graba

87 NF motor...top exhaust stud on #5 cylinder is loose. The nut is "seized" to the stud...but luckily (I think) I can turn the nut which turns the stud and things tighten up..for a few days or so. (symptom is ticking when cold...goes away when warm)

Suggestions? Replace the stud and nut? Can I do this without removing the exhaust manifold? Do I use antisieze or thread lock on the stud? Pushing the limits of my experience!

thanks as always.

-Tom

TonyOldSchool

unscrew out and examine the threads, if there is any aluminum inside the threads, then it is stripped. It's pretty close to impossable to remove the lock nut from the stud. If not stripped, try screwing the "assembly" back in the head by hand. Make sure your socket fits before you screw in, seem to remember it was wierd, like 11mm. You don't want to cross thread the screw. If PO had the head off, that assy may not have been tightened down enough and just loosened out or he stripped it, and snugged it so it won't leak. Hopefully, the individual gasket did not blow out (mine did!). If so, the EM's must be removed. Pretty tough retreading w/ the IM on, so thats got to go too. Alot of posts can be found if you do a search. Frankly I think I'd rather do a head job and deal with the stud issue with the head on the bench. Then do the WP, Time Belt all in one batch. If you like the car, its worth it, but have a backup for this ordeal!

graba

thanks Tonyoldschool,

the "assembly" seems to tighten down ok (12 mm, BTW).

I'm pretty sure I can easily pull the assembly and check it out.

If I'm lucky and it's not stripped, can i just put a new stud in with some loctite and then torque a new nut on and hope it holds?

thanks,

Tom

Tom Faust

I am pretty sure you could drill it and insert a Helicoil without pulling the EM. That would give you new threads. Haven't tried this myself.

graba

thanks Tom.

Guess I wasn't too clear. I don't think anything is stripped. The stud is loose...I can tighten it via the nut...but I'm scared to overtighten it (break the stud or worse) and it just loosens up again pretty quickly.

So ASSUMING no signs of stripping:

What I think I'd like to do is put in a new stud and a new nut without remving the manifold. I think I can reach everything ok and have enough room to remove the old stud/nut "assembly". But I'm not sure how to properly install the new one.

Should I locktight the stud and put it in finger tight and let it sit overnight and then put the nut on and torque to spec?

other suggestions?

thanks much!

Tom

a-talk

I'd do just what you mention - locktight in a new stud, let it dry, then tighten it down w/ a new nut. They're pretty cheap, and that's WAY easier than the headache I know you're trying to avoid!

audijim113

the nut is a copper lock nut, which may be 11mm now, but when it started out, it should have been 12mm before it got worn down. definitely get a new stud, use locktite on the stud. if there is room, "lock" the nut futher out together with another nut. (Turn the nuts one against the other) This will allow you to tighten the stud into the head and the locktite will hold it. if you just tighten the locknut down, there is a chance the stud won't tighten into the head.

graba

Thanks Audijim113 and A-talk:

from what I've read in the archives, the stud should be installed finger tight...Audijim, you seem to be suggesting that I get the stud tighter than finger tight. Care to clarify/comment?

thanks for the help,

Tom