Interference and Timing Christine Stewart
Objective The objective is to impart a basic knowledge of interference engines and timing belts.
Parts of the Engine Engine Block – the housing of the engine Cylinder – the cylinder where the piston moves Piston – a circular block that forces air and fuel in, compresses it, combusts it, then exhausts it (four-stroke engine) Crankshaft – turns the connecting rod which pushes and pulls the piston
Spark plug – creates a spark for combustion of air/fuel mixture Valves – let fuel in (intake valve) and exhaust out (exhaust valve) Camshaft – controls the valves (opens and closes them) Timing Belt – a belt made of rubber that links the camshaft and crankshaft – the camshaft is geared to turn at half the rate of the crankshaft
Non-Interference vs. Interference Engine Source:
Interference Engines The timing belt on any engine is hard to inspect – located under a cover on the front of the engine Manufacturers will recommend a time interval when the belt should be replaced On a free-running engine, if the timing belt breaks it won’t cause damage On an interfering engine, if the timing belt breaks it causes severe damage – the whole engine may need to be replaced
For cars with an interfering engine, if timing is incorrect, the pistons and valves collide, and the car will automatically stop working If a belt is replaced it must be properly synchronized with the movements of the pistons and valves Timing belt made of rubber with fiberglass or Kevlar fibers in it Engine must be running well or else the rubber degrades, which can cause severe problems
Conclusion There are both interfering and non- interfering engines Interfering engines need to be brought in for check up to make sure the timing belt is still in good order Timing is extremely important for a smooth-running car
References m m m me.htm me.htm me.htm