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. Dura-Spark II systems have an adapter between the distributor housing and cap. 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.