As your engine runs, the intake valves need to open up to allow air into the engine. They remain closed while the air and fuel is compressed and ignited, powering the piston. Then the exhaust valves open to release the exhaust. This all has to be timed very precisely. It is the job of the timing belt or timing chain to make sure all of this is synced up properly.
Timing belts are made of a very tough compound that can last for a long time. Timing chains are made of metal and last for a very lon... read more