HELP! Engine Stuck from sitting '68 280se
 

Just acquired a '68 280se which has been sitting since '94. Engine is frozen. Previous owner stated that the car ran perfectly untill he stored it in the garage and left it.

I removed all the plugs and "pickled" the engine with Marvel Mystery Oil. I noticed that the oil level in all cylinders eventually drops after a few days except for # 2 and 3 which stay full. I removed the radiator to gain access to the crank pulley bolt and have a breaker bar attached. Have been rocking back and forth daily for the past 2 1/2 weeks, but still no progress. I can't see any place where I could gain access to the flywheel to turn from that point. Any ideas??

IMO wrong oil.
 

Try to remove the Marvel oil.
Refill with PB blaster = PB Penetrating Catalyst, you can buy it in gallon cans.

http://www.pbblaster.com/

I just used it on a Bronco 2 that was Locked solid, three weeks of soaking, and it cranked over with a short half inch ratchet. :)

I filled the cylinders, and dumped the rest into the throttle plate, when I came back three weeks later, all of it was in the oil pan.

OK, that is exactly what I did this evening. Now, do you think that the #2 and #3 cylinders where the oil level does not drop could be the "problem" cylinders? The car is from Florida, and even though the car was garaged, the humid air found it's way onto the cylinder walls.

Hmmm
 

They may be at or near TDC = small volume.

Most likely, the piston rings are stuck in the ring grooves. The cylinders that sat with the valves open, will not do well. Nor will the open valves/seats. If you do get it to turn over, you will have some dead holes for sure. You will most probably be taking the motor apart, is you expect to run it.

I don't beleive there is any way to tell at this point in time if you have an engine problem. My father bought a old willys jeep that sat at least 15 yrs. It to was froze up. He would pour a mixture of kerosene and oil down the spark plug holes every day. At the same time try to turn the crank with a large wrench. Using a big hammer to hit the wrench once or twice. within a week the crank became unfrozen. He continued this for another week, moving the crank and adding the mixture. Wal La it now turned over freely and started and ran for many years. good luck

I use Marvel Mystery oil in cases where an engine sat a long time and things are stuck due to old oil getting thick, esp stuck rings. I wouldn't fill anything more than just the cylinders.

MM Oil is slightly acidic in nature and that explains how it dissolves gum too. But Blaster probably works better but I've not used it b4 (because I didn't have any).
But if you have really rusty cyl walls that is entirely a different matter as it builds a bond onto adjacent metal. Good luck and let us know after the head is off what it looks like.