Technical Broken head bolt

Mine had to soak one month and some change. See the yellow straw in the head bolt area ? Used 3/4 can of Kroil, and a third quart of 50/50 ATF/acetone .... over the five weeks. Sh#t, mine was a new motor supposedly. Popped the cover to adjust valves ... thought it was MISSING a head bolt .... NOPE .... broken during assembly. GRRRR .... I bought it from some rat bastard cheat .... obviously. So who knows ?

In agreement on sh#t EZ outs. Yeah, don't use those on head bolts. Not designed for it. Buy great bits. Not cheap .... but you'll be driving. Is what it is.

 

when i was a kid i did a head gasket on a chevy 250 in my dads old pickup. i torqued all the bolts down and was about to start putting the push rods in when i heard a creak......then a crunch, pop, crack and one of the head bolts shot out of the head hit the hood and flew over my head. it had snapped flush with the block but after removing the head, the broken piece unscrewed using a dental pick.

 

Working on flathead Fords for decades you learn a few things. I have broken my share of head studs. I have soaked them for months in every known substance prior to starting work. Heated them repeatedly with a torch. (This does have some value.) Used a very expensive Snap-On collet type stud extractor with a torque wrench set to 75 ft/lbs. They usually break at 80. These days I still try the pre heat, soak in Kroil and then use one of the stud extractors that has an eccentric knurled ring that pinches the stud. Give each stud a good pull and some will come out. Those that don't I weld a 1/2 inch nut to the stud top and bottom with a MIG. That puts a lot of heat into the stud, then let it cool. Take my impact and turn down the air pressure so it just tap, tap, taps clockwise to start then counter clockwise then repeat. If still no activity up the pressure a small amount and repeat. This will usually break them free. I then put down the impact and use a hinge handle and go back and forth, increasing the counter clockwise rotation a small amount each cycle. Add some more penetrant as you go. This will usually get them out. If i should snap one off I use the welded washer, nut trick. A TIG would be best for this as you can more easily control the heat and filler, but I only have a MIG. I have found that turning up the heat and slowing down the wire will give the best result. It may take several, sometime many attempts but have never failed to get one out. Just my .02.

 

I used to wrench on a fleet of Ford F350's with 460 engines. They would routinely break exhaust manifold bolts, usually at the rear where they were hard to get at. I never got one to come out and usually had to drill the hard suckers and re-tap.

 

Once had a head bolt broken off flush on a small block. Guy came over and blew it out with a torch! Could not believe it--worked fine.

 

Went by my buddies house yesterday he gave us a 350 motor with trans that's what my girl really wants but honestly I think the 6 has more of a cool factor

 

Just keep at it.
I have had to do that more than 5 times.

 

You can soften the bolt by heating it cherry red then turning the torch down and keep enough heat on it so it cools slowly.

I have used a mini 90 degree angle die grinder and a carbide bit in tight places.
Harbor Freight has one for $14 and diamond bits for $9

 

I use the washer and nut method myself. I use a Lincoln buzz box welder with a 6011 or 6013 rod. Weld washer to stud, then weld nut to washer. I then put the impact on it just as it changes color from red to black. I bump it tight, then loose, then tight, then loose, never more than a short burst at a time. It may take 3-4 times welding the washer and nut on. If the bolt is below the surface, they sell a rod that won't stick to the cast block or head. Expensive, but they really work. I used about 20 of them on some 1/2" bolts in a farm tractor that were broken below the surface. Got 7 out of 8 out, the last one I finally gave up on. Oh, I did soak them all with PB Blaster, about a can.

 

Yes. Left hand side of the car has left hand lug nuts. There's an "L" stamped on the end of the wheel stud. I had the privilege of replacing wheels after someone just about pulled the lug nut through the wheel by going the wrong way....

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Have done this several times at work but not on an engine. Need to to get the stud red hot without heating the surrounding metal. Using the correct size cutting tip is real important.

 

^^^ the guy that blew the broken headbolt out of my 406 small block with a torch did it with no issues-I was amazed!!

 

AT the risk of sounding like a jerk, I would remove the flathead six, and install an engine with two more cylinders. I know I'll probably get flamed for this, but everyone I know that had one of these in a car when I wore a younger man's clothes, either got rid of the car, or swapped in a v8 as soon as they could afford to do so. I know there is quite a following for these flathead six engines here, and I really don't understand why. But that is just me, I guess. Flame away, but that's my two cents worth, even though you didn't really ask for it. Make your daughter happy.

 

You likely have never driven a good running flathead. super smooth idle. and yes they are not fast engines. But the days of everything being high HP and gas guzzling are over for many of us.

 

When I worked in a muffler shop I did this all the time on broken off manifold studs. There is a knack to it. If you know someone who works in a muffler shop they can blow that stud out in a minute. I would save this for a last resort.

If you use an easy out get the straight kind not the screw kind. I mean the square straight easy out. Drill the bolt, heat it red, tap the easyout in and unscrew it. Used to do this too on the Chev V8s that had tapered spark plugs. The metal was paper thin and if you left them in too long they would break off. You had to cut or drill thru the inner fender well to get at them but saved the customer hundreds of $$$ bucks by not taking the head off.

 

A lot of suggestions and some are not too good. Welding a washer and or nut on a head bolt is not a good idea. A head bolt is basically a grade 8 bolt and the heat will destroy the properties of the metal. This is why your weld breaks at the point of fusion. Melting and blowing out the bolt would work but I would only use this method if the engine was out and laying on it's side. The molten metal has to go somewhere and in your case, it will go up and everywhere. If you break you drill bit or easy out off in the hole, you've just made your job harder by about a factor of 5. I would just start by center punching the bolt in the middle so the drill bit can start drilling straight without walking all over. I would do my best to rent or barrow a mag drill so you can make sure the whole is straight and you can turn the speed down real low. Use a good cutting oil and back the drill out of the hole every 1/8" and blow the chips out. You need to drill all the way through the the bolt. You could start with a 5/16 bit and then go to a bigger size such as 1/4 to use with the easy out. Once you get to the easy out, if the bolt turns at all, stop and use more penetrating oil. You need to make a number of back and forth motions to free up the bolt. Use a thread chaser and not a tap to clean out your threads prior to using new head bolts.
Picture of a mag drill if your not familiar with one.