Melted a bearing

CA Victoria

CA Victoria

Well-known member
Thanks JWL for the direction.
Here is a picture.
Fresh rebuild with 100 miles on the engine. Stock stroke resized .083 pistons. Modified for full oil filtering. The engine came partially machined. I cleaned all components very well after some local work was done.
I have disassembled the engine for inspection. The cam bearings are aligned, and the front 4 Rod bearings show wear, the rear do not. The crank came with the project turned .010/.010. I did not pull the crank plugs and that may have been the origin of my problem. I had
two instances of a metal to metal sound that lasted for a couple of seconds at 2400 rpm last week. Sounded like a throwout bearing.

I am concerned that with enough image.jpg heat to melt the bearing and weld it to the crank and heat the rod to soften it, that the crank tempering is compromised.
I will call EGGE today to see if they can turn a set of Pistons to fit my odd sized bore.

Anyone with a std 8ba crank out there?
 
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CA Victoria said:
The engine came partially machined. I cleaned all components very well after some local work was done.
I have disassembled the engine for inspection. The cam bearings are aligned, and the front 4 Rod bearings show wear, the rear do not. The crank came with the project turned .010/.010. I did not pull the crank plugs and that may have been the origin of my problem.
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Are you saying that you did not pull the clean out plugs before the crank was turned or the replacement ones after turning?
Sure looks like oil starvation.
 
I have dealt with babbit bearings in many of the machines in my shop, and have seen melting like in your picture. In every case, it was caused by oil starvation. Babbit bearings work only because the journal is riding on an extremely thin layer of oil; remove the oil, and the journal heats up and melts the babbit, smearing it as your photos show. Depending upon the type of babbit used, the melting point could be pretty low (lead) or pretty high (tin/antimony alloy). Lead babbit would melt at a temp below that which would damage the journal; tin/antimony alloy melts at a high enough temp that the journal metal could be affected. You need to find out why. Were your clearances correct? Too tight on the journal and there is no room for oil.

Other than knowing a bit about babbit, I have no knowledge as to what you do next, as I am a novice when it comes to the engines.

John
 
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Agree on oil starvation. System was running 60 psi, 40+ at idle.
All bearing clearances were good.
So far no other components show signs of failure to cause metal or debris in the engine.
Will cut open filter to see what I have.
If the galley feeding both were plugged should have had even damage?
I did not pull the galley plugs in the crank. The engine block was cleaned well.

EGGE can supply resized Pistons.
 
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How long did it run before this happened? Minutes, a few hours, months, years? Since you modified the oiling system, and the problem is lack of oil, I would double check all that first.
 
I have a couple of 8BA cranks, let me check the diameters. Shipping is some bucks, might do better to find one locally.
 
deuce_roadster said:
I guess I need to read a BIT closer! Thanks JS. It's hell getting old!
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LOL, I can identify with that!!:D

I would have the crank checked out before getting all excited about replacing it. The first order of business is to identify what the cause was and I would start with the oil passages in the crank. The crank may clean up fine, needs to be checked.
 
What sort of oil filtering system are you using. With out stating the obvious have you checked the oil lines are hooked correctly to the filter and the block. If they are in reverse it may show good oil pressure but that will be read before the filter . I do know someone that had a fresh motor and drove 100 or less miles and it seized up for this very reason.
Have a peek at the other mains perhaps.
 
" Modified for full oil filtering" If it's the so called 95% system, did the cross over galley plug get installed?
 
My gut was in a knot when I went back to pictures of the engine compartment. The oil lines are reversed. This would explain a high constant oil pressure pushing against the valve in the filter and why the front bearings show wear due to starvation and the rears don't.

Expensive lesson.
I will take the crank in for inspection tomorrow.
 

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This is a great example what problems "reinventing the wheel" can produce.The original lubrication system works great why mess with it ? Just my opinion.Phil
 
trainguy said:
This is a great example what problems "reinventing the wheel" can produce.The original lubrication system works great why mess with it ? Just my opinion.Phil
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That is one prospective, but on the other hand, almost any engine part installed incorrectly is going to have consequences.
 
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