An Interference engine is a type of internal combustion engine
where in the event of a serious valve train failure, or a 180
degree timing error, could lead the valve s and piston s to
strike each other. The most common cause of this a broken timing
belt , but a catastrophic timing chain failure can also bring
about this situation. The reason for this is that for an engine
to work properly, the actions of the pistons and valves must be
precisely harmonized. This is accomplished in three ways. In
racing engines, gears may connect the camshaft and crankshaft.
In street engines, that task is accomplished by a timing chain
or belt. When the chain or belt is installed, the camshaft and
crank must be turned so that the number one cylinder is at Top
Dead Center, or when it is at the maximum of its stroke.
Generally, there are timing marks on the timing gears. or
pulleys to aid in this, and the gears themselves are usually
keyed to prevent misalignment. However, some people do screw it
up. If the belt or chain breaks