Well I've got my 1966 poly 318 torn down except for the crank and pistons. In 1977 the truck locked up and has sat ever since, I cannot get the crank to turn so I can loosen the final bolts on the pistons. Ive had the pistons soaking in oil and wd40, tried turning with the breaker bar and by hand. I cannot get this thing to budge, any ideas?

 

What are your plans for the block and how scored is it?? It will probably have to be bored and new pistons,rods,and crank any way...I had a 340 like that and had to beat the pistons out of the block with a piece of wood & BFH...I replaced the rods crank bearing and pistons..And went .010" over pistons and .010 under sized bearings on the crankshaft...I sent my crank and had it turned...Lets see what other advice you get before you use brute force and ignorance...Bill

 

Ya this things gonna have to be bored at least .40. So far I've only been able to break one piston loose. It locked up when one piston either exploded or dug into the side wall and turned the rod into a z.

 

One of the boat motors I built some time back (Brand-X) sank to the bottom of the lake... When the motor was brought to me. Kind of the same thing happened.... What I was able to do. Was pull all the rod caps. (Marking them of course). Pulled the mains. Managed to get the crank out of the block with just some minor damage to it. Had to beat the ever living crap out of the pistons to get them out.... I broke 5 of the 8 getting them out of the block.
I was very lucky the block was savable also.....
Good luck..

 

Maybe try soaking it in the blaster for a few days? This stuff works wonders.

 

I hate the smell of PB blaster.. But it does work well so does Krohl...Bill

 

After some research that blaster keeps coming up so I'm gonna try some of that. Thanks guys!!!!!

 

Spray everything well with PB blaster or Kroil, top, bottom and everything in between. Put some Marvel Mystery Oil in the cylinders and coat the rods and mains. Turn the block over and put the MMO on bottom of pistons. Let it sit a few days and turn it over again. This s not gonna happen overnite, a few days up and a few down and repeat. Use lots of PB and MMO. During all of this try turning left and right on the crank bolt. Hope this works for you before you have to get out the BFH.

 

Best penetrating oil, hands down, is a mix of transmission fluid and acetone. It is flammable but it works! Try it, I mix 50/50 in an oil can.