Success! I finally cot the cam back in time and the chain pinned together. By cranking it around by hand several times, it comes up about 1/2 or 1 degree retarded, a big improvement over 5 degrees off when I started. It took me a while to figure out how to jump the chain over the sprocket, and then I got confused and went back the wrong way and got bound up again, but I finally prevailed. Many thanks to those who replyed to my post. davidg