Main bearing foot lbs,on a B
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=133909
Printed Date: 09 Jun 2025 at 8:01pm
Software Version: Web Wiz Forums 11.10 - http://www.webwizforums.com
Topic: Main bearing foot lbs,on a B
Posted By: Tom Elder
Subject: Main bearing foot lbs,on a B
Date Posted: 17 Jan 2017 at 11:50am
|
I am in the middle of overhauling one of my 2 Bs I had it line bored ,rods conditioned, sleeves installed etc. at the machine shop.My auto mechanic of 30 years put the crank and rods in it yesterday.The machine shop advised him to only torque the main bolts to 50 instead of 80 ,because the were grade 5 not grade 8, .Is this a bad or good move? Thanks ahead of time,Tom ------------- 2 1949bs,one with belly mower one with side sickle bar |
Replies:
Posted By: steve(ill)
Date Posted: 17 Jan 2017 at 12:10pm
|
why were they changed to grade 5 ? SPEC is 80 ft pounds on factory bolts ------------- Like them all, but love the "B"s. |
Posted By: Tom Elder
Date Posted: 17 Jan 2017 at 12:17pm
|
they are what was in it.with holes for safety wire ,i just figured the machine shop could tell by the head markings or something,along those lines,thanks
------------- 2 1949bs,one with belly mower one with side sickle bar |
Posted By: Allis dave
Date Posted: 17 Jan 2017 at 12:22pm
| 3 head marking means grade 5. The stock head bolts on my WD45 are grade 5's but they are torqued to 90lbs. Seems high for a grade 5 1/2 bolts but that's what the book says. I would do what the manual says. Someone might chime in and confirm that they had grade 5 from the factory. I bet they did. |
Posted By: Brian Jasper co. Ia
Date Posted: 17 Jan 2017 at 3:50pm
|
I'd follow the shop manual. I ran into a similar situation when I overhauled my 262. Without looking IIRC the head bolt torque is something like 120 ft lbs on 1/2" bolts. Nominal torque on a grade 8 1/2" bolt is like 80 or 90, somewhere in that area. Original A-C bolts are higher. Whatever is in the manual is what the factory did... ------------- "Any man who thinks he can be happy and prosperous by letting the government take care of him better take a closer look at the American Indian." Henry Ford |
Posted By: steve(ill)
Date Posted: 17 Jan 2017 at 8:45pm
Im not sure all the bolts in 1940 were marked on the heads. Here is a photo that DICK posted a couple days ago.
 ------------- Like them all, but love the "B"s. |
Posted By: Tom Elder
Date Posted: 17 Jan 2017 at 9:01pm
|
thanks bunches men
------------- 2 1949bs,one with belly mower one with side sickle bar |