In many of the ignition system manuals it is claimed that the coil wire should be no more than 15 inches. With big aftermarket coils this is often impossible. Also it is benificial to get the coil away from the heat of the engine. What are the thoughts on this?
I have had a couple of conversations about this with IgnitionMan. He told me that any coil that can bleed heat off, like an oil filled core coil, will cool just fine in any place within the engine compartment, as long as it is placed upright, not on its side or up side down, except, of course, bolted directly to an exhaust manifold. Epoxy core coils, like those in the caps of HEI's, and even those epoxy coils that are cannister types, just don't bleed their core heat off, and run hot, no matter where they are placed. Another thing he pointed out about both a Buick, and a Ford conversion was that the coils placed where I did (at the front of the engine), allowed the air from the fan to pass over them, and even though the fan was/is pulling hot air out of the radiator, that air was cooler than the coil placed at the rear of the engine, or off to the side on a fender well. He has done a dozen HEI conversions for me to date, and none of them have had any problems. As far as coil wire lengths, I have three of his systems with coil wires longer than 15 inches, and he says as long as a good set of wires are used, no issues. What does cause probpems is, if those wires don't have sufficient shielding to stop voltage leakage out of the wires, which over workes the coil. Dave is really insistant on using the largest diameter wire he can, 8 or 8.5mm, and magnetic suppression, spiral or magna core. He says trhe key is to make sure the wire has the absolute minimum of RFI leakage, and that meanss it needs the best spiral or magna core shielding you can find. Regards, Milton
