need nut size for exhaust manifold

have had an intermittent squeak somewhere in engine area, found out there is no nut on one of the #1 exhaust studs. i believe it is 8mm with a 12mm head but i need to know thread count/pitch as i dont have a vw shop nearby. im relegated to the hardware store.

I always use the special copper ones with the locking nut incorporated. They are same thread as the 13mm nuts - which you can use but will probably need open end to tighten. Doubt you'll find them at HW store.

http://www2.cip1.com/productdetails_popup.asp?productcode=VWC%2D175%2D129%2D650

8mm 1.5 pitch

You'd be amazed at what you can find at an Ace Hardware store, fastener/bolts section!

Just for the record - when I installed a BAS header on my type 4 engine, I had to use a bastard combination of nuts to secure the exhaust ports in place. The header came with 13mm hex nuts. Due to wrench clearance issues I also utilized 12 mm and 11 mm hex nuts. The end result is leak-free.

I often wondered if that size selection would have been available had the fasteners been SAE?

Some people warn against using the so called copper ones. I think at least some are copper colored steel. It is said they can cause problems with the studs.

I just bought some flanged steel nuts that used a 3/8" wrench for extra clearance from aircooled.net. These are also nice for intake manifolds.

I really like the brass 11mm ones, had them on for 5 years and removed/reused them several times. Also, copper exhaust gaskets are the BOMB!

The brass ones are a Good choise . But the 13 mm ones at the hardware are fine also.