You are far to anxious to start takeing the engine apart, stop doing that. I have far to many fellows come to me with engines in peices and determained that there is something wrong when in reality the is nothing and this often agrivated by these forums.

When receiving a used engine if there is no rough turning crank the first thing to do is run it not start stripping it. Perhaps if it was in a dirt bath yes but not with every engine period.

This whole thing about your berings and rusty crank while it could be true should not be stripped down unless there is a tangible problem that is identifiable simply by a rough turning feel to the to the crankshaft after top dead center. Some discoloration or even rust on the crank journal is often present when there is no real bering rust problem.

As the fellows have indicated about the 'pinch' this is typical of all ABC and ABN engines and what the purpose of this is: The cylinder is actually taper bored with it smaller at the top than it is at the bottom. What this does is when it gets hot the Bronze sleeve will will expand a greater rate than the aluminum piston and the tight fit at the top of the cylinder will open slightly to the perfect clearance to maintain the best seal possible when the engine is hot.

Now with new engines when cold you can feel this interferance fit if you turn it over by hand, Perfectly Normal' and you should avoid unneccessary turning it by hand, when cold and dry untill ready for starting.

John