An interference engine is a type of 4-stroke internal combustion piston engine in which one or more valves in the fully open position extends into any area through which the piston may travel. This means that if the cam stops turning due to a broken timing belt, there is insufficient clearance between the valves and pistons, which can lead to the valves and pistons striking each other. In contrast, a non-interference engine is one in which the piston does not travel into any area into which the valves open, so there is no risk of the valves and pistons colliding.
Interference engines rely on timing gears, chains, or belts to prevent the piston from striking the valves by ensuring that the valves are closed when the piston is near top dead center. It is important to note that interference engines are prevalent among modern production automobiles and many other four-stroke engine applications.
In the event of a serious valve train failure or a timing error, such as a broken timing belt or a catastrophic timing chain failure, the risk of the valves and pistons striking each other is present in an interference engine. This can lead to extensive internal engine damage, such as bent valves, damaged pistons and cylinders, or broken pieces within the cylinder, which may affect the connecting rods.
To determine whether a specific car engine is an interference engine or a non-interference engine, it is essential to refer to a complete list that provides information on different engine models and their interference characteristics.
In summary, an interference engine poses a risk of internal damage if the timing mechanism fails, while a non-interference engine does not have this risk due to the design of the engine.
