Ignition System: Description and Operation

The ignition system consists of a distributor assembly, ignition coil, four spark plugs and high tension leads. The timing of the spark varies to suit engine speed and local conditions.

The distributor is mounted on the rear face of the cylinder head and is driven off the end of the camshaft. The ignition advance is mechanically controlled, according to engine speed, by governor weights and a dual diaphragm vacuum advance. Advance is also controlled, according to engine load.

On non-turbo models ignition timing is modified by the electronic control assembly (ECA), based on inputs from the barometric pressure sensor (BP), at altitudes of 3,280 ft (1000 m) or higher, the ECA will signal the ignition module to advance ignition timing. On turbo models ignition timing is modified by the electronic control assembly (ECA), and the knock controller.


The high tension spark plug leads are of the carbon impregnated suppression type. All four plug leads vary in their overall length and are numbered for ease of identification. The number one cylinder is considered to be front cylinder on the right hand side of the vehicle.