Hi Don
You say you have no compression? now when you say 'no' do you mean none or that its very weak? if it is weak I would not worry too much and as long as you can turn the engine smoothly I would run the engine and see if the rings come in. use a small ish prop and get the rpm up and the engine leaned out (not fully) fairly quickly. I would run it for about 2 minutes to warm it up and then open it up. Don't screw the life out of it, but you need to get the engine upto temperature and the rpm up a bit as well.
If you have no compression at all do as bj suggested and put some oil into the cylinder. Swirl it around so the ring and valves are covered in oil and see if you still have nothing. if so then most likely a valve is stuck