500, 472, 425, 368 Discussion, Strange Knocking from 500 Engine- Solution in Cadillac Engine Technical Discussion; After many diagnostics from many different 'experts', some saying big end bearing, others saying lifters, piston pins et al. I ...
After many diagnostics from many different 'experts', some saying big end bearing, others saying lifters, piston pins et al. I finally found an elderly gentleman in Selmer, Tennessee who had worked on these cars for most of his life and he suggested we check the flex plate or flywheel. Sure enough we found a crack and the offending part was duly replaced ...... Voila ! no more knocking sound.
Just wanted to post this result as a help to others.
Automobile(s): 1995 ETC, 75 Deville, Cad500 powered 73 Apollo, 94 Mark VIII
Re: Strange Knocking from 500 Engine- Solution
I'd like to know where you got your info that the 500/472s are all solid. I have a 472 in my posession with a windowed flexplate, I've measured the stroke and I know it's a 472. It could have a different flexplate, but that would be pretty odd if it did.