Originally posted by jwallis
I have a 400 SBC chev (4 bolt) that I marine converted. I got it from a local car guy, and it was supposed to be rebuilt. I plastigaged the bearings, and all looked well, although # rod bearing was at the minimum clearance within spec. I installed it, and it ran well with great oil pressure, until a got a knock. I pulled it out, and #1 bearing was fried. The bearing material was pulled with copper showing. The only problem I could find is one I overlooked last time I had it apart. # 2 rod bearing is on backwards. The piston is in right, but the rod chamfer is facing # 1 rod instead of facing the crank throw side. It didn't hurt # 2 rod bearing at all except for some wear along the edge of the bearing. Two questions:
1) Would the #2 rod installation cause the failure of #1 bearing?
2) Are these rods offset .060 in the pistons? (In other words, you can't just turn it around, can you?) I figure the mark on the piston is there for a reason. Any help is greatly appreciated.
If you put a rod in backwards you should have noticed this when you turned the engine over.I would say by doing this your rod side to side clearance is greatly reduced.A marine application is very much like a circle track application and you would need a min. of .015 of an inch.The chamfered side always goes towards the thrust side of the crank.What was your rod bearing clearence?