1940 B Crank

Rik-CO · Dec 16, 2008

1940 B. Can anyone tell me the max out of round crank journal they have experience and still be ok. I still will have to get new babbitts poured for the rods. Rick

tim s · Dec 16, 2008

Do you mean "out of round" or "under size" a big difference ?...

Mike M · Dec 16, 2008

The adjustable babbit rods seem to be more forgiving then the insert type.
I had an insert type in a late B running on a journal that if I remember right ? was only .001" out of round and I could here it rapping at an idle. Had to have it taken to the next size under. It was allready done once before in it's life.
You may get away with .001" with a babbit rod ?

How far out are yours ?

Rik-CO · Dec 16, 2008

I am talking out of round. As much as .010" on one and .007 on the other. Sounds like it needs ground.

tim s · Dec 16, 2008

Yes, it will need ground,nasty job pulling the crank but it won't be right unless you do..

Rik-CO · Dec 16, 2008

Thanks for the advice. I have already pulled the crank. It was nasty.

Mike M · Dec 16, 2008

Grind it or find another one used and with rods and mains.

PBrowning · Dec 16, 2008

Rik -- Now that you have the measurements, a very good call to make would be to Russ @ 816-587-4747. He I so good at this very subject and such a gentle man to talk with -- could set you on track to save both money and heartbreak! (PatB)

Jake Winn · Dec 16, 2008

I have a nice crank out of a 40 B that I just parted. Have the mains to go with it if needed.

Thanks

jake

RyaninKS · Dec 18, 2008

while on the topic, is there anyway to check main bearing without tearing it down completely? An old farmer told me one time to mount a dial indicator on the crank and LIGHTLY put pressure on it with a jack to see how much play is there. Is there any truth to this?

Duane Larson · Dec 18, 2008

Ryan,
That will provide some useful info - at least you will know if you should remove some shims or not. The crank should measure 2.250" with a tolerance of 0.002 and the bearing should be 2.254" with a tolerance of 0.001". You might do the check at different positions of the crank (ie, measure, rotate the crank 90 deg and measure, etc.).

Rik-CO · Dec 19, 2008

Yes can check it that way and then remove shims as nessasary to tighten up.

1940 B Crank

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tim s

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