No, if you read reply #8 you'll see I am not looking for a shortcut and I DO intend to remove and rebuild the engine. However, it's going to be some time before I can do so and for now I merely wanted to see if I could get the engine free and keep it that way. I thought this forum would be a great way to get some advice as to whether or not other folks have had any success with such exercises. I wouldn't take a shortcut with a rare and difficult to replace engine. :-)
Personally, I think it is a good idea to get the engine freed up before storing it longer. A real good idea. Maybe you can find just one cylinder with a problem as I often have before, and just maybe you can do it without pulling the engine. Now, since the rarity of good engines is more so today, I am not suggesting you should follow this path (below) exactly, but it might give you some ideas.
I'll give you my first example of a frozen FE 390, I bought at a junkyard for $25 (circa 1974) as a core. It only had about 30K miles so felt it a good engine and worth the risk of the $25.
First (after it was taken out of the vehicle) it was freed up using the method with the flywheel. Looking at the plugs and using a flashlight, we discovered that only one cylinder had an issue. It only took about 15 minutes to get it going all the way around after setting overnight with the oil. (we used ATF fluid) BTW, this is common that only one cylinder might have an issue because usually, only the cylinder(s) with open valves will get moisture on the cylinder walls. This applies mostly to engines not directly out in the elements (like this first example I am writing about) After freeing it up, we had already filled all the cylinders with the ATF, we spun it over with all the plugs removed using the starter for a minute or so. Then (while the engine was out) preceded to get ignition and fuel to the engine and started it up. A compression test afterwards revealed the one cylinder that had the rust on the spark plug, was very low. We pulled the head and sent it to a machine shop to have the valves ground on that head and noticed some pitting still on the cylinder wall. (piston positioned all the way down) We cleaned the cylinder as best we could, and after the report from the machine shop that a new valve seat was needed, we ended up exchanging out that head, put it back on and and ran another compression test. We ended up getting only about 80 lbs while the others mostly where well over 125 lbs. We felt it would improve over time so then put it into the pickup truck we needed the engine for. BTW, that engine lasted the life of that pickup (about 75K miles over 3 or 4 years) but it never got the compression to come all the way back up on that cylinder.
Summary, every frozen engine is damaged. Some are worse than others but ALL can be freed up. Freed up does not mean reusable (some are extremely damaged) In the later 70's I began rebuilding engines for resale. I purchased MANY frozen engines and freed up and saved almost every block. I found that kerosene or diesel fuel was a good solvent for the soaking. The method Jeff mentioned is one way but honestly, the flywheel seemed to work better most of the time. Once I had an Internatonal truck engine I couldn't get free with the flywheel. I pulled the crank and tried the way Jeff mentioned. End result was a destroyed piston and a cracked block. It was however frozen from being out in the elements and probably not savable in the first place.
Richard