Farm Equipment - 149 cu in rod bearings

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149 cu in rod bearings

Printed From: Unofficial Allis
Category: Allis Chalmers
Forum Name: Farm Equipment
Forum Description: everything about Allis-Chalmers farm equipment
URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=56351
Printed Date: 05 Sep 2025 at 9:19pm
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Topic: 149 cu in rod bearings

Posted By: Leon B MO
Subject: 149 cu in rod bearings
Date Posted: 04 Sep 2012 at 8:05pm

I dont have a book on a 149 motor or for a D-14 yet but I will get one. I am making one good motor out of two and just getting started. I have both broke down and will need a set of rod bearings. From what I found the originals were 1.937, my crank is measuring about 1.905 right now. What oversize bearings are avialable for this motor? Is there a .040 over available? The other crank has larger rod journals but then the main bearings would have to be oversized. I'll get the crank turned to fit the bearings.

Thanks

Leon B MO

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Uncle always said "Fill the back of the shovel and the front will take care of itself".

Replies:

Posted By: DrAllis
Date Posted: 04 Sep 2012 at 8:49pm

The way we do it around here is take the crankshaft to our local machine shop and tell them to clean and magnaflux it for cracks. If it is crack free, then polish it or grind it and get me new bearings, which are usually available in std...-.010"...-.020"...-.030" and -.040".

Posted By: Leon B MO
Date Posted: 04 Sep 2012 at 8:54pm

Thanks, I didn't know how hard those bearings where to find.

Leon B MO

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Uncle always said "Fill the back of the shovel and the front will take care of itself".

Posted By: Lonn
Date Posted: 05 Sep 2012 at 5:53am

.040" undersize weren't available from our local machine shop 10 years ago for that engine and would not be recommended as you are getting past the case hardening of the crank. I know someone who looked for bearing back then at .040" under.

Take it to a reputable machine shop and have them mic it or you can do this yourself if you are familiar with a mic and how to mic properly and maybe it only needs a polish. If my math is correct your crankshaft is ground to .030" under right now.

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Posted By: JimD
Date Posted: 05 Sep 2012 at 10:08am

I agree, that is so close that I would have it professionally mic'd. .040 bearings are impossible for me to source. The machine shop might have them.

JimD

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