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Rotary Valve

A semi-circular disc in a two-stroke engine that opens and closed the intake port.

Rotary Valve Steering Gear

A type of power-steering gear.

Rotation

1. A term used to indicate that a gear, shaft, or other device is turning. 2. A term used for tire rotation.

Rotational Motion

Movement that occurs when a shaft turns (rotates) on its axis. A dynamic seal is required to contain fluids were rotational motion is present.

Rotator

A device in the cylinder head that causes the valve to rotate to reduce carbon build-up.

Rotor

1. Disc-shaped component that revolves with hub and wheel. The lining pads are forced against the rotor to provide a friction surface for the brake system, so as to slow or stop a vehicle. 2. In a conventional ignition system, the part that transfers the secondary voltage from the center terminal to the outer terminals of the distributor cap as it rotates inside the cap. 3. The rotating part of an alternator that provides the necessary magnetic field to create a current flow.

Rotor Face

The flat, parallel surface on each side of the rotor contacted by the pads (linings) during stopping.

Rotor Oil Pump

A type of oil pump in which a pair of rotors produce the pressure required to circulate oil to the engine parts.

Rotor Pump

A positive-displacement pump that uses an inner drive rotor and an outer drive rotor to produce an oil flow. Lobes on the rotors create a fluid chamber of varying volumes and eliminate the need for a crescent as used in a gear pump.

Rotunda

Test equipment manufactured for Ford Motor Co. by many different manufacturers.

Roundy-round Racing

An kind of oval-track racing.

RPA

Abbreviation for Rear Park Assist (GM) (Back up RADAR).

Rpm

An abbreviation for revolutions per minute.

RPO

An abbreviation for regular production option.

RRDM

Abbreviation for Right rear Door Module (GM).

RS232

A standard defining interface voltage and current levels and other signal characteristics used to couple digital equipment to a transmission link.

RSM

Abbreviation for Rain Sensor Module (Chrysler).

RTV

An abbreviation for room temperature vulcanizing.

RTV/Silicone

A silicone-based RTV.

Ru

Ruthenium An element with the atomic number of 44.