desertdatsuns.net

During two different trips in my Roadster the car began to run rough and died after idling for an extended period of time. After letting it sit for no more than 5 minutes, the car started right up and ran fine again. I was pretty sure it was an ignition issue of some type. I'm running Pertronix without a ballast resistor. Last night when this happened, I nearly burned my hand on the coil (140 degrees when checked at home) while looking for a loose connection. Today I had the car out again and checked the temperature of the coil after a 20 minute run and it was 160 degrees. This is where it gets interesting, I called Pertronix this morning and shared my issue. He asked me two questions, is the coil mounted vertically or horizontally? Are the terminals at the 6 and 12 position or 3 and 9. Mine was 6 and 12. He claims they need to be at 3 and 9 or there will be an air bubble inside that prevents the coil from cooling optimally. I've changed the position on my car but can't yet verify that it has solved my issue. This sounds a bit crazy. Anybody else ever hear this???

Actually I have heard this.

While not as specific certain MSD coils recommend they only be mounted vertically, and I have had to remount several ones that failed that were mounted horizontally.

I had an Accell coil that seemed to be over heating in the horizontal position. I switched to the OEM ZX coil and have had no issues.