I started tearing down a 312 today to hopefully rebuild it for my '57 T-bird.  I had attempted to tear down the original motor from the Bird 3 yrs ago but was foiled by not being able to budge the rotating assembly.  (couldn't access all the rod bolts)  I'm afraid I'm looking at the same thing again.  I filled the cylinders with PB Blast over 2 years ago, and of course it's still seized.  I'm hoping someone here might have a trick or two for getting THIS Y-block apart they wouldn't mind sharing.  I'm at a total loss for what to do next. Thank You In Advance

BOO- YA!!!

Pull the heads,put some ATF in the cylinders and try tapping on the pistons with a wood block and mallet as you try to turn the crank.If the engine had water in the cylinders you may have a SERIOUS problem getting the pistons loose! ROY .

52Mercury,292,5-Speed

I had the same problem when taking my 272 apart. I took the rod caps that I could get too off and I used a box wrench to unloosen the ones i could not get a socket on. You might want to try a distributor wrench like the type used on the older gm cars. I was able to tap a few pistons up a little bit so I could turn the crank shaft then I drove the pistons down enough so I could hone the cylinder then I drove them out that way. Another thing you can try is to heat the cylinder with a torch and then try moving the piston to free it up. Hope that helps a little. 

Troy.  Are the heads still on the engine?  If so, then the ATF in the cylinders and pressurizing the cylinders with air can possibly help.  I had a 352 years ago that this worked on.  I let it sit overnight after pressurizing with air and it broke loose the following day.

Lorena, Texas (South of Waco)

You can also try some COKE in the cylinders. It contains a weak phosphoric acid and will dssolve rust, within reason.

All of the above plus pull all the main caps.  Remove the bearings except for the ends and be sure the ends are free or at least oiled then end caps back on but not too tight. Also pull the cam drive chain. Try to turn it with a big pry bar on the starter ring gear leveraged on the 1/2" bolt into the bell housing mount. 

Doug T

The Highlands, Louisville, Ky.

As Doug suggested,remove the timing chain.I had one of these engines stuck one time years ago and it wasn't the pistons stuck.It was the lifters stuck in their bores.After removing the timing chain,the engine freed up.

 

Paul,

Boonville,MO

Hey,

My 5 cents worth all ideas posted have credibility, I have had success with filling the block with boiling hot water, the expansion of the block with cool pistons/ rings can help break the rotating assembly free,

1957 ________________ Ford

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Y Blocks, The New Flathead!

Thank you for all the suggestions, fellas. Alas, she's still stuck tight- sometimes you can't win for losing, I guess.  Again,  -Thank You-

BOO- YA!!!

O.K. One last suggestion in desperation, make an adadter for the spark plug hole on a cylinder on the down stroke and fit a grease nipple to the adapter and see if by filling the cavity with grease you can hydraulic the piston downward with a lever action grease gun, obviously you could do more than 1 piston providing they are all headed down ward. if its that stuck its worth a shot, you aint got much to loose.

1957 ________________ Ford

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Y Blocks, The New Flathead!