AWD-Tony
Proven Member
- 6,801
- 3,735
- Sep 11, 2017
-
Cincinnati,
Ohio
I’ll try to keep this short. Built short block with about 1k with balance shafts and new bearings. Break in oil looked normal and nothing seems off. Been adjusting oil pressure by shimming the oil pressure relief valve nut (the big one). Finally got it close all the way through the rpm band. I haven’t gone wot until this was fixed. So did several wot pulls and everything was fine. Last one I did, the oil pressure was only at 50psi at about 6k so I let off and drive it home. Next morning I start the car and there’s a clack every 10-15 seconds. Turned the car off and looked around and didn’t see anything. Started the car again to figure out where it was coming from and the clack changed to a constant rattle. Pulled the motor and found the rear balance shaft bearing came out.
Checked a rod bearing and it looks fine so I assume the mains should be alright.
Oil pump gears and front case looks fine also but going to double check that.
Balance shaft journal in the block looks fine.
Balance shaft is slightly scored and barely feel grooves.
What do think caused this?
Could the bearing have been installed backwards? Not sure if that
Is it possible to install a new bearing at home?
Is the balance shaft toast?
Again, sorry for the long post.
Since that bearing doesn’t have an oil port, I assume it gets oil from the crank spinning. If that’s the case, could the girdle prevent oil from getting to that bearing? It sits right behind the girdle. @kiggly
Checked a rod bearing and it looks fine so I assume the mains should be alright.
Oil pump gears and front case looks fine also but going to double check that.
Balance shaft journal in the block looks fine.
Balance shaft is slightly scored and barely feel grooves.
What do think caused this?
Could the bearing have been installed backwards? Not sure if that
Is it possible to install a new bearing at home?
Is the balance shaft toast?
Again, sorry for the long post.
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Since that bearing doesn’t have an oil port, I assume it gets oil from the crank spinning. If that’s the case, could the girdle prevent oil from getting to that bearing? It sits right behind the girdle. @kiggly
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