Forum Discussion

trop-a-cal's avatar
trop-a-cal
Explorer
Jan 11, 2014

454 Head back on engine started #7 piston noise

Now with full compression on both heads the 43,000 mile 1997 454 vortec has the same noise that it had prior to it shutting down completely. The noise was checked by removing spark plug wire and heari...
Class A
JimM68's avatar
JimM68
Explorer
Jan 14, 2014
connecting rod bearings typically knock "at the top"
If you rev the engine briefly, the rod will clatter near the peak of the rpms and a lil on the downhill side.

A connecting rod knock = excessive clearance between the rod bearing and the crankshaft. the rod bearing may be worn to copper or worse, and the crank may be worn as well.

A "spun bearing" = the bearing shell has come loose in the rod, and moved. This will ALWAYS damage the crank.

About Motorhome Group

38,766 PostsLatest Activity: Jan 10, 2026