Timing Belts

Does Your Engine Have a Timing Belt?

Since the mid-70s, many import car engines have featured a timing
belt to operate the single and double overhead camshafts of
small displacement; usually under 3-liter (3000cc) engines. And in
recent model years several small American-made engines now use
timing belts to operate overhead camshafts. Now we are seeing even
larger sized engines using a timing belt for overhead camshaft operation.

The timing belt is a strong, wide, square-toothed type of belt which is
driven by the engine's crankshaft. Once installed and properly tensioned, a timing belt usually will operate without any further service or maintenance
for 60,000 or more miles.Almost every engine with a timing belt also has a manufacturer's recommended mileage for its replacement.
Only a few car makers offer no replacement recommendation. But to be
safely conservative, some timing-belt manufacturers suggest a
maximum 60,000-mile replacement interval -- to avoid inconvenient
and possibly costly engine damage.

You see, when a timing belt breaks, it usually does so when the
engine is running. This kind of operational breakage very often results
in expensive engine damage, due to fast-moving pistons in the engine
block impacting valves which may be open.

Not all timing belt breakage will end up causing serious valve-to-piston
damage.Some engines are of the freewheeling type, that is, due to their cylinder head design, valves and pistons are very unlikely to collide,
therefore no damage will occur.

Others are known as interference-type engines, where valve-to-piston
contact is almost sure to happen when the timing belt breaks.

Replacing a timing belt will take between 2.5 to 5.5 hours, depending
on how easy it is to make the change, given the limited under-hood
space in many of today's cramped engine compartments.Prices will vary, depending on shop labor rates and the time needed for the job, but $200
to $500+ is the range for a straight timing-belt replacement.

We recommend that front engine seals also be replaced along with the belt. Oil seals are inexpensive and will leak eventually if not replaced with the belt. Some models also recommend water pump replacement at the
same interval.

Sound like a lot? If you drive until the belt breaks, you could be facing
anything from a cylinder head overhaul to a major engine rebuild.

Engine timing belt replacement is a required maintenance job on a
growing number of engines today. So...do you know how your
engine's valves are operated? If it's with a timing belt, get to know the
car maker's recommended replacement interval.