For an engine to work at its best, the fuel /air mixture in each cylinder Must fire just as the piston reaches top dead centre ( TDC ). It takes a certain time for the spark-plug to ignite the Mixture and for the combustion to build up. This time stays roughly the same no matter how fast the engine is running The timing mechanism is set to fire the plug a short time before the TDC. But because the mechanism is worked by the motion of the engine, This time would normally decrease as the engine ran faster, And the plug would fire too late. So a mechanical device is fitted to advance firing Make it happen earlier – with … Continue reading How engine timing works