502 MerCruiser MPI head and cylinder issues
03-15-2025 | 01:31 PM
#31
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From: DFW
Looks like it is pulling the gasket apart which also indicates detonation. Ring gaps might be too small and piston to wall clearance like others have said. Does your builder do many marine engines ?
Also looks like somebody sprayed the gaskets with copper coat ? Those gaskets are designed to go on the way they come out of the box. They have a coating on them that "flows" when heated and putting copper coat on them defeats the purpose. But that did not cause your failure.
Also looks like somebody sprayed the gaskets with copper coat ? Those gaskets are designed to go on the way they come out of the box. They have a coating on them that "flows" when heated and putting copper coat on them defeats the purpose. But that did not cause your failure.
03-15-2025 | 01:35 PM
#33
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From: DFW
Do you have any idea what the gaps should be on a 502 MPI that is .60 over? Im thinking this may be the issue as well.
03-15-2025 | 10:35 PM
#36
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From: Omaha/LOTO
03-16-2025 | 06:30 PM
#37
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From: Waldorf, Md
I was just looking at the pictures again and find it strange that the wear on the cylinders is to the front and back of the engine. Usually if pistons are too tight it will be on the sides where the skirts are. Have to wonder if the rings arent butting.
Do you have an itemized list of the parts they used ?
Do you have an itemized list of the parts they used ?
