wondering if anyone has tips or tricks on removing pistons that are siezed in the bores?i have the bores cleaned pretty well and have been soaking them with penetrant for a few days now and no luck .ive tried driving them out with a large dowel and 3 pound hammer from the bottom but they won't budge.Im also having trouble with the rod caps they are extremely difficult to remove (not seized) ive got 2 hours into them and got 2 off so far using the light tap back and forth method. thanks

 

I've heard of one scenario which apparently works quite well and another method which I saw my uncles perform on a big old gnarly piston in a JD tractor.

(1) First method. The key here is this. The cylinder must be allowed to very slowly cool overnight any attempt to rapidly cool the engine from the extreme heat can cause the piston or cylinder wall to crack. At any rate, you soak the piston with ~1 cup of ATM fluid and ~1 cup of brake fluid. Some place a piece of cotton t-shirt in the cylinder then add the ATM/brake fluid. Fire it up and let it burn down completely. Allow the engine (cylinder/piston) to cool overnight and apply the exact same method you've already attempted with the wood dowel. I've heard a 4" x 4" post can be fashioned into a very nice solid whacking block. I would think (actually a guess) if you could place that engine in a 16 cubic foot deep freeze the next morning after it had completely cooled down, you might gain even more benefit from the contraction of the metal(s).
(2) The one my uncles used. They fashioned a circular piece of ~1/2" hardened steel to fit as nearly as possible into the cylinder then hooked up a pneumatic jack hammer to a compressor. The continual and repeated "jacking" of the jack hammer took a little while but the piston slid right out.

I'm sure others have stories.

 

Jeff,
The pistons are junk anyway right ? Take a 5 lb sledge and a piece of 2x4 and wail away on the top of the piston. Loosen the main cap bolts up some too or just remove them so the crank can move down. It will move eventually, believe me. Once the pistons start moving then you can spray some PB Blaster in the bores and try beating them out from the bottom. Forget about the wood dowel. Use a piece of 3/4" steel rod up into the bottom of the piston.

Same with the rod bolts that are probably not going to be any good. Use a brass punch and just punch them out of the rod. Then you can take the cap off

I know this sounds "Blacksmith" but after doing this for 40 years you learn that when an engine is seized up you dont need to be nice to it.

 

Bill I took this advice and went back out with a perfect size piece of firewood and wailed it with my 6 pound hammer in each cylinder and can see the pistons visually moved . Will go back at it tomorrow . You are correct I will toss the pistons but would like to use the crank and rods. If I drive out the studs will this hurt the rods ? Thank you

 

Wont hurt a thing. They come out when we recondition the rods anyway. Just try not to scar up the crank if possible though it will probably need grinding anyway.

 

I've heard an overnight soak with 50/50 mix or white vinegar and distilled water will do wonders to loosen a stuck piston in the bore. I've never tried it.