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
Archaic Southwest Archaic Southwest The Archaic Southwest was the culture of the southwestern United States between 6500 BC and 200 AD (approximately). The Paleo-Indian tradition before that dates from 10,500 BC to 7500 BC. The Southwestern United States during the Archaic time frame can be identified or defined culturally in two separate ways: As the climate warmed at the end of the Ice Age, mammoths and large animals such as horses and camels began to disappear. Hunter/gatherers gradually adapted to these changes, supplementing their diet with a variety of plant foods and smaller game. The Archaic people used nets and the atlatl