Rod bearings

BirchRidge

BirchRidge

Member
Pulled the pan tonight and found some babbitt in the oil so I checked the bearings and found this.. How bad is it? Is it over or usable?
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Is that rod centered on the crank ? Possibly more important how much thrust movement do you have on the crank. ( fore and aft)
 
JB-WELD and then check to see how the bearing sits while someone turns the engine over, could have a crooked rod or thrust problem as mentioned. I would use it until it no longer works
 
Someone who does Babbit could "dabble" a bit on the sides of that con rod (like soldering, only with Babbit) and adjust the width of the big end to fit the journal. I would do that and keep driving.
 
Ok, thanks guys.. I will check the rest of the bearings today and see what it looks like.
How much crack endplay is ok?
 
How did the engine sound and run prior to finding this?

If you had no idea that anything was wrong, I would do as mentioned above.

Put it back together and enjoy. Might recommend using 20-50w oil.

Model A's run forever.
 
Were you hearing the knock all the time.

When spark was fully retarded?

Lugging or pulling up a hill?

Going down a hill under no load?
 
Some people will question what I am now going to recommend.

If everything else looks good underneath, put it back together.

Use 20-50w oil and add a bottle of STP oil treatment. The STP will help on the flat tapped, and any worn surfaces. Giving the engine some cushion. I also always recommend Marvel Mystery Oil in gas only, helps with valve noise.

I am an old guy that does not like to fix things that don't need fixing.

I have seen and also owned Model A's that knocked. There are cases where Shake Oil will help. If this does not help with the knock, than you can cross that bridge.
 
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^^^agree^^^,the missing babbit isn't in the thrust area,however the thrust area witness mark indicate a slight misalignment of the rod/rod cap to journal,which could be a number of things,but not worth worrying about..run it,and look for the 'thump' elsewhere.
 
Ok, I will check clearence on all bearings again and then start it up and see what happens
Thanks for the advice and answers
 
I agree with # 13 and 14, except as long as the rod is out I'd have it checked for straightness.
As mentioned, the engine had a slight knock and the witness mark on the babbit looks like a slightly bent rod.
 
BirchRidge, did you find out where your knock came from yet? Reason I asked is that I have similar problem.
 
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