If you were asked the question “What part of an internal combustion engine is the most important part?” I wonder what your reply would be. Some would argue that the crankshaft is; others would say that the con rods are. However, an engine design that incorporates an “interference” engine type design needs a timing belt that won’t break. Without the timing belt functioning properly, this engine is certainly in a sad state.

As the name suggests, the timing belt ensures the internal running of the engine is kept performing like clockwork. The timing belt provides a quiet, flexible connection between the camshaft and crankshaft to keep the valves opening and closing in phase with the movement of the pistons.

Timing belts are used in two types of engines designated “interference” and “non-interference”. If the timing belt breaks on a non-interference design, there is enough clearance between the pistons and valves to prevent damaging contact. An interference design does not have sufficient clearance between those parts and costly engine damage would result from a broken timing belt.

If the timing belt is neglected and not replaced at the correct time, the chances are very high that the timing belt will end up breaking. However, breakage is not the only reason to replace your timing belt. Looseness and wear will allow the timing belt to slip and change valve timing resulting in very poor performance, a no-engine-start condition or engine damage.

Timing belts are made from a strong synthetic material and have notches or teeth to ensure a slip-free drive between two or more components is maintained. There are some very successful engine designs that incorporate a chain instead of the belt to drive the camshaft and the crankshaft. A chain requires much less maintenance. We hope that helps answer the question ‘What is What is a Timing Belt?’!

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