Glossary of Terms
P
Are cars that were used to pace the Indianapolis 500. Many of these cars that actually used at the race were equipped with special options. As a result of these special cars many car makers built limited addition clones of these cars for sale to the general public.
Panhard Rod --A rear axle lateral locating device, which uses a link to connect the rod to the axle housing on one end, and connects directly to the car structure or bodywork on the opposite end.
Parkerizing --The commercial process of treating a metal part, usually a camshaft, to increase resistance to scuffing in the event of a break-in.
Parking Brake --A manual brake system usually engaged when a vehicle is parked to stop the vehicle from rolling once parked.
Parking Light --A light, or assembly of lights, existing with the sole purpose of illuminating the extremities of the vehicle when parked.
Phase --Refers to the angular relationship between two rotating parts, or otherwise the relationship between a single rotating part and a periodic event.
Pickup (Suspension) --Refers to the area in which a component of the suspension is attached to the frame or structure of a car.
Pilot Bearing --A bearing, found within one end of a shaft, and serving the purpose of supporting another separate shaft in the event of relative rotary motion.
Piston --A component of a reciprocating engine that provides a partial vacuum inducing the flow of fuel/air into the combustion region. From here the combustion pressures are converted to reciprocating motion, and the expelling of exhaust gases occurs.
Piston Ring --A reciprocating engine component mounted on the engine, and when the engine is in operation, capable of providing sealing or oil control functions.
Pitman Arm --A steering system component responsible for converting the rotation of steering gears to the linear motion of steering links.
Plenum --A chamber within the induction system that is generally interposed between either carburetor(s) or air intake(s) and ducts feeding ports.
Points (Ignition) --In a distributor, the switch portion, actuated by cam lobes, and interrupting the current that flows through the primary windings of an ignition coil, thus resulting in the generation of high voltage pulses transmitted to the spark plug.
Polish (Verb) --The act of reducing surface roughness through mechanical, chemical, or electrochemical processes.
Polyglas GT --Was a Goodyear tire used by the auto makers in the 1960s for the muscle cars.
Port --The opening in an enclosure through which fluids/air may enter.
Posi-Traction --the name derived by GM for its limited-slip rear differentials.
Power Brakes --A system of braking in which a servo mechanism derived from a manifold vacuum assists the driver-initiated braking actions.
Power Steering --A steering system in which the actions of the driver on the steering gears are assisted by a servo mechanism. This process usually involves the actions of a hydraulic pump driven by the engine.
Pressure Equalizing Device --A component of the braking system that is used either to equalize or allow adjustment of relative pressures in the different branches of the hydraulic system (e.g. front/rear).
Pressure Plate --The component of the clutch assembly that possesses the power needed to create enough friction to couple the engine to the next part in the drive train.
Pressure Regulator Spring --A spring responsible for determining the pressure at which a valve or valve system will open to permit the flow of fluid. A Pressure Regulator Spring’s installed force determines what the prescribed pressure necessary to open the valves will be.
Profile (Verb) --The act of measuring or reshaping the contour of a camshaft lobe, rocker arm, or any other similar component.
Proportioning Valve --A component of the braking system that has a provision intended for the adjustment of the hydraulic pressures available in separate branches of the system (e.g. front/rear).
Protect-O-Plate --A steel plate that contains the production codes and serial numbers of GM cars. Such information is stamped directly onto the plate.
Pulley --A rotating part that is grooved to support a drive belt.
Pushrod --An engine component that is cylindrical or tubular in shape and is capable of transmitting reciprocating motion from the camshaft rotation to, or toward, the valves.
Pushrod Tube --The tube holding a pushrod and located in the area between the engine block and cylinder head.
