We are hearing a grinding noise, between 1000rpm and 1800 rpm, seems to be coming from behind the crank/cam gear cover. No noise before or after this rpm span, all else sounds fine. This is a 1989 502ci Crusader, right hand rotation, with 580 hours. We have had several engine/marine engine speialists in to listen, all perplexed. This is a very reparable service yard, old school! The only problem is that they don"t have a lot of experience with 502 R/H Crusaders or their (noises).
A little history, this spring started her up, big vibration, STOPPED IMMEDIATELY! Called for help, ...#8 cyclinder had water from riser over the winter, bent pushrods. Pulled head, bench check, new values, new exhaust manifolds, risers, both sides, back together! Restarted, run up, at dock all is well. During that run up, heard the grinding noise. Stethoscope indicated at front gear cover area. Pulled cover and all looks great. Compression check all 8 good, consistent within specs. Engine starts, ideals & runs fine at the dock.
The yard feels that maybe it might of been there before; but the only time I was down there was at ideal at the dock, and at 3200 rpm at cruise to check temps, shafts, leaks...etc. I have never heard it before. ?????????????????????
A little history, this spring started her up, big vibration, STOPPED IMMEDIATELY! Called for help, ...#8 cyclinder had water from riser over the winter, bent pushrods. Pulled head, bench check, new values, new exhaust manifolds, risers, both sides, back together! Restarted, run up, at dock all is well. During that run up, heard the grinding noise. Stethoscope indicated at front gear cover area. Pulled cover and all looks great. Compression check all 8 good, consistent within specs. Engine starts, ideals & runs fine at the dock.
The yard feels that maybe it might of been there before; but the only time I was down there was at ideal at the dock, and at 3200 rpm at cruise to check temps, shafts, leaks...etc. I have never heard it before. ?????????????????????
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