Re: Retorquing heads etc.

[Pete Naylor <pete@xxxxxxxxxxxxxx>]

PLPKLT@xxxxxxx wrote...

> I would say you are looking at a Heli-coil job.  Worse problem is all the shaving you are going to make putting it in.  Grease is your friend here, It can catch the shavings but you have to work at it, to make sure you catch 100% of them... Here a 99 is not a passing grade...
> 
> I know the early 94 RS seemed to really have this problem and would reqularily have studs strip out.
> 
> I am a bit puzzled that you heard much noise at all,  Usually stripping a stud out involves more just never being able to tighten it up.  It would sound more like you broke the stud off but you should have then been able to pull it clear out as it wouldn't be attached to anything any more.

Thanks for your comments Paige.  I did eventually manage to remove the
stud - I don't know why but it was really quite difficult to remove.  I
didn't want to push the situation too hard because my Clymer manual
mentions them as non-replaceable.  Here's what the end of the stud looks
like...

<http://www.geckoworks.com/r1100_stripped_stud.jpg>

All the thread failed - sheared clean off - hence the noise.  The hole 
seems to be closed - that is, it doesn't go all the way through the 
crankcase - which is good news since I needn't worry about metal castings 
falling into the crankcase when I'm cutting the thread for an insert.

Now, I'm stuck trying to decide what to do.  Obviously I need to use a 
thread insert of some kind - helicoil or similar.  But... if one failed 
this way when I was applying torque exactly as specified, what's to stop 
the others?  10 years ago I stopped playing with old air/oil cooled 
opposed cylinder Volkswagen engines and figured that my days of dealing 
with studs stripping out of crankcases were behind me - apparently newer 
designs haven't completely resolved the problem either.  I seem to recall 
that many Volkswagen engine builders fitted thread inserts as a matter of 
habit just to avoid this eventuality completely.  I'm wondering if I 
shouldn't do the same on this BMW engine.  Then again, I could potentially 
get into more trouble attempting to do that.

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