busted off bolt in engine block

This didn't happen to me, it happened to a friend of mine today. It
reminded me of the kind of stuff that used to happen to me when I worked
on cars a lot many years ago. Anyway, he is trying to fix a big exhaust
leak in a Chevy 2.8l V6, and he discovered that one of the exhaust
manifold bolts was broken off. He tried to drill it to get an EZ out in,
but the 1/8" drill bit broke off, about 1/4" of it. Now he's really feeling
depressed. Is there any solution short of EDM? He doesn't want to pull the
engine if he can get around it. He needs to sell this car.
Grant Erwin
Kirkland, Washington
Reply to
Grant Erwin
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The mistake was to try drilling it. It's often best to weld a nut or a bolt onto the broken end then take it out in the normal way with a ring spanner.
Reply to
Pipper
You need to get a better opinion on this than mine, but I thought the standard was to burn it out with a torch. A cutting torch will not touch the cast iron, but it will eat the steel stud. IIRC.
Jim
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Reply to
jim rozen
Well, it depends if it broke off flush with the head or not. If it's still proud, remove the exhaust manifold on that side to get access to the end of the stud. A good tip given to me by an engineer who works on farm equipment is to wrap rags around the seized bolt /stud and soak it in diesel. Leave it 24 hours then use a stud extractor to pull the stud. I didn't believe it until I tried it and was most surprised to find how well it worked. Taking 1 head off isn't a huge job compared to pulling the engine, so even if it is beyond what can be done at home, it's still feasible. Martin.
Reply to
Martin Whybrow
I was thinking the same thing. Did it for an unfortunate young man last Xmas and it works really well. That *is* a cast iron block he has?
michael
Reply to
michael
Grant Erwin wrote in news: snipped-for-privacy@corp.supernews.com:
Get a handfull of carbide drills. NOTE: if he breaks a carbide drill off in there....he will most definately have to pull the head.
Reply to
Anthony
This motor is in the car. You are seriously suggesting you get down under the hood with a CUTTING TORCH? Whoa.
To the other respondents: no, the bolt isn't sticking out, not any.
Grant
jim rozen wrote:
Reply to
Grant Erwin
I tried a suggestion I saw here recently to drill out a broken ez-out- I used a cheap carbide tipped masonry hammer bit and sharpened it, drilled a bit and then sharpened some more. I also used a carbide deburring bit in an angle grinder and that actually worked pretty well too, especially to get a hole started. Next time I'm using left-handed drill bits instead of ez-outs.
Reply to
ATP
I think at this point one either has to deal with the busted off drill in the stud, by heating it with a torch, or performing the cutting torch operation, or removing the motor from the car and working on it on a stand.
Or simply ignoring the busted off stud, and using the ones that remain.
I had a close friend who drove his opel cadette for years with one end of the exhaust manifold held in place with a C-clamp.
I have personally never done this (torch out a stud while the motor is in the car - maybe somebody here could advise if this is feasable, and what sensible precautions one would take.
I have drilled out studs in awkward places, but I've been quite careful to use a larger than average pilot drill, and to not snap same off in the stud. Or the tap drill, or the tap.
Jim
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Reply to
jim rozen
If he snapped off a HSS drill, he won't have much luck with carbide.
IMO trying to do a HSS drill with a carbide drill, in an offhand situation, *will* lead to grief. This can be done in a milling machine, with a carbide endmill, but by hand? Don't think it's a good idea to try.
Jim
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Reply to
jim rozen
if you talking about the two bolts that hold the pipe to the exhaust manifold they sell what looks like a small C- clamp that goes over the are to hold the flange to the manifold with looks like a small C-clamp with a bolt on it.. think i saw it in the J.C.whitney catalog... look it up and then you know what it is called and then do a search for it and see where it can be located locally......
Reply to
jim
imo, no big deal, I was removing a timing belt cover on a ford 302 and the bolt has rusted at the block surface and broke off. Thought I was screwed after breaking off a drill bit in the 5/16th bolt. I used a solid carbide square die drill from mcmaster carr. Cost me 25 bucks. It went in like butter and then broke. I was horified and pissed. And said "F it", and cleaned out the broken carbide fragment and using the broken tip drill finished it up. It did so well I didn't need to use a helicoil as I had planned. Since only the very tip does any cutting it won't eat up the threads if you should vear off. I went for broke and just shoved it on to the broken original bolt and HSS drill and did my best to hold it straight. Worked like a charm in light of pulling engines and whatever else to remove it. You will be amazed how easy it cuts thru the bolt or HSS.
hope this helps
Reply to
V8TR4
Get out your Dremel and a diamond burr. You should be able to burrow 1/4 inch deep in the stud so that all of the bit is ground out. Be aggressive in removing metal. Who cares if you mangle the top one or two threads in the head. It will clean up with a tap. This might take up to half an hour, and cost a couple of burrs. But you will have the bit out and a starting pit to drill a bigger hole for a more robust E-Z-Out. The other tips regarding heating and a soak in diesel oil or other penetrant still apply.
A bolder approach (used by farmers and rednecks who've never been told you can't do this) is to clamp a nut over the broken stud. The nut should be smaller than the stud -- say 1/4 inch nut over a 5/16 stud. Then weld them together by striking an arc at the bottom of the hole and welding your way out. All over, for better or worse, in about five seconds. Open a can of your favorite refreshment. You will only need one spoonful of beverage to cool the new weld, so dispose of the rest in an approved manner. Say a couple of prayers, and apply appropriate wrench to the nut.
Pat
Reply to
JWDoyleJr
If it is a manifold bolt on a 2.8 it is also not in the engine block. It is in the cyl head. Pull the head and take it to a machine shop with the equipment to remove it. Carefull taking off the head so you don't snap one of the torque to yeild headbolts (comm>> >>
Reply to
clare
I worked in a garage for about ten years- burning out broken studs/bolts on the engine is SOP.
-Carl
Reply to
Carl Byrns
Second that to get the first drill bit out. Been there. Use a Dremel abrasive disk to cut slices into the top of the stud (or perhaps the burr to depress a centered hole) to center a new drill to resume drilling out the old bolt. Get the Heli-coil kit with the drill bit; this will be a good quality bit that should reliably drill out the stud with lots of coolant. Then you Heli-coil the hole. This will take some hours, of course.
Reply to
Richard J Kinch
The torch trick does work, but it is no job for an amateur. A staring hole is a great help, as is a through hole to give the junk someplace to go. (Works great for bolts that go into the water jacket) But a blind hole stuffed with a broken drill is sure to send a blast of molten steel right back in your face.
I would only tackle this one with the head off. Only takes a couple of hours to get it off if you are determined.
jim rozen wrote:
Reply to
Roy J
A couple of things that may help this approach: A small cardboard washer between the nut and the block gives the weld someplace to shrink to. It WILL burn up, don't become emotionally attached to it. A wire feed machine, with 0.9mm wire is a bit easier to use for this method, as compared to stick electrode. You also _NEED_ to put the earth (ground) clamp as close as possible to the area you will be doing the welding. Stray electric currents are a bad thing for bearings.
Reply to
Wayne Bengtsson
"V8TR4" planned. Since only the very tip does any cutting it won't eat up the
Can't locate a "square die drill" in the McMaster web site. Just trying to learn from this thread.
Also, I'm curious as to why a cutting torch won't harm the cast iron engine block. What is the science involved here?
Lane
Reply to
lane
Hi, sorry I didn't give the part number
8839a16
that is for a 1/4" diameter.
doa search for that part number in mcmasster site and then view the catalog page. or go straight to page 2280
Good luck
Reply to
V8TR4

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