Overhead Valve:

Originally used to describe an engine with the intake and exhaust valves in the cylinder head, i.e. above the piston, but now that all engines have valves above the piston it specifically refers to an engine with the valves operated by pushrods from a camshaft located in the cylinder block. The old V6 used by Holden until the VZ Commodore was a pushrod engine, as is the current Gen III V8 Holden uses.


Is the rate of work generated by an engine. It’s comes into play at higher engine speeds and is measured in kilowatts (kW).

Rear-Wheel Drive:

The traditional way of propulsion was to deliver the drive to the rear wheels, until the advantages of front-wheel drive where the complete drive train is combined in one package at the front of the vehicle which means the drive train intrudes less on the interior space. Today it’s the cars with sporty pretensions that retain rear-wheel drive.


A term generally used today to describe a two-seater sports car. It once referred to a two-seater car with few frills.

Shock Absorbers:

Employed on each wheel to dampen the movement of the wheel as it moves over bumps. Without them the wheel will bounce up and down without control. Car makers calibrate the shock absorber rate according to the sportiness they want in their suspension set-up.


Similar to turbo charging, but the supercharger is driven by the engine rather than the exhaust gases. There is no delay in response with the supercharger, it responds as soon as the driver presses down on the accelerator, but being driven by the engine it does use up some of the engine’s power. Supercharging is preferred for larger engines where the power loss is less critical.


Is the turning or twisting force generated by an engine. It’s generally what gets a car going and is measured in terms of Newton-meters (Nm). It’s generally at its peak in the lower part of the engine’s speed range, diminishing as the revs rise.