Broken / Frozen Exhaust Flange Bolts

[buickyouth]

what a revolting development this is!

Alas, friends, I have terrible news.
One of the head bolts broke off flush with the engine. I'm not sure what to do at this point. Some people have told me to scrap the bike, others think it's not that big a deal and I'll be able to drill it out or something.

Whats the consesnus of the guys and girls of course here?

Are there any ways to get this thing out that won't cost me a bundle?

Please respond.

[fredintoon]

helicoil!

Hi Ian,
doncha hate it when that happens?
There are removal tools for busted studs but I'd advise against using one. They have a left-hand spiral and you hammer them into a hole you drill in the end of the stud and twist. But they are harder than any drill-bit so if one breaks off in the stud there's no removing it and you are totally f**ked.
Best you drill out the stud's broken remains and salvage the thread in the cylinder head with a Helicoil or a Time-sert. You can do this with the engine in the bike if you are careful.
Fred Hill, S'toon.

[dwales]

You won't believe this. I bought one of those stud removers at a garage sale last summer for 25c. The guy didn't even know what it was!

[lsippell]

Broken off*?!@%#!

I had one break of in the head of ths xj I'm rebuilding. I drilled it out and used an extractrer. It not only removed the broken stud, it broke a chunk out of the boss the stud was monted in ( it is tapered and as you screw it in, it puts a lot of pressure against the wall of the drilled out stud).

I salvaged it by having it welded up and then I redrilling and taping it, but next time would drill and helicoil it.

Louis

[Ken Talbot]

With a bit of patience, you can grind out most of the broken stud with a diamond or carbide burr in a Dremel tool, then twist out the remining shell with an appropriately sized extractor. This might be easier than trying to drill enough of a hole with a regular drill and bit. You only want to be careful not to try to do this with too small of an extractor. If you get cranking on a small extractor and break that off, you'll really have your work cut out for you. DAMHIKIJD...

[randy]

Or you can drill it with a lefthanded bit and part way through it will begin to back itself out.

The trick is to get your hole exactly centered in the stud so you don't rip any threads out of the head. the best way to approach this is to start with a very small bit, so it's easier to center it. Then, progress to larger sizes. When I have to do this, I usually do it in three or four steps with increasingly larger bits.

[randy]

OOPS. forgot to add the source for the left hand bits:

Toolsource.com

Take your time and it can be done!

[DiverRay]

I agree with Randy, The left hand bit and a reversable drill has saved my bacon more than once. Use the dremel to get a center start dimple for the drill, and go slowly with cutting oil on the first bit. If you use a propane torch to warm the head up, it should help. I usually get the start dimple on the flat broken stud, warm up the head, apply penetrating oil, and drill. This has worked a few times for me, and saved a lot of cash. You may need to retap or helicoil when you are done, but just go slow, keep the head warm (about 200 F), and use oil.
Good luck!!
Ray

[Dan Hodges]

Re: what a revolting development this is!

Originally posted by buickyouth
Alas, friends, I have terrible news.
One of the head bolts broke off flush with the engine. I'm not sure what to do at this point. Some people have told me to scrap the bike, others think it's not that big a deal and I'll be able to drill it out or something.

Whats the consesnus of the guys and girls of course here?

Are there any ways to get this thing out that won't cost me a bundle?

Please respond.

You are only one of many that has experienced this nightmare.Before you screw it up completely,take the head off and have a competent welder weld a bolt to what's left of the headstud,heat it up and back it out. That works 99 percent of the time.If that fails, it can be placed in a jig and drilled out with a drill press and carbide bit.Vice grips have ruined more things than any one thing I know of.

[erithanis]

ok, so I'm more likely to be able to get my hands on a blow torch than a competent welder. A previous post explained how to heat up the bolt and use penetrating oil, but I don't know how I'm supposed to make sure I don't go over the described temperature.

[DiverRay]

Just leave the end of the flame on the aluminum for about 5 seconds, then move it to another spot. If you heat up the INSIDE of the exhaust port, you don't have to worry as much. The aluminum will transfer the heat quickly, the steel stud will hold the heat. the idea is to heat the aluminum head, cool the stud with a shot of oil, and then try and back the stud out.
Plan on running a tap through ALL the holes, to clean everything up BEFORE installing the new studs. And so you know, the newer Chevy small block exhaust stud is an 8mm!!! I have one on daily ride....

[erithanis]

So far the rest of the threads have been pretty good and so I'm nervous about ruining them if I use a tap. I've never done that before. Anything I should know about in advance?

[thewiz]

What Randy said about the drilling .... center punch as close to the center as you can and start small working up to a drill size that is just slightly smaller than the threads in the head.. You don't want to drill any threads. Often by the time the hole in the broken stud gets big enough you can take a small screwdriver or an awl and collapse the remaining threads into the hole and either unscrew 'em or just pull 'em out with some needlenose. Patience is the key.

[AlanB]

Hi erithanis,

If you can get the bike to someone who welds, just hold an 8 or 10mm nut over the end of the broken stud and weld it onto the end. Heat of welding will "unfreeze" the stud, and you can then unscrew the stud with the nut. If the stud is flush with the head, then just blob a bit of weld on the end to build it up a bit so that it sticks into the centre of the nut.

The welding does not need to be particularly good; If it breaks off, just weld it back on, as often as needed.

Weld obviously does not need to be neat; once the stud is out, you will throw it away!

The weld will not stick to the ally of the head, and cannot do any harm; drilling studs out without damage is extremely difficult, and if it goes wrong, you are left with a much bigger problem. Don't get involved with drilling unless you have a way of dealing with the aftermath!

Best of luck!

AlanB

[Dan Hodges]

Studly

I will second Alan's motion on removing the stud by welding as this is by far the easiest and cleanest method. Several years ago I tried to remove one with some Vice-Grips and butchered it up so badly I was unable to weld a nut onto it and had to remove the head. I then placed the head in my drill press and drilled out the remaining portion of the stud with a carbide bit. It has been my experience, that you cannot drill out a stud with a hand held drill or a cheap hardware store (Stanley) type bit as the stud is harder than the bit and you will butcher the hole 99% of the time. After I removed the cantankerous little stud, I tapped the stud hole for a Time-Sert threaded insert. It all worked out nicely but taught me never to try and get one out with the Vice-Grips ever again. If the studs have been in the head for several years but not broken, they are almost grown to the head. I remove them by first installing two nuts locked together, then heating them with a propane torch after which I strike them slightly on the end with a hammer and they back out without a problem. The stock studs are junk but you can get aftermarket studs that are made of grade - 8 material which doesn't have the tendency to break after being subjected too heat like the stock and cheap aftermarket ones which are usually grade-4-6 or less. If you are doubtful as to the grade/quality of the studs because of the lack of any markings, you can buy commercial grade 8 bolts of the correct size and thread design and cut them to the correct length and in this way you are assured of a quality stud that won't break off. While on studs, don't use stainless steel exhaust studs in aluminum heads as stainless has a tendency to seize in this application, ditto for chrome nuts. When you install the studs, you can use a drop of "blue" Lock-Tite which will prevent them from loosening up for the first few miles after which the heat will devour the Lock-Tite and they won't come out. I installed a set one time in my FJ using anti seize on them and had one of them come out on a road trip and so I have used the blue Lock-Tite on them ever since. Broken exhaust studs rank right up there with a broken heart however Jack Daniels will cure a broken heart but broken exhaust studs will be there when the morning comes.