SpudFiles

Hi guys , i need yours help again yee. I wanted to build qev valve beacuse they are expensive in my country But it leaks and dont work

this is your problem

The surface that the piston pushes against has to be flat and polished.

I made a QEV with a 1/2" T and it works really well
This is the sealing face, I turned it in a drill press and used a file to shape it. Piston is made from a nylon block with a hard rubber face. [youtube][/youtube]

I polished the surface and nothing its leaks , but maybe the problem is that the sealing face is too short? idk

I made something similar to this QEV , My piston is made from hot glue and rubber washer glued , and its slide easily in the nypel . But when i am trying it , air flies out from pilot . Air is little escaping from port R (exhaust?)

Haniball1337 wrote:But when i am trying it , air flies out from pilot . Air is little escaping from port R (exhaust?)

When this happens, it's usually because the piston is not tight enough in the tube it is traveling in. Try wrapping it with tape until it is snug.

I did that , piston is little snug it works but very poor , its not loud and air leaks from the exhaust port so i have 6 sec to shoot untill air escape

Sounds like it is still not sealing on the rubber face

The sealing face is polished and sharpened

Try softer rubber on the seal face.They sell this white "kinda foamy" sealing. Then maybe a slightly more powerfull spring that pushes the piston. And to prevent leaks, you may use epoxy glue instead of teflon tape on some threadings (which need not be dismantled for servicing or testing).