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Reply to "Coil Failure"

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@Stan Galat posted:


...For posterity - apparently, the coil supplied with the Magna-Spark kit is too hot for the pickup module supplied in the distributor...

Run a different coil, or a CDI box, or suffer through the purgatory Bob has endured.



Still, you have to wonder how CBP keep selling these and how the coils work OK for a lot of folks.

And why the cheap pickup units in the dizzies (Pertronix, Magnaspark, whatever) also seem to work for some folks while others have repeated failures. Yeah, the quality control is terrible, so one example may be weaker than the next, but why does one guy have to replace three, while others put in one and are good for years?

I keep coming back to the difference in environment from one installation to another — in particular how much heat (and vibration, too) a given installation subjects a coil or dizzy to.

Heat is the biggest enemy of electronic components. The heavy current a 1.1 ohm coil sends through the module in the dizzy in itself  isn't the problem. It's the heat that current creates that melts and fatigues components. Depending on how much power an engine generates, how well the oil is cooled, how much outside air flows through the compartment, and how hot the ambient temps, one engine bay could typically run 30 degrees hotter than another. That could well be the difference between ignition components surviving or failing. One guy concludes these coils are great, another says they're worthless junk.

When we configured my engine, my biggest concern wasn't being the fastest kid on the block. It was surviving our, ahem, dry heat and living to drive another day. It's a 'conservative' build at best, but here I am 10 years and 40K miles later with the original (blue) coil, without ever having to replace a dizzy module. (OK, I swapped out dizzies mid-stream, for better mechanical bits, but not because of electronic component failure.) And 'the build' went beyond the engine itself. It included oil cooling, crankcase ventilation, fuel line placement, engine bay ventilation, and of course, complete tins. As we say here a lot, all the little bits need to be happy with each other to produce a system that works.

My point is that if you're losing electronic components, especially the same one repeatedly, take a step back and look at the bigger picture. There are many more reasons to reduce the heat in the engine compartment than just lowering CHT and oil temp. And even if your options are limited, something as simple as repositioning a coil can help a lot, too.

Last edited by Sacto Mitch
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