649I cylinder head torque
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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=170966
Printed Date: 19 Oct 2025 at 1:39pm
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Topic: 649I cylinder head torque
Posted By: fourthgeneration
Subject: 649I cylinder head torque
Date Posted: 09 May 2020 at 2:38pm
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So I am torquing a head on a 649I in a 7020. The front of the book says torque final torque is 165. Under the procedural part it says 150. In the 8010 service manual it says 165 in both spots.
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Replies:
Posted By: Lynn Marshall
Date Posted: 09 May 2020 at 3:10pm
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Torque it down to 150 first and then finish it at 165. 165 is the final torque.
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Posted By: SteveM C/IL
Date Posted: 10 May 2020 at 1:23pm
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Lynn,would you do that final after warmed up and then cold or just as the final step. Can't remember if the 426 gets torqued again after initial assembly
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Posted By: Lynn Marshall
Date Posted: 10 May 2020 at 7:48pm
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Steve, my own personal torque procedure have changed over the years. I used to torque to 150 and then 165 when assembling. Then run the engine to warm it up and then retorque it to 165 while still hot. Reset the valves too at that time. But, the head gasket materials have changed and don't usually require any sort of sealant or gasket dope. Schellac, aluminum paint, and even white lead have been used as gasket sealers over the years. Anymore, I just tighten to 150 and then 165 cold. Run it and recheck the valves. If I were to retorque after running, I would probably do it with a cold engine. This is for the 301 or the 426. Opinions may vary on this subject.
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Posted By: SteveM C/IL
Date Posted: 11 May 2020 at 7:37am
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You are right that things have changed over the years
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Posted By: Hurst
Date Posted: 11 May 2020 at 8:21am
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When I did my 649T a while back, the consensus I believe was the torque it cold upon assembly 150 and 165, then run it to temp, let it set overnight to cool down completely, then retorque to 165 and check valves.
Hurst
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1979 Allis Chalmers 7000
5800 Hours
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Posted By: fourthgeneration
Date Posted: 11 May 2020 at 7:41pm
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I was told in the older service manual that there was a clarification that if the bolts had washers then the torque was 150. And if it was flange bolts then 165 was the final torque. My Service manual is a newer print. I have the 8010 and 7020 649I manual.
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