Timing belt is a toothed belt that connects the engine crankshaft to the
camshaft or camshafts.
The timing belt is needed to synchronize
the camshaft to the crankshaft position, so the valves will open
and close at the proper time
in relation to the position of the pistons. The camshaft rotates
at exactly 1/2 speed
of the crankshaft; meaning two revolutions of the crankshaft
are equal to one revolution of the camshaft.
Not all cars have a timing belt.
Some of them use a chain or gears
instead.
Mostly, you can find the timing belt in small and medium
size domestic and import passenger cars. For example, All VW
Water Cooled except
VR6,
Audi, Volvo BMW Most Toyota, Honda, Acura, Mazda,
Some Nissans
Lexus, Subaru, Suzuki they all have a timing belt.
The timing
belt must be replaced at a specified mileage. This interval may
vary from 60,000 miles to 105,000 miles (in our
shop we highly recommend
60,000-80,000 miles). In addition, the timing belt must
be replaced if it has any damage like cracks, cuts or excessive
wear. If not replaced
in time,
it may break possibly causing serious engine damage. When
a timing belt breaks, the camshaft stops turning leaving
some of the valves
in
the open
position. The crankshaft, because it's heavier, continues
to rotate by inertia. In an interference engine, this will
cause the pistons to strike the valves
that left open. This may result in broken or bent valves,
damaged pistons, and possibly, destroyed cylinder head.
The damage will be less extensive in a non-interference engine but in either
case, the engine will stall, leaving you stranded.
The manufacturer may also recommend the replacement of
other
parts, such as the water Pump
and seals,when the timing belt is replaced because the
additional cost to replace the water pump is negligible
compared to
the cost of accessing the
timing belt.
