If you want to reduce cooling as an experiment, Lauri's idea would be a good way. Another method would be to put a shroud over the cylinder head fins. This can be pretty easily fabricated from 1/64" plywood and maybe some balsa. One member here had problems with his new-ish Brodak .40 stop cold at the top of the RWO. At my suggestion, he made a nice muff for the cylinder head to get more heat into the head and cured the problem for the short term. When his engine had more time on it, I'm sure it was no longer needed. The deal is that the part of the cylinder head that fits down into the cylinder (most, not all engine) can be too loose a fit. When it fits correctly, the head will stretch and stabilize the cylinder diameter at the top ("pinch") and keep it
round. Those are important details.
I really don't understand designers of engines like the XLS Magnum/ASP engines and the ST G.51 going away from that (head sits entirely on top of the liner flange), except that it saves weight and material. Brass and chrome aren't as cheap as aluminum, especially if they can use a casting with much less machining required. These do run just fine, but I'd expect a different piston/cylinder fit...less taper toward the top. That also saves $, since it's easier to hone a straighter bore than it is getting the taper just right, plus the cylinder head then has no tight tolerance diameter requirement. Tight tolerances cost money, by increasing the scrap rate and/or increased machining operations, i.e., roughing cutter, tool change, finishing cutter, part check on the machine, etc. Ewwww. Reminds me of how I wasted my daylight hours prior to May 2010!
Steve
Topic: Can a stunt engine run too cold? (Read 1855 times)
