Alright!!!--This thread is officially finished. the engine runs, it runs reasonably well, and it runs with cast iron rings. The fan does keep the cylinder and head cool, after running 3 tanks of gas thru back to back at 20 minutes per tank. I never did solve the blow back thru the carburetor issue, and I think that is purely a factor of too much valve overlap at top dead center for this engine in a single cylinder configuration. I have found that yes, the Loctite does hold the cams to the cam shaft without slipping or coming unstuck, which is a really good thing to know. this is the first engine I have built which uses a jockey gear between the crankshaft gear and the camshaft gear, and that works fine. The ability to determine whether there is enough crankcase oil in the sump to keep the big end of the con rod lubricated by splash lubrication is a very "iffy" sort of thing. You have no access to it to put a drop of oil on it, and there really is no good way to check the oil level, that I have found. If you don't run water cooled cylinders nor a propeller, you will definitely have to fabricate some type of belt driven fan as I did, or this engine will run way too hot. I don't think I will try any more engines with cast iron rings. There is far too much screwing around involved, and even after 6 hours of continuous running, the engine had nowhere's near the compression it did with a Viton o-ring. It is a very pretty little engine, and I have used up May, June, and a damn good chunk of July to get to this point. Thank you so much to all of you who have followed this thread, I know it has gotten very long winded.----Brian
