recently when i pulled my head exchangers for doing the clutch etc, several exhaust studs pulled out due to the nuts rusting to the studs, So i ordered new ones. I just wanted to make sure when i put the new ones in can i prevent this from happening in the future by using locktite, or is this not advised due to head at this location? if so which kind? AND should anything be applied to the threads before the new copper nuts are put on when the H.E.s are put back in place.

Thanks.

Milk of Magnesia

Anti-sieze .......... I use it on installation of studs and on the studs when bolting up the HEs. Actually I use it on most of the fasteners on a car and spark plugs.

of course MOM does the same thing.

Your turn for the lecture. Shoulda kept a copy of the last one so I don't have to keep repeating myself. First, the factory did NOT use ANY type of self locking nut on ANY air cooled application. They used two kinds of exhaust nuts, one for the 1.7/1.8 cars, a Helicoiled regular looking nut, and another for the 2.0 cars, with a thick flange as part of the nut, and also containing a Helicoil (see the picture below). Second. Those "copper nuts" aren't copper, they're copper plated steel. They were first used on the VW Rabbit in 1974 and spread, like an unstoppable infection, to the aftermarket aircooled scene.

You don't want a locking nut because it increases the chances of breaking or pulling the stud. Pulled studs can affect the threads in the head, and then you have a REAL problem.

Click to view attachment

Have fun, and THINK about what you're about to do. BTW, I think I still have a little over 1 set of those nuts in the picture, and they're for sale.

The Cap'n

I will have to 2nd the Cap'n. I once used lock tight. I was having exhaust leaks. Thought the nuts were backing off. But the real issue was I was not using the right nuts. I will spare the details but one replacement 2.0 head later I got the right nuts and no exhaust leaks.

understood- i had seen your F/S on those- PM sent

If your question was in regard to securing new studs into the heads with locktite,
I say use the high temp permanent variety.

No Loctite will help. The temperature is too high. It may help hold the stud in place when installing the HE's but that is where it stops. Once it heats up, any holding power is gone

Red Locktite (271) is good for 482 F (250 C) that ought to be good enough.

David

Yep, I am with the cap'n...

That said, a trick that I learned a long time ago was to use a very long nut that does not allow any thread protrusion, or I double nut them to cover the exposed threads and coat it all with Milk of Magnesia.

What makes exhaust nuts so hard to remove is corrosion on the exposed threads that the nuts have to pass over when loosening. This galls the threads and breaks things. Keeping the threads covered keeps them protected from corrosion.

Loctite is a waste of time on the ex studs. Nothing out there will handle the heat. I coat them up real well with copper based anti-seize and pack it in the threads down in the head so as the stud is installed it displaces the anti-seize and forces it into the threads.
And like Jake said, use long nuts to cover the threads completely. Coat 'em with copper anti-seize and they'll come right off. If the nut does freeze to the stud the anti-seize will help keep it from galling aluminum when the stud un-screws from the head.

Len,

Thanks for the tip.