A year ago I installed a different head on my b18. It ran great, for a few months. Now I check the compression and I've got 50 in #1, 90 in #2 and 4, and 120 in #3. I squirted oil in the cylinders and the readings went up about 10 pounds...so I think it's not rings.
I have been setting the valves to .018. I see in my green book that the higher compression heads for 1966 are to be set at .022. Hindsight suggest that may be what I have, the higher compression head.
Is this the likely cause of the head going bad? Another thing that comes to mind is I always use the cheap grade of Chevron gas. Plus I was experimenting with the timing back then, may have had it advanced too much.
I will get the head redone. Just looking for ideas on how to avoid doing this again.
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