broken exhaust manifold studs-how to remove?

[rfuerst911sc]

This past weekend I removed the exhaust off my 78 3.0 project engine and broke 5 exhaust studs. All of them broke with stud still exposed of about 1/8 or larger. Now that the exhaust is out of the way what's the best way to remove them? I have been soaking them with PB Blaster and I do have oxy/aceteylene so do I heat them cherry red and grab them with vice grips? And should I remove the studs that didn't break? And when installing new studs do you apply anti-seize or Loctite? Thanks

[Nine9six]

This has been discussed many times...Do a search on broken studs, and read to your hearts content.
Cheers

[slammed1000]

i just went throught this on my 3.6. fortunately there was a drilling jig made to drill them out and just pull the threads out with a pick. i then ran a tap down them to clean up. problem is that most drilling jigs bolt on to one of the studs and if you have 2 broken in the same exhaust port this posses a problem. i think pelican sells the tool for the 3 liter as mine is diferent. there are plenty of people that has them that you might be able to borrow. i have done a 3 liter in the past to ended up having to helicoil most of them. i didnt have a drill jig back then though. i have tried heating them up to remove them. on the 3.6 i spent over 3 hrs. trying to get them out. i even tig welded a nut on the stud to use a wrench to turn it out. once red hot all that happened was the stud wanted to just twist. i did get 3 out this way by heating it up, squenching it with wd40 and wrenching it out. my sugestion is to get the drill jig. in the matter of 20 min. i had three done and retapped...do a search as you will see plenty of ways of doing this. it sucks either way. i use copper coat anti seize when installing them.....

[Nine9six]

Originally posted by slammed1000
i just went throught this on my 3.6. fortunately there was a drilling jig made to drill them out and just pull the threads out with a pick. i then ran a tap down them to clean up. problem is that most drilling jigs bolt on to one of the studs and if you have 2 broken in the same exhaust port this posses a problem. i think pelican sells the tool for the 3 liter as mine is diferent. there are plenty of people that has them that you might be able to borrow. i have done a 3 liter in the past to ended up having to helicoil most of them. i didnt have a drill jig back then though. i have tried heating them up to remove them. on the 3.6 i spent over 3 hrs. trying to get them out. i even tig welded a nut on the stud to use a wrench to turn it out. once red hot all that happened was the stud wanted to just twist. i did get 3 out this way by heating it up, squenching it with wd40 and wrenching it out. my sugestion is to get the drill jig. in the matter of 20 min. i had three done and retapped...do a search as you will see plenty of ways of doing this. it sucks either way. i use copper coat anti seize when installing them.....

If at all possible, rather than using a tap, try using a thread chaser. They are designed to clean and straighten out threads with minimum cutting. Taps are designed to cut threads.
This means, a tap met by any resistance, such as remaining thread fragments, will have a tendency to shave existing thread form from threads, on the opposite side of the tap, from where the resistance is met.

[Superman]

I would do NOTHING until I had the jig in my hand. I've drilled out a lot of studs in my day. If you want to "cowboy" this, use reverse drill bits and the Snap-On screw extractor set. Best twenty-five buck I ever spent.

And bring ALL your patience. Go SLOW.

[JP911]

I drilled out 4 broken studs free-hand, and I would NEVER do it again. Get a jig.

[rs6er]

I used the jig from Christian, A_Quiet_Boom on this forum. Worked great. Do a search.

[kimlangley7]

Jig is the best option ... but I've done the free-hand method of drilling a pilot hole in the center of the stud > then using a screw extractor that is hammered into place > and the stud backed out perfectly.. maybe I was just lucky...

[Joe Bob]

20/20....you should have asked how to do the nut removal w/o busting the studs. 5 studs out of 12 is a pretty bad average.

On the fix, use the jig. Don't make the bad situation worse.....

[theiceman]

I imagine those sruds are harder than the surrounding heads, are cobalt bits required for this Job ?

[dlagerstrom]

I just did 3 with the tool from Christian.

Worked pretty slick.

He recommends carbide bits, but I couldn't find any. I think I eneded up with titanium coated, similar to cobalt. 17/64s if I remember correctly is what you need with the jig.

The only issue I had was with one that appeared to already have a helicoil it in. I got the thread chasing set from Snap-On (one of the best $38 I have ever spent) and when chasing that hole, I snaped off the corner of the head! Nothing was open so I just JB welded it back into place. It appears to be OK. I guess I will find out.

[Tim Hancock]

If you have more than 1/8" sticking out on at least some of them, you "might" get them out by applying heat to the head to expand it's grip on the stud, then back out the stud with vice grips. My guess is that you do not have enough sticking out though to get a good enough bite on them though.

Like someone else said above, you should have used the "hot wrench" on the NUTS prior to attempting to remove them. Too late now, one way or another, (free hand or with a jig) you are going to have to drill them out now and with a jig, you might be able to save the original threads, if not you will simply need to install helicoil inserts.

I would not try using a screw extractor as if it snaps off inside the stud, you will not be able to drill it out. I have never tried left hand drill bits, but it sounds as if Supe has had some success with them and if it even backed one of them out, it would be worth it.

If you decide to change all of the remaining studs, please use heat on the head before trying to remove them unless you find the drilling process fun.

[dweymer]

Part number for the thread chasing set please...

[dlagerstrom]

Stock #: RTD15M

Here is a link:

http://buy1.snapon.com/catalog/item.asp?P65=&tool=all&item_ID=14287&group_ID=1147&store=snapon-store&dir=catalog

I guess it is $38.95 instead of $38. Sorry, I am starting to sound like my wife. "How much was that?" "Only $50." (59.99)

Like I said, the best money I have spent on any tools. I use these all the time. The set includes parts for internal and external threads. I chased all the old studs with the external thread part and it made assembly much easier. I am using these things all the time now on old fasteners.