removing heat exchangers

[limble]

Firstly, I searched threads for this issue but didn’t find anything that matched.
I went to remove the heat exchangers and noticed that the 8mm driver spins freely and doesn’t go very deep into the socket head cap screw. Four of the remaining six seem to be o.k. but those other two may pose a problem. PO may have stripped them out don’t know.
I see tips on removing the nuts but not the socket head cap screws. Heating them up will cause them to expand making the situation worse. I'm reluctant to apply too much heat to the heads so..,

Has anyone else out there had this problem?
I will apply heat while removing the nuts per suggestions from this board and other sources.
I was thinking E-Z-out but guiding it down through the heat exchanger looks like it might be a real pain. Sawsall and buying a new exchanger is another option.

2.2 70 911 is the patient.

Thanks,
Mike

[Jadams1]

Did you try tapping in the allen wrench with a hammer to make sure it's all the way in? Maybe a larger hex wrench tapped in what's left of the barrel nut will get it. Maybe a low profile not splitter?

I was lucky, I got all mine off. One actually cracked and I had to put a small hose clamp around it so the hex wrench wouldn't slip.

[BGCarrera32]

Mike,

I believe if you heat the bolt, the block will expand faster (aluminum) than the steel bolt. The thermal expansion rates are dissimilar...that's why it works. I have a small (like Menards small) oxy-mapp torch that would get that thing red and should pop it free. Let me know if you want to borrow...you may need to buy some replacement tanks of fuel (like $4-5 each as mine might be empty.)

-BG

[1974carrera]

Mike,
I just ran into the same problem on mine...2 0f the 5 (SSI's use 5 not 6) socket head cap nuts were internally eroded/worn. The 8mm hex key would just spin in one of them and was loose enough in the other that it was going to lose its bite also. I was able to get a 6-inch Vise Grip on each of them and get them started turning...then in place of the hex key, I used a blade screwdriver that would wedge into the nut interior to finish turning them. The threads weren't rusted so I didn't have to use heat to loosen them. Oh ya, I was able to do this on the barrel nuts on cylinders 1 and 6.

Even though these were too loose to hold an 8mm key, a 9mm hex key was too large to force in, so that doesn't work. I don't think there is a Torx that is the right size to jam in there either, but I wondered about trying a 12-point or triple-square key of some size, but didn't get that far. As crude as using vise grips sounds that is what ended up working.

Get all new barrel nuts for the reinstall (they're pretty cheap) and use a good nickel anti-seize.

[limble]

BG-
I have the oxy-mapp tank (yellow) that connects to a std propane set-up is that correct? Is there a particular tip that works for this application.
Brain fart on the dissimilar metal expansion rate issue. Oh well, I doubt any of my profs' are monitoring this board anyway.

John-
I tried tapping them in with a hammer but they didn't go in any more.
It doesn't engage much more than .050 in. Although when I get home I'm going to slide a dial calipers down the hole to check.
Could some one have twisted off a cheap hex driver in there?

Thanks guys!