Which Valve hole works best???

CZKid · 01-13-2010, 06:10 PM

I was wondering what vent hole of the four on the valve is most recommended for the VM-68. I’ve always set the whole that is just larger than the smallest diameter hole facing up when installing the valve. I’m guessing this is just one more way to regulate the amount of air that is released with every shot although I'm pretty sure they all release pressure due to the placement of the 2 o-rings. Thanks for the input!!

Chaos · 01-13-2010, 08:15 PM

Depends on the velocity you're trying to get and how your gun is set up.The holes are your primary velocity adjustment and the screw in the bolt is the secondary adjustment.I used to run mine on the largest hole and do some fine tuning via the bolt,but,sometimes I had to adjust the valve down one as I was using co2 at the time.

CJOttawa · 02-17-2010, 02:00 PM

I heard from someone at a local field vent holes can be used to tweak performance (read: "attain acceptable performance") when switching between liquid-CO2 from a siphon tank and gaseous CO2 or HPA.

I know little about this but would like to hear more from someone who knows. A friend of mine about 15 years ago had a VM-68 and was always looking for liquid fills. He was miserable when he couldn't draw liquid.

Schmitti · 02-17-2010, 02:18 PM

Valve holes are indeed the primary adjustment method.

For the best performance, I found that putting a regulator in the front asa and then running the tank in a bottomline or rear asa adapter was the way to go. Or.. if you can find one, a VTS from Skanline (good luck with finding one though as they haven't been made in over 10 years and they hardly ever pop up for sale)

E

russc · 02-17-2010, 02:23 PM

I found I always needed the largest valve hole for HPA, or even needed to drill it out for more.

Schmitti · 02-17-2010, 02:27 PM

That's because HPA does not expand from a liquid state to a gas state. VM's were designed to use CO2... of course god forbid if you had the gun set up to run on gaseous CO2 and you got liquid in the valve and it didn't expand... or your pressure dropped... freaking jackhammer. Either way, use you would possibly need to modify the valve for HPA if you do not have a spring tension type velocity adjuster for the main spring.

E

Bored383 · 02-18-2010, 12:41 AM

the big expansion chambers can act as volumizers . . . my air america black rain VM runs pretty well on HPA

as for the valve holes, I always seem to end up on the biggest setting and then use the bolt for tweaking velocity. on my $20 wonder I drilled the largest valve hole out as big as possible since its one of the later bodies with the big transfer port, and just use a regulator to tweak velocity

also - I always ditch the valve spring in all my VM's

sparky · 02-19-2010, 11:42 PM

Quote:

Originally Posted by russc

I found I always needed the largest valve hole for HPA, or even needed to drill it out for more.

Going to have to try this one out, my VM's hate HPA with a passion. Any suggested hole size?

01-13-2010, 06:10 PM	#1 (permalink)
CZKid Newbie Join Date: Jan 2010 Location: Canal Zone	Which Valve hole works best??? I was wondering what vent hole of the four on the valve is most recommended for the VM-68. I’ve always set the whole that is just larger than the smallest diameter hole facing up when installing the valve. I’m guessing this is just one more way to regulate the amount of air that is released with every shot although I'm pretty sure they all release pressure due to the placement of the 2 o-rings. Thanks for the input!!

01-13-2010, 08:15 PM	#2 (permalink)
Chaos I'm Comin' To Getcha! Join Date: Mar 2006 Location: Hudson,MA	Depends on the velocity you're trying to get and how your gun is set up.The holes are your primary velocity adjustment and the screw in the bolt is the secondary adjustment.I used to run mine on the largest hole and do some fine tuning via the bolt,but,sometimes I had to adjust the valve down one as I was using co2 at the time. __________________ Chaos PoG Member # 1018 LPPC Member #71 NO'MAAM #5 My Gallery My Feedback

02-17-2010, 02:00 PM	#3 (permalink)
CJOttawa Tempus fugit. Join Date: Dec 2006 Location: Canada's National Capital	I heard from someone at a local field vent holes can be used to tweak performance (read: "attain acceptable performance") when switching between liquid-CO2 from a siphon tank and gaseous CO2 or HPA. I know little about this but would like to hear more from someone who knows. A friend of mine about 15 years ago had a VM-68 and was always looking for liquid fills. He was miserable when he couldn't draw liquid. Last edited by CJOttawa; 02-17-2010 at 03:12 PM.

02-18-2010, 12:41 AM	#7 (permalink)
Bored383 random probability waves Join Date: Mar 2006 Location: Sandy Eggo by way of Mobtown	the big expansion chambers can act as volumizers . . . my air america black rain VM runs pretty well on HPA as for the valve holes, I always seem to end up on the biggest setting and then use the bolt for tweaking velocity. on my $20 wonder I drilled the largest valve hole out as big as possible since its one of the later bodies with the big transfer port, and just use a regulator to tweak velocity also - I always ditch the valve spring in all my VM's __________________ Check out my website http://www.bored383.com, hosted at http://www.angryhosting.com/ We need to save ourselves from those who would save us from ourselves. TANSTAAFL A book has moving parts. They're called pages. “Well, Art is Art, isn't it? Still, on the other hand, water is water. And east is east and west is west and if you take cranberries and stew them like applesauce they taste much more like prunes than rhubarb does. Now you tell me what you know.”

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02-17-2010, 02:18 PM	#4 (permalink)
Schmitti Red=Moderator Join Date: Apr 2006 Location: Schen. NY	Valve holes are indeed the primary adjustment method. For the best performance, I found that putting a regulator in the front asa and then running the tank in a bottomline or rear asa adapter was the way to go. Or.. if you can find one, a VTS from Skanline (good luck with finding one though as they haven't been made in over 10 years and they hardly ever pop up for sale) E

02-17-2010, 02:27 PM	#6 (permalink)
Schmitti Red=Moderator Join Date: Apr 2006 Location: Schen. NY	That's because HPA does not expand from a liquid state to a gas state. VM's were designed to use CO2... of course god forbid if you had the gun set up to run on gaseous CO2 and you got liquid in the valve and it didn't expand... or your pressure dropped... freaking jackhammer. Either way, use you would possibly need to modify the valve for HPA if you do not have a spring tension type velocity adjuster for the main spring. E