Farm Equipment - Allis C engine rebuild

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Allis C engine rebuild

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=208473
Printed Date: 10 Oct 2025 at 9:13pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com

Topic: Allis C engine rebuild

Posted By: 3rd generation
Subject: Allis C engine rebuild
Date Posted: 09 Oct 2025 at 8:15am

This is my first post. I have an Allis C with original steel pistons. My bore gauge is showing .003”- .006” over 3.375”. The two inside bores have slight pitting. This tractor will be used for mowing with any luck for the next 20 years.
Are all rebuild piston sleeve kits the same in quality? Second question. The valve seats need ground. What is the acceptable tolerance for valve guides. My AC book lacks wear specs.

Replies:

Posted By: steve(ill)
Date Posted: 09 Oct 2025 at 6:35pm

all of the aftermarket kits for the B-C motors are overbore 3-7/16 inch dia and you get aluminum pistons and new lines... Good plan.... if they all come from the same factory in CHINA, i dont know... have not heard of any "kits" that are better or worse than others..

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Like them all, but love the "B"s.

Posted By: steve(ill)
Date Posted: 09 Oct 2025 at 6:37pm

normally valve guides have .002- .003 clearance.... if you up to .005 then you need new guides.... intakes will suck oil past them if your past .004

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Like them all, but love the "B"s.