See Figure 1
The Dura Spark II ignition system features a tang-driven distributor assembly with a top weight centrifugal advance mechanism, a concentric vacuum advance mechanism, and a concentric coil stator assembly. The Dura Spark II ignition system is a solid state ignition system. The system uses 14mm spark plugs, which have a screw-on gasket. The spark plug boots includes a seal for the spark plug cavity to keep it clean and dry.
The Dura Spark II ignition systems consist of the typical electronic primary and conventional secondary circuits, designed to carry higher voltages. The primary and secondary circuits consists of the following components:Primary Circuit
The basic operation of the distributor is the same as a solid state distributor. With the ignition switch in the RUN position, the primary circuit current is directed from the battery, through the ignition switch, the ballast resistor, the ignition coil primary, the ignition module and back to the battery through the ignition system ground in the distributor. When the engine is being cranked, the rotating armature induces a signal in the stator assembly. This current flow causes a magnetic field to be built up in the ignition coil. When the poles on the armature and the stator assembly align, the ignition module turns the primary current flow off, collapsing the magnetic field in the ignition coil. The collapsing field induces a high voltage in the ignition coil secondary windings. The ignition coil wire then conducts the high voltage to the distributor where the cap and rotor distributes it to the appropriate spark plug.