A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
G
G or g: Unit of force equivalent to the force of the Earth's gravity.
G-force: A force on an object equivalent to the force applied by the Earth's gravity.
G/C Clamp: A clamp (hand tool) shaped like a G/C.
Gaiter: A rubber (or similar) boot used to cover working components. It is used to keep dirt out and in some cases lubrication in place. Also slang for alligator...
Galleries: See Main Gallery.
Galvanize: A protective process for steel sheet where a thin surface layer of zinc is applied by hot dipping the steel into a bath of molten zinc.
Ganged Switch: An electrical switch that operates two or more circuits from one switching point.
Gas: A fluid state of matter when the atoms are free. The least dense state of matter which can have three states, solid, liquid and gas.
Gas Analyser: Electronic equipment that measures exhaust gas constituents.
Gas Turbine: A type of internal combustion that uses rotating blades in a compressor to provide charging of the combustion chamber. The output gas pressure is used to drive turbine blades which are connected by a shaft to drive the compressor and a transmission gearbox or in the case of aircraft jet engines to provide air propulsion.
Gasket: A material that is fitted between faces to take up the irregularity of the surface finishes and provide a gas or liquid seal.
Gasoline: A hydrocarbon fuel made up from carbon and hydrogen elements. Used as a fuel for internal combustion engines. Also petrol.
Gate: In transmission systems a device to guide a gear into any one position at any one time. In electronics a logic device for regulating electrical current flow according to input voltage levels.
GCM: Governor Control Module.
Gear: A method of providing leverage. Toothed wheel that meshes with another toothed wheel.
Gear Brake: Part of an automatic gearbox, the brake is often a band of friction material.
Gear Cluster: A series of fixed gears on one shaft. Used to provide gear selection by engagement with freely rotating gears on another shaft. The selection is made by locking the freely rotating gear to the shaft. This can be by the use of a sliding hub or a sliding gear splined to the output shaft.
Gear Clutch: A clutch that connects or disconnects drive to a gear.
Gear Cogs: Toothed wheels that mesh with other toothed wheels.
Gear Lash: The clearance between the teeth of two meshing gears. Also known as backlash when applied to gears.
Gear Pump: An oil pump using two meshed gears to provide a positive pumping action. The teeth are of the two gears run in mesh. Where they come out of mesh a small chamber forms to allow oil to flow in, the oil is carried round the periphery of pump in the gear teeth and when the teeth come into mesh the chamber is reduced in size and the oil forced from the pump.
Gear Ratio: Ratio of angular velocities of pairs of meshing gears. Number of teeth on driven gear divided by number of teeth on driver gear.
Gear Reduction: A gear drive that reduces the rotational speed of the output shaft below that of the input shaft.
Gear Train: Two or more gears in mesh that transmit a drive through them.
Gearbox: A housing containing gears to allow different ratios to be selected.
Geared Distributor: A distributor driven by a gear from the engine.
Gearshift: The mechanism for selecting gears in the transmission. Consists of the driver's gear lever, the linkage to the transmission gearbox, and the selectors in the gearbox.
GEM: Governor Electronic Module.
GEN: Generator.
Generator: Machine for converting mechanical energy into electrical energy.
Generic: A common type or something that is used for a variety of tasks.
Gerotor Pump: A type of positive displacement oil pump that uses two gears on eccentric axes. One gear is on a shaft inside another rotating in the housing. The pumping and carrying chambers are formed between the gear teeth.
Glaze: Polished surface where two rubbing components slide together. Examples are brake linings and cylinder walls.
Glazier: Person who works with glass.
Glow Plug: Cold start device for diesel engine. Fitted into the combustion chamber and heated by an electrical current so that the injected air and fuel is heated as an aid to ignition when the engine is cold.
GND: Ground.
Governor: A control device that limits the speed of a unit or controls or senses the operation of a unit. An example is the governor in a diesel injection pump which controls the engine speed.
Governor Pressure: The control pressure in an automatic transmission that senses vehicle speed. It is applied to the hydraulic control unit or valve body to effect gear shifts in relation to vehicle speed.
Governor Valve: The valve in an automatic transmission, which is fitted on the output shaft. The rotational speed acts on a spring-loaded valve to regulate pump pressure. The governor pressure acts on the gear shift control plunger in the valve body.
Grab (Brake): A braking condition where the brakes lock up when light pedal effort is applied. Caused by brake linings digging into the drum or disc on application. Usually cured by forming a chamfer on the leading edge of the lining.
Gravity: The attraction that all masses experience as a force towards the earth - or any other planet for that matter!
Grease: A thick sticky lubricant made from a variety of bases, usually derived from crude oils, and used for bearing and chassis lubrication.
Grinding: A metal working process that uses a rotating abrasive wheel to cut the surface of a metal component.
Grommet: A blind grommet is a rubber insert fitted into a hole in a plate to blank off the plate. Other types are used to provide protection for cables or pipes that pass through a hole.
Groove (Tyre): (1) A channel cut in the tread of a tyre to facilitate the dispersal of road surface water. (2) The machined slot around the piston into which the rings are fitted.
Ground (Earth): The electrical termination for components connected into a vehicle direct current ground return circuit. On mains electricity a safety route for an electrical short circuit used as a means of protecting people or electrical components from electrical overload.
Ground (Earth) Cable: The battery cable connecting the return side of a vehicle circuit to a terminal on the battery where a ground return circuit is used.
Ground Clearance: The dimension under a vehicle which clears any obstacles in the roadway.
Ground Test: A test to make sure the earth or ground or chassis electrical connection is in good working order.
Gudgeon Pin: The piston pin that connects a piston to a connecting rod. Fitted at the little end of the connecting rod. Also wrist pin.
Gum: Petroleum distillate formed during combustion particularly with poor fuel quality. The gum is deposited on cylinder walls and increases the tendency for glazing.