20
Ignition
The ignition is of basically standard design, but incorporates two features which may be strange to
some owners. These are, a ballast resistor mounted in series with the coil, and twin contact breakers
fitted to the distributor.
The ballast resistor is a variable resistance in the ignition primary circuit. During low speed operation,
when the current flow through the primary circuit is high, the temperature of the ballast resistor rises,
increasing its resistance. This reduces the current flow, thus prolonging the life of the contact breakers.
At high engine speeds, when the current flow in the primary circuit drops off, the ballast resistor
cools down, thus allowing more current to flow, and more efficient high speed operation. As an aid to
easier starting, the ballast resistor is bypassed when the starter is in operation, thus allowing full
battery voltage to the ignition primary circuit.
The twin contact breakers are fitted to reduce spark erosion at high speeds (on an 8 cylinder engine).
The gaps should be set as if for a single unit, in fact the engine will run with only one set. When
setting the gap on one, the other should be blocked with a thin strip of insulating material, such as
mica.
Distributor
Every 8,000 miles 5-10 drops of oil should be added to the oil cup and 2-3 drops of oil to the rotor
wick. The cam and bumper block should also be thinly coated with grease. At the same time the
points should be cleaned and checked.