Ignition timing
Videos
In a spark ignition internal combustion engine, ignition timing is the timing, relative to the current piston position and crankshaft angle, of the release of a spark in the combustion chamber near th
Timing light
Distributor
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A distributor is an electric and mechanical device used in the ignition system of older spark-ignition engines. The distributor's main function is to route electricity from the ignition coil to each s
Ignition timing
…real time by an engine control unit use a computer to control the timing throughout the engine's RPM and load range. Older engines that use mechanical distributors rely on inertia (by using rotating weights and springs) and manifold vacuum in order to set the ignition timing throughout the engine's RPM and load…
Distributor (side view) with input shaft (bottom) and vacuum advance unit (top right)
Breaker arm with contact points at the left. The pivot is on the right and the cam follower is in the middle of the breaker arm.
Distributor cap. At the center is a spring-loaded carbon button that touches the rotor. The number of contacts (in this case 4) is the same as the number of engine cylinders.
Rotor. This rotates at the same speed as the camshaft, one half the speed of the crankshaft.