Thread: siezed pistons

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Hey Guys just picked up a 1958 392 hemi engine for $100. The pistons are all siezed in the clyinders. Whats the best way to get them out

I'd buy a quart of Marvel Mystery Oil, divide it between the 8 holes and let it soak for a few days.

Are the heads off? There's a bunch of different ways and you may need all of them! Oxy/Acetylene torches with a "rosebud" tip, lots of penetrating oil, or make you're own with acetone and auto tranny fluid 50/50 mix.. Also a big block of wood that fits the bore real well and a Big F'n hammer, give'em a few wacks and even use combinations of the above to shake'em free.

On another site I frequent, they play with large stationary motors and those guys even go so far as using charcoal briquets and getting things real hot and then let'em cool enough to smack'em with the hammer deal.

I did a 427 Ford last year and it took me weeks to get'em all out. The hardest part I thought was that I couldn't turn the crank to free the nuts of the pistons that were free! Also I used the flywheel ring gear to help add pressure. Hope this helped.

I've had good luck using PB Blaster penetrating oil and cranking the engine over with a 1/2" breaker bar, not with too much force but enough to eventually maybe break things loose! I've never tried it, but a pal who does resto work on original T's and A's has a oil drum that he sets the block in on end, then fills it with diesel fuel.....

If they are all stuck, it can be a bitch. Any rod caps that you can get off, you can pound the pistons out from the bottom. As long as they are hooked to the crank, they all have to free up at the same time. If some come out, put the heads back on and shoot a pressure washer down the plug holes. Push hard and the water pressure will move the piston if it can move at all with the crank not free.

Make a metal or wood framework for the motor so it will sit still and not move around. Fill the cylinders above the pistons with some sort of solvent as posted above. Put a 6 ft. long bar on a socket at the crank. Every time you walk past the motor, give the bar a tug each way. It shouldn't be more than a couple of weeks until she starts movin'. Just keep pushin' back and forth on the bar until you can make two complete revolutions.

On the pistons that are down in the hole, take some sand paper and get as much of the rust out of the cylinder as possible (no sense having more crud wedge between the piston and bore). I've had good luck with Kroil, but everybody has their favorite. If it's really bad you might consider vinigar or citric acid (both of which disolve rust) and let it sit for a week or so. Once you get it to turn a little rock the crank back and forth until you can get to rod caps and start removing pistons.

Muratic acid for swimming pools also desolves rust and easy to find at pool supply places in a low percentage altho be very careful breathing it and watch(look away quickly) if you spill any-------and any pets-----------------