Safe to Heli-coil AC bracket to cylinder head?

[Olypen Guy]

I work as a welder @ a machine shop. We extract bolts like this all the time. We weld a flat washer to the stud, then a nut to the flat washer. We do this with a TIG welder, and weld it with 630 inconel. In your case, I would fill weld the broken stud with 630, so I could tie in the flat washer to the stud. Then weld the flat washer to that 630 build up on the stud, then a nut to that washer. Let it cool for about 10 mins, and unscrew it. With the broken off easy out in there, you will never drill that out because it is harder than the drill bit. As mentioned above, find a machine shop with a good welder that can do this for you. The biggest issue will be seeing to weld in there. You have to be able to see it to weld it, and this means with a welding hood on. As for a heli coil , you still have to get the stud out of there, but if you mess up the threads, then yes that will work. Also, you will want to chase the threads with a tap before you put new bolts in.

I had originally thought about doing just that. But I'm concerned that the bolt is broken just far enough in the hole that I won't be able to get a good weld without messing up the beginning of the threads. At this point it might as well be worth trying though. If I have to Heli-coil it and there's a little bit of filler metal added in there, it just means I have to drill away a little more material. I'll have to get a Cobalt bit to drill out the busted piece of easy out, tried shattering it as a last resort to no avail. May try a small bit and drill a hole at each corner of the easy out to see if I can relieve enough tension since Cobalt bits are spendy as hell. Now I just need to find a Tig setup that I can get to my place for a bit...

 

[Olypen Guy]

Drive it to a welding / machine shop. They'd probably well a nut on for next to nothing. Worth a shot to call and ask

Not an option to drive it right now. It took several stops to cool down just driving it 4 miles back home. Took over 2 hours.

 

[Olypen Guy]

If you are feeling brave, get some long jumper cable and a battery. Set the battery downwind, ground battery to head, clamp a bolt in the jumper cable. Then press bolt end to the broken stud. if all works well you have a bolt welded to your busted stud.As a plus its all hot n toasty so hit it with a can of dust off to shrink the stud and crank it out!. *result may vary **safety certainly not garunteed

I've heard of battery welding, but have never brought myself to try it. LOL

 

[Olypen Guy]

Your not to be able to drill a easy-out out of it. You'll end up drilling along side of it. Not sure how you're going to solve that. maybe take a punch and tap on it and get it loose. It's really going to need edm'd. The method I use is to center punch the broken bolt, start drilling with a 1/16 or1/8 bit paying attention to depth and keep stepping the bit size until you get to the size bit for the tap. Tap it. 9 times out of 10 it will tap clean and your good to go. If not then go to the heli-coil. I actually prefer Time-serts or thread-serts over heli-coils. I quit messing with easy outs after I broke a couple.

Before this one, I swore I would never deal with easy outs again... But being on hard times money wise, I had a lapse in judgement. LOL. I have tried just about everything to get that busted piece of easy out to come free short of drilling it with a Cobalt bit. I think I will try a small bit at each of the 4 corners, as close as I can get to the easy out and see if that relieves enough pressure from the biting edges.

 

[Kirth Gersen]

.... In your case, I would fill weld the broken stud with 630, so I could tie in the flat washer to the stud. Then weld the flat washer to that 630 build up on the stud, ...

What prevents the welding rod from also melting & attaching to the cylinder head, instead of just the broken stud?? The stud is recessed below the surface of cyl head.

 

[kennythewelder]

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What prevents the welding rod from also melting & attaching to the cylinder head, instead of just the broken stud?? The stud is recessed below the surface of cyl head.

Not to be an ass, but if you have to ask this question, then you don't have the skill to do the job. First off, the weld won't stick to cast like it will steel. Also this is why it needs to be TIG welded. A good TIG welder can weld the bolt without getting weld metal onto the outer threads. This is why you build up weld the bolt first. So that you will have weld metal sticking out of the hole. Then you have some metal sticking out of the hole to weld a flat washer to the bolt, then a nut to that flat washer, TIG allows a very fine ,small strong weld, that will hold up to the torque needed to extract the bolt. All that is needed is a little weld bead that can be tied into a flat washer. Then a nut welded to that flat washer after it is welded to the bolt. This gives you something to put a wrench or socket on. I did this on a blower for a car wash yesterday. The bolt was broken off with nothing sticking out just like on your head. Next thing is we have to correct tools and equipment to pull this off. Hell my welding helmet cost over $400, it is one of the best welding helmets made.

 

[Bob L]

In my opinion there is no such thing as an easy out.

 

[Shaun Anderson]

You will not be able to drill the hole with broken easy out. I am very cautious using easy outs to extract broken bolts for that reason. Most of the time I've found easy outs not able to extract and I skip that method all together.

I usually weld a flat washer to the busted off bolt, then a nut to that. I only have a wire feed welder with flux core wire to weld with and it works pretty good. TIG method would be much better. Even if the bolt is broken 1/4" below the surface I've been successful filling the hole with weld till it gets to the washer. The cylinder head is a giant heat sink, so the weld doesn't bond to the threads, just fills the hole. Once the washer is welded, then I weld a nut to it and attempt to wrench it out. 1/2 the time it works, other half it just snaps the weld, most likely due to weld contamination from using flux core wire.

I like the suggestions about chilling it with canned air. Rapid super cooling has to help, though it would serve to make things brittle. I'd use caution with the canned air, because liquid R-152A (canned air) is flammable in liquid and vapor form. And if it does ignite, do not inhale the vapors. They're quite toxic.

 

[kennythewelder]

I have the best boss I ever worked for. It takes a lot to make him mad. He is also the owner of out shop. But the one thing that will set him off, is if someone uses an easy out. There is nothing that will cut an easy out. No drill bit, no tungsten carbide end mill, nothing will cut an easy out. Guys keep in mind, I work @ a machine shop. When we do get a stuck bolt with an easy out broke off inside of it, ( because a customer used one) I weld a flat washer to it, then a nut to that. That is the only way to get it out, unless you get lucky enough to brake the easy out into peaces so that they can come out like that. The real issue with the head that has the broken bolt in it, is not that the bolt is recessed, the real issue, is being able to get to , and see what you are doing, to weld it. You also need to have a steady hand while welding the bolt, along with being able to see the whole weld puddle all the way around the bolt, while you are welding it. If the head was off of the engine, it would make things a lot easier.

 

[Olypen Guy]

Kenny, agreed 100%! To top it off, I have not been able to locate a power supply. Tig is what I'm trained in, but there's just not good sight and room. I've got everything together now, and will be pulling the heads this weekend with any luck. Just really wish I had the funds to swap out from the TBI heads while I am going this far... Oh well! Got to get the truck back on the road one way or another and finding time to work on it is of a premium right now.

So much for trying to save a buck when I knew better in the first place! Hahaha