new oil pump installed? new oring? might be pinched.

 

Ported the oil pump and yes new O ring installed. I took off the pan to check the O ring first. It was seated all the way and it was the red one, I pulled it out and not a thing wrong with it. Up until the low oil pressure thing it's never been below 40psi.

I need to get it out so u can check the cam bearings and the rest of the mains. Everything leads to low oil pressure. Warped crank from what I can tell would leave a super bad spot in the bearing, not wipe the whole thing out.

 

What were main bearing clearances? Did you double check with plastiguage? What was crank end-play?

It sure looks like the mains were too tight or the crank had too much runout. Did crank spin free during the build? Any tight spots?

Loss of oil pressure bad enough to kill the mains like that would also kill the rods. I once built a Chevy inline 6 with mains too tight. The mains came out in ribbons after 200 miles, looked a lot like what you've got there. Rod bearings looked OK. Not great but OK.

 

Everything was within stock requirements. I had the big fat GM book at my side the whole time I was building. It's been months so I don't recall the exact numbers and I threw my cardboard away that I was writing on. I did use plasti guage just to see if it matched and it did. What I don't get is I used stock size bearings and did not grind the mains or anything like that. The crank turned nicely with out the rods, I could rotate it with one finger. I need to get it out and see if maybe there is crap in the oil passage some how. Which main feeds which rods?

 

What happens if bearings are too loose? I just remembered I took pics of the plasti gauge sanity check. The thrust was .003. I asked a few shops and they said for performance engine that would be fine. Did I beat the bearing out of it?

 

If all mains were loose you should have had low oil pressure from the get-go. If only the thrust was loose, it shouldn't have hurt anything, unless the shell crush was insufficient and/or fit was loose enough to allow it to spin in the main housing bore.

Was the thrust in the worst shape? If the loose thrust allowed the crank to wobble, the thrust will be the worst and #1 and #5 will be in the best shape.

 

I have only got to take off 2 and 3 so far. I'm going to pull it Saturday. But yes number 3/thrust was beat up bad. The thrust sides were good to go just not the bearing portion.

 

I need a good machine shop here in jax Florida or middleburg area.