High Compression Heads and Fouled Plugs

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High Compression Heads and Fouled Plugs

Post by Go Go Diablo » Sun Jan 08, 2023 10:32 am

I've been at this hobby for many years and occasionally, I still learn something new.

We had a Diablo that has been giving the owner and I headaches for over a year now trying to figure out why it fouls plugs on occasion. I went through the motor putting gaskets and seals in it along with the usual points, condenser and plug wire. After it still fouled plugs, he put an ignition coil in it. We adjusted the timing. Grrrrr..... Still fouling plugs!

The darn motor pulled over hard. This was a 500 so it was a pull start. When it ran, it had plenty of power. It dawned on me while I was drifting off to sleep one night that maybe the cylinder head held the secret. So the next day, the motor came back apart and sure enough, it had a high compression head on it. I might have seen that when the motor was originally apart, but it's not the first high compression head I've seen so I probably did not think twice about it.

Swapped out the head and problem solved. It pulls over much easier, does not foul plugs and runs like it should.

Mark that up for a lessoned learning experience.
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