B 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=187689
Printed Date: 21 Aug 2025 at 8:06pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: B engine rebuild
Posted By: JudgeguyBob
Subject: B engine rebuild
Date Posted: 15 Apr 2022 at 8:42am
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How hard should it be to turn a newly rebuilt motor on a A-C B by hand? Even with plugs our I can't turn it with the crank. The starter will turn it over but very slowly. Thanks for any suggestions! Bob
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Replies:
Posted By: steve(ill)
Date Posted: 15 Apr 2022 at 9:02am
should not be that hard... you set in the crank and shim / tighten each bearing one at a time and check rotation after each bearing is torqued.... should turn easy by hand... Then you put the pistons in one at a time and set bearing clearance/ tighten the nuts and rotate the crank to check... I use to use a toque wrench on the front end and see what one piston drag would be.... then go to the next piston , install / torque.... its the "RINGS" that should cause the drag, NOT THE BEARINGS.... Have not done an engine for 10 years, but seem like it was 25-30 ft pounds on the crank to get it to "move" after all 4 pistons installed... You should have oil on all the bearings and rings, and it will turn a little easier once it is rotating, but takes 25-30 ft # to get it to start.
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Like them all, but love the "B"s.
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Posted By: Sugarmaker
Date Posted: 15 Apr 2022 at 9:32am
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Bob, Yep sorry it sounds too tight some where. I would assume bearings mains or rods as mentioned. I put a Ford (1932) "B" engine together last summer. switched out a set of rods from another engine and it did not like those at all. Had to switch back to the original rods. This is just and example. So you may have to remove the pan and start loosening rod caps and main caps while trying to rotate? I am not a engine builder. But as mentioned they should roll over fairly easy with a breaker bar. Regards, Chris
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D17 1958 (NFE), WD45 1954 (NFE), WD 1952 (NFE), WD 1950 (WFE), Allis F-40 forklift, Allis CA, Allis D14, Ford Jubilee, Many IH Cub Cadets, 32 Ford Dump, 65 Comet.
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Posted By: steve(ill)
Date Posted: 15 Apr 2022 at 9:36am
Yes, Chris is right........ You COULD do this "in frame"... Take the pan off... then loosen the #1 rod nuts 1 turn... try to rotate... then loosen #2 rod nuts 1 turn.. try to rotate... If you have all 4 rods loose and still turns HARD, the do the same with the crank caps.. 1 turn loose will not hurt as you try to rotate by hand... when you find the tight one, add .002 shim and try again........ remember, the RINGS will have 25- 30 # drag on a torque wrench.
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Like them all, but love the "B"s.
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Posted By: juniorp53
Date Posted: 15 Apr 2022 at 11:21am
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the last two i rebuilt (finished yesterday) the starter spun them a little slower till broke in(still 6v) . with all the plugs out should be able to whirl it over with hand crank pretty easily
other than what steve already mentioned ... did you gap your rings? Are the rods facing the correct direction? a little oil in the spark plug holes should loosen it up some
-Joe |
Posted By: KMAG
Date Posted: 15 Apr 2022 at 8:12pm
"Are the rods facing the correct direction? "
This suprises many rebuilders.
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Posted By: Sugarmaker
Date Posted: 16 Apr 2022 at 9:53am
Yes I have heard about the rods being out of position on these engines too. Brother in law put one together in AG class in high school for his uncle. Could not get the thing to roll over! Yep That was the problem.Just saying its something to look at. I have never rebuilt a Allis B engine. Regards, Chris
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D17 1958 (NFE), WD45 1954 (NFE), WD 1952 (NFE), WD 1950 (WFE), Allis F-40 forklift, Allis CA, Allis D14, Ford Jubilee, Many IH Cub Cadets, 32 Ford Dump, 65 Comet.
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Posted By: JudgeguyBob
Date Posted: 16 Apr 2022 at 12:28pm
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Thanks for all the replies and suggestions! Very much appreciated! Bob
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Posted By: bluewavecaptain
Date Posted: 20 Apr 2022 at 5:44pm
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http://www.allis01.com/fossto/39RC/ac-RC-engine5.html%20" rel="nofollow - http://www.allis01.com/fossto/39RC/ac-RC-engine5.html
Here's information on connecting rod orientation.
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Charles(Two Rivers,WI)
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