OK, decided just to move on to plan "B". What I'll be doing is reconfiguring the engine to be more along the lines of a traditional steam engine. I had to go down the road with my first idea far enough to get it in my thick head that there's a good reason why traditional steam engines don't have closed crankcases - a lot of steam blows by the piston and inevitably turns the oil into foam (you can see it on the ground in my YouTube clip). So, forget having oil in a closed case. I'll drain out what's in there and cut a "window" in the front of the case. This will give me access to the crank and wrist pin bearings so I can squirt some oil on them before running the engine. I can put a cover over this to keep crud out (I still have the upper vent and the case drain). To oil the shaft bearings I think I'll use a syringe oiler (from my slot car days) to shoot some oil in right through the seals. You can't get to these bearings from a window in the case because they are behind the counterweights. This is not an engine that will be running for hours on end, so this should work fine. bchowk suggested a steam whistle valve on the feed line, run off a cam on the shaft, to time the steam inlet. I had also been thinking of this approach, so concurred and ordered a whistle valve today. I'll post some pics when I start making the modifications.