3.0 lacks compression but doesn’t misfire?
Sep 16, 2018 | 08:35 PM
#1
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3.0 lacks compression but doesn’t misfire?
So I just rebuilt by 3.0. Had the heads and the block machined and the heads rebuilt by a machine shop. Everything went back together and has been running great. More power than before and sounding great. One morning I go to start it and it just cranks for a while before turning over and has done that worse and worse on every start up. After doing a compression test I find that cylinders 1 and 5 are only making about 50 psi which would explain the hard start but it isn’t misfiring and still runs great after it’s warmed up. No smoke from the exhaust or gas in the oil so I don’t think it’s the rings. Any ideas before I take the heads off again?
Sep 17, 2018 | 07:07 AM
#2
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From: San Francisco East Bay
I'd suggest a Leak-down test. The numbers are really only good for comparison with "before," but the test itself will give you a lot of information about WHERE you are losing compression (valves, rings, gaskets ...)
Sep 17, 2018 | 05:43 PM
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Oct 8, 2018 | 07:13 PM
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I’m hoping the shop messed up valve clearances and I can fix the heads in the car. If not, I’m going to remove both heads and take it from there.
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