I am trying to free up my dad's old flathead (been under the bench for 50 years)
I guess too many freeze and thaws. The engine was a fresh rebuild when put under the bench. i can see virtually no rust cylinders or anywhere else for that matter. I have been soaking the engine for 3 weeks now but I still cannot get it to turn over. I have managed to get the cam and lifters out with tons of patience.
A little heat help me get the oil pump out (that was a real task).
Now I am looking for advice, I have been soaking the cylinders in Kroil and jarring the pistons by hitting a piece of oak on top of the pistons. Since its not moving, I was wondering if I should loosen the mains and rods a bit and try rotating the crank again?
Is there another trick that might be helpful?

Doc

 

I'd start removing the rod caps and then tap on the rods/pistons from the bottom to try and determine which one(s) are stuck.

 

With the cam and oil pump out, it has to be the piston rings are rusted to the bores, possibly only 1 or 2 of them. If you are resigned to having to replace the pistons, smacking the block of wood will eventually do it. You want to do it in a way that won't damage the rods, by hitting at 12 o'clock and 6 o'clock when facing the banks from the side.

Heating the pistons with a propane torch might help, not real hot tho.

How are you trying to turn it? I'd be careful using the bolt in the snout of the crank.

 

i have been trying to rotate it by using a 2 foot pry bar on the back of the crank using the flywheel bolts.
Funny thing is, there is so little rust I am certain you are right about the rust in the rings. I really do not want to damage anything yet...

Thanks!

 

seen somewhere that a old timer took a camp stove and boiled motor oil and then poured it over the cylinders. Something about the thermal shock that would free it up.

 

50 years is a long time. Be patient...

 

My dad often said the best tool in your tool box is patience! I was only a couple of years old but remember wanting to go with my dad to park the old truck on the farm....
It took days to get the lifters out enough to rotate and remove the cam-but then it was frozen by hardened grease behind the plate on the back of the engine. I lightly love tapped the cam back and forth liberally applying penetrating oil until it moved freely (almost). The same with the oil pump-3 days of cleaning freeing up and then heat, followed by rotating it back and forth with a pipe wrench.
I am just looking for ideas that might help me work the pistons and rods back and forth until I can coax them out. If it was as fresh a rebuild as dad said, I would love to save as much as I can. For instance the cam is spotless...

 

PB Blaster or any other good penetrating oil will work...with time. I have very good results using Picklex 20 on flash rusted sheetmetal, dissolves the rust without leaving a thick black oxide layer afterwards. No experience with it on stuck engines though. Pretty pricey to be using to run experiments.

 

It isn't always possible to free a stuck flathead. Case in point, my 46 project. Despite months of soaking and pressure on the crank nut - nothing. It took some serious beating - and breaking the pistons into pieces - to free this one. There were a couple of rusted rings on two cylinders.

Trying to 'save' the rebuild may only be delaying the inevitavble. Sorry.

 

I would try a thin oil heated on the stove and poured into the suspected cylinders. It makes its own gap to get rusted piston rings loose and coats the cylinders for you to move the rings up and down the wall.

 

You can try GB Sisson's method of pouring ATF in the cylinders and lighting it up: https://www.ford-trucks.com/forums/1...l#post16083450

 

Point of order, I think that was marvelous mysterious oil. And marshmallows. LOL!!

 

I think I will try al of your guys ideas in increasing possibility of doing damage...Might want to put more modern 3 ring pistons in ...

Going out now that the rain has let up-I'll rool her out to try the heated oil first.

Doc

 

I would undo the rod caps and crank caps and lift the crank out. If the cam was frozen with old grease, the crank will be the same. you will have to use pipe cleaners to clean out old grease from the oil passages.

 

I don't think you can get to all the rod bolts unless you can rotate the crank.

I worry about using the flywheel bolts to pry against. They are very special threads, any damage to them and you're screwed. If you can bolt a long piece of angle iron there, tightened down, that would be better and would give you better leverage.