That's pretty interesting... Especiacially since engines have different coils and gap requirements. So this 30KV number....... Is this unique to the 4.0 or what? Because I've had bigger draws than that on a turbo aircooled engine that didn't result in coil failure as it was designed to do so with a corresponding Mallory ignition coil...NESW20 said:electicity tries to find the easiest path to ground. i think you're all familiar with that. when you have excessive plug gaps, yes, the coil can fire the plug still, but once you start getting up to the point where you have 30KV+ required voltage (the amount of voltage required to jump the plug gap and fire the cylinder), it starts grounding through the coil body, causing carbon tracking and dielectric leakage. it's not the current you need to worry about. i'm not talking about "overheating" the coils. it's the voltage.
once you have carbon tracking in the coil, the problem only becomes worse, until a point where even if you change the plugs and have the correct plug gap, the carbon track through the coil body will have less resistence than the plug gap, and the coil will no longer fire the cylinder, no matter what.
i didn't feel like typing all of that out the first time, but since i now feel it wouldn't be wasted typing...
The 2.7L has aluminum heads too. As said before, the only reason for 30,000 interval in the V-6 is non-iridium plugs.Steelheart said:The main reason for replacing the plugs in the V-6 is it has aluminum heads and the plugs will "weld" themselves to the head unless anti-seize lubricant is installed. Removing a seized plug is something you don't want to experience.
make sure you use anti-seize that is metal based. conductivity = good.Steelheart said:The main reason for replacing the plugs in the V-6 is it has aluminum heads and the plugs will "weld" themselves to the head unless anti-seize lubricant is installed. Removing a seized plug is something you don't want to experience.