Exhaust stud broke, Shold I just send them off to a shop? Options

[Kerrys914]

There is about 1/8"-1/4" of threads above the head?

Can I remove this myself with standard tools (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif)

[J P Stein]

It depends what you call "standard tools".
I have drilled out the stud undersized then re-tpped the hole.
It's one of these "don't try this at home deals" unless your confident (or deluded (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif) )

Another way is to weld a nut (standard tools?) on the stud stub, heat (oyx/ Acetylene) it bright red & unscew the sucker.

[DJsRepS]

Ive seen a good exaust shop weld on to the broken stud an old bolt and remove it. I do a little welding but would not even try this one. He used an mig welder for the dirty deed.... Thats a big ouch. I hope you get it out alright. Were you going on or off with the nut. Not that it matters I was just wondering.

[Kerrys914]

I was/am starting my shortened version of a teardown of my 911 engine. I was removing the 911 heat exchangers and it was the last one of 12 to be removed (IMG:http://www.914world.com/bbs2/html/emoticons/headbang.gif)

Since I don't know too much about the engine except "It ran well when removed" I was going to get it running and THEN do some test on it.

I might just send the head off to get worked on now. I have one price of $300 to rework the heads and install new guides.

Cheers

[IronHillRestorations]

I would weld a nut on what is left of the stud. If it breaks off flush with the head, that's probably where you'd end up anyway. Usually the heat of welding the nut on will break things loose. I'd probably want to replace all the exhaust studs at this point. You don't want to have some break when you put on the new exhaust, and then end up in the same place you are right now, only with the engine in the car, blah blah, blah.

Do not try to drill out the broken off stud with a hand drill! If you think you've stepped in it with a broken stud, you'll be in deeper if you FUBAR the head.

Generally speaking it isn't recommended to rebuild only one cylinder head. If for some reason the mounting surface of the head has to be machined in anyway, you've got to do all three head on that bank. The 911 heads all have to be the same deck height or the cam tower won't bolt up square, and the cam will end up in a bind.

Unless you've got the tools and experience to do so, I wouldn't remove the cylinder heads. This isn't to say that you couldn't do it, but you want someone there with you that's had some experience. The flat six has more critical assembly points than the fours, and it is easy to make a mistake that could cost you your engine.

Where did you get your engine?

If the engine is "portable", I'd think you could find a machine shop that could tackle this for you.

[sixnotfour]

(IMG:http://www.914world.com/bbs2/html/emoticons/agree.gif) A picture would help asses you situation., trying to replace them all is not that easy on a 911 motor, You will probably end up breaking more off.
I would replace only upon visual inspection deems neccessary. That's alot of studs.

[Eric_Shea]

(IMG:http://www.914world.com/bbs2/html/emoticons/agree.gif) with dem guys.

911 exhaust studs break. Too late now but, the best way to get them off is with a MAP torch. Heat each nut red hot and then remove.

Now... weld on a nut if you have a welder. As mentioned previously, the welding may help break the bond. If not. Heat it red hot and attempt again.

Re-studding is a great idea if you're taking all the heads in but it can be costly. Your $300 price is about average. You'll probably pay $8-10 per stud for the exhaust stud fix (IIRC).

What Perry said... if it's portable enough, get it to a machine shop. This will conquer you objective of getting it back together for a trial run.

[Kerrys914]

Thanks guys. I was going to send all or none to the shop. I don't undersytand the statment about NOT REMOVING the heads? (IMG:http://www.914world.com/bbs2/html/emoticons/huh.gif)

Other then the special socket, what special tools are needed? I am sending my heads off to a machine shop on the west coast. I will need to remove them and pack them up for shipping.

The engine is out of the car, never been in my car (IMG:http://www.914world.com/bbs2/html/emoticons/biggrin.gif)

Cheers

[IronHillRestorations]

QUOTE (Kerrys914 @ Dec 26 2004, 01:57 PM)

Thanks guys. I was going to send all or none to the shop. I don't undersytand the statment about NOT REMOVING the heads?

Removing and re-installing the heads on the flat six is a little involved. If you haven't done it before, the I wouldn't recommend going it alone. You must remove the cams, cam towers, chain tensioners and boxes, and the oil return tubes. Tools you must have include the cam nut crowfoot and cam socket to remove the adjustable timing sprokets on the cams, as well as a dial indicator and Porsche style holder to correctly time the cams when you put it back together.

If you don't know what I'm talking about then don't do it. I don't mean to sound like a jerk, but it's a expensive engine to learn on.

[J P Stein]

QUOTE (9146986 @ Dec 26 2004, 04:05 PM)

QUOTE (Kerrys914 @ Dec 26 2004, 01:57 PM) Thanks guys. I was going to send all or none to the shop. I don't undersytand the statment about NOT REMOVING the heads? Removing and re-installing the heads on the flat six is a little involved. If you haven't done it before, the I wouldn't recommend going it alone. You must remove the cams, cam towers, chain tensioners and boxes, and the oil return tubes. Tools you must have include the cam nut crowfoot and cam socket to remove the adjustable timing sprokets on the cams, as well as a dial indicator and Porsche style holder to correctly time the cams when you put it back together. If you don't know what I'm talking about then don't do it. I don't mean to sound like a jerk, but it's a expensive engine to learn on.

(IMG:http://www.914world.com/bbs2/html/emoticons/agree.gif)

It ain't rocket science, but it is a considerable undertaking.
It's also expensive.

My cost for having EBS do my heads was over 800 bucks.
A "top end rebuild kit" is around 200 bucks.
Tools alone (as Perry mentioned) are gonna be about 200 bucks.

Having said that, my first aircooled rebuild was my 2.7L.......but I *really wanted* to do one. It took me bout 6 months.....but it runs gud.

[Trekkor]

I like the idea of threading on a nut to what's left and filling the nut with weld to the stud.

Try it!

KT

[Maltese Falcon]

The weld-the-nut to the remainder of the stud works good. I use a wire feed mig, just make sure all areas are brushed clean of scale and get a good ground point close to the weld area. You may want to slightly hammer the stud with a small punch and jostle it just before wrenching it out. (IMG:http://www.914world.com/bbs2/html/emoticons/welder.gif)

[URY914]

Have you tried biting it? Yea, I mean with your teeth. This works on German beer bottles for me and I thought maybe it would work on a German car.

Maybe not, but worth a try. (IMG:http://www.914world.com/bbs2/html/emoticons/confused24.gif)

P

[Carrera916]

Ummm...

heat the stud/nut red hot to remove it??? Nah, that will BREAK off in no time....

what I did in the past, weld a nut on cleaned broken stud, just enough to make a bolt out of nut and stud.....then heat the side of the exhaust port where the stud is thread upward...just enough that it's a bit too hot to TOUCH, not melting or RED HOT....this will make the aluminum expand faster than the steel stud and pronto, use the socket, extension and ratchet....it WILL come out...oh yes, a punch and a hammer to jolt the stud first then heat the port side...

I had a customer who didn't want to take the engine apart when the exhaust stud broke off and it's absouletly flush to the stud hole that it was no way the nut or anything could be welded on. So we haul the engine to a place (cant remember now) where they had a tool very much like a plasma cutter but damn, it evaporized the broken stud! The stud hole was so clean that I was amazed and just retapped it along with new stud....

so, i hope this give you different option to correct your problem. Oh yes, if you have never taken a 911 engine apart, get help first cuz it's way beyond the simple T4 engine.....

good luck

j

[IronHillRestorations]

QUOTE (Carrera916 @ Dec 26 2004, 07:10 PM)

they had a tool very much like a plasma cutter but damn, it evaporized the broken stud! The stud hole was so clean that I was amazed

That would be a EDM machine. Electric Discharge Machining, I think it's called, and you're right it just vaporizes the metal, very cool. I've had some tooling made with a wire EDM, kinda like a very precise metal bandsaw, only with a very fine wire doing the cutting.

[Kerrys914]

Thanks guys (IMG:http://www.914world.com/bbs2/html/emoticons/smilie_pokal.gif)

I got a few 911 engine books over xmas (Anderson's, Wayne's two) and have a better idea now of what is needed.

I think I am going to get the correct tools and pull the heads myself. Who knows I may need these tools again if I build a larger engine in a few years (IMG:http://www.914world.com/bbs2/html/emoticons/smash.gif) (IMG:http://www.914world.com/bbs2/html/emoticons/smash.gif) (IMG:http://www.914world.com/bbs2/html/emoticons/smash.gif) I plan on taking some good and alot of photos just incase an issue pops up (IMG:http://www.914world.com/bbs2/html/emoticons/headbang.gif)

I now need to degrease the engine to get it ready for the tear down. The temp outside will be in the 40's on Thursday so I should be able to get the hose working again (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif) The water doesn't flow too well at 13F (IMG:http://www.914world.com/bbs2/html/emoticons/sad.gif)

Thanks again..

[Root_Werks]

Good luck Kerry, the exhaust studs can be a real pain. When I installed my six in my 914, I replaced most of them that looked questionable. I recently had one break off on me and found out a PO had put in a timesert that had stripped out. While drilling the hole out for an even larger time sert, there was a small piece of drill bit still stuck up in the hole I didn't see. Kicked the drill to the side and now I had a HUGE hole on my hands. (IMG:http://www.914world.com/bbs2/html/emoticons/mad.gif) Unless I wanted to pull the engine and weld it (Lots-o-work), I would up making my own time-sert out of another bolt. Anyway, guess I am saying take your time with it. It is only one broken stud, don't make it 6! They can be a PITA! (IMG:http://www.914world.com/bbs2/html/emoticons/ohmy.gif)