Ignition timing Ignition timing In a spark ignition internal combustion engine, Ignition timing refers to the timing, relative to the current piston position and crankshaft angle, of the release of a spark in the combustion chamber near the end of the compression stroke. The need for advancing (or retarding) the timing of the spark is because fuel does not completely burn the instant the spark fires, the combustion gases take a period of time to expand and the angular or rotational speed of the engine can lengthen or shorten the time frame in which the burning and expansion should occur. In a
Ignition magneto as larger engines may be too difficult to crank at sufficient speed to operate a magneto, even with an impulse coupling. As the reliability of battery ignition systems improved, the magneto fell out of favour for general automotive use, but may still be found in sport or racing engines. Engines which power Top-Fuel drag-racing cars, which burn nitro-methane fuel require three spark plugs in the cylinder driven by three magnetos because the nitro-methane fuel mixture burns so slowly. Ignition magneto An ignition magneto, or high tension magneto, is a magneto that provides current for the ignition system of a spark-ignition