psycix wrote:Oeh that gap between the sliding tube and valve seat looks a short (read: flow restrictive)
The valve is nice, but you just HAVE to use a longer piston and a shorter sliding tube.
D/4 does NOT APPLY to a barrel sealing T valve.
D/2 or more would be better.
It's not 1/4 of the barrel diameter, it's more like 3D/8. On this project, I was willing to sacrifice a little power (read: not much) for looks, and that was the best I could do with the tools I had and the materials I had at my disposal. I doubt there would be much if any performance increase if I were to lengthen the opening distance to half the barrel diameter, and then I would have to rebuild another valve and lengthen the carriage pipe to extend out of the tee, and that would not look nearly as good.
I've included the plans I was going off of when building this. In the diagram, 1px = 0.01". In the 2" pipe in the rear, I have to fit 1.) A plug, which counts for 3/16" for the o-ring groove, about 1/4" for the bolts, and 3/8" for safety on both sides of the bolts (3/4"). Plus, I have to fit in a 1/4" bumper, the opening distance, and the length of the piston that needs to remain sitting in the carriage pipe to stay aligned and sealed. I don't see much more opening distance I could squeeze out of this setup.
EDIT: also, the valve is a little tilted to the side in that last picture, so the distance might look a little shorter than it actually is. The measured distance (not from the diagram) is about 1/2" (0.504", but that's not too reliable), so it would be about 0.31 times the barrel diameter.