RE: stronger exhaust manifold studs?

[Don Muirhead <dmr@kwic.com>]

Kenn Thyrsted wrote...

Any idea on how to remove a OM-stud broken 2mm below head surface, - and
what to replace with ?

The OM is cracked, and i'll be ordering a new two-piece soon.
- Will i have to drill the holes larger ?
- Will that impact durability ?

If it was my head, I'd have it on the drill press and drill out the broken 
stud then clean-up (re-tap) the threads (which is what I did on the 
weekend).  If you don't have a drill press and your hands don't shake like 
mine you might try this free hand and add some anti-seize before you start 
boring and start with a 4mm bit then try a 4mm LH tap, it should be enough 
to bring out the broken stud.  A word of caution - a broken stud will have 
an uneven surface so when you start drilling you must make sure your 
alignment is perpendicular to the broken stud.

Over here you can purchase bolt/rod/screw extractor kits from machine shop 
and automotive supply houses.  Some have special adapters for extracting 
broken studs/rods/screws below the surface but not all and the ones that do 
cost considerably more.  A product called Drillout, a LH bit and extractor 
is specifically designed for this application but I don't know whether it's 
available in Europe or the UK and I'm not sure whether it's available in 
all metric sizes.

You can also take the head over to your neighborhood machine shop.  They 
can plop it on their Monti (or equivalent), setup is about 5 minutes 
removal 30 seconds re-tap (clean-up) threads 2 minutes.  Here (Canada), the 
going rate would be $69-79.00/hr with a minimum 1/2 hour charge, so $35-40 
bucks plus tax or in lieu of cash a case of beer (taxes incl.) you can get 
it done professionally.

So I guess you have some choices.

Don
-----Original Message-----
From:	Kenn Thyrsted [SMTP:thyrsted2@olsy.dk]
Sent:	Monday, September 20, 1999 7:04 AM
To:	quk@isham-research.freeserve.co.uk; dmr@kwic.com
Cc:	quattro@audifans.com
Subject:	Re: stronger exhaust manifold studs?

Any idea on how to remove a OM-stud broken 2mm below head surface, - and
what to replace with ?

The OM is cracked, and i'll be ordering a new two-piece soon.
- Will i have to drill the holes larger ?
- Will that impact durability ?


Kenn Thyrsted
'87 200(t)Qavant (On Jack Stands)

----- Original Message -----
From: Phil Payne <quk@isham-research.demon.co.uk>
To: <dmr@kwic.com>
Cc: <quattro@audifans.com>
Sent: 18. september 1999 17:47
Subject: RE: stronger exhaust manifold studs?


> In message <01BF0171.21AD4900.dmr@kwic.com> Don Muirhead writes:
>
> > I found a couple studs broken on my coupe last weekend and picked-up a
> > handful from the Dealer today.  The ones I grabbed today are the same 
as
> > the ones that were replaced under warranty 13 years ago and at only a
$0.75
> > ea. (CDN).  So I'm not going to worry about the studs breaking for at
least
> > 10 years.  But that's only my opinion and my $0.75
>
> Broken studs are a real problem on the turbo cars, perhaps because the
> weight of the damn thing is entirely carried by the exhaust manifold.
>
> I've made two major advances in the last year.  One was acquiring a
> FACOM 287B.8 stud remover.  This device slides down over the stud and
> grips it using three internal rollers - the force applied to the stud
> during removal is coaxial with the stud and thus old studs are less
> tempted to snap off.  It also helps if you apply lubrication as soon as
> you have movement and screw the stud back in and out to spread the oil
> down the threads.  Note my criticism of the Dialynx manifold in this
> regard - in contrast with the Audi original, it's impossible to get a
> socket onto four of the nuts from above with the Dialynx beast.  You're
> left with a 12mm or 13mm 6-point box (ring) wrench (spanner) from the
> side, with an awful lot of shear component.
>
> The second major advance was a FACOM 885 stud remover kit.  It's a
> 25-part kit comprising drills, locating sleeves, removing splines and
> driving nuts for the splines.  It really is _magic_ in operation.
>
> So far, on 100,000+ mile ur-quattros, I've taken off about ten manifolds.
> In every instance, at least one stud broke - but I've got it down from
> an average of four to only one on each of the last two.  Both #5 upper,
> as it happens.
>
> But as before - I'd rather have a stud snap than drag out the threads
> from the head.
>
> --
>  Phil Payne
>  UK Audi quattro Owners Club
>  Phone: 0385 302803   Fax: 0870 0883933