Main Bearings
Post Fiend
Joined: Feb 2001
Posts: 6,624
Likes: 8
From: Missouri
Main Bearings
The method I use to tell if an engine has worn main/rod bearings is to rev it up to about 2500rpm and listen for a deep knocking sound coming from the bottom end. Main bearings and rod bearings make about the same sound and if your mains are worn more than likely your rod bearings are too and vice versa. There is a way to distinguish which bearing is making the noise when you rev it and let off but I don't remeber or do I care. If you replace the mains you are gonna replace the rods anyway.
