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wd 45 head

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=187078
Printed Date: 26 Oct 2025 at 4:24am
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Topic: wd 45 head
Posted By: D14JIM14
Subject: wd 45 head
Date Posted: 16 Mar 2022 at 3:43pm
After many attempts I got a compression gauge and I got no readins at all . The gauge bounce a litle on # 2 cylinder and nothing on all others. when I out my thumb on the spark plug hole and thurned the engine over i could not feel any push back.
I pulled the head and found the front push rod slightly bent and am now looking at getting the head checked out .I learned fom the former owner they thought the head gasket was bad .
This is on the tractor that has set for 30+ years.
The cylinders are dry and lots of questions on my part now .

The pistons are the concave type on top .

may have to pull block .

Never tooeasy .



Replies:
Posted By: DrAllis
Date Posted: 16 Mar 2022 at 3:54pm
You had the throttle wide open, right ??


Posted By: DaveKamp
Date Posted: 16 Mar 2022 at 9:44pm
If you're not feeling any pressure using your thumb, and the gauge isn't moving, then it's a pretty high likelyhood that you're not generating any compression.  IF there's pistons, moving in the cylinders, then it is most likely that either there's very large holes through the pistons, OR one of the valves isn't closed.

Since you've already noted bent pushrods, I'd bet you have a valve problem.  If the engine has been sitting for 30 years, I would find it hard NOT to have sticky valves.  It probably had sticky valves and straight pushrods until someone tried to crank it over, and the sticky valves pushed open just far enough to unseat, but not far enough for the pushrod to stay within it's abilities, and the end result is a pretzel'd pushrod.

Lift off the head, spray penetrant into the stems from the top (through the springs) and bottom (in the ports) then use a wood-block and a light mallet to carefully work them free.  Once they move fairly freely, compress the springs, remove keepers, and drop the valves out of the guides, chuck 'em in a cordless drill, and introduce them to a wire wheel, scrub off all the crud... then wire-wheel the stems, and use a valve guide cleaning tool to clean the guide bores, then scrub the ports and chambers clean, check all the valve springs for proper height and pressure, and reassemble the whole setup... install the head with some replacement pushrods, then try your compression test again.


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Ten Amendments, Ten Commandments, and one Golden Rule solve most every problem. Citrus hand-cleaner with Pumice does the rest.



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