Thread: Ignition Help
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Old 03-04-2020, 03:08 PM   #11
40cpe
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Default Re: Ignition Help

Help me with this concern with high voltage coil: I have been under the impression that in a properly installed system the voltage only rises to the level needed to arc across the spark plug. If there is high resistance due to faulty plug wires, bad connections in the secondary side, wide plug gaps, etc, the spark will arc across at the weakest point of insulation. If my understanding is correct, the only down side of the HV coil is maybe more expensive.

On the OP's question of the use of the ballast resistor: A 12V system needs 3.0 (or maybe a little more) total resistance in the primary circuit. This would be a combination of the resistance between the + and - terminals and the ballast resistor. If the coil has 3 ohms resistance, there is no need for the ballast resistor.
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