If you have cast pistons, this way works well. When I was a kid and made money selling scrap cast, every junk dealer would dock you half the weight because of the aluminum pistons. Removed literally dozens of pistons this way and I can't remember the block being damaged on any of them. Never encountered forged pistons but I would bet you couldn't use this method on them.

I'll go with wrong ...

Be careful smashing out those pistons , I tossed a 68 440 HP2 block because a friend smashed out the pistons , and smashed a huge hole in one cylinder wall.

Get dry molasses and a big tub and soak it in it for a few weeks ...

Kroil is useless for something like that .

I had a 400 that was stuck , but the crank wasn't stuck , i put it on an angle and sprayed PB blaster on the tops of all the pistons after hitting the walls with a wire brush on a drill to remove the scale. did one side then the other , long pipe on a breaker bar and a brass hammer hitting the tops of all the pistons I could reach and I got the thing to spin over. rust was only above the pistons though.

It was a 230 block but still needed 5 sleeves due to pitting and core shift.

Next to impossible, if not impossible, to find those type hot tanks anymore thanks to the EPA...

Plus I don't think the owner of said tank wants his solution trashed ...

Yep, knocking the tops off the pistons from below is quick and dirty. I will say that any engine with rusted pistons is probably junk though due to pitting. If the block is worth the money you can probably sleeve it but check the water jackets for rust. Usually if the cylinders are rusted then the water jackets are trash also.

yella 71 - dude - I am so clueless. ya see - I thought this was a place where I could ask questions and get answers. You ever want to match car collections let me know...champ

John RR, I did cracked and sleeved 2 years ago smashing the hell out of it - exactly what i'm trying to avoid

MRO you are doing great, post all you want/whatever you want. this is where we solve problems/dilemmas. EDIT the bore(s) may need drastic overboring and or sleeving but at least getting the pistons out WO damaging the bores is good procedure/mindset. (keeps Mr Murphy at bay). I would sharpen a bit & get after it.

Thanks - finally building/finishing my 69 RR after 13 years of metal work and body work. Went slow because of my job. Anyway - I did forget a lot of stuff on these cars from when I was younger - but not everything.

Here's how I got the pistons out of a Mercedes block that had had a head gasket leak and the ethylene glycol had literally glued the pistons in.
Before starting, the crank has to come out.
First I got a chunk of aluminum the same size as the bore, placed it on a piston top and gave it a couple of hearty whacks with a 2 1/2 lb hammer. The piston moved but was in no way going to come out. So,
I got a piece of 5/8" rebar and turned the block upside down. Placing the rebar inside the piston skirt, I knocked the tops out of the pistons. IMHO someone who gets into the cylinder walls doing this is either unlucky or careless.
Turn the block over and thread a length of small diameter wire rope around the wristpin, and out the top. Here's the tricky part, I used a hollow piston hydraulic jack and was able to run the wire rope through the center, clamp it on top.
Then I jacked the pistons out.

The first oversize is 0.5mm or 20 over. I bored the block myself at a high school auto shop and then had it finish honed with a Sunnen power hone. After the cylinders were honed to fit the pistons, there were still some small grayish-black pits visible. I put the engine back together and it runs great.

At that time, 1979, a new bare block was $1300. So I had no desire to bore any larger than I had to. Never had another problem with that engine. BTW, that engine had a forged crank and every journal showed the signs of being induction hardened. It was way too complicated but that engine was beautiful inside.

R.

I've never had to jack the pistons out after knocking the tops off. Those must have been really stuck in there. On all of the locked up Mopar engines I've worked on the assembly frees up once I've knocked a couple of pistons out. If the engine was store with the heads on usually only one or two cylinders have open valves and rust in the bore.

"smashing pistons". Sounds like a band name from the '90s.

My strategy has always been to just beat the almighty living crap out of them any way I can and somehow they come out.

Handheld air chisel?

Taking a short j bar to them with a sledge - I know they will need sleeves. I like the idea of drilling reliefs. ThANKS for all the input. m

I had a very rusty engine last summer that I went through this with. It soaked for 3-4 months in and out of the molasses bath as parts SLOWLY came off. After everything was off the engine except the crank, rods, and pistons I tried everything to get the pistons out. A couple did come out with the hammer and a heavy rod, driving them out the top. In the end after several weeks of trying I ended up pulling them out. I drilled a 5/8 hole on each side of the wrist pin, opposite of each other on the end of the pin and dropped a 1/2 wire rope cable down around the pin. A cable clamp to tie the cable together, a block of wood, a large pipe and a 20 to short bottle jack pulled them out of the holes. I put pressure on 1 at a time with the jack, heated the cylinder the best I could through the soft plug holes and used lots of ATF/acetone mix. I would give the jack a couple of pumps each morning before I would leave for work, come home and put some heat on it and give the jack another pump or two, what ever it would take. Some holes took 2-3 days before they came out, but every day you could tell they were moving. I did not hurt the bores in the block.

Interesting thread.
I have a 68 TNT 440 with stuck pistons.
I thought it was junk.
I recently read an article on this and saw a
couple pictures of holes drilled into pistons.
Not much mention of ring ridge removal.
Is it not an issue at this point?
Lots of good advice and alternatives here.
Gives a fella hope.
Thanks guys.

I would for sure would use it first IF I took em out as is.

The hammering isn't going so well. I may not have the hang of it -
though...but none seem to move - the backstory - this engine came with one of my RR and it is numbers matching....the reality after thinking about it is it might have been a junk engine anyway. My thought was to have it rebuilt - and put it back in. I mean - the original owner must have pulled it for a reason. Anyway - I beat it last night - NOTHING MOVED...outside of my shoulder. And the engine in the car will probably stay there. I figured the rebuild to stock would be 3500 - start adding removal and sleeves - it will escalate quickly - and for what ? Just thinking - I don't know. Not sure.

You can't get any pistons out? You should have a least a couple of pistons near TDC at any one time so work on those first. Take the rod caps off and tap out the rod bolts so you don't scratch anything and then pop those pistons from below. Once you get those guys out move on to the next couple of pistons that you can get to. Once you get 3 or 4 easy ones out you might be able to rotate the crank and get the next ones out.

I thought the same thing - none moved.