MOTORCRAFT DURA-Spark II Ignition Systems: Operation: Distributor

An armature, containing the same number of teeth as the engine has cylinders, turns with the distributor shaft. A stator (pick-up coil) contains a permanent magnet, causing a magnetic field around the stator's pick-up coil. As the teeth of the armature pass the stator, the magnetic field builds and collapses, causing a signal to be sent to the electronic control module. In turn, the control module turns the ignition coil off and on. The cap is larger than on conventional distributors and the secondary wires have a heavier insulation for the very high secondary voltage. Distributors also have centrifugal and vacuum advance mechanisms.