Exhaust Studs

[biergoat]

I am upgrading the exhaust on my car w/ SSI's and need some advice. Six studs came out without any issues, the other six remain, all threads intact. The problem is that the new headers have a thin flange and the remaining studs are spaced for the thick flange headers. I have 12 new short studs, sized for the thin flange, should I leave the six old studs and use spacers, or, should I temp fate and try to remove and replace? I tried to remove the old studs by seizing two nuts together on the thread without success, what is the best way to get these out? Any advice? Thanks!

[efhughes3]

I'd leave well enough alone and use spacers. All it takes is one of the remaining six to break, and you instantly have a bad day.

[gtc]

Did you try heating up the studs with a torch first? That usually helps loosen them. If the double-nut trick doesn't work, there are two types of stud removers. I like the collet-type stud removers, because they have a more secure grip on the stud without affecting the threads, whereas the more common cam type usually crushes the threads.

[fredmeister]

You are much better off using spacers because you increase the effective length of the stud which helps tremendous with thermal expansion loads. The reason for the thick flange was 2-fold, better stiffness for sealing (remains flat over time) and reason I just mentioned above.
Think of it like the reason cylinder head bolts are stronger when they are longer.....increase the length of the bolt and the ability to absorb stretch goes up.
Plus you don't risk breaking them off in the heads.
Make sure the spacers have clearance holes for the stud to pass thru. I took some nuts and drilled out the threads to create my spacers for my 930 headers with thin flanges.

[john walker's workshop]

unless you don't mind drilling out the 6 remaining ones, use a spacer sleeve. they really don't like to come out and will likely break off, regardless what method you use.

[biergoat]

Thanks for the advice! I think I'll play it safe, leave the 6 old studs in and use spacers.

[tdatk]

Although too late for your setup, the thick flange's had the additional benefit of the internal flange that helps with exhaust gasket leaks.....easier to install too.