School us on igniters

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Oct 28, 2003
Upon searching for information about electronic ignition and igniters, there is a lot of conflicting information. Can someone school us on them? What do they do? Why do some people suggest bypassing them? Are they really needed? What years have ballast resistors?
Man, this is too much crap to have to write, but I'll dive in anyway. :frown:

An ignitor is nothing more than a solid-state (electronic) switch. It interupts primary current to the ignition coil, which results in the discharge of the coil secondary (due to the collapsing magnetic field) and firing of the spark plug for whichever cylinder the distributor rotor is pointing to. By having electronics interrupt the primary coil current rather than points, you eliminate maintenance (cleaning and/or replacment of burned points) and more-frequent adjustment of the points. The timing of the ignitor firing can be controlled by points, as in the '76 ignition, or by a reluctor and mag pickup, as in the later systems. If you have an earlier, semi-electronic ignition system with points controlling the ignitor, you can bypass/eliminate the ignitor and just use the points which are already there, but you'll be back to dealing with more points maintenance (the points stay cleaner with the ignitor doing the actual opening of the primary coil circuit). With the later, fully-electronic ignition circuits that have a reluctor and mag pickup in the distributor, you have to use the ignitor (you have no points or other means to interupt coil primary current).

A ballast resistor reduces current flow through the coil primary to reduce the heat generated and extend the life of the coil. Early coils typically needed the ballast resistor. Later coils had additional resistance built in.

Bottom line: The ignitor is just a better way, than points, to control firing of the spark plugs. With your (Dianna) ignition system (I believe you said you upgraded to the '78 or '79 ignition), you do need the ignitor and you do not need the ballast resistor.
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Thank You!!!

Exactly the information I was looking for. Thanks spotcruiser!
The ballast resistor is just a necessary part of a circuit that is designed to make starting more reliable in cold weather. When the engine is cranking, the ballast resistor is bypassed to put full battery voltage to the coil that is designed to operate continuously at 6 to 8 volts. After the engine starts, the ignition voltage is fed through the ballast resistor which drops the 12 V nominal battery voltage to the 6-8 V that the coil needs to operate. In other words, the coil determines whether you need a ballast resistor or not. Running a coil designed to use a resistor without the resistor will overheat and burn out the coil. In year model 79 and up, the resistor is built in to the ignition wire and it says "resistor" on the wire.

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