siezed piston

[Daniel H.]

I can use some help.my 71 350 was outside under cover for many years without being started. I tried to turn it over by hand but it wouldn't budge. I tried filling the cylinders with marvel mystery oil,then tried deep creep, no luck. So I pulled the motor to find out what the problem was. The #2 piston is froze solid near the bottom of the cylinder.i can't remove the crank until. I get it out. I've soaked it in deep creep, then pbs blaster, tried hammering it out from the bottom with a piece of pipe.( I am putting new pistons and rods in after I can get it machined and probably bored out). I don't have an oxygen torch to heat it anymore and I doubt apropane torch will do much good.any ideas would be a great help, otherwise I'm going to have to take it to the machine shop and add to my cost. Its only a 270 hp motor, so its not real valuable.thanks

[Joe L.]

Re: sized piston

I an use some help.my 71 350 was outside under cover for many years without being started. I tried to turn it over by hand but it wouldn't budge. I tried filling the cylinders with marvel mystery oil,then tried deep creep, no luck. So I pulled the motor to find out what the problem was. The #2 piston is froze so.id near the bottom of the cylinder.i can't remove the crank until. I get it out. I've soaked it in deep creep, then pbs blaster, tried ham ering it out from the bottom with a .eight of pipe.( I am putting new pistons and rods in after I can get it machined and probably bored out). I don't have an oxygen torch to heat it anymore and I doubt apropane torch will do much good.any ideas would be a great help, otherwise I'm going to have to take it to the machine shop and add to my cost. Its only a 270 hp motor, so its not real valuable.thanks

Daniel------


I've had this experience with a short block that I stored for many years. It was almost impossible to remove the pistons. So, I sent it out to the machine shop since it was going to need machine work anyway. The shop told me that they had to break apart the pistons in the bores to get them out using chisels and sledge hammers.

[Domenic T.]

Re: sized piston

Daniel,
When I worked as a mechanic a fellow brought a 66 Chevelle in with a 396 he rebuilt. Car was towed in and story was that the engine would not start and sat for over a year.
It had what is called indifference in metals and some pistons welded to the cylinders. It had a white powder like substance. I talked to a lab guy and he said that most likely this can happen when engines don't start and gas is left in the cylinders. He said that raw gas and oil will turn to some kind of acid.

Dom

[Daniel H.]

Re: sized piston

Thank you John for the advice. I guess I will just take it to the machine shop and let them handle it.

[Joe L.]

Re: sized piston

I guess I will just take it to the machine shop and let them handle it.

Daniel-------

...if you can find a machine shop that's willing to take it on.

[Bill M.]

[John R.]

Re: siezed piston

Had the same situation. Let PB blaster sit for days, weeks and still could not move it out. Then tried a heat gun where I let it heat up and cool down while applying PB blaster and that did it. Used a hammer an rod to push it out.