Farm Equipment - perkins 236 248 head bolts

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perkins 236 248 head bolts

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Category: Allis Chalmers
Forum Name: Farm Equipment
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URL: https://www.allischalmers.com/forum/forum_posts.asp?TID=200328
Printed Date: 23 Sep 2024 at 5:18pm
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Topic: perkins 236 248 head bolts

Posted By: rick ky
Subject: perkins 236 248 head bolts
Date Posted: 15 Mar 2024 at 9:53pm

on the diesel head bolts, what tool is used to retighten the bolts after the engine has warmed up to operating temperature? the three basic tool suppliers Snappy, Mac and Matt should have a tool to reach under the rocker arm assembly. if any one knows the the numbers of the wrench extension to go under the assembly, past or present so I would be able to look for and purchase it. If not the assembly must come off to retighten the torque on the bolts, and then reset the valves again. I have had friends to give me wrenches to go under but not all of the bolts are accessible with their tools. If multiple have to be puchased trhen multiple tools have to be purchase.

Replies:

Posted By: Codger
Date Posted: 15 Mar 2024 at 10:18pm

Most head gaskets produced in the last 20 years or so do not require a retorque. I've rebuilt many 4.236, and 4.248 engines and have never done a retorque on any. Have always used new bolts however, and hold torque for about five seconds upon the fasteners at proper torque rating.

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A career built on repairing and improving engineering design deficiencies, shortcomings, and failures over 50 years now.

Posted By: rick ky
Date Posted: 16 Mar 2024 at 7:44am

i thought I read in technical manuals to recheck torque on head bolts new or used. my father was a airplane mechanic in pacific in wwII, helping me and my brothers over 30 years ago he always made us recheck head bolts. if I had paid more attention then, I wouldn't be asking for confirmation now. Thanks

Posted By: Codger
Date Posted: 16 Mar 2024 at 7:55am

[QUOTE=rick ky]i thought I read in technical manuals to recheck torque on head bolts new or used. my father was a airplane mechanic in pacific in wwII, helping me and my brothers over 30 years ago he always made us recheck head bolts. if I had paid more attention then, I wouldn't be asking for confirmation now. Thanks [/QUOTE

That procedure was quite relevant then and not a bad idea even today. In most cases however it is not required. I always use a thin lubricant on clean threads in a freshly machined block and using a calibrated torque wrench bring the fasteners to proper tension in three steps. The final torque I hold the wrench in place for about five seconds.

I have a fresh 4.236 on my shop floor, and a 4.248.2 hanging on my gantry as I type this to go back into my Hyster lift truck this next week.

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A career built on repairing and improving engineering design deficiencies, shortcomings, and failures over 50 years now.

Posted By: steve(ill)
Date Posted: 16 Mar 2024 at 8:38am

recheck the OUTER bolts that have easy access... That might convince you that everything is TIGHT..

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Like them all, but love the "B"s.