We know that a cambelt is an important component in internal combustion engines - but what does a timing belt do, exactly, and how do different types of timing belts play similarly crucial roles in a variety of other systems and mechanisms?
Timing belts are typically ridged with a circumference of protruding rubber ‘teeth’, and In an engine it’s these teeth that enable the loop of timing belt material to turn the camshafts via the crankshaft as the various parts rotate at a consistent ratio of speeds. Together, these components are thus responsible for opening and closing the intake and exhaust valves in an engine.
When a cambelt is in good working order and functioning correctly, the opening and closing of these valves is maintained at an optimal rhythm to match the up-and-down motion of pistons within the engine’s cylinders, allowing for smooth and efficient functioning of the entire apparatus as the engine cycles through each of its various ‘strokes’ (usually intake, compression, power and exhaust).
In the case of a broken or failing timing belt, it’s possible for engine valves to be left stuck in an open position, which risks serious damage to the mechanism of so-called ‘interference engines’ if they’re then able to be struck repeatedly by the pistons. Non-interference engines avoid this particular complication by keeping the valves and pistons separately confined, but the engine will still be effectively immobilised without a functioning cambelt installed.
Because timing belts loop around a series of pulleys to connect up all the relevant engine components in sequence, they tend to rely on a number of tensioners being attached in order to keep the ideal tension on the belt along its full length. These will usually need to be replaced along with new cambelts, as they’re almost always roughly the same age as the main belt and will generally have a similar sort of expected lifespan.