Just posting this to see if anyone else has run into this problem before. I rebuilt my 2.2 ohv from my 2000 cavy. I put a custom ground cam in the engine and just went all the way on the rebuild. The two center bearings #2 and #3 had a little bit of wear prob from the small wet shot of nitrous I had used, and the engine having 160,000 miles on it, but the #1 and #4 rod bearings didn't look bad. so I got the engine running late at night and by the end of the next day the engine sounded like a hammer was loose in it. It just trashed the crank. It looked like the #1 main journal was starved of oil as well. I figured why wait for a machine shop to turn the crank when I work at an auto parts store and can get a crank kit for about 150 bucks. I thought since the engine had sat in my garage for almost a year taken apart there may have been some trash or a bug or something clogging the oil port. I held a bucked of oil up to the oil pump screen (Oil pump was pretty new too. Only had about 6 months of running time on it before I took the engine apart.). I primed the pump with a drill and had plenty of oil coming out of all the ports. Still I really didn't have a sure answer. but all seemed well so I re- plastigauged the crank to check all the tolerances and it all looked great. Put the motor back in the car primed the pump and fired her off. Ran awesome with no noise and I was averaging about 100 miles a day on the engine. towards the end of day three (about 300 miles on the car) I started to hear a small tapping noise when it was able to echo off fences or buildings. Isolated the noise to the oil pan so I pulled the oil pan and pulled the #1 and #2 rod bearings and once again I have a #1 "only" rod bearing failure. crank is ok this time though. Oh I also had installed an oil pressure gauge to monitor the pressure and all was well with the pressure. I am stumped and was hoping for any answers on what to do next. I'm just afraid that replacing the rod bearing again will put me right back to It knocking again.

#1 rod is the next to last that gets lubed IIRC.

sometimes clearances can be too tight. oil has to be able to flow.

what are your side clearances on the rods?

I suspect the oil pump may not be doing as well as it appears.

dennis

I was also told that even though there is a channel for oil to find the oil hole on the cam bearings, that if you don't line up the oil holes on the rear bearing,because its the first one to get oil in the engine, that it can starve the front of the engine for oil. Has anyone heard of this? I'm going to pull the engine this weekend.

I'm sure that's true...but after the first bearing got destroyed did you have the rod cleaned up?

What do you mean by "having the rod cleaned up"? it didn't spin the bearing in the rod it just chewed up the bearing. It was only knocking for a day. I have the motor back out now and am going to tear it down today.

Hmmm...interesting. I would measure the big end of the rod for taper/out of round once its apart, but honestly, I have no idea. Wish I could be more help

check for crank bore alignment while you're in there...a straight edge will work