New Exhaust Studs??

[vesnyder]

I am swapping out my OEM heat exchangers for a set do SSI's. Would you recommend changing the mountings studs and hardware? Some of the studs came out when I removed the original heat exchangers and was wondering if new studs and nuts would reduce the corrosion and make removal easier next time.

Thanks

[hwgunner]

I am going through the same thing, sort of. I removed my heat exchangers but none of my studs came out. I do have one bent stud though. Several people have said to replace but 3 different long time Porsche mechanics said less is best with exhaust studs and to not mess with them, even though my engine is out of the car. Just one broken stud can be a real hassle.

Jonathan
Hwgunner

[Jesse16]

I'd recommend if they aren't damaged after removing your exhaust, just clean em and leave em. Use anti-sieze at assy. I replaced mine and think it was a useless effort and expense. You don't or should not torque them much and the heat while not low isn't extreme for steel anyway. My exhaust system came off pretty easy after a few days of penetrant and using the "tighten till you hear/feel a ping", then loosen the nut technique. All the nuts came off easy.

[trak ratt]

I'd replace all that came out and try to remove the others. They're prolly old, with lots of heat cycles. Studs aren't very expensive and why would you want to reuse old fasteners for a new exhaust system.

[aston@ultrasw.c]

Replacing the studs is a great idea right up to the point where you break one backing it out.

Leave 'em

[gregwils]

Originally Posted by aston@ultrasw.c

Replacing the studs is a great idea right up to the point where you break one backing it out.

Leave 'em

+1 If they didn't snap in the process of removing the heat exchanger and the threads are decent enough to rethread, I would agree - leave them. I had one snap off even with the head when I tried removing the nut and even though I had a special stud drilling guide I needed to install a timesert. As Aston suggested, you won't be happy if your project gets a lot bigger for no real benefit. Just coat the studs with anti-seize.

[andyt11]

I also agree to leave them. Sure its a good idea to do it, but not if you are going to break one.

If you leave them, they will last for many years to come, by which time it will not be a concern of yours anyway. And if they break at some point in the future, they were gonna break when you tried to extract them anyway.

I would probably take the step of reassembling with new nuts though and lots of anti-seize. Will at least give the next owner of the car a fighting chance.

[KTL]

If you have some studs that came out when you removed the nuts, you probably weren't using heat to remove them. Which means you got VERY lucky that you didn't break any. I too got lucky like that when I first bought my '87 twelve years ago.

Do yourself a favor and put three new ones in there and LEAVE THE REST ALONE. You're "playing with house money" right now, so quit while you're ahead!

[Ronnie's.930]

These are easy questions to answer - new nuts = yes . . . new studs = HELL NO (for the reason(s) others have given)!

[don gilbert]

I got tired of leaks because I was afraid of going to tight on the old crusty studs after the SSi swap. Finally broke a few and decided to fix it for good when i pulled the engine for something else. Drilled the holes out to 10 mm and used allens, can tighten the heck out of them, and no leaks since. Be sure and get the 74 down gasket, lots thicker than the thin copper for 75 up.

[Geronimo '74]

If your engine is out of the car, replace them.
Use lots of heat and be careful
Some will/might snap and that sucks but it's not like the world will come to and end...
Heat cycling makes them brittle.
SSI's thick or thin flange? Thick, and you may need longer studs anyway...
Replace and be done with it, I say.