|11-14-2012 09:00 PM|
Big block chevy bearing wear
Hi Guys, been a while since I was here.
Looking for some experienced opinions on what would cause what I think is excessive main and rod bearing wear in a big block chevy. It was a mild build with .040 over forged flat tops and a comp 268h cam. Maybe 9:1 static as I milled the heads .020 and decked the block .015. line bored the block mains and used the stock cast crank. The rod ends were resized and the bearing clearances were good. Never did have an oil pressure problem(40-80 psi minimum) I did remote mount the oil filter with an adapter which may have contributed to dry start wear, but the majority of wear is on the rod journal at the top side of the journal at bdc. every cylinder is worn the same. all conecting rods are down to copper on the corresponding side. the rod journals are grooved pretty good. No shrapnel scars just the whole bearing imprint worn into the shaft about a good 1/32" .I did drive it hard on occasion, but nothing more than usual that most small blocks would endure no problem. Will post pics later, my main computer just crapped out. I originally thought maybe too much advance as I ran manifold vac to the vac advance can (adjustable)but the wear is worst on the side of the journal opposite to compression stroke.(Piston at bottom of stroke) any thoughts would be appreciated.