Dictionary of Automotive Terms: W-Y-Z

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WANDERING (Steering): Condition in which front wheels tend to steer one way and then another.

WANKEL ENGINE: Rotary combustion engine that utilizes one or more three-sided rotors mounted on drive shaft operating in specially shaped chambers. Rotor turns constantly in one direction yet produces an in take, compression, firing, and exhaust stroke.

WATER DETECTOR: Sensor in diesel fuel system which warns driver of water contamination of fuel.

WATER JACKET: Area around cylinders and valves that's left hollow so that water may be admitted for cooling.

WATER PUMP: The pump, usually a centrifugal type, used to circulate coolant throughout cooling system.

WEDGE: Engine using wedge-shaped combustion chamber.

WEDGE COMBUSTION CHAMBER: Combustion chamber utilizing wedge shape. It is quite efficient and lends itself to mass production and as a result is widely used.

WEIGHT (Curb): Weight of vehicle (no passengers) with all systems (fuel, cooling, lubrication) filled.

WEIGHT (Shipping): Basic vehicle weight including all standard items but without fuel or coolant.

WEIGHT (Sprung): See Sprung Weight.

WEIGHT DISTRIBUTION: Percentage of total vehicle weight as carried by each axle (front and rear).

WELD: To join two pieces of metal together by raising area to be joined to point hot enough for two sections to melt and flow together. Additional metal is usually added by melting small drops from end of metal rod while welding is in progress.

WET FRICTION: Resistance to movement between two lubricated surfaces.

WET SLEEVE: Cylinder sleeve application in which water in cooling system contacts a major portion of sleeve itself.

WHEEL ALIGNER: Device used to check camber, caster, toe-in, etc.

WHEEL ALIGNMENT: Refers to checking or adjusting various angles involved in proper placement or alignment of both front and rear wheels.

WHEEL BALANCER: Machine used to check wheel and tire assembly for static and dynamic balance.

WHEELBASE: Distance between center of front wheels and center of rear wheels.

WHEEL BEARING: Ball or roller bearings on which wheel hub rotates.

WHEEL BRAKE: A brake operating at wheel, either drum or disc design.

WHEEL CYLINDER: Part of hydraulic brake system that receives pressure from master cylinder and in turn applies brake shoes to drums.

WHEEL HOP: Hopping action of rear wheels during heavy acceleration.

WHEELIE BARS: Short arms attached to rear of a drag racer to prevent front end from rising too far off ground during heavy acceleration. Arms are usually of spring material and have small wheels attached to ends that contact ground.

WHEEL LUG or LUG BOLT: Bolts used to fasten wheel to hub.

WIDE TREADS, WIDE OVAL, etc: Wide tires. Tire height (bead to tread surface) is about 70 percent of tire width across outside of carcass.

WINCH: An electrically or mechanically driven drum that will wind in a length of cable. Used to remove vehicles from mud, ascend very steep slopes, pull logs, etc.

WINDSCREEN: British term for windshield.

WIRING DIAGRAM: Drawing showing various electrical units and wiring arrangement necessary for them to function properly.

WISHBONE: Radius rod setup used in many older Ford cars to keep axle square with frame.

WITNESS MARKS: Punch marks used to position or locate some part in its proper spot.

WOBBLE PLATE: A round, flat plate with a shaft passing through its center. Plate is affixed to shaft at an angle to shaft centerline. When shaft turns, plate will rotate but will also wobble from side to side. Used on axial air conditioning compressor to operate pistons.

WORK: A force applied to a body causing body to move.

WORM GEAR: Coarse, spiral shaped gear cut on shaft. Used to engage with and drive another gear or portion of a gear. As used in steering gearbox, it often engages cross shaft via a roller or by a tapered pin.

WORM AND ROLLER: Type of steering gear utilizing a worm gear on steering shaft. A roller on one end of cross shaft engages worm.

WORM AND SECTOR: Type of steering gear utilizing worm gear engaging sector (a portion of a gear) on cross shaft.

WORM AND TAPER PIN: Type of steering gear utilizing worm gear on steering shaft. End of cross shaft engages worm via taper pin.

WRIST PIN: See Piston Pin.

- Y -

YIELD STRENGTH (Elastic Limit): Maximum force (in pounds per square inch) that can be sustained by given member and have that member return to its original position, length, shape, etc., when force or pressure is removed.

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ZENER DIODE: A silicone diode that serves as a rectifier (allows electrical current flow in ONE direction only) until voltage being applied to diode attains a certain level (called Zener voltage) at which point diode becomes conductive.