wrote:
http://www.wallyblackburn.com/engine.html

Is the shaft that appears to be attached to the valve spring-loaded? Is
it a single shaft or two that stick out opposite each other? I assume
there's no internal linkage or you'd have turned the flywheel and seen
movement at the valve chest..

I wonder about the fact that steam can't be gotten to both ends of the
cylinder (assuming double-double acting) I see what looks like a tube
going to the head opposite the shaft, but it's quite small to be feeding
steam to that end of the cylinder. Is that a tube connected to the
center of the head and the flange? If so, I could see that having
something to do with working the valve.

I can imagine a couple of methods of valving an engine like this with no
linkage, but they wouldn't be very ideal..

As Jon says, it could be missing valve gear, but I just don't see any
room on the crank for it, unless the counterweight worked as a cam, but
I just don't see that happening..

Regardless, you've got a nice little engine and I'll bet someone here is
going to know what the score is.

John