Fixing exhaust stud in aluminum head that has failed once before.

I broke an exhaust stud on my 550 spyder running around somewhere. Not sure how but found a major exhaust leak from the header to the head. I am running a older set of matched 44x36's that I do not want to replace. Exhaust stud has been repaired once before by drilling it out and putting in a timecert. Now that has no more material to grab onto. Is there some sort of epoxy that will work to hold a stud in place that I can fill the cavity with and that will hold a stud. The heads are aluminum and I am 100% certain there is not enough material to hog it out and put a larger cert in there. 

I can pull the head and fill it with weld and then retap but never done that and wanted to get back on the road. 

wearymicrobe said:

 The heads are aluminum and I am 100% certain there is not enough material to hog it out and put a larger cert in there. 

I can pull the head and fill it with weld and then retap but never done that and wanted to get back on the road. 

Theres your answer.  

If you can put an insert back in (if it isn't too loose) and use an appropriate epoxy to grip the base material.

Second on fill with weld and redrill/tap.

Also, if the stud has broken twice, then you may want to open up that stud hole in the manifold side, in case the thermal expansion is side loading the stud.

If it were somewhere else other then an exhaust stud I would probably try another inset bedded in epoxy. However as others have said the real answer is weld the hole up with a filler rod similar to the head. 

Before going through the trouble of removing it, I would try Belzona 1111 or 1511. 

If you use an epoxy, it might be a bear to weld up later on.

Alright I will pull it off tonight and fill and retap it. 

In lieu of retap or helicoil. fiind  a Time Sert.  More surface area and the sealing top hat ensures a good seal.

stafford1500 said:

Second on fill with weld and redrill/tap.

Also, if the stud has broken twice, then you may want to open up that stud hole in the manifold side, in case the thermal expansion is side loading the stud.

This, and pay close attention to torque specs and proper fasteners.  They may need to be "just tight enough" while still being loose enough to allow the exhaust to shift around, and this usually requires special weird-shaped washers and self-locking nuts.

Ass-u-ming this is on an ACVW head, I wouldn't THINK that thermal expansion of the exhaust should be an issue compared to, say, a truck engine with a log manifold, but it's failed twice now...

Did it break at cylinder 3?

Have you considered going slightly oversized on the stud?  That way you won't have to pull the head and you should have enough material to tap.