c169 head studs, trying again

Well that was interesting. Posted this last night and the entirety of the text disappeared. I tried to make this as short as possible, but there is a lot to relate...
Trying again-
I recently purchased a 300u on gasoline that looked to be all original, but supposedly has "A busted block".
Fair enough, I got her under the tree and pulled the head, immediately drove the head over to my favorite machine shop.
Hey, I can dream, can't I?

Well worn valves, and three WILDLY bent pushrods, but no breaks or cracks. When I pulled the oil pan plug, there was about a quart of antifreeze and about a gallon of fairly clean motor oil. After oiling each hole and application of moderately strong language the lower end turned over fine. There are three different (yes really) pistons in the holes, so somebody has been in here before.


So, I decide to dive in and see about the block. I have a c175 handy so no worries if I can't save her, but it would sure be nice if all the casting codes lined up.
The top of the block looks really ugly and of course all of those studs would be inconvenient if the block is crooked so I decide to pull the head studs while the engine is still attached to the tranny for leverage. Every stud not into the water jacket came out without any drama, but every stud in the water jacket has refused to budge. I should mention that this tractor is in West Texas where back in the day a fellow might run ditch water in the radiator if they had to get the cotton in, and that the radiator had around 5/8" of fine sandy silt in the bottom tank. The sheet metal jacket cover on the side of the block had a rust hole I could stick my finger through, so it has been many years since this old soldier would hold any coolant.

So far I have managed to twist off two head studs, and now I am rolling up my sleeves for an extended siege. On the two studs that I broke, I drilled the center with no problem, but when I tried to drill larger than 1/4" (5/16") the stud was file hard. I attempted to anneal the stud by using a torch, but so far even with direct torch heat I can't soften the stud. I am using doubled head stud nuts to turn, and have been able to apply enough torque to twist the studs off. Here is a abbreviated inventory of what I have tried so far, each attempt was punctuated by application of penetrating oil and several hours of pondering:

*Pool penetrating oil at top of stud and tap downwards on TOP of stud/ nut with a hammer to encourage the oil to penetrate.
*Same as above only used an air chisel.
*Same as above only used an air chisel sideways on the stud close to the block working my way around.
*Heated the block with a torch.
*Heated the block A LOT with a torch.
*Heated the block a TRULY FRIGHTENING AMOUNT with a torch.
*Heated the stud directly above the block to a blue black heat.
*Heated the stud above the block to cherry red.

What sort of material would they have used for head studs in 1956 that would fight back like this? I don't have any experience with a case hardened fastener that couldn't be annealed with a torch, that one has me really puzzled.

Any comments or suggestions are welcome, or if you just want to have a good laugh at my expense, well, that is okay too.
Jeff

If the block is salvageable/good, QUITE before you injure it!

I would have the ones you've drilled through blown out with a torch in the time it took you to type this, even without a hole they can be blown out.

Or, better yet, find a reasonable machine shop in your area with and EDM and they can even more safely burn 'em out of there.

I would leave the remaining studs in the block unless they are rusted to a point of failure at torque. The material of the stud has probably been deep case hardened, and was better than grade 5 when new. If removal is necessary, heat the stud to cherry red and let cool about 4 times, then on the last time, as it gets below 200 degrees, put candle wax on the base and let it puddle at the threads. (do not try to remove them between heatings) With the removal nuts threaded on, smack the top of the stud with a ball peen hard enough to ring its bell as though you were driving a nail. Now give it the stud some turning force back and forth back and forth. Never putting twist into the shank, but just shy of deformation. Good luck. Jim

A few thoughts to add to your mess. Are new studs available? Usually the threaded end in the block is a different thread from the typical nut/bolt thread. I don't know what it is called or the specification of it. Ugly enough to be interference fit. Which is why you are have such a wretched time getting them loose. I have a Farmall A block apart now and the threads are different on each end. There is a tool made for stud remove and install, uses 1/2 in drive, probably some bigger ones at places like shipyards. With the different thread in block common tap may not work to restore thread. Never had to go there, not knowing where it would end. Good luck, George

Success!
Well, One down at any rate. I used Jim's method, and the first of three left standing gave up the ghost about an hour ago. George, Very good advice to make sure the studs are available. They are, and I have a quite comprehensive collection of taps. The block is 7/16"-14tpi, so for now it just boils down to work. Bob, I went ahead and blew the first broken stud out with a torch, very pretty sparks like the 4th of July, so they are something a little different from the stuff at Home depot. Luckily all of the holes in question are on the side of the block with the water jacket cover, so through drilling, tapping, (and torching) are possible. Thanks again guys, Jeff