Exhaust manifold bolts...cont.

How long should I wait for the exhaust manifold studs to cool before trying to get them out?

And if they brake inside the block, besides welding a nut on what is left of the stud, my only option is to drill them out?

Good times...thanks for the help.

Robert

Read your earlier post, I don't think you'll have to wait on them to cool completely as they should not be heated to more than a real dull orange for the most part. Take your time with each step when trying to work them out. The heat and some impact if you can without causing any damage if the old ones are to be salvaged, ought to eventually work. Welding a nut on the protruding shank or flush if broke off, (you will have to shield the block with something like copper or washer so it does not fuse to the cast) is better than drilling and or using an easy out or extractor.

If you have to use anything like that, use lots of care, take your time and do not put excess force on it, meaning don't break it off in there, lot harder to drill those out. I don't particularly like these, but have used them successfully many times, they are risky. If broke flush, but the face of the break is jagged, its not easy to strike a center punch in the center to align the drill bit into the middle, in my opinion you need to center punch and dimple it in the center to align the bit so it only drills the shank of the bolt. Start with smaller size bits and work up to larger ones. There is also the method of using a reverse drill bit, or drilling until its thin, use the cutting torch to help free up the thin remains and not damage the threads. Some of this is better for experienced hands. I'd stay with the heat and maybe welding a nut, get a good bite, work both directions, but not in excess, if it is week, its likely to break, but most times its when too much force is applied, vs taking your time, heat, penetrant or something to wick in, though I think heat does most of it as often times I see no sign of any penetrating oil wicking in. I have wicked in anti- or nevr seize on coarse threads when hot.

With the manifold warm, and the stud cooler, then expansion, and contraction can help. This is very hard to achieve! As you said welding on a nut helps, but you should let the stud cool, after welding on the nut. There again , you will have expansion on the stud, with it hot, and that is the oppisite of what you want. Using a center punch on the stud, and drilling a hole thru, and then using an easy out, may do the job. If using an easy out, it is imperitive to have your drilled hole centered.

If you can touch them that's good, I'd double nut them and give them a couple medium raps on the end with a hammer. Main thing is don't get in a hurry and snap one off or your in for some grief.

I have removed many over the years. In agreement to most replies and can only add---after heating the studs to an orange color, let them cool completely. Welding a nut will also heat the stud and then heat nut and stud.
Carefully BACK AND FOURTH while removing with lubricant (WD40) or your choice.

They talked about the physics of this on Car Talk one time. The theory being that it's hard to heat the stud or the piece that it's screwed in to,without heating the other part. In other words,you can't really heat one to get expansion without heating the other and that all heating really accomplishes in the long run is to loosen the rust or other particles bonding the two halves together.So if they remain nearly the same temp through the process,letting things cool until strength is returned to the stud is about the only goal.

I like to double nut them after heating around
the stud, then rap on the end of the stud with a
hammer a few times. Quite often that will help
even with no heat, just have to hit it square on
the end. If you do all this and don't get one out,
and accidentally DO snap one off in there, just
use oxy acetylene torch to blow remainder of
stud out of the hole. The stud will always melt/
cut out of the hole before you melt the cast iron.
Also is much easier if you drill a hole 1/4" or so
through the stud before you use the torch, it
takes less time to pierce it out of there. With a
good dark shield, you can look right in the hole
and see the threads appear as the stud melts
away. Usually have to stop and chip slag out of
the hole a couple times before you are done.
Run a tap through down the hole, insert new
stud with anti-sieze, done. Most people are
afraid to try it, but it works very well. I used to
do this all the time removing broken lower roller
bolts on dozers and excavators. Some through
holes, some blind holes, most in steel track
frames. Had 17 broken bolts on one side of an
excavator that had been broken forever that I
had to take out one time. Good luck

Ross

didn't read all the replies but multible heating and cooling is best and the faster you cool the better

(quoted from post at 13:26:03 05/30/15) I like to double nut them after heating around
the stud, then rap on the end of the stud with a
hammer a few times. Quite often that will help
even with no heat, just have to hit it square on
the end. If you do all this and don't get one out,
and accidentally DO snap one off in there, just
use oxy acetylene torch to blow remainder of
stud out of the hole. The stud will always melt/
cut out of the hole before you melt the cast iron.
Also is much easier if you drill a hole 1/4" or so
through the stud before you use the torch, it
takes less time to pierce it out of there. With a
good dark shield, you can look right in the hole
and see the threads appear as the stud melts
away. Usually have to stop and chip slag out of
the hole a couple times before you are done.
Run a tap through down the hole, insert new
stud with anti-sieze, done. Most people are
afraid to try it, but it works very well. I used to
do this all the time removing broken lower roller
bolts on dozers and excavators. Some through
holes, some blind holes, most in steel track
frames. Had 17 broken bolts on one side of an
excavator that had been broken forever that I
had to take out one time. Good luck

Ross

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If I decide to drill out the broken off stud, how do you prevent prevent fragments from falling into the unknown. I don't have he engine off the tractor.

Thanks.

I have had good success also using the cutting torch to blow out broken studs in cast iron, never tried it in plain iron. it may be a little more tricky. The hole first is a good idea. stan

My dad always used bees wax for this, swore by it especially on ex manifold bolts, I use it sometimes still, doesn't seem to evaporate as fast when heated. Also, Boeing makes a product called Boeshield they use on thier planes as a fastener protector, spendy, but works wonders also, main ingredient...bees wax

Anybody ever try the can of spray freeze to super cool and shrink rather than heat and swell? I plan to next time I have a fight on my hands...heard good things

(quoted from post at 18:36:53 05/30/15) didn't read all the replies but multible heating and cooling is best and the faster you cool the better

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Yessir, that is correct.

Candle wax has never failed me.......

Ditto on [b:09879eb635]RBoots[/b:09879eb635] post.

Why let them cool? Get 'em red hot and grab 'em with a Vise Grip. Hot bolts come out as easy as a hot knife cuts through butter. If they start to get hard to turn, apply some more heat.

torch always worked best in our shop.

You can put heavy grease on the bit and turn
turn it slow so the grease won't fly off. Not
usually a problem on manifold bolt holes in a
head as I've never seen one that wasn't a blind
hole. It would be a different story if you were
drilling, say, over an open intake or such. Stuff
holes you don't want slag or drillings in with
wet rags, and cover things you don't want
melted/pitted with wet rags, especially cover
glass. A couple months ago I had to blow 4
broken studs or bolts, not sure which, out of the
passenger side head, of my cousin's 99 Chevy
pickup with a 454. They had been broken off for
about 10 years. Only access I had was through
the fender well, what a pain. Had to lay wet
towels over the fuel lines and wiring harnesses.
Took quite a while as after I blew the four holes
out, my cousin bottomed out a tap and broke it
off in the hole, then broke another off in a hole,
that tap had clearly been cracked halfway
through for quite some time.

Ross

(quoted from post at 00:25:45 05/31/15) [b:aa9be63ee3]Why let them cool? [/b:aa9be63ee3]Get 'em red hot and grab 'em with a Vise Grip. Hot bolts come out as easy as a hot knife cuts through butter. If they start to get hard to turn, apply some more heat.

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Hot bolts twist off a lot easier than cold bolts. That's why.

K, I have used it with amazing results in at least two instances. A plug on a final drive hub would not come out. A strong young man could not turn it out. I took my freeze can and sprayed it for a respectable length of time and it turned out very easy.

I tend to give it a good long spray to get it cooled down good.

Paul

I don't recommend you do it that way if you have never run a torch before though. It's pretty easy to burn your threads out as well. Use a somewhat smaller flame too. Most guys who do that with a torch seem to think the bigger the flame the better.

(quoted from post at 17:08:27 05/30/15) I have had good success also using the cutting torch to blow out broken studs in cast iron, never tried it in plain iron. it may be a little more tricky. The hole first is a good idea. stan

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I third the idea of drilling a hole first before using the torch. Seems like the inside of the stud will blow out of there first and it will work out to the edges. Sometimes if I'm worried about nicking the threads with the torch I will drill the hole, blow a little out with the torch and then try an easy out. If the easy out doesn't do, and it should because now the whole stud is red from top to bottom, I then blow it out the rest of the way with the torch.

This just got me to thinking, which is dangerous, maybe just drilling the hole and then blowing a fine flame inside the hole with a small brazing tip to try to heat the stud clear to the bottom, then cooling and try an easy out. I have a couple of broken exhaust studs on a Dodge 360 to reluctantly tackle some day. I might give it a try on that project.

One difficulty that I have found with this method is that the molten metal from the stud blows right back onto and into the torch head. Found it to be just a bit rough on torch tips. BUT.....it surely does work!

(quoted from post at 15:38:56 05/31/15) One difficulty that I have found with this method is that the molten metal from the stud blows right back onto and into the torch head. Found it to be just a bit rough on torch tips. BUT.....it surely does work!

Click to expand...

Yep, you start with a clean torch tip and you have to re clean it when you are done. One of the disadvantages to doing it with a torch.