502 MerCruiser MPI head and cylinder issues
03-16-2025 | 11:38 PM
#42
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From: DFW
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 ?
Piston Rings Mahle Part # MAH-3150108035 Summit Racing
03-17-2025 | 05:40 AM
#43
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From: Waldorf, Md
According to the KB catalog the piston to wall clearance should be between .0055" and .007" and the top ring gap of .018"
Last edited by BillK; 03-17-2025 at 05:44 AM.
03-17-2025 | 07:55 AM
#44
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From: DFW
Those should be correct but they are definitely file fit rings. You should be able to look at the ends of the rings and see if they were butting up against each other. They will be shiny if they were.
According to the KB catalog the piston to wall clearance should be between .0055" and .007" and the top ring gap of .018"
According to the KB catalog the piston to wall clearance should be between .0055" and .007" and the top ring gap of .018"
03-20-2025 | 01:25 PM
#48
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From: DFW
yes, I did set the base mode maybe at 10, but I would think that would make that much difference but I guess it could have. Would 2° make that much detonation difference?
