Office of Steam Forum for Model & Toy Steam Gas & Hot Air Engines

Hi Ben,...Yes, ...There's almost an addictive interest in trying to slow down the non-loaded rpm & hits per min but only so much can be achieved with flywheel/governor spring & weight mods & the stock firing hit "kick" indicates maybe too much stock compression exists..I ran some engine impulse power output to compression ratio flywheel inertia math numbers & it seems by significantly Reducing the Compression Ratio may be the Key modification to reach the ultimate Low rpm/hits per min goal..Since the sparkplug-cylinder head runs way to cold (even without water) anyway, I'm considering reducing the C/R by using 1/16--1/8" thickness rubber cyl head gasket spacer/thermal isolator to produce a hotter running cyl head cleaner combustion + slower running results...Happy motoring,...tom.

The head gasket spacer idea is a good thought.  My immediate concern however would be if one could achieve significant reduction with the stock cylinder head screws, (easy enough to use longer screws), and the existing exhaust valve pushrod?   One of our members shaved the piston I think .110”, and dished it out about another .040”, if memory serves. So you’re talking about an eighth inch spacer to achieve similar results?  Nevertheless, I like the idea, especially since it’s completely reversible if results aren’t to your liking.