ignition timing

It is important that the spark coming from the spark plugs ignites the air-fuel mixture at the correct moment determined by the manufacturer of the engine. Often this is a few degrees before top dead center (BTDC). Suppose the specs indicate that it should be set at 5 degrees BTDC, but in actuality it is set at 6 degrees. In that case, the timing is advanced. If it were set at 4 degrees, the timing is retarded. Incorrect ignition timing may result in poor performance and excessive fuel consumption.
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Dictionary of automotive terms. 2015.

Look at other dictionaries:

  • Ignition timing — in an internal combustion engine is the process of setting the time that a spark will occur in the combustion chamber (during the power stroke) relative to piston position and crankshaft angular velocity. Setting the correct ignition timing is… …   Wikipedia

  • ignition timing — The timing of the ignition spark with respect to the piston position in the cylinder of a reciprocating engine. The ignition of the fuel air mixture must take place when the piston is still moving upward during the compression stroke for the… …   Aviation dictionary

  • ignition-timing control — See vacuum ignition timing control …   Dictionary of automotive terms

  • dynamic ignition timing — Before the introduction of a strobe light, ignition timing was done statically in that the distributor was moved a certain measured amount. With modern engines, a timing light or strobe light is used. It is connected, generally, with the spark… …   Dictionary of automotive terms

  • static ignition timing — An obsolete timing procedure carried out by rotating the engine until the timing marks are aligned and then connecting a test lamp or a voltmeter between the negative coil terminal and ground; when the points open, the test lamp lights up or the… …   Dictionary of automotive terms

  • basic ignition timing — The ignition timing on a non running engine according to the specifications. After the engine is running, the timing can be set more accurately …   Dictionary of automotive terms

  • stroboscopic ignition timing — See dynamic ignition timing …   Dictionary of automotive terms

  • mechanical ignition timing — Centrifugal and vacuum advance …   Dictionary of automotive terms

  • vacuum ignition-timing control — See vacuum control …   Dictionary of automotive terms

  • Timing mark — on pulley at 6° before TDC. A timing mark is an indicator used for setting the timing of the ignition system of an engine, typically found on the crankshaft pulley (as pictured) or the flywheel, being the largest radius rotating at crankshaft… …   Wikipedia

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