Easy to understand guide on how automotive timing belts work, this information pertains
to all timing belt driven engines.
A timing belt is a rubber toothed belt which is designed to drive the camshaft,
balance shaft, water and oil pumps depending on manufacturer's engine design, via
the engine crankshaft.
A tensioner is used to hold pressure on the belt which is spring loaded, oil
pressure activated or set manually.
The cog of the timing belt is what drives each accessory and when these teeth
fail the engine will stop running, a timing belt is a normal service item.
Timing Belt Tensioner
Many things can be driven by a timing belt, including the engine oil pump.
Timing Belt Cogs
Timing belts are more common in overhead cam engines and are more easily serviced
than a timing chain. A timing belt is constructed of a fiber reinforced rubber with
vertical ribs vulcanized to the inside of the belt. When a timing belt fails it
will allow the ribs to shred stopping the driving motion. To check the condition
of the timing belt (engine off) remove the timing belt cover (upper), using a flash
light inspect the condition of the belt, check for cracks especially at the base
of drive teeth. An engine has a unique set of crankshaft, camshaft and accessory
The timing belt or chain needs to be replaced per manufacturer's specification
and can fail without warning which stalls the engine. Because a timing chain configuration
is more durable, a timing belt will need to be replaced more often, comparatively.
Article first published 2016-02-05