I'm working on building a Webster. The drawing note that rings can be purchased from Otto Gas Engine Works but I've been unable to locate them on the web. Anyone know if they are still in business? If not, I will try to make my own. However, I don't see a thickness listed in the drawings. The only ring information provided is 3/32" x .875". Piston ring groove diameter is .771" so maximum thickness would be .052 which does not account for piston expansion. Trimble's recommendation would be between .043 and .045 times bore diameter which is .0376 to .0394 for this bore. Is that a reasonable thickness or is it too thin for the specified piston ring groove depth?
