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what would be causing me to keep burning up coils. I have changed points over to pertronix a couple of months ago and have burned up a pertronix coil and now a msd street fighter coil? pertonix lasted about 120 miles and msd only lasted 25 miles and the top of coil seperated and oil went all over engine bay?
 

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I'd check the voltage going into the coil after the car is running. It should only be about 9 volts if the resistance wire is connected.
 

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What causes coils to overheat? A basic question and one that's easily answered. The coil primary circuit consists of a wire wound around a iron core then proceeding to a switched ground. When the ground is active, current passes through the windings to, essentially, a dead short, creating a magnetic field around the iron core as well as turning the windings into, for all practical purposes, a heating coil, like in your seat heater or electric blanket. That's what the oil is for... its "coolant" for the windings.

The more dwell (the period that the coil primary remains grounded) the hotter the windings get. The more voltage supplied to the coil the hotter the windings get. When the temperature exceeds the design elements of the coil, or if it is physically damaged, the coil fails. The sign that the top has separated from the canister means the oil inside overheated and the expansion blew the top off.

The one variable (dwell is pretty much set on the Ignitor I) is voltage. Most canister coils with 1.5 ohm impedance are designed for a 6-volt input (6-8 volts depending on charging system output). Doubling the voltage quadruples the wattage, so that coil designed for a wattage of around 30 is now producing 120+ watts. If you've ever touched a fully "warmed up" 100W light bulb you'll understand why the coil went "poof".
 

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Not understanding what you are saying, bad igniter?
No. Too much voltage at the coil. Yes, you need 12v for the red wire on your Igniter I. No, you still need the resistance wire in the system for the coil. There are almost as many opinions about this out there as there are on "what's the best engine oil" but the fact remains that the coil is overheating and there are only a couple possibilities and although a bad Igniter is POSSIBLE I have never seen one that still allows the car to run that could possibly be the culprit.
 

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... Doubling the voltage quadruples the wattage, so that coil designed for a wattage of around 30 is now producing 120+ watts....
Not doubting anything else said, but I thought Watts = Volts x Amps. So if Volts double and Amps remain constant, Watts double too, not quadruple.
 
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