I'm tearing down a 312 block and there is one piston that will not come out. I've tried hitting it out the top, the bottom. I've used a wood block, a steel chisel and lots of PB Blaster. The piston is in #2 cylinder and is at the TDC position. Any suggestions would be greatly appreciated.

Steve

Steve

Can you tell if the cylinder is rusty? If that is the problem you could turn the block upside down and fill the cylinder with a weak phosphoric acid ( like COCA COLA ) and give it time and some occasional heat. Pete

Pete, It doesn't look rusty but it sat outside, without heads, for many months. I'll try the Coke.

thanks

Steve

If all else fails or you're in a hurry you can cut out the top of the piston with a hole saw, then carefully collapse it enough to get it out.

Steve. Another thought to free the piston. After soaking a couple of days put the cap on the rod and use a wooden rod to try to twist the piston side to side and free up the rings. Pete

tight piston 312,just had same isue 292,drilled several holes around the piston,both sides of the wrist pin. 1/2 in holes. then gave it a spach withe hard wood block and a 5lb hamer,piston broke up enough to come loose,tho the water damage  made 1 sleev inst necesarey. cliff

Flip the engine with the crank side up and try filling the bottom of the piston with dry ice pieces and let it sit for a while. The piston might shrink enough to pound out.


~DJ~ AKA "Bleach"
1956 Ford Fairlane Town Sedan 30K original miles

The boys over in the marine business, recommend a mixture of acetone and auto trans fluid, mixed half and half.  Only drawback they say is it's a volatile mixture so take care.

since its at the top drive it down first.just enough to break it free.if you hit it hard enough it will go down.use a mall not a hammer.

I have had good luck with heat, the penetrant of your choice and a piece of fence post about 2' long that is close to bore size.After a few days of heat and penetrant put the  piece of fence post on top of the piston and hit it with a sledge hammer.If you are  at .TDC you will need someone to hold the piece of fence post.Once it moves at all you have it,just keep moving it a little at a time.