stk 3.2 wanting ssi exhaust q's...

911 tweaks · 01-03-2015, 06:56 PM

in removing a very old & tired stk heat exchangers on a 1987 911 carrera with stk 3.2 engine, 2 exh studs broke off flush with the outside surface of the thick flange...

Q:1: if I use thin flange ssi's so I have threaded stud that will stick out beyond the outside surface of the thin flange, will these fit & work properly = p/n 91.911ssi...??

Q2: if the "thin flange ssi's" = 91.911ssi will fit, does it require "backdating" the heating set up on the engine to have working heat...?

Q3: pelican says for a model 1987 911 carrera the correct ssi p/n is 91.936ssi...I would guess this ssi set up is thick flange...?

Q4: whether I use a thin or a thick flange ssi, all of the ssi systems require a 2 input muffler right...?

thank you...

michael lang · michael lang's Garage

1. I do not think the thin flange will fit on your heads. I seem to remember reading somewhere there is a difference in them not aligning properly.
2. Yes, backdating or a modification there of the heat will be required. Search the forum, there is so much information avail on that subject, I was a bit confused about it at first but after spending some time looking into it, it became very clear. It really is not that hard.
3. Yes, the correct SSIs are thick flange
4. Yes, SSIs are a 2in set up.

If you don't mind me saying so, if your engine is as old & tired as you described, why not just remove all the exhaust studs and out in new ones. It's not that hard, give them a good soaking in PB Blaster or Kroil to help break up some of the frozeness over the last couple of decades, add some heat and out they will come. If a couple of the current studs broke, I wouldn't be surprised if a couple more snapped when you were retorquing them down when installing the new heat exchangers.

911 tweaks · 01-04-2015, 04:32 AM

thx mike...I am leaning your way = also think the thin flange either has a narrower spacing of exh studs and/or the stubby of ssi pipe that sticks into the exh port is smaller in dia than the 3.2... as for replacing the exh studs, r u speaking from experience when u say why not just heat em up & use kriol/pb and out they come...? almost all of the exh studs that I have had to remove usually snap off flush to the head when using my snap on collet stud grabber which in my opinion is the best way to remove stubborn studs successfully...
Any one else have any input...?? thx again mike

911 tweaks · 04:34 AM

...

VFR750 · 01-04-2015, 05:16 AM

Old exhaust studs are very likely stuck in the heads.

I had to drill out a broken one several years ago. Took 2 hours. It was a pain. Literally and figuratively; I got a metal sliver in my eye. Did it under the car.

Recently anchor Atlantic rebuilt my heads. Bob had to drill out several studs because they broke during removal, and use timeserts to fix the threads. A few came out whole, with effort.

In both cases, what appears to happen is the steel stud rusts inside the hole, and outside of the head. Rust grows. So the the rust that forms between the stud threads and the head locks the stud into the heads making it difficult to remove.

What does this mean to you?

Well, if it were me (and it was me a several years ago) , I'd get the one stud replaced
and leave all the others alone. If the other studs still have useable threads, they are good to go.

The risk on this turning into a big project is too high. You will likely break a few more. And replacing studs was not your intent for this project.

Later, when the heads are off, then get all the studs replaced.

michael lang · michael lang's Garage

Quote:

Originally Posted by 911 tweaks

as for replacing the exh studs, r u speaking from experience when u say why not just heat em up & use kriol/pb and out they come...? almost all of the exh studs that I have had to remove usually snap off flush to the head when using my snap on collet stud grabber which in my opinion is the best way to remove stubborn studs successfully...
Any one else have any input...?? thx again mike

You're welcome. I did have a couple snap on me and there were a couple that gave me a little trouble but the heads were coming off so I could send them out so it didn't bother me too much. One of them was on the #6 cyl and it was the one closest to the cooling fin and it didn't my Collett tool too much in the way of space to grab onto the stud which caused it to break. I truly believe my soaking the bolts every night for a week was why the majority of them came out w/out an issue. I only used the heat on the ones that gave some resistance.