Removing stuck pistons

carguybill

carguybill

Senior Member
I have an 8BA type engine (apparently out of a military vehicle since it has a tag saying it was rebuilt on a military base) and I want to get the block checked for cracks but I have a couple of pistons that have resisted all efforts to be removed. I would be willing to break the pistons to get them out but I would like to salvage the rods and not otherwise damage the block.

I'm looking for good ways to break the pistons without causing other damage.
 
Best method guys on the barn hav come up with is probably using a hole saw. Use a short pilot drill so it doesn't hit the rod.then beak out what's left. I use a good piece of hardwood.
 
Yes, use a hole saw to cut the top off, then be carfull and slot the piston with a saw all. Trying to drivve the oistin can crack a cylinder wall. How do I know that???
 
OK, thanks.

I'm trying to visualize the hole saw process. I'm assuming that one would use a hole saw , say 2 1/2" in diameter or so, and cut through the top of the piston and positioned such that the hole saw or guide drill does not hit the rod or the wrist pin. At this point I would then I would have a 2 1/2" hole in the top of the piston through which I would cut with the Saws All out to the piston rings. A couple of such cuts and I would be able to break out a chunk of the piston wall.

Does this sound about right?
 
I have never done that before but I would imagine that I would take some sheet metal and mold it to the shape of the cylinder and put it in the hole to protect the wall. sawzalls can be jumpy and I would not want to mess up the cylinder wall.
 
I never worried about the cyl wall because I would bore to 3 5/16, so a few nics didn't matter. You don't have to cut too far, just a coupla slices around and some 50/50 mix and cross your fingers.
 
If the rod is not connected to the crank, pour some hot kerosene into the bore with the bore setting up straight, wait a couple of days .Using s large block of wood and a heavy hammer start hitting the wooden block. May take a few days but has worked for me.
 
I haven't tried the hole saw trick yet, sounds good though. And I have cracked a cylinder wall when trying to beet out a very stuck piston, block was already scrap due to lots of other cracks so didn't matter, Did surprise me how relatively easy the wall cracked. Will use the hole saw method in the future.
Martin.
 
I'm hoping too that I haven't cracked a cylinder wall. I have soaked with every conceviable solvent. including Coke, and pushed and pounded. My last attempt was to machine a wooden block which filled the cylinder and pounded on the block with a sledge.

If nothing else, the hole saw technique will be a learning tool and perhaps I will be able to salvage some useful parts. I will photograph the process and, if I ever figure out how to post photographs on this site, will post them.

Thanks to all who responded.
 
IMAG0149-Version2.jpg


Now I've seen it all,makes sense mixture of brake fluid and bbq starter let it burn out and it will free up the piston. Takes a few hours but some swear by it.You could roast wieners while waiting "LOL"

R
 
carguybill said:
I'm hoping too that I haven't cracked a cylinder wall. I have soaked with every conceviable solvent. including Coke, and pushed and pounded. My last attempt was to machine a wooden block which filled the cylinder and pounded on the block with a sledge.

If nothing else, the hole saw technique will be a learning tool and perhaps I will be able to salvage some useful parts. I will photograph the process and, if I ever figure out how to post photographs on this site, will post them.

Thanks to all who responded.
Click to expand...

Sent you a PM
 
Hot charcoal briquets in the bore is how we free up old one-lungers that have been sunk,
or buried for decades.
 
32forddump said:
I have never done that before but I would imagine that I would take some sheet metal and mold it to the shape of the cylinder and put it in the hole to protect the wall. sawzalls can be jumpy and I would not want to mess up the cylinder wall.
Click to expand...


Use a long blade and wind a bunch of electrical tape on the ends of the blade, this will keep you from cutting the side of the cylinder wall.

Hole saw: use a smaller hole saw off center, all you have to do is get the sawzall blade through it... Select location so that you can get the blade where you want it...

Karl
 
I have unstuck dozens of motors the way Ronnie shows. Try it. Use a small amount of brake fluid and fill the rest of the way with starter fluid. Let us know how it works
 
26 lakes said:
I have unstuck dozens of motors the way Ronnie shows. Try it. Use a small amount of brake fluid and fill the rest of the way with starter fluid. Let us know how it works
Click to expand...

I could see how this might work for a single cylinder as shown but I'd be afraid that using this technique for a single cylinder in a V-8 block might crack the block due to differential thermal expansion.
 
I burn one side, four cylinders at once. I can almost set my hand on the block when I do this. It gets about as warm as operating temperature. I have rescued dozens of blocks headed to the scrapper. Look up a post I did in 2012 How to properly warm up a flathead.
 
You must log in or register to reply here.
Back
Top