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

Personally i think it is a design fault .
The valve should float but i think the biggest issue is the ports in the cylinder block .
No amount of work by you will fix it properly.
I think the two, inlet ports are to far from centre..
Take the non floating valve off the spindle
Place it in place on the ports when it is moved the same distance as  the eccentric will move  it 
One port should be exposed and at the same time the recces in valve should cover center port and the other  port.