exhaust manifold stud replace?

[paul j]

I need to replace a missing em stud. What is proper torque for 8x1.25 steel stud going into the aluminum head?
Should a thread locker or a hardening gasket sealer like Permatex 1B be used also?

 

[snailspool]

I don't believe there are torque specs, as they are not supposed to be torqued (like head studs). Hand tight, and some blue threadlocker, just a dab. Don't forget anti-seize on the nut portion.

 

[prove_it]

Do not torque studs. Ever. Only tighten til it's snug, it should go in by hand. If it doesn't then you need to repair the threads in the head with a chaser. It will tighten when you install the nut. I don't recommend the use of thread lock at all. These studs are meant to be installed dry and thread lock will only make any future repairs harder.

Don't use regular anti-seize, it won't last. You need high temp anti-seize. The biggest reason for stud failure is improper tightening of the nuts. Try to torque them down. Otherwise don't tighten them so damn tight. The manifold will expand and tighten up the stud even more.

 

[BogusSVO]

Prove it is for the most part spot on.

The only place I will differ is the use of some sealant on the bottom center exhaust stud, it is an open hole and enters an oil return port.

But for the other 8 studs, dry and finger tight.

 

[jnava]

The guys are correct, I replaced mine when I purchased the FP manifold. Just hand tightened and I think I do recall adding anti-seize.

 

[prove_it]

Guess I never realized the center bolt was an open hole. I'll have to look, but could be the source of my oil leak. Thanks.

 

[BogusSVO]

It is a fairly common leak.

Hope it is a quick fix for you.

 

[prove_it]

Hope so. What kind of sealant works best in that spot since their is higher heat? Copper RTV?

 

[BogusSVO]

RTV, gasket maker, liquid teflon, about anything that will clog the threads. any and all seem to work.

 

[snailspool]

I like to use just a dab of threadlock as anti-seize seems to wear out over the years and I hate it when the stud backs out with the nut, YMMV. Also, torquing from the middle out, a 1/2 turn at a time after the manifold is flush, really seems to help the seal, and keeps the torque even.

 

[G]

This stuff works pretty good. click

 

[paul j]

Three bond link says it is good to 200C=392F. Loctite red & blue is good to 300F.

 

[turbowop]

I've always used plain old ultragrey RTV. Never had an issue.

 

[paul j]

After head service (175k) should bottom center stud be removed and resealed?

 

[BogusSVO]

If it is broken or leaking.

If it is not giving issues, leave it alone.

 

[Whoodoo]

I know all about that bottom center. When I replaced my head, the threads in that hole all pulled out when I tightened the nut. I fixed it by installing a threaded steel sleeve, but didn't realize the hole entered the oil passage until after I drilled it out. I had to pull the oil pan back off and clean out all the chips that fell into the engine.