Talking CarCar fanatics may find automotive jargon a breeze. To the novice, however, it can be a confusing language! There are different terms used for vehicles from different eras and many models of cars seem to come with their own automotive dictionary! Dedicated enthusiasts of motorised cars will be well versed with these automotive terms.


EGR SystemAn EGR valve or Exhaust Gas Recirculation valve recirculates a portion of your exhaust by running it through the combustion process again. It will help your vehicle to run more efficiently and stops unburned fuel being released into the atmosphere. This vacuum controlled valve lets a certain amount of your exhaust back into the intake manifold. It helps to cool the combustion and keeps the engine cooler. If your car is having trouble accelerating or idling roughly, it may mean the EGR valve needs replacing.

Cotter Pin

Cotter PinThis metal pin is also known as a split pin. There are also circle, bowtie and hairpin cotter pins. Cotter pins are used to fix a crank to a crankshaft or a piston rod to a crosshead. Cotter pins have a split end that spreads after being pushed into a hole to attach parts. The pin will secure and provide safety for bolt connections. Choose the right size pin, as there should not be any movement when the cotter pin is inserted. The ends can be bent around for security.

Bronze Guide

Valve GuidesThis is a valve made of bronze alloy. When heated, bronze expands 1.5 times faster than cast iron.
Cast iron is not very elastic when heated, so bronze valves are used only when the cylinder head is made of aluminium because the expansion of aluminium is similar to that of bronze. This means the aluminium head should not suffer from distortion. If rebuilding a cast iron head, use cast iron valve guides.


Bearing RaceWith ball bearings, the load is transmitted from the outer race to the ball and from the ball to the inner race or the small race that the shaft rides in. A ball bearing is a smooth sphere and comes in many different forms. The rolling element of a ball bearing ride on races.

Intake Runner

Intake RunnerThe intake system on a four stroke engine gets as much air/fuel mixture into the cylinder as possible. When the intake valve is open, air gets sucked into the engine. The air in the intake runner moves quickly toward the cylinder. When the intake valve closes suddenly, the air stacks up, forming a high pressure area. This then makes its way up the intake runner away from the cylinder. The runner connects to the intake manifold and the pressure descends back down the intake runner.

Diff Lapping QLDMany automotive parts will need machining and honing at some time. For expert advice, contact Diff Lapping QLD. This can save you a lot of time and money and you may be able to reuse existing parts rather than having to outlay money for an expensive new part.