Re: exhaust manifold stud replacement -Reply

[Gross Scruggs <GScruggs@wposmtp.nps.navy.mil>]

Regarding stud removal, the Eastwood company sells a set of left-hand twist
drill bits.  Their heat and torque direction will often back out a broken bolt. 
Use lots of penetrating oil!!  Best I've seen is called Kroil, by Cano
Industries in Nashville.  Industrial facilities use Kroil when expense is no
object.  I've seen it used to remove turbine blades that are "Christmas-treed"
into place on a 12 foot diameter turbine spool from a 100,000cfm compressor.  

Regards,  Gross Scruggs

>>> Steven Buchholz <steveb@falcon.kla-tencor.com> 05/29/97 01:36pm >>>
> When checking the exhaust manifold studs re the exhaust leak there I found  >
fully 7 studs were sheared off. (New record perhaps?)
> So as recommended by this list the intake manifold, turbo,wastegate etc will 
> come off to see if the studs can be drilled in situ or else the head will come
 > off.
> Those who have drilled in situ (dremel tool I remember) are there any special 
> thinks to be careful of?
> It was suggested that I machine the manifold for flatness, any specs? or other
 > work do do while machining?!...
> If I have to remove the head is there any special R&R I should do while it is 
> off? Is there anything I should check on the turbo etc.  The car has 305,000 

I have had to deal with this myself some time ago.  My experience was that 
having the manifolds removed made it fairly easy to access the foreward  studs
and remove them pretty easily.  The problem is if you have broken  studs near
the rear of the engine.  I had a drill with a right angle  drive and I still
messed up because I did not drill the hole axis parallel  to the stud's axis. 
If you break off the extractor in the stud it is a  pretty big deal ... led to
my pulling the head.  Once I did that I found  the cracks in the head between
the intake and exhaust valve seats.  Bentley  states that cracks smaller than a
certain size are OK (FYI).  

Since then I found a set of extractors that had an integral drill (Alden  Corp?)
... but I have yet to try them out.

I did have my exhaust manifold machined and the results have been favorable  (no
problems in 8 years).  Unfortunately I took the EM to a shop that did  the
dealer's work, so I didn't give them any flatness specs, I just asked  them to
do what they did for the dealer!  Perhaps you can talk to the folks  at the
machine shop to determine a reasonable specification.  

HTH!
Steve Buchholz s_buchho@kla.com
San Jose, CA (USA)