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Re: studs etc.
Brandon, I hope you don't object me copying this post to the list. I
received similar questions from a few other listers.
Brandon Hull wrote:
>I'm "refreshing" (new seals, gaskets, other replaceables) a 3B engine
>prior to transplanting it into a '91 Coupe. Your exhaust stud warnings
>correspond with my experience: when I removed my em, I snapped one of
>the #1cyl bolts,
Pretty typical. BTDT twice on #1 and twice on #5. They warp most.
> fortunately at the nut, leaving a half-inch to grab with vice grips.
You're lucky. I never was.
> However, I'm tempted based on your experience to simply
>replace all the studs before reassembly. I'd be interested in your
>opinion: Is the risk of breaking others while doing this offset by the
>benefit of having all fresh studs?
ABSOLUTELY! In '94 I was too cheap and replaced only 4 studs: on #1 (one
was broken) and on #5. Figured, the inner ones were under less stress
and as the saying goes, if they were not broken I won't fix them. Wrong!
Well, now I am paying for it dearly. Both studs for # 2 cyl broke, and
they did not want to come out. I ended up breaking TWO screw extractors,
one in each stud. Jeez, what a moron I am! BTW, one was an American made
Craftsman #3, which has fewer spiral flutes and was fairly easy to drill
out with the Dremel tool, carbide tile drill bit and lotsa oil.
On the second stud for #2 cylinder I tried a German made screw
extractor, (Black and Decker #3), which has more raked flutes, and the
spiral pitch is far denser and hence has a far better bite into the
hole. On top of that the German tool was made out of some incredibly
tough steel, (yes, even tougher than the American made one). I broke
that one too. The broken piece of this extractor was a bloody nightmare
to drill out of the stud! Never again...
> What can I do to improve the odds? (oil preferences? heat?)
There's no better penetrating oil on the market than Zep. Not sold in
stores, but every pro in every shop has it. Those guys don't use Liquid
Wrench and WD40. After having used Zep a few times I tend to agree with
The much praised Ammonia did not work for me. OTOH, even Zep was unable
to loosen both studs and I had to mill them out.
I was reluctant to use heat on the Al head.
>Any benefit to replacing with aftermarket (eg raceware) studs?
There would have been, if Raceware made the EM studs. Alas, they don't.
BTResearchedT. They make head studs only (at least for Audis).
Don't use ANY studs other than OEM Audi! Audi has a new superceeding
version, which is forged and heat treated.
> Do you use a stud removal tool or just stack nuts on the stud?
I always use two old OEM nuts. A camlock stud remover would work even
better but I don't have one.
>(I actually wonder if grabbing the shank with the vicegrips
>doesn't confer the best load distribution...)
No difference. The annealed studs can not handle the torsional load
applied and snap at the weakest point: they brake at the end of the head
side threaded portion, flush with the head surface. Your lucky example
hereabove is the first one in my experience. Don't count on it to repeat
>Second unrelated question: I'm going to need to outsource the heavy
>wrenching part of this project. I seem to recall that you know George
>Baxter in Bristol. Could you comment on his capabilities, professionalism
It's top shelf! I know VERY few people who know Audis at his level. Too
bad he's not on the list, he could've been a very heavy contributor.
'89 200TQ -- 18psi (TAP)