Hi Rob, on the twin it was intended to be bash valve with stainless ball (you can see the chamber in the heads -- screws are temporary --another upper head layer will be added to take the steam inlet and form the stop. The exhaust will be uniflow ports. This was the simplest valve actuating combination possible. I wanted to try very simple pipe based engines to go with my pipe boiler. The square end plate was left that way while building to serve as an index for machining operations -- intent was to cut it back to round and fit side bearers when finished. It could be be retained as a radial mount plate, but probably not.
I decided half way through making the twin that I also wanted to try out piston valve engines, and finding that 3/16" rod was a good sliding fit in 1/4" copper tube, thought I'd try another rapid build variation on the pipe theme. So the single was put together as a quick and dirty test of that. It has an internal cam on the crankshaft, which I thought would be kinda cool with an external valve guide. Also intended as a uniflow exhaust. Shooting for 20% clearance volume to lower pressure requirements, since there's no auxiliary exhaust valve.
I've wanted to see how far I could mimic the look of early motor bicycle engines -- depending on which valve arrangement I liked best, the ultimate aim being casting better shaped crankcases which would look decent . Still these aren't too bad looking as "functional" test pieces -- the single has a sort of steam punk quality I'm kinda warming to. Needs much more to complete, including bearings (though oddly the steel on steel plate now spins easier then the steel in twin's brass bearings). Same for the twin, it's just a work in progress at this point.
I decided half way through making the twin that I also wanted to try out piston valve engines, and finding that 3/16" rod was a good sliding fit in 1/4" copper tube, thought I'd try another rapid build variation on the pipe theme. So the single was put together as a quick and dirty test of that. It has an internal cam on the crankshaft, which I thought would be kinda cool with an external valve guide. Also intended as a uniflow exhaust. Shooting for 20% clearance volume to lower pressure requirements, since there's no auxiliary exhaust valve.
I've wanted to see how far I could mimic the look of early motor bicycle engines -- depending on which valve arrangement I liked best, the ultimate aim being casting better shaped crankcases which would look decent . Still these aren't too bad looking as "functional" test pieces -- the single has a sort of steam punk quality I'm kinda warming to. Needs much more to complete, including bearings (though oddly the steel on steel plate now spins easier then the steel in twin's brass bearings). Same for the twin, it's just a work in progress at this point.