Exhaust nuts?

CRH911S · 03-19-2003, 11:20 AM

The Pelican Parts Catalog list two types of exhaust nuts; exhaust lock nut and exhaust barrel nut. My question is are both types untilized or is it a matter of preference? When I look at the parts diagram it looks as though the barrel nuts are inboard and the nuts on the outboard side.
Regards,
Clinton

Doug Zielke · 03-19-2003, 11:33 AM

The barrel (allen socket) nuts are intended for the studs that would be inaccessible with a regular hexnut/wrench. This due to the heat exchangers blocking access to those studs. The access holes on the bottom of the HE's indicate where the barrel nuts are to be used.

KTL · 03-22-2003, 09:03 PM

Copper nuts can be used in place of the standard M8 hex nuts if desired. They have less tendency to rust/freeze onto the exhaust studs. I got mine from Paragon Products.

Gotta be careful with the copper nuts though. Copper is a much softer metal and therefore much easier to round-off the heads if you're not careful!!!!

Jim Sims · 03-23-2003, 06:15 AM

Copper on steel has the undesirable characteristic of turning the fastener arrangement into a minature "battery" if any electrolyte is available in the form of road chemicals (salt) and water. The steel in the stud is eaten away by the electro chemical action. I too installed the copper nuts on one engine exhaust but I think it was a bad idea; next time just steel nuts with plenty of never-seize. Jim

Doug Zielke · 03-23-2003, 06:46 AM

The "copper" nuts I recently installed, were just copper *plated*.
Got 'em from the Audi dealer. Still used lots of industrial-grade Nevr-Seize.

KTL · 03-23-2003, 07:25 PM

No kidding!!! Wow. I did not know that.

Excellent info. as always Jim.

My exhaust studs have PLENTY of antiseize on them and the car rarely sees poor weather. Nonetheless, standard steel nuts shall be the norm from now on.

Wayne 962 · Wayne 962's Garage

Steel on steel, coated with anti-seize is what I use...

-Wayne

snowman · 03-31-2003, 10:50 PM

Solid copper is the only way to go on exhaust nuts. They are a little more expensive, but they will NEVER sieze up. They are used as std on higher end BMWs like the M series. The problem of electroalalisis is a non problem. They are available in self locking and differen't outter wrenching sizes from any "real" hardware store.