lostinatl

'84 911, just started my project to remove the heat exchangers to do the SSI's and muffler. After soaking w/PB I got one to come loose. The other five, one is backing out but the stud is coming with it....Are the head studs screwed in? Or pressed in? The other four are groaning and I am assuming will back the stud out. As long as I don't shear off the stud am I okay? Will I be able to insert another stud?

912outlaw

I recently replaced my heat exchangers with bursh headers and had two studs back out. Clean out the threads in the heads with carb cleaner and compressed air and new studs should thread right in. Don't torque them. You can use some blue thread locker to keep them in place if you like. Make sure you get the correct lenght studs to fit the flange on the new ssi's.

EM

69' 912-6 2.2L T

Naitove

I did my SSIs recently. If your stud comes out you're lucky. I had to drill all mine out after they broke. Just buy new ones and screw them in. I wouldn't use the old ones anyway. Blue Locktite is a waste of time. The heat will melt it. I would just coat it (I did) with Permatex antiseize and screw it in. If you break one, it's not the end of the world. Christian on Pelican makes a tool that will allow you to drill it out perfectly.

lostinatl

Thanks guys. So they are reverse threaded.

Naitove

No. They screw in normally and stop at the flat part that is not threaded.

theiceman

lostinatl

The fact they came out when you were trying to undo the nuts tells you they are not reverse threaded. if they were they would tighten as you tried to undo the nut and surely snap. Studs coming out is a FANTASTIC thing and most wish there studs had done that.

lostinatl

After I typed it I realized my error. I have now gotten 5 of the 13MM nuts off. Only one of the studs is backing out. Yes, you are correct much better backing out then breaking off. Can you buy the allen tool from Porsche? Or do I need to wait until I get the SSI's? I heard it come with the removal tool, but I would like to get them off before hand. Also, any tricks with removing the allens? They have been soaking with PB every couple of days.

Peter Zimmermann

Buy the allen socket from SnapOn...
Pete

theiceman

what do you mean any tricks ? you should be telling us your tricks given you are half way there with no studs broken :-)
did you use heat ? did you just soak ? did you tighten before losening?. did you use hand tools?

lostinatl

Soaked it with PB for about a week. Hand tools, I used heat on the ones that would not budge, but I still do not understand how the heat works.......the stud would have to heat up also, which would mean they are both expanding? Just really nervous about the allens now.

theiceman

I think the heat has something to do with the co-eficient of expansion of the disimilar metals. when the steel stud goes cherry it basiclly epands the aluminum casing, and when the red goes off it contracts and the heat goes into the alluminum. My brother is a ford mech and they run into this all the time given the relatively low quality of parts they use. He swears by heating it until cherry and as soon as the colour goes off try to loosen it. He has a lot of experience with bleed niples and swears he has never ruined a caliper yet.

lostinatl

I borrowed the tool from my Mercedes mech.....I can't believe he loaned me a tool. The allen heads are not bolts at all they are very small allen nuts. I did not expect this, I do not think I have read anywhere that they were nuts....always bolts. I was less worried about removing these than the 13mm nuts. In hindsight I should have been more worried. The allen's seem more likely to break then the nuts. Anyway, all are off the came off w/one hell of a pop....and a puff of smoke. Really a sight to see. I will post the rest of the project as it progresses if anyone is interested. And, if anyone in the Atlanta area needs help, I now consider myself certified nut remover.

Naitove

You are a very lucky person.

theiceman

Wow great Job. Did you use the PB blaster on these nuts also ?

lostinatl

Yep, those were soaking for close to three weeks while I tried to figure out how to get the tool. I am trying to get parts ordered from Rennsport....the SSI and Monty but can not reach them by phone or e-mail? What is up?