Topic: Ignition Coil Wiring
in Forum: C3 Electrical
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The wiring coming off both sides of the coil on my 69 is rather shabby to say the least. I want to replace it but am not sure about the correct gauge of wire to use. Any help or suggestions wouls be appreciated.
Eric
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It's usually only 14 gauge...but you can go bigger to AWG 12.
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Careful here...there is one wire on the coil that is cloth covered(or was/should be from the factory)...it is the resistor wire from the ignition switch. You certainly do NOT want to replace that with regular wire. Unless you have the TI(transistorized ignition) ignition system, or you put a resistor in-line, leave that wire the same...
Joel Adams
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Yes, be carefull of changing some of the wires.
The "s" terminal on the starter sol is the input to crank the engine. The "i" terminal is an output that signals the vehicle the starter is cranking.
Most older vehicles do not operate the coil on 12 volts, or charging system voltage. They operate at 9 volts. The resistor wire Joel tells about is the method of operating the system at 9 volts. If it ran at 12 volts it would make a stronger spark, but it would burn up the ignition coil.
The reason is basic. When the engine is cranking, voltage in the system drops due to the starter draw. This would make the spark very weak when it really needs to be quite strong to get the car started. To fix this problem, the coil operates at 9 voilts, but the resistor wire is bypassed with the power coming out of the "i" starter terminal, going directly to the coil. As the system voltage drops to perhaps 9 or 10 volts in some conditions (maybe only 11 v) by using the bypass, the coil creates full if not stronger than full power to the plugs to get the car to fire up.
Once the key is released the "i" terminal shuts off, and the resistor wire supplies the coil once again. Ford also uses this, Chrysler uses a ballest resistor in place of the wire.
If you have HEI the system does not use the "i" terminal, and does not bypass the system. In this case there is no resistor, and the distributor operates at battery or charging system voltage at all times. Granted this can make a weaker spark to start the car. But the old point systems operated at 20,000 volts,or 20 KV. He newer HEI systems operate at 40 KV, twice as much. So when cranking even if you loose 1/4, you still have 30 KV available to start the car. More than enough.
See if you have a wire on the small "i" terminal on the other side of the start sol from the "s" term used to crank the car. If so, be sure to keep the resistor wire operating.
in Forum: C3 Electrical
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