Farm Equipment - Mixing 201 Connecting Rods and Caps

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Mixing 201 Connecting Rods and Caps

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=203338
Printed Date: 22 Sep 2024 at 11:27pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com

Topic: Mixing 201 Connecting Rods and Caps

Posted By: wjohn
Subject: Mixing 201 Connecting Rods and Caps
Date Posted: 22 Sep 2024 at 7:29pm

I've been struggling with new con rod bearing clearances in the WD engine I'm rebuilding. Crank was ground .030 under and is right on the money, but a couple of the rods give me .001-.002 INTERFERENCE when I torque them down and measure with a dial bore indicator set to a micrometer for the corresponding journal on the crankshaft. Swapped in several new sets of bearings with no change.

For kicks I grabbed a random cap off of a junk set of rods I have, and voila, the bearing clearance is spot on. I'm thinking there's something up with my engine's original caps.

It looks like my options are to either have a machine shop resize the connecting rods, or swap the caps from the bad rods onto these rods. Is mixing and matching caps acceptable or not?

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1939 B, 1940 B, 1941 WC, 1951 WD, 1952 CA, 1956 WD-45

Replies:

Posted By: Les Kerf
Date Posted: 22 Sep 2024 at 9:44pm

This is not normally considered to be good practice but if the parting lines match and the bore is round (within reasonable tolerance) it should work just fine