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4.2L detonation

Posted: February 20th, 2017, 7:52 pm
by Trevordavis0521
I have a summit HEI distributer in my 87 wrangler w/ the 258 4.2L and it is detonating under load from 2200 RPMs+
I have turned the vacuum advance alll the way down and brought the timing down to 8 degrees and I still have problems. I wrote the timing down for every 500 RPMs. I've actually brought the timing down to 6 degrees since I've wrote them down and I still have problems. Any feed back would be great. The table I made is in order from RPMS|mechanical advance only|W/ vacuum advance|degrees vacuum advance adds to mechanical
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