valve pinning question

[airriflenut]

I have read quite a few forum posts (here and browsing other forums) on pinning the 22xx valve body for bulk CO2 and HPA.  All of them say to pin inline with the exhaust port of the valve body. 

I'm not sure I understand the reasoning on that.  I would think that drilling and tapping to pin the valve in the area of the stem would be a better place to pin since the valve is the thickest in this area.  Plus, if you were to want to open the exhaust channel it would further reduce the depth you could drill/tap. 

The Disco valve is pinned the same way so I don't dare attempt to open the exhaust channel.  Is there some safety issue I don't know about if pinning further back into the thicker walled stem area.  I've got a new 2250 valve body and Disco valve cap on the way for a pistol build on the laser etched 2250 tube.  I am going to test the bulk-fill versus 12 gram and keep the parts to make it either one when desired and I was considering pinning back by the stem.  Good or bad choice on that?

[Monkeydad1969]

I have read quite a few forum posts (here and browsing other forums) on pinning the 22xx valve body for bulk CO2 and HPA.  All of them say to pin inline with the exhaust port of the valve body. 

I'm not sure I understand the reasoning on that.  I would think that drilling and tapping to pin the valve in the area of the stem would be a better place to pin since the valve is the thickest in this area.  Plus, if you were to want to open the exhaust channel it would further reduce the depth you could drill/tap. 

The Disco valve is pinned the same way so I don't dare attempt to open the exhaust channel.  Is there some safety issue I don't know about if pinning further back into the thicker walled stem area.  I've got a new 2250 valve body and Disco valve cap on the way for a pistol build on the laser etched 2250 tube.  I am going to test the bulk-fill versus 12 gram and keep the parts to make it either one when desired and I was considering pinning back by the stem.  Good or bad choice on that?

I'd like to see your idea.  It makes since to me.  I hope someone can chime in on this with facts and pics.

Joe

[tinker]

Sterling,
As far as I know there are no known issues about the location of the valve retaining screws.  It's just that most everyone prefers that all the holes are aligned as in the Disco.  I have even seen the valve front drilled and tapped for valve retention! 

As for enlarging the exhaust port on the valve I don't see why not.  On my .25 Disco build I replaced the mounting screws with 10-32 screws and ported the valve!  I have filled to 2700 psi but usually use 2400 psi. I get just 6 shots over 50 fpe. 

Glen

[Monkeydad1969]

Sterling,
As far as I know there are no known issues about the location of the valve retaining screws.  It's just that most everyone prefers that all the holes are aligned as in the Disco.  I have even seen the valve front drilled and tapped for valve retention! 

As for enlarging the exhaust port on the valve I don't see why not.  On my .25 Disco build I replaced the mounting screws with 10-32 screws and ported the valve!  I have filled to 2700 psi but usually use 2400 psi. I get just 6 shots over 50 fpe. 

Glen

What did you port your valve to?

[airriflenut]

What did you port your valve to?

I opened the exhaust channel behind the valve to .250" stopping at the point where the stem begins in the opening of the channel.  I am using a stem with a 60 degree Delrin valve.  The stem was die threaded 8-32, the valve tapped 8-32 and both epoxied together.  The valve cap is factory, no threads cut off and no boring out the valve body.

This was with the Beast rifle.  Bulk-feed from a GMT 12 ounce CO2 tank.  With the above mods there was a noticeable velocity increase.  Since I am unorganized for the time being I'm not sure which velocities were written for what.  Now I have a 3-ring binder to organize everything.

I am going to get baseline numbers on the Disco convert and pistol build in factory configuration and modded set ups.

[airriflenut]

Sterling,
As far as I know there are no known issues about the location of the valve retaining screws.  It's just that most everyone prefers that all the holes are aligned as in the Disco.  I have even seen the valve front drilled and tapped for valve retention! 

As for enlarging the exhaust port on the valve I don't see why not.  On my .25 Disco build I replaced the mounting screws with 10-32 screws and ported the valve!  I have filled to 2700 psi but usually use 2400 psi. I get just 6 shots over 50 fpe. 

Glen

Glen, thanks for the info.  The valve in the 2250 tube pistol build was actually pinned for the 2260 tube for future bulk-fill build, holes inline with transfer port.

It shouldn't be an issue to drill/tap the valve behind the transfer port while in the tube.  One valve body can be pinned for two tubes...seems pointless if I have a new body on the way I can pin to the 2250 tube but I'm at a stand-still on the builds waiting for UPS and I'm getting bored.

[tinker]

  I used this information from RStrene's  Disco build.  You need to work slowly and carefully, the Disco valve is aluminum not brass like the 22xx valves.

"Using a 1/8" mill at a 20 degree angle, I re-machined the exhaust port.... I then smoothed off the corners with a 1/8" ball grinder in a Dremel.... I enlarged the exhaust port to at least 5/32" (0.157") or possibly 0.161".... I drilled the transfer port to 0.166" and the barrel port to 0.169".... "

Sterling,
  The wait is always the hardest part!

Glen

[airriflenut]

Thank you again Glen!!  I'm not sure how the HPA would perform with CO2 mod methods, I know that each are nothing like the other.  I was going to angle the port since it is one of those "it just needs to be done" mods, i dont have an 1/8" end mill but I do have a Dremel 1/8" bur for the angle cut.  The port i.d. i may leave as-is for now.

Patience is something I have little of but I have surprised myself on this build.  I want to get some "no mods" chrony numbers and then mod numbers, this will be the first opportunity to do so since I got the chrony.  I'm trying to maintain some patience on the pistol project, pinning the valve would pass some time this evening.  I'm looking forward to shooting for numbers and groups!  I will post up some data as I get it and some pics of the builds.

[tinker]

The HPA mods will work with CO2 but the shot count is gonna suck big time.  So I would go with what has work for you before.  Then do the HPA mods when you are going to switch to HPA.  Angling the port passage and rounding the corners are the standard valve mods.

As for the ports you could go to 70% of the pellet size for the openings or leave things alone.  You can go 75% but that's usually for using HPA. 

Glen