[AT] Torque for bolts vrs studs in cylinder heads?--followup

[charlie hill]

Larry I've never actually torqued one of those torque to yield head bolts 
myself so I don't know the mechanics of it.

Speaking of working up a sweat with a torque wrench.  Have you ever been 
around anyone rebuilding a big Cummins diesel like the one's in over the 
road trucks?   It's been over 20 years since I was around one being rebuilt 
but if I remember right the head bolts torque to something like 350 ft/lbs. 
It takes a BIG torque wrench and a big man (or men) pulling on it.

Charlie

----- Original Message ----- 
From: "Larry D Goss" <rlgoss at evansville.net>
To: "Antique tractor email discussion group" <at at lists.antique-tractor.com>
Sent: Saturday, April 28, 2007 4:27 PM
Subject: Re: [AT] Torque for bolts vrs studs in cylinder heads?--followup


> If I remember correctly, the instructions for one of those engines reads
> something like: Torque to XX ft-lbs and then turn the bolt 180 degrees 
> more.
> It's the only type of engine that ever caused me to work up a sweat while
> torquing head bolts even while working outside on a cold day.
>
> Larry
>
> ----- Original Message ----- 
> From: "charlie hill" <chill8 at suddenlink.net>
> To: "Antique tractor email discussion group" 
> <at at lists.antique-tractor.com>
> Sent: Saturday, April 28, 2007 12:32 PM
> Subject: Re: [AT] Torque for bolts vrs studs in cylinder heads?--followup
>
>
>> John,  some of the new light weight auto engines use head bolts that are
>> "torque to yield"  which means they are tightened to where they are just
>> at
>> the point of failure.   When you remove the heads on those engines you
>> MUST
>> replace the head bolts.  Those first GM diesel car engines (the 5.7 built
>> from a gasoline block) were that way.
>>
>> In other words they used the smallest, lightest head bolts they could get
>> by
>> with and they won't stand up to being re-used.
>>
>> Charlie
>>
>>
>> ----- Original Message ----- 
>> From: "John Wilkens" <jwilkens at eoni.com>
>> To: "Antique tractor email discussion group"
>> <at at lists.antique-tractor.com>
>> Sent: Saturday, April 28, 2007 1:22 PM
>> Subject: Re: [AT] Torque for bolts vrs studs in cylinder heads?--followup
>>
>>
>>> Many thanks guys for educating me about head bolts!   To be sure,
>>> I'll stick with studs!    John W.
>>>
>>>
>>>
>>> At 08:08 PM 04/27/2007, you wrote:
>>>>
>>>>John, There are a whole bunch of GOOD reasons to stay with all of the 
>>>>OEM
>>>>parts and torque specs on head bolts! You may get away with some
>>>>non-OEM parts
>>>>sometimes but it is like gambling with your engine's life span. Granted
>>>>it
>>>>varies from engine to engine, usually older engines have more room
>>>>to play with
>>>>and more modern engines have tighter specs with almost no room for 
>>>>error.
>>>>Some  head bolts are TTY and can only be used once. The headgasket
>>>>thickness also
>>>>  matters on some engines especially if you have had the head 
>>>> resurfaced.
>>>>Sometimes the OEM manual will give 2 torque specs with the head bolt
>>>>dry or oil
>>>>on threads. Studs or bolts of the same grade should be the same spec I
>>>>think.
>>>>If  you lower the grade of bolt you may be asking for problems. Just my 
>>>>2
>>>>cents.  Willard Smith, Tacoma, WA.
>>>>
>>>>About how much more torque would be required for using bolts in an
>>>>engine head vrs. the regular studs?  (One for the  experts!)   John W.
>>>>
>>>>In the wide-open spaces of NE  Oregon
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>>************************************** See what's free at
>>>>http://www.aol.com.
>>>>
>>>>_______________________________________________
>>>>AT mailing list
>>>>http://www.antique-tractor.com/mailman/listinfo/at
>>>
>>>
>>>                    In the wide-open spaces of NE Oregon
>>>
>>>
>>>
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