Can't turn engine by hand -- help--
 

I bought an engine from a salvage yard and wanted to check the timing chains before I installed the engine, so I removed my timing cover and was turning the engine by hand to get to TDC and the crank got tight, so I backed it off a little and it turn another full turn and got tight again and wouldn't turn anymore but I didn't force it after that. What would cause this ? Could it just be dry cyclinders and a ring was hanging up or would it be something to do with a valve hanging up or hitting a piston ? Any help would be appreciated !!! Thanks !!!

So 77 views and no one has any advice to offer, im surprised lol, I'm working on it still so I'll let you know if I figure anything out.