or assisted steering.
| power stroke: The third stroke of the four-stroke
cycle. The piston
moves downward from top
dead center to bottom
dead center as a result of the force of combustion
acting on the top of the piston. |
 |
power take off: (PTO) The
end of the crank (usually on the other side from the magneto
or starter)
where the motion of the crank is transferred to the transmission
or power output.
power to weight
ratio: See power-to-weight
ratio.
power-to-weight
ratio: Ratio of horsepower
to the weight of a vehicle.
power train: See powertrain.
powertrain: An engine and transmission
combination. See drivetrain.
power valve: A valve in a carburetor
that is operated by vacuum
or mechanical linkage
to provide more fuel at wide open throttle.
power windows: Side windows
which are raised and lowered by an electric motor which is operated by a switch.
The British term is "electric windows"
PPM: Acronym for
"parts-per-million." Term used in determining extent of pollution
existing in given sample of air.
Pratt and Whitney
key: A bar like a flat
key except the ends are oval shaped.
prechamber: See pre-combustion
chamber.
pre-chamber: See pre-combustion
chamber.
precision
insert bearing: A very accurately made replaceable type of bearing, it
consists of an upper and lower shell, the shells are made of steel to which a friction
type bearing material has been bonded, connecting
rod and main
bearings are generally of the precision insert type.
precombustion
chamber: See pre-combustion
chamber.
pre-combustion
chamber: A small chamber located outside the combustion
chamber of some cars in which a small amount of rich fuel-air
mixture can be ignited to increase fuel
efficiency and cut emissions. Found principally on diesel
engines and stratified
charge engines. Also called "pre-chambers."
precured tread
rubber: Pre-cured rubber, usually of high density and available in various
tread designs, is lined with cushion gum before applying to a buffed casing
using the cold
cap method of retreading. Recently it has been applied in some hot
cap molds employing a smooth matrix or other modifications.
preheating: [1] Temperature to
which a metal is heated before an operation is performed on the metal (welding,
cutting, forming, etc.). [2] The application of some heat prior to the later
application of more heat, cast
iron is preheated to avoid cracking
when the welding process is started. A coil
(ignition) is preheated prior to testing. Also see converter
preheating.
preignition: The fuel charge
being ignited before the proper time. Sometimes causes pinging
or detonation.
This is the combustion
of the fuel-air
mixture that is not a result of the spark
plug's firing, but by high pressure, a flame, or a hot surface.
preloading: Adjusting an
antifriction bearing, ball
joint, or spring so that it is under mild pressure, this prevents bearing
looseness under driving stress.
pre-owned vehicle: A used
vehicle.
pre-selector
gearbox: An arrangement that enables the driver to select a gear speed
before he needs it and then depress the clutch pedal when he desires to use the
selected gear.
preselector gearbox:
See pre-selector
gearbox.
press, drill: See drill
press.
press fit: An interference
fit. A fit so tight that an object must be removed with a puller
or a press. Also see drive
fit, interference
fit, force
fit.
pressure: The force due to the
weight of a substance exerted over the area the substance occupies. In metric
measure, it is the force acting on each square metre. To calculate pressure,
divide the force (in newtons) by the area (in square metres). It is measured in
newtons per square metre (N/m²). In Imperial (U.S.) measure, it is measured in
pounds per square inch (lb/in.²) (psi). Also see atmospheric
pressure, back
pressure, boost
pressure, center
of pressure, clutch
pressure plate, extreme
pressure lubricant, mean
effective pressure, oil-combin
ation splash and pressure system, oil-full
pressure system, oil
pressure gauge, pressure
bleeder, pressure
cap, pressure
radiator cap, pressure
relief valve, safety
pressure cap, and static
pressure.
pressure bleeder: A
device that forces brake
fluid under pressure, into the master
cylinder so that by opening the bleeder screws at the wheel
cylinders, all air will be removed from the brake
system.
pressure buildup: As a
tire heats up as it travels on the road, the air inside the tire expands and
thus increases the air pressure. Any increase exceeding 15% above starting cold
pressure should be investigated. The practice of bleeding
the excess or hot pressure should be avoided.
pressure cap: A special cap
for the radiator,
it holds a predetermined amount of pressure on the water in the cooling
system, this enables the water to run hotter without boiling. In this way,
the engine can operate at a higher and a more efficient temperature without
danger of overheating. The cap also has a vacuum
valve that lets air into the cooling
system if the pressure falls too low to prevent outside air pressure from
causing a partial collapse of the radiator.
pressure plate: See clutch
pressure plate.
pressure radiator
cap: See pressure
cap.
pressure relief
valve: A one-way valve designed to open at a specific pressure to prevent
pressures in the system from exceeding certain limits. Also see blowoff
valve.
pressure
wave supercharger: A supercharger using the pressure waves created by the
expanding exhaust gases to compress the inlet charge. Also called "Comprex
supercharger."
Presta valve: A bicycle
tube valve whose stem has a small nut on top, which must be loosened during
inflation, instead of a spring such as is found on the Schrader
valve.
primary brake shoe:
The brake
shoe that is first to press against the brake
drum. The other shoe is the secondary shoe. When both shoes are pressing
against the drum, the amplification of forces is called "servo
action."
primary circuit: The low
voltage
(6 or 12 volts) path of the ignition
system which goes from the positive
pole of the battery
to the primary
windings of the coil,
through the breaker
points, and into the ground which leads back to the negative
pole of the battery.
primary compression:
A term that is used in two-stroke
engines. Primary compression takes place in the crankcase
and is then pushed up into the combustion
chamber where secondary
compression takes place as the piston
squeezes the mixture. If the crankcase
seals are poor, primary compression will be reduced resulting in reduced secondary
compression so that it may be difficult to start the engine.
primary
forward brake shoe: The brake
shoe that is installed facing the front of the vehicle, it will be a
self-energizing shoe.
primary terminal: The
clip found inside the distributor
which allows electric current
to pass from the points to the condenser
and provides the insulation
to keep the current
from contacting other metal parts.
primary winding: The low
voltage
(6 or 12 volt) windings in ignition
coil, the primary winding is heavy wire; secondary winding uses fine wire.
primary windings: The
low voltage
(6 or 12 volt) windings in ignition
coil, the primary winding is heavy wire; secondary winding uses fine wire.
primary wire: See primary
wires.
primary wires: The wiring
which serves the low voltage
part of the ignition
system. Wiring from battery
to switch, resistor, ignition
coil, distributor
points.
prime: [1] To paint bare metal with primer
to prevent rusting. A second color (often different from the prime color) is
painted over the primer. [2] Pronounced PREEM, a stage in a bicycle race.
prime coat: primer
or surfacer applied to the old paint or bare metal before the finish
coat is applied.
primer: The surfacer that acts as a bond
between the metal surface or old paint and the color coat.
printed circuit: An
electrical circuit made by connecting the units with electrically conductive
lines printed on a panel, this eliminates actual wire and the task of connecting
it.
PRND: Acronym for the order in which an
automatic transmission
is displayed to the driver
and stands for "Park," "Reverse," "neutral,"
and "Drive." Sometimes, two or more drive positions will be displayed
as D1 and D2.
probe: A pointed tool, like an icepick. It
is used to determine the extent of injuries during the tire inspection. An awl.
product design: the
process of planning the product's specifications.
product planning: a
function whereby an enterprise is responsible for the efficient, planning,
scheduling and coordination of production activities.
product testing:
rigorous methods whereby a product's quality and durability are measured.
production
engineering: planning and control of the mechanical means of changing the
shape, condition of materials toward greater effectiveness and value.
production
retread shop: A shop which schedules its production not on the basis of
day-to-day orders but rather on long runs of purchased tire
casings in order to secure the lowest cost per unit.
productivity: relative
measure of output per labour and/or machine output.
profile: The aspect ratio of a tire.
Also see cam
profile.
program cars: automobiles sold
by manufacturers for fleet use. Usually applies to very large fleets, such as
those of car rental companies.
program Objectives:
A consensus of what has been determined to be the most marketable product for a
given model year.
progressive linkage:
carburetor linkage
designed to open the throttle
valves of multiple carburetors.
It opens one to start with and when a certain opening point is reached, it will
start to open the others.
progressive
rate spring: A spring with an increasing spring constant. For example, if
the first inch of spring motion requires 100 pounds of force, the second inch
would require more than an additional 100 pounds, and the third inch would
require still more. Progressive-rate springs become stiffer as they are
compressed, unlike single-rate springs, which have a fixed spring rate.
progressive spring:
See progressive
rate spring.
progressive
suspension: A system in which the suspension
stiffness changes depending on the amount of change required. On light bumps,
the suspension is soft; but on greater bumps, the suspension is stiff.
progressive
transmission: An older version of a manual
transmission. When you wanted to go from low
gear to the highest gear, you had to go through all the gears in between.
Likewise when you wanted to go from the highest gear to the lowest, you had to
proceed through all the intermediate
gears.
prony brake: A device using a friction
brake to measure the horsepower
output of an engine.
prop shaft: Abbreviation for
"propeller
shaft." See driveshaft.
propane: A petroleum
product, similar to and often mixed with butane,
that is useful as an engine fuel. In Canada this is the term used for LPG.
propeller shaft: The
shaft connecting the transmission output
shaft to the differential
pinion shaft. Also called driveshaft.
propeller
shaft safety strap: See driveshaft
safety strap.
proper
proportion of air and fuel: One of the essential factors in a combustion
engine (Fuel, Air, Proper proportion of mixture, compression, timing, spark).
proportioning: The act of
distributing something (e.g., brake fluid) to several components in equal
measures. See brake
proportioning valve.
proportioning valve:
See brake
proportioning valve.
production car: !!!
Definition under construction !!!.
proton: A positive charge particle
forming part of the atom.
prototype: The test model of a new
car design that is intended to be produced in quantity. Also see mock-up.
PS: Acronym for "power
steering."
p. seat: Abbreviation for "Power
seats."
PSI: Acronym for "pounds per square
inch." A unit of inflation for a tire, or a unit of measurement for an
engine's compression.
Normal atmospheric pressure at sea level is 14.7 psi. Metric measurement uses
kilopascals.
PSR: Acronym for "power sun roof."
PTO: Acronym for "power
take off." A device (usually a pulley) on an engine or wheel which
drives a secondary device.
puck: See brake
pads.
pucks: See brake
pads.
puddle: Portion of weld that is molten
at the place heat is supplied.
pull it down: A term often used
in reference to dismantling and overhauling
an engine. Same as "tear it down."
puller: A device for separating two components
which are secured by press
fitting them. See stud
puller.
pulley: A grooved wheel carrying a
string, rope, chain,
or belt which turns the wheel. Also see crankshaft
pulley, idler
pulley, and jockey
pulley.
PULSAIR: A GM system similar to the air
Injection Reaction System (AIR) except there is no air
pump. Instead exhaust
pressure pulses draw air into the exhaust
system. Fresh air that is filtered by the air
cleaner is supplied to the system on a command from the Electronic Control
Module (ECM).
pulsation damper: A
device used to smooth out the pulsations or surges of fuel from the fuel
pump to the carburetor.
Also see damper.
pulse arc welding: A
type of welding arc in which the arc welding current is interrupted or pulsed as
the welding arc progressed.
pulser coil: See coil.
pump: [1] A device for moving liquid or gas
by decreasing or increasing the pressure on it. Also see accelerator
pump, air
pump, fuel
pump, oil
pump, vacuum
pump, and water
pump. [2] As a verb, it means to move something energetically up and down.
See pumping
the gas pedal and oil
pumping.
pump gasoline: Normal
gasoline (whether regular or premium) available at service stations in contrast
with racing fuel obtained from specialty locations.
pumping, oil: See oil
pumping.
pumping the gas brakes:
A method of repeatedly applying the brakes so that optimum braking can be
established without creating brake fade. In anti-lock brakes, this procedure is
unnecessary.
pumping the gas
pedal: Forcing the accelerator
up and down in an endeavor to provide extra gasoline
to the cylinders,
this is often the cause of flooding.
It is especially harmful to cars with fuel
injection.
pumping
the throttle pedal: Forcing the accelerator
up and down in an endeavor to provide extra gasoline
to the cylinders,
this is often the cause of flooding.
It is especially harmful to cars with fuel
injection.
pump the brakes: See pumping
the brakes.
pump the gas pedal:
See pumping
the gas pedal.
pump the
throttle pedal: See pumping
the gas pedal.
puncture: A penetration of a tire's
air chamber by a foreign object, nail, glass, etc. resulting in loss of air.
Such loss can be rapid with the collapse of the innertube, or relatively slow in
the case of tubeless tires.
PUP: Acronym for "Pick-ups" (like
Ford Blackwood or GM Sierra).
purchase price: The price
of a vehicle that the consumer pays.
purchasing: total materials
purchased for manufacturing/assembly into auto parts (i.e., steel, plastics,
rubber, textiles, etc.).
push: A colloquial term for understeer.
push button: See pushbutton.
push-button: A switch which is
engaged by pushing a button in. In most cases there are several button
options so that when one is selected, the previously selected button is pushed
back out (de-selected).
pushbutton: A switch which is
engaged by pushing a button in. In most cases there are several button
options so that when one is selected, the previously selected button is pushed
back out (de-selected).
push rod: The rod that connects the valve
lifter to one end of the rocker
arm. Used on valve-in-head installations where the cam is below the piston
and the valves are above the piston. The rods are moved by the cam and activate
the valve lifter. Engines with overhead cams do not need push rods because the camshaft
connects to the valves directly.
putty: A malleable cement. See body
putty.
PW: Acronym for "power windows."
pylon: A highly visible marker for
controlling traffic.
pyrometer: A device which
determines the temperature in various parts of a tire.
pyroxylin paint: An
early type of quick drying synthetic paint.
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