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Posted By: Davey Whiplash 1937 216 Crankshaft Compatibility - Mon Oct 12 2020 02:04 PM
Good morning,

Long team reader...first time posting.

I have a Frankenstein 1950 3100. It has the Chassis of 1953, Cab of 1950 and soon to have a rebuilt 1946 216 Engine.

I have tried to do some research and I have not found a definitive answer.

I am in the process of rebuilding a 1946 216. It has a crankshaft that can be refurbished. However, I was able to acquire a NOS 1937 Crankshaft with matching Babbitt poured connecting rods. Here is my question: Will the 1937 Crankshaft work in a 1946 motor?

Here is some additional information:

The crank that came out of the 1946 engine has cast of 839775.

The cast for the 1937 Crank is 838877.

Per the Master Parts Catalog the replacement numbers do not match, so I am assuming the answer is no. Hoping there may be a work around though as it will save some $.

Thanks in advance for your help.
Posted By: Davey Whiplash Re: 1937 216 Crankshaft Compatibility - Thu Oct 15 2020 08:00 PM
I must of really stumped everybody. Nobody has a hypothesis?
Posted By: 46Sparky Re: 1937 216 Crankshaft Compatibility - Fri Oct 16 2020 01:04 AM
Davey
I do not know the answer to your question. But, based on my experiences with my ‘37 and ‘46, added to the info you provided from the Master Parts Catalog, my guess is this swap will likely end in more expense of time and money than finding correct replacement parts.
Good Luck.
Posted By: Hotrod Lincoln Re: 1937 216 Crankshaft Compatibility - Fri Oct 16 2020 01:06 AM
My specifications on 216 crankshafts don't go back into the 1930's. I do have diameter specs on 216's from the 1946 engine, which has wider connecting rod big ends that the 48-53 models, I believe. My Federal-Mogul shop specifications manual lists the connecting rods that fit the 839775 crank as having a width of 1.240". You might try measuring the rods for the earlier crank to see if they have a different width. Also, measure the main bearing diameter and the width of the #3 (thrust) bearing to see if those dimensions match up. The main bearings have 4 different diameters, with the shaft size getting bigger toward the rear.
Jerry
Posted By: Pre '68 Dave Re: 1937 216 Crankshaft Compatibility - Fri Oct 16 2020 02:57 AM
1940 was the first year for a rear main seal. Before that they used a slinger. The 1937 crank will not fit the later engine.
Posted By: Davey Whiplash Re: 1937 216 Crankshaft Compatibility - Fri Oct 16 2020 03:22 AM
Thank you everyone for your feedback. It really helped. I will use the existing crank. Guess I’ll put the NOS crank out on the swap section.

This truck has been a blast to work on! Learning tons.

Thanks again.
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