Need to pick some brains.

[Ryker Carruthers]

Lately Dad and I have been talking about making a piston valve (Of the baker design of vaportight baker valves and piston rings circa 1905) for our half scale 65 horse case traction engine. I do not have the full size valve on our big engine to mesure. But, i do have the one out of our 20 horse advance rumely. They are very similar in size, 65 is 10" bore 11" stroke and the advance rumely is 9x11 and they run at 150 and 175 psi respectivly.. The half scale is a 5x5 1/2 cylinder at 150 psi. As of now it is a very good performer and will put out more power than most. But we want more. Lol. The piston valve out of the big engine is 5" in diameter. Now, i do not have a ton of room in the steam chest. So I am designing a valve 2" in diameter. With the math we have done it should give us 2/3 more valve area. Not only that. But eliminate alot of wire drawing and almost all stress on the valve gear. The problem i am having is that on a case, with a woolf valve gear the valve stem has an arch motion. The D valve didnt care. It went with the flow but the piston wantts to go in a straight line. You will see the cage and spool (piston) in the pics. The cage is held against the valve seat by the steam chest cover. The big piston valve i have does not allow for arch forgivness because it was off an engine that had a straight valve stem travel. In the 3rd pic you will see it has a nut that can slide around. That is just to center it. I do not want to put a hinge external of the chest. Any ideas how to make something on the end of the spool? My creative juices have dried up...
Thanks!
Ryker

 

[Ryker Carruthers]

Not letting me upload pics... Try again in awhile.

 

[Ryker Carruthers]

Only letting me do one at a time...

 

[Ryker Carruthers]

Another shot of the cage.

 

[Ryker Carruthers]

Spool. That is the nut the stem screws into. it will slide to align itself. I need the models to slide like that, and be able to rock for the arch motion.

 

[Ryker Carruthers]

Another shot of the spool.