Farm Equipment - Piston scoring D-21/210/220/7030 engines

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Piston scoring D-21/210/220/7030 engines

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=209128
Printed Date: 27 Nov 2025 at 10:40pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com

Topic: Piston scoring D-21/210/220/7030 engines

Posted By: DrAllis
Subject: Piston scoring D-21/210/220/7030 engines
Date Posted: 27 Nov 2025 at 9:09pm

Trying to finish up this customers knocking 220 engine. I've experienced this problem for I'd say 30 years off and on. It's always the engines that don't have piston cooling spraying oil from underneath to keep piston temps down that seem to do this. Replacement pistons and sleeves are parts that work fine in 7040's and bigger because they do have piston cooling, but the newer design piston/sleeves do not like being used in the old non-piston cooled engines. Unfortunately, the old piston/sleeve parts have been discontinued for a very looong time. All you can purchase now is the newer designed tighter fitting parts. The older engines used to spec piston skirt to cylinder sleeve clearance at .007". All the newer piston/sleeve kits are .003". Sometimes they work for years and then, just like this engine, you've got a mess to deal with. I've got a jig made to take my sleeves to a favorite machine shop and have (new or old) sleeves power honed out an extra .004" to alleviate this problem. It's an unfortunate event with no warning whatsoever. My advice is if you are overhauling one of these older non-piston cooled engines, you'd better loosen it up a little or you might get to do it again someday down the road. Pictures on the way.