broken exhaust manifold studs

[Eddie]

Just picked up an R6 that I've been eyeballin' for a few weeks. Super excited to have it. (2007), completely stock. Ordered a y-pipe to remove the catalytic converter. While removing the stock exhaust, I snapped the two studs in the middle of the head, leaving about 1/4in of the studs protruding from the head.
I've tried:
- plenty of PB blaster
- heat, cautiously around the aluminum head
- vise grips
- welding a nut on the stud (about 8x)

No luck so far.
Picking up a metric stud extractor set this afternoon. Trying to avoid the helicoil fix if possible.
Curious to see if anyone else has had experience with this model and this problem, as well as their final solution.
thanks!

 

[borislav]

You are doing everything good just keep in mind that aluminum dissipate heat really good so it will take longer to get desired heat at that spot. In situations like that I heat than spray PB blaster couple times before I attempt to remove stud. Idea behind this is when you spray hot area around stud with cold PB blaster fluid gets sucked in which will help you specialy because studs on the head are pointing down.
Now if that stud(s) have been crossthreaded good luck!

 

[wmhjr]

Had the same problem on an '05. Had to have a friend make me a jig to drill out a stud. It was a real PITA. Worse case scenario, you might have to go that route. We did it with the head still on the bike, but it was NOT fun. BTW, the only tough part about using a helicoil or timesert (my preference) is getting the correct angle. Those studs really don't have to carry that much stress once they're in.

 

[Eddie]

Well, finally got it fixed and put back together over the weekend. After welding two dozen nuts on the studs, I gave up on that approach. A friend told me I just wasn't using enough heat, but I just wasn't comfortable heating this aluminum head any hotter. I decided to start drilling. One of the two got a little more off center than I would have preferred, but still usable. Just had to ream the corresponding manifold bracket a bit. The curious thing is, the stud never came out! The part of it that remained after drilling it slightly off center, still remains! I increased the hole diameter incrementally until I was up to tap drill size, threaded the hole, and installed stainless studs with plenty of anti-seize. Manifold torqued down okay, so I'm fairly confident.......

I did re-use the old exhaust outlet copper crush gaskets. Any opinions on that?
Book says to fit with new, I figured I'd try the old as I had none on hand. No leaks so far...

Lesson learned here:
Do everything you can to remove those nuts without breaking the studs!!!
Had I torched those nuts, pretty sure I could have removed them and saved a lot of headache.

Hope this helps someone tackling this in the future to make all this misery worthwhile!

 

[LarsDunaway]

For what its worth, the jaws on vice grips expand apart from one another when you lock it down. The best ones I've owned are snapon, and they have a pretty flat locking phase, but there's still some expansion. For my tough jobs I use Bluepoint Parrot Jaws. Channellock makes a decent version of it called a Nutbuster. No expansion of the jaws, and the teeth point towards the direction of rotation, rather than towards the center of the bolt.

 

[wmhjr]

My own personal opinions - nothing more....

I never use exhaust gaskets more than once. They're too cheap, and I hate dealing with leaks.

I'm also not a big fan of stainless in this particular application. They will probably be fine, but even if you're using precipitation hardened stainless, it is much more prone to stretch and galling.

I've been where you were. It really sucks, so I'm glad you've gotten through it.

 

[Eddie]

Thanks for the input. I'll go ahead and order the gaskets. It'll bug me now if I don't. So far the only leak I have is at the new Y-pipe to header connection. Guess I'll try cranking that clamp a little more.
I would've thought stainless would be ideal for exhaust studs. I guess it just doesn't have the tensile strength due to its hardness?? Metallurgicaly challenged.
I'll leave them for now. Like you said, they're not highly stressed fasteners.
My, how the scope of a project can change so quickly!
Looking at it as a learning experience.

Now, I've got a little over a month to get brakes and tires on this thing.
April 3rd here we come!!

 

[wmhjr]

Don't tighten that y pipe too much. I typically use a tiny bit of exhaust sealant on those joints.

Stainless is a bit of a pain. It work hardens very easily and is very soft. It can also have a reaction with dissimilar metals. On cars I've used it pretty extensively but carefully. You can even buy sort of the equivalent of grade 5 hardened -precipitation hardened stainless - but it's expensive and just not the same. A good source is totallystainless.com. But, if you use it, always use a ton of anti-seize, never EVER use a power tool, and even go slow when tightening hard. It will also affect desired torque values in many cases. Like in suspension or chassis applications.

 

[borislav]

Totally agree on dissimilar metals WILL have reaction specialy when moisture get introduced to the area.
I would add one thing and that is to tighten your nuts in steps (a little bit at the time one than the other), I always start from center out.
This may not be critical on the bike with full exhaust (100 little sections) but very important in stock headers bikes,cars...