Terms Starting with T
Tachometer-A meter used to measure the speed of a rotating shaft.
Tappet-Another term for valve lifter.
TDC-Position of the piston at top dead center.
Tensile strength-The amount of pressure per square inch a bolt can withstand just before breaking when being pulled apart.
Thermal efficiency-A measure of how effectively an engine converts heat energy in fuel into mechanical energy at the rear of the engine.
Thermistor-A sensor that is able to change electrical resistance because of a change in temperature.
Thermostat-The part on a cooling system that controls the engine coolant to its highest operating temperature.
Thermostatic switch-A heat-sensitive switch used to turn on and off an air-conditioning compressor.
Threads per inch-A number used to identify bolts by the number of threads per inch.
Throttle body-A part of a fuel system where fuel is injected into the air stream. The throttle body injector is located above the throttle plate.
Throttle plate-The plate or circular disk that controls the amount of air going into the engine. It is controlled by the position of the operator’s foot.
Throttle valve (TV)-A valve used in the automatic transmission that changes oil flow based on the position of the engine throttle.
Throw-The distance from the center point of the crankshaft to the center point of the connecting rod.
Thrust bearing-An antifriction bearing designed to absorb thrust along the axis of the rotating shaft.
Thrust load-An axial load of a rotating shaft.
Thrust plate-The plate used to bolt the camshaft to the block, which absorbs camshaft thrust.
Timing-The process of identifying when air, fuel, and ignition occur in relation to the crankshaft rotation.
Timing diagram-A graphic diagram used to identify the time in which all of the events of the four-stroke engine operate.
Toe (in, out)-The inward or outward pointing of the front wheels as measured in inches or millimeters.
Torque-A twisting force applied to a shaft or bolt.
Torque converter-The coupling between the engine and transmission on an automatic transmission. It is also used to multiply torque at lower speeds.
Torque converter clutch-A valve used in conjunction with the lockup clutch mechanism on an automatic transmission.
Torque-to-yield bolt-A bolt that has been tightened by the manufacturer to a preset yield or stretch point.
Torsional rings-Piston rings that have a slight twist when placed within the cylinder wall. These are made by adding a chamfer or counter bore on the ring.
Torsional vibration-A vibration produced on a spinning shaft caused by torque applied to the shaft.
Traction-A tire’s ability to hold or grip the road surface.
Transducer-A device on many electrical computer circuits that uses one type of energy as the input and another type of energy as the output, such as a piezoelectric crystal that uses motion as the input and electricity as its output.
Transistor-A semiconductor used in electrical circuits to turn a second circuit off or on. Also used to amplify an electrical signal.
Transmission band-A type of hydraulic clutch that uses a metal band fitted around a clutch housing. As the band is tightened, the clutch housing is stopped.
Tread bars-Narrow strips of rubber molded into the tread. When the tread bars show, the tire is worn enough to be replaced.
Trouble code-A code stored inside a vehicle’s computer that tells the exact component that is faulty.
Trunnion-The arms of the four-point U-joint which serves as the inner bearing surface or race.
Tuned ports-Intake ports used on fuel injection engines designed to produce equal and minimum restriction to the airflow flowing into the engine.
Turbine-The rotary part or vaned wheel inside a torque converter, used to turn the transmission gears and clutches.
Turbocharger-A device that uses the energy in the engine exhaust gases to turn a compressor, which pumps more air into the engine.
Turbulence-A term used to describe combustion chambers. It means rapid movement and mixing of air and fuel inside the combustion chamber.
Turning radius-The amount (in degrees) that one front wheel turns more sharply than the other front wheel.
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