Well...I finally got around to pulling off my old heat riser valve...and the 2nd nut I loosen snaps off the tip of the exhaust stud at the collector. The other stud loosened itself fine, and I got it completely removed from the manifold. It's about 3" long, and after I wirebrushed it, it looks fine. The other is still stuck in the manifold. I tried snugging up two nuts near the mating surface and working it loose with a wrench, but it seems stuck in there. I could try hitting it with the impact gun, but doing that may break it again. I'm only short about 1/4" at the tip...the retaining nut may be able to engage 1-2 threads if I try putting things back together...but I'd rather not. Maybe I could try a 9/16" shank nut on this stud? I think the sleeve would fit within the holes of the collector plate.
Either use some Kroil, or 50%/50% mix of ATF and Acetone. (weasel pee) Apply that and then drill and use and EZ out. and it will likely come out without too much trouble. You might need to "work it" back and forth a bit and apply more "juice" and let it set and work it again. But it works against some seriously rusted and corroded fasteners. I took my 1964 Skylark down to the main body and frame. Pulled everything out of it, and only broke one rear lower control arm bolt. But everything else came off without much trouble at all. I rather spend a little extra time getting things apart in one piece than spending more time trying to find a good part or fix things I broke and no longer can get. Good luck.
Thanks for the recipe. I have lots of acetone & ATF...may give it a try. There's a copper gasket between the riser & manifold. If I replace it with Hi-Temp Copper ATV...it may give me one more mm of thread on the broken stud...
Get out to aparts store and get a can of PB blaster , Acetone vapors are not good and just as flamable as Gas vapors! Flood that stud up for 1/2 hour, then double nut it again and beat on it some which will displace the treads and it will then back out.
The Blue wrench is the best way, you run the risk of breaking the stud off flush with the manifold,now the problem is multiplied big time.
In this situation heat is your best friend. Map or propane will eventually work but acy/ox torch is your best bet. Get the ear around the bolt red hot then work it back and forth until its loose. Good luck
Gas axe is generally the winner, but after you break it off flush a washer and nut welded on there has worked for me in the past. The stubborn ones might have to be welded several times but they come out eventually. Just have to have patience.
I do have an oxy/acetelyne bottle if I need to heat things up, but I need to take a closer look at the broken stud. It may not be threaded in like the one which I removed. If it is pressed in, I risk breaking it further and screwing up my plans for Reno at the ROA meet. The bi-metal coil which came with my heat riser didn't seem to work correctly (too tight), so I used the coil from my original riser valve, and assembled it with the retaining clip. Seems to have comparable tension with the old setup...so at least that's okay. I'm gonna clean things up with the 3M roloc pads and try re-assembling what I have. If I substitute hi-temp copper RTV for that riser gasket, I may have enough threads on the broken stud to get everything back together. Thanks to everybody for the input. I'll post some pics to make it interesting.
Another option may be to weld a nut to the end of the broken stud. Use a cheap arc welder and the heat from the weld may loosen the stud. The nut will give you something to turn it with. I used torches on mine before attempting to put much torque on them and had no issues. I used never diesel when reassembling. Forget the RTV and get a proper gasket or you will have a leak.
Too late. I've gone the RTV way...for better or worse...for now. If I can get a new stud & some free time, I'll try extracting it & going with the original perforated copper gasket. But I cleaned everything up, put a 1/8" bead of fresh copper hi-temp between the riser & manifold, and it seems to be holding. I've attached pics of the busted stud piece in the nut, my original gasket & good stud, and the shiny new heat riser. I used the original bi-metal coil since the replacement one didn't seem to be at the correct tension. Drove it to work this morning, and it is soooooo much quieter.
