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Removing Stuck Pistons

HEMI RAM

HEMI RAM

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What is the best way to remove stuck pistons? The engine sat for around 20 years, the pistons and wrist pins are seized up tight. Is there a chemical that will eat the corrosion without harming the block?
 
Fill the cylinders with light weight oil or transmission fluid and wait for it to do it magic. Might take awhile.
 
I do as iraqivet01 does,
Then I hit them out with a rubber mallet and wood
 
Last edited:
At the shop we use a dead blow hammer or carefully use an air hammer/chisel.

marvel mystery oil....it sat in a willy's flat 4 for about decade and never did that piston come loose.

Use force.
 
You might try some dry ice on top of the piston to shrink it prior to trying to move it- after you've tried the chemical processes.
 
Soak it with PB Blaster or similar bolt loosening penetrating oil. REMOVE the ring ridge at the top of the cylinder. Unbolt the rod that you want to remove with that piston. This may be difficult if the whole engine is seized up. Lay a block of wood against the bearing surface of the rod that is hooked to the stuck piston. With the rod pointing straight away from the piston, strike the wood with several heavy blows from a hand held sledge hammer. This should gradually move the stuck piston out the top of the cyl bore. It may take repeated soakings and hammering on the wood block before you get results.
 
The previous owner has been soaking it with trans fluid. I used a steel rod with a three pound sledge and can't get any movement out of any of them. I have four cylinders soaking in blaster now. If I can't get them out I guess I will cut the rods to save the crank and machine them out.
 
diesel and brake fluid
 
I've never heard of that one.
 
I haven't tried CLR. Will it attack the cast iron? I thought about it because I've seen it in action against corrosion but wasn't sure of the reaction on the block.
 
Kroil from Kano Labs, I saw a very stuck inline 6 have a gallon split between the cylinders and after about a week it broke loose. It's not cheap, but it works.
 
Can you unbolt the rods and get the crank out?

Once the crank is out I bet you can beat the pistons out the bottom. I did that on a 360 that sat outside for 2 years.
 
The crank is stuck because the rods are stuck also. Kroil looks kind of expensive so I think I'll try the trans-acid trick first and work my way up, I have plenty of time to wait I'm not really in a hurry. Maybe I'll try a few cylinders each way to see what works best.
 
I mixed PB Blaster and Marvel Mystery Oil together and let it worked its magic
 
Thanks to everyone for all of the help, I will try a combination of all of the different suggestions here and see what happens.
 
have you tried the new wd40 rust remover?we tried some here at the shop and were very impressed.took off all the rust on a seized control arm bolt overnight.
 
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