ALT-5 What is a Timing Belt
A timing belt is the heart and soul of internal combustion, an engine cannot run without proper timing. An improperly timed engine is similar to holding a lit match six inches away from a candle, and expecting it to light.
In older engines a heavy chain was employed to time an engine ... super strong rubber and/or nylon belts have taken over this chore in the past several years. This could be viewed an improvement over the chains, or not. The chains did stretch after a while and cause poor performance, and they were prone to jump out of time when they became stretched.
The belts, if in good shape are a better alternative, however they can break without warning, and cause engine failure.
In order to run efficiently, an engine must fire a high energy spark at the precise moment when compression is at its peak. This is called Top Dead Center, this is the moment when the piston is right up against the cylinder head. The gasoline/air mixture is compressed to it's maximum at this split-second in time. This coordination is the job of the timing belt.
It runs over a pulley on the crankshaft, and over another one on the camshaft. The camshaft has egg-shaped lobes that lift and drop the engine valves. The valves have specific times designated by the location of these lobes, to open or close at the proper time.
Half of the valves are intake valves, allowing a gas/air mixture to enter the combustion chamber. The other half are exhaust valves, opening to allow burnt gases to escape through the exhaust system.
Without this precision timing an engine will not run, at least not very well. A worn or loose belt can cause a vehicle to run poorly, even if the timing is off only a fraction of a second.
Most newer vehicles recommend replacing the timing belt after X amount of miles, usually around sixty-thousand. This could help prevent engine failure, and also insure peak performance and gas mileage. Some engines can be severely damaged if a timing belt breaks under normal driving conditions.
There is a time and place for all things, and the firing of an internal combustion engine is no exception ... the timing belt makes it happen.
