Sometimes you need to take apart an engine that is stuck. Those *@!!* pistons are stuck tight in the block. What do you do?
There are various ways, but the primary ingredient is time. If you're in a big hurry and you don't need to worry about the old pistons, buy a long star chisel - they're used for making holes in concrete - and use a five pound sledge to break the pistons into chunks. Cast pistons usually break right up; forged pistons can give you much healthy eexercise.
If you have an oxyacetylene torch, you can just melt the pistons out, or cut the connecting rods so you can get the crank out to sledgehammer the piston from either side.
If you don't want to be so destructive, use a penetrant.
First, take a wire wheel or sandpaper and clean the rust off the tips of the bores. Use a wire or pick to dig out as much as you can from the crevice between the piston top and the side of the bore.
Turn the block so one bank of cylinders is upright.
Next, select your penetrant. I use Diesel fuel. It works, it's cheap, and I usually have some on hand. Another proven penetrant is a 50/50 mix of acetone and automatic transmission fluid. It probably works better, but the acetone will evaporate out and you're left with ATF, at which point you might as well use Diesel.
Break Free, Kroil, Knock'R'Loose, and other commercial penetrants will also work.
Cover the tops of the pistons with a quarter inch or so of penetrant, give it a couple of days, and use a hammer and a chunk of wood to tap on the pistons. Often they'll move. If not, wait some more. I've seldom had to wait more than a few days. Return to Dave's home page