What is the curent thinking on exhaust stud nuts, Copper or regular? Options

[thomasotten]

Are the copper coated nuts the way to go, or is using regular bolts, double bolting the way. I read something yesterday that said the copper nuts should only be used once...why?? Should I coat the studs with anything?

[Cap'n Krusty]

There's an interesting article on stainless steel hardware (and it's appropriate uses) in last month's issue of Motor Magazine. Non-geek that I am, I dunno how to get you the pages from the PDF, so I'll give you a link. Once you have the PDF, go to page 26. Perhaps we can end this clueless insistence on the use of SS hardware. Here's the link: http://ct.emeraldmail-usa.com/rd/cts?d=7-1...25-0-0-0-1-2-23

BTW, the factory used one kind of exhaust nut on the 1.7/1.8s, and another on 2.0 cars. BOTH were steel with a SS insert. A Helicoil, or whatever brand they use in Germany. I save and reuse them as often as I can, as they work just fine unless/until they get rounded off. They are the best thing I've found to maintain the torque in the hot/cold environment of the exhaust system. I also paint the studs with anti-seize.

Maybe someone can get the contents of the article into an e-mail so we'll have it here for all to see.

The Cap'n

[jk76.914]

There's an interesting article on stainless steel hardware (and it's appropriate uses) in last month's issue of Motor Magazine. Non-geek that I am, I dunno how to get you the pages from the PDF, so I'll give you a link. Once you have the PDF, go to page 26. Perhaps we can end this clueless insistence on the use of SS hardware. Here's the link: http://ct.emeraldmail-usa.com/rd/cts?d=7-1...25-0-0-0-1-2-23

BTW, the factory used one kind of exhaust nut on the 1.7/1.8s, and another on 2.0 cars. BOTH were steel with a SS insert. A Helicoil, or whatever brand they use in Germany. I save and reuse them as often as I can, as they work just fine unless/until they get rounded off. They are the best thing I've found to maintain the torque in the hot/cold environment of the exhaust system. I also paint the studs with anti-seize.

Maybe someone can get the contents of the article into an e-mail so we'll have it here for all to see.

The Cap'n

Heli-coil calls them "heli-nuts". They were designed for aircraft applications originally, and they are very forgiving in environments with wide extremes of temperature. The helicoil has some give to it , or spring if you prefer. It allows for some expansion and contraction with temperature. If you look into them, you'll see that the middle couple of threads are flattened, which gives some locking effect. They are advertised on Helicoil's website as reusable multiple times. I called them a while back, and found out that they aren't stocked any more. I could probably have had some made, with an minimum order of 25000 or so I guess.

My '76 2.0L was first disassembled in 2002. 7 of the 8 nuts came off without damaging the stud. The 8th one unscrewed the stud from the head. Not bad for 98000 miles and 25 years, I'd say.

Does anyone know where I can get 6 of these????

Jim