Re: Head Stud and Nut Torqueing`

[Bob Hadden <kbhadden@xxxxxxxxxxx>]

Tom and all,  This is what I was referring to when I suggested that the 
loose studs suggest to me there is a problem.  I'm concerned this guy 
will put the head on and not be able to achieve torque before the studs 
will pull out.  Not his fault maybe, but the PO.

I think as a minimum, he should be replacing the studs to assure they 
are not the problem.  Maybe he needs to also helicoil all around.  
Can't suggest that without looking at the bike though.

Bob Hadden - '05R12GS, '62R27

On Apr 5, 2006, at 12:57 PM, Tom Brown wrote:

> To Summarize:
> <snip>------------
>
> The Studs:
>
> If the nuts have ever been overtorqued, the studs will be stretched 
> out and
> should be replaced.    Once they're stretched out, they'll never work 
> right.
> This may be what's happened with the original writer with the oil 
> seepage.
> The last item to torque is an allen or star bolt.  It's tightened to, 
> I think,
>
> The studs are screwed in to the proper length.  I don't believe thread 
> locker
> is specified by BMW for the studs.  The thread fit is Class 1, which 
> is pretty
> exact and unsloppy, so if your studs are fitting in loosely, in a way 
> that you
> can move the stud around in the hole, they've probably been 
> overtorqued.  No
> torque spec is given for the studs, so the length is the determiner, 
> not the
> torque.  There is a logic to all this.
>
> Even though listers claim to have had studs creep out on them, I'd bet 
> on BMW
> here.   I'm guessing each one of the listers had attempted to tighten 
> their
> own head nuts and over done it at least once.
>
> I wouldn't put thread locker in an engine block if none is specified.  
>  You
> may not be able to remove the stud!
>
> -TB

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