Help with release valves..

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evanmcorleytv
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Sat Oct 15, 2011 5:40 pm

Hey.. I have been working on a rifle for about six months.. and I have decided to modify it.. again.. It's already been modified five times, and I can't seem to get a good release valve.. The main valve is a Humphrey QE4 ( 3/4 inch exhaust, and 1/2 inch in and out) and all in all, it IS a good valve, BUT I can't seem to get the release valve right.. So, it's had a 3/4 ball valve as the release valve, and it worked well, but not well enough.. it would give me a quick HISS, and then it would be done.. I then tried your average 1/4 inch blowgun, and that gave me almost the same result, just a little slower.. THEN I tried JUST putting the quick connect to the pilot area, and when I ripped the disconnect off, it gave me a quick, loud, deep, and very satisfying BANG.(These methods were all out of order by the way.. it was the blowgun first, then the disconnect, then the ball valve..)

So, I was thinking I would try to modify it one last time.. The only method that I could think of that would pilot the QEV as fast as the quick disconnect separating from the quick connect was either a 1/2 inch slide valve, or a 1/4 inch QEV actuated by a modified blowgun (it would still be an average blowgun..) SUGGESTIONS ARE WELCOME!!
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Gun Freak
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Sat Oct 15, 2011 5:44 pm

I say ditch that QEV because it's obviously mentally challenged, and go for a euro 3/4".
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evanmcorleytv
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Sat Oct 15, 2011 5:52 pm

A Euro 3/4? Well.. I can't use anything that goes for less that 400 psi.. and what do you mean by Euro 3/4"?
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dewey-1
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Sat Oct 15, 2011 6:16 pm

Gun Freak;

QE4 uses a shuttle rather than a diaphragm.
So it is a "euro QEV"

The QE5 would have been a better choice for a higher Cv.

http://airinc.thomasnet.com/viewitems/s ... ust-valves
evanmcorleytv
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Sat Oct 15, 2011 6:35 pm

that's the thing.. I have a relatively small chamber volume..
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Gun Freak
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Sat Oct 15, 2011 6:40 pm

Ah, sorry, I didn't bother searching or clicking the link haha 8)
In that case it is a terrible valve because they generally have good responses.
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evanmcorleytv
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Sat Oct 15, 2011 6:46 pm

well.. which of those two choices would be best? a 1/2 inch slide valve, or a 1/4 inch QEV ( a fluid dynamics QEV ) actuated by a modded blogun to actuate the large valve..?
evanmcorleytv
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Sat Oct 15, 2011 7:18 pm

Also.. The valve is STUPIDLY sensitive.. The reason it won't actuate fast enough is because the piston moves if BARELY any air escapes.. And a ball valve is just.. TOO SLOW!! That's what I was asking for.. A MUCH faster pilot valve..
evanmcorleytv
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Sat Oct 15, 2011 7:18 pm

Sorry.. accidental double post.. had to edit this one..
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Hotwired
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Sat Oct 15, 2011 7:30 pm

So you've tried all these things.

How were you attaching them to the valve?


The other thing is you mentioned a very small chamber volume.

It could simply be that you are using a valve far bigger than you need to which is causing the valve to apparently malfunction.


A picture would help enormously.
evanmcorleytv
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Sat Oct 15, 2011 7:35 pm

the chamber is 1" by 12" it pretty nicely sized, and with the quick connect, and quick disconnect method, I shot toilet paper through 3/8 inch plywood.. I just need a FAST pilot valve, something as fast as pulling the disconnect off of the quick connect!!
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Fnord
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Sat Oct 15, 2011 8:19 pm

If you haven't already, check inside the valve to make sure there's no dirt or other stuff in it which may be causing problems(I've noticed teflon tape tends to get sucked into things quite often) .

If you're sure it's just a flow problem, go with the 1/4" QEV as a pilot valve.

A picture of the valve/internals could really help us if there's something funky going on though...
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evanmcorleytv
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Sat Oct 15, 2011 8:36 pm

I can't, it was a modified version that I bought, and all of the screws are stripped, and again, the valve works great, if there is a fast pilot valve.. AND FOR NEW READERS, PLEASE MAKE SURE TO READ THE THREAD BEFORE YOU POST!!
evanmcorleytv
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Sat Oct 15, 2011 9:05 pm

Hey.. I finally got the back off.. It was filthy.. I cleaned it up, and I am planning on modding it by cutting out the "star shape" inside the valve..
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Sat Oct 15, 2011 9:10 pm

P. I. C. T. U. R. E. S.
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