Locked Engine

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Kegan B

Kegan B

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Anyone know a way to unstick pistons from cylinder walls that actually works?

Thanks! Kegan B
 
Repetitive soaking & patience has worked for me. Safe to assume they are stuck from rust?
 
Yes. Last turned over in 2001.
 
Do you want to save them? Is it still in the car? If you wish to save them and in the car, LOTS of PB Blaster, a mash hammer (about 48 oz) a 2x4, or 3x3 piece of hard wood (several, they may splinter) , with the heads off, soak each cylinder VERY liberally, wait a day, wack each one with hammer and block of wood.

Out of the car, on a stand, take oil pan off, loosen rod caps a little; wooden dowel and hammer from back side, flip over hammer and wooden block from front side.

Don't want to save pistons, 1/2 inch steel bar, hammer, take rod cap off, break crown off piston from back side, drive piston out 1/2 inch bar on pin boss.
 
I have done this to two engines, one being a jeep 4.0l and a 318 dart: start by soaking everything in Marvel Mystery oil. fill the cylinders with it. drain the engine oil and cap back off. fill pan with a couple quarts of fresh oil mixed with a half quart of MM oil. Take distributor out and use oil priming tool (TIP VERY IMPORTANT TO MAKE SURE OIL PUMP WILL SPIN BY HAND BEFORE USING POWER DRILL.) Then start to work the crank back and forth by hand. Works like a charm!
 
JBurch said:
Do you want to save them? Is it still in the car? If you wish to save them and in the car, LOTS of PB Blaster, a mash hammer (about 48 oz) a 2x4, or 3x3 piece of hard wood (several, they may splinter) , with the heads off, soak each cylinder VERY liberally, wait a day, wack each one with hammer and block of wood.

Out of the car, on a stand, take oil pan off, loosen rod caps a little; wooden dowel and hammer from back side, flip over hammer and wooden block from front side.

Don't want to save pistons, 1/2 inch steel bar, hammer, take rod cap off, break crown off piston from back side, drive piston out 1/2 inch bar on pin boss.
Click to expand...

THIS is pretty much exactly how I would get stuck pistons out when I worked at a shop years ago. Chances are they are the pistons are toast. I did manage to get a few sets out like this and in every case they were paper weights. If they are lightly stuck it is one thing but if it sat open for any & all moisture to wreak havoc I would just take the hammer and blocks of wood to them. I

In a very drunken stupor decades ago I helped a friend with a sbc in his 4 speed Nova. Heads were off. Soaked the snot out of them. Threw several hundred pounds of weight in the trunk hoping this would help prevent the tires from just skidding. Hooked it to his Pops truck and took it for a drag....Repetitive shocks from repeatedly dropping the clutch did free them up. All of the pistons were toast, but we had a hell of a good time so.....
 
50/50 mix of acetone/ATF

Pour in cylinders and let it do it's thing for a few days.

Beat vigorously with piece of wood and heavy hammer.
 
My method saves the block and crank, but not the rods or the pistons.
I use a torch and cut the connecting rods which allows me to remove the crank. You can then soak the pistons in PB Blaster (from the top and bottom)and beat them out with a sledge hammer and steel pipe (I like to put the pipe over the cut off rod).

I've never had a locked up block that didn't eventually give it up.
 
ATF is a very agressive detergent, just pour enough to cover the pistons and let it sit for a day, try to rock it, if they are low (which is good) add more...
 
Thanks all for the tips. Motor is still in the car for a couple more days. I could care less about saving the pistons they will be replaced by 10.5:1 Forged Ross's.
 
Ran when parked. Std bore '68 340.
 
hope you don't have deep rust pits on the cylinder walls.I had a 440 with rusted pistons 2 cylinders didn't cleanup. good luck.
 
50 50 kieen flo diesel fuel conditioner and atf .thats what we use on saltwater stuck engines and anthing else that is froze up. we call it panther piss
 
Marvels mystery oil . Took a slant six locked up solid and it was running in 3 days . Same thing with 2 VW engines .
 
Soak it in any of the above methods, let it set.
Paintance is the key to getting them loose.
 
I would get it out of the car and take it apart, like somebody else said, it might not be froze at all. Kroil is expensive but works quite well.
 
Most likely the rings are corroded in the piston lands, so the pistons are toast. Take the heads off, soak the bores with any of the goop stated above. Take a breaker bar with crank bolt socket and while someone is standing on that, another dude is beating on a 4X4 wooden block on top of the pistons ( one at a time) until they all start to move. Then remove all pistons for inspection. Hone the cylinders to clean up and if they do,install the new pistons, rings and bearings.

Good luck!
 
I've soaked them with ATF and used 2x4's to beat on the top of pistons on both banks. Just make sure you beat on the pistons that are on the way up or on the way down. If you hit on a piston that is at TDC or BDC your just hammering on the crank.
 
Put a mix of B12 chemtool and marvel down spark plug holes for about a week and rock it back and forth by hand slightly after a week and continue adding liquid til the engine is free.
Did this with the 340 in my 73 and it worked great with new plugs and used wires fired right up
 
Kegan,personally seen the diesel unlock a big block chevy.Took weeks.Acetone/ATF,works well too.
 
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