Re: gen2 .22 valve porting (New MAX 45.74 FPE)

[shorty]

I started my vacation today so I have off until Jan 5. I have valve mod fever and really want to make some improvements to increase shot count and bring up the fpe.

All this and I don't want to take the valve out to do it. Does this sound possible without destroying the valve or anything else?

What I was thinking was just to open up the Valve exhaust to .15" or .16" , TP to .15" or .16", and the barrel port to .15" or .16".

The valve part is the one I am scared to do without taking it out? I was thinking if I go slow and degas while Iam drilling, the shavings will blow out. Is this too risky or will it even work?

With all the ports opened up to .15" or .16" without hogging out the valve, will the fpe and shot count go up? I guess that should have been the first question.

I don't really have a goal for FPE but I can run a 10 shot 40fpe tune already and I can already hit over 60 shots at 20fpe under a 3%ES. So whatever would be better than what I have.

Be easy on me and no, I don't want to buy anything unless it's a replacement that I messed up. Let me have it.

[PakProtector]

the throat area is a .140 hole equivalent...making other stuff bigger is not going to do so much I think until you deal with that. which of course requires taking it all apart.
cheers,
Douglas

[HillGSA]

I started my vacation today so I have off until Jan 5. I have valve mod fever and really want to make some improvements to increase shot count and bring up the fpe.

All this and I don't want to take the valve out to do it. Does this sound possible without destroying the valve or anything else?

What I was thinking was just to open up the Valve exhaust to .15" or .16" , TP to .15" or .16", and the barrel port to .15" or .16".

The valve part is the one I am scared to do without taking it out? I was thinking if I go slow and degas while Iam drilling, the shavings will blow out. Is this too risky or will it even work?

With all the ports opened up to .15" or .16" without hogging out the valve, will the fpe and shot count go up? I guess that should have been the first question.

I don't really have a goal for FPE but I can run a 10 shot 40fpe tune already and I can already hit over 60 shots at 20fpe under a 3%ES. So whatever would be better than what I have.

Be easy on me and no, I don't want to buy anything unless it's a replacement that I messed up. Let me have it.

- -



Maybe you could have Santa email me 
contacttimhill@gmail.com

[bstaley]

You can realize some gain doing just what you describe.  The total resistance to flow, and thus loss of pressure of a flowpath is the sum of all of the indiviual resistances along the way, so anything you can do to improve flow will help.

Also because of the way that boundry layers form, having a throat that is somewhat smaller than the rest of the path is not as significant as if that smaller restriction were further down the path.

[shorty]

Is there a cross section of the valve posted anywhere?  It sounds like I am missing something (the throat).

[RayK]

Why not take the valve out?  It is a piece of cake.  Just make sure you have at least four 118 o-rings (and some silicone grease) for the parts inside the air tube.

I just made these install instructions with pictures for the WAR high-energy valve, but it is the same idea for the stock parts.  http://www.wickedairrifles.com/installation-instructions.html

Ray

[shorty]

I was hoping that I did not have to take it apart because I really don't want to mess things up. So I manned up, bit the bullet, and started working on it. I had no NEW orings to replace so I was just extra careful and lubed everything up when reassembling. I hope it doesn't leak. I really don't want to do this again (yea right).

So here's what I did,

Valve cap drilled out to 5/16" and then lead in with a step bit. Followed up with clean up with 600 wet dry sand paper.
Valve exit drilled to .156" then clean up with 600 wet dry sand paper.
Transfer port sleeve drilled to .15" then cleaned up with 600 wet dry sand paper.
Finally drilled barrel port to .15" then cleaned up with 600 wet dry sand paper.

Filling the gun now which feels like for ever with this POS Benji pump.

Anyone have any ideas what I may get out of this 2 hr project if anything ?

[shorty]

small picture of the parts

[shorty]

Well I got to shoot a string. I set the gun to the settings that I have tracking High fps shot string with 21.14 grain. All the settings are the same.
HS-5 HT0-VAS5

Iam not sure if i did anything. Maybe I just need some 25 JSB's to get that extra FPE.

I guess efficiency testing will be done tomorrow with CHP's to see if anything there improved.

3000-2500/v5,hs5,ht0   3000-2550/v5,hs5,0-10lb spring   3k-2.65k HS5HT0V5 10spr valve p
896   933   952
905   935   943
904   929   947
896   929   935
899   925   936
902   922   924
895   915   924
898   916   933
887   914   931
892   912   925

[rsterne]

I guess the limiting factor, like Pak said, is the valve throat area.... as you only gained a few fps....

Bob

[Motorhead]

Poppet spring in the gen II valves is pretty robust, tad softer spring such as a gen I may be of some use in the chase for more power.

Also agree with previous statements that Throat diameter behind poppet is a strangle spot.
Reaming it within a lathe to .250" will buy you more power.  * Don't drill it ... to hard to keep centered !! If the raised seat gets uneven poppet likely won't seal !!

[shorty]

Valve throat really seems to be the factor. I just don't have a lathe or know how to turn a lathe to open up that throat without destroying it. I did everything today with drill bits, a battery drill, and sand paper. LMBO

Now you all know why I was scared to even try it.

[Bill G]

So far, you have managed to increase the dead space.  Net outcome should be on par with what you got.  Increasing the throat to .25 is the upper limit on that factory valve i think.  I haven't been in a .22 but I'm sure Scott, Bob and Douglas know about them.  Even a 10% increase in throat will have a pretty good effect.  If the gun is unreg'ed you will likely get a steeper curve when tuning.  You mentioned wanting more fpe and more shots and it is possible but everything comes with trade offs.  If you don't want to attempt the throat work, you could use a heavier spring. This may reduce efficiency. The 30 shots that you show are fairly nice.  I really like shot 11-30, nice spread and speed.  Your thought on going heavier on the pellet is what I would do if I were in your shoes.   Heavier pellet with more spring tension.  Bob can link you to his tuning method to obtain good efficiency with current porting config. Goes from a near coil bind and keep reducing until velocity just barely reduces.  that gets you to a point where wasted air is reduced.  IMO you have a good setup, just needs some fine tuning.  How well does it shoot at that fps and have you tried it slower?

Bill     

[shorty]

I think I may have confused some of you with how the numbers got cut and paste.

All with 21.14 grain and starting pressure 3000

Stock spring
HT 5
HS 0
VAS 5
896
905
904
896
899
902
895
898
887
892
ending pressure 2500

10lb hammer spring and .14" transfer sleeve
HT 5
HS 0
VAS 5
933
935
929
929
925
922
915
916
914
912
ending pressure 2550


10 lb spring (and what was done today)
HS 5
HT 0
VAS 5
952
943
947
935
936
924
924
933
931
925
ending pressure 2650

I did one last string with one of my custom springs too.
051" wire 1.87" long spring
HS Full CW (I think 8 turns)
HT 0
VAS 5
895
897
899
898
901
900
899
903
905
907
ending pressure 2800

That last string with the custom spring is probably what I will be working on tomorrow using chps to see if anything got more efficient. I may make one of those dual wire springs again to see if I can get over 952 fps with the 21.14.
I sent one of those dual wire springs over to Bullfrog to see if it will tame down is monster and still be able to hit his high FPE. I can't wait to hear how it works out.

Thanks for the comments on the stuff guys.

So when you guys  open up that throat, do you use a lathe with a bit or do you use an end mill on the mill ? How do you get that poppet face right ? Can you use an end mill bit and chuck it in a drill press to get that clean face for the poppet ? That probably sounds stupid.

[rsterne]

If you try and open up the throat larger than the seat diameter, you will have to rework the seat to get a seal.... However, you can usually enlarge the throat a bit without touching the seat.... I'm not an MRod guy, but Pak will have the dimensions at his fingertips for how big you can go without damaging the seat.... One or two drill sizes (1/64" - 1/32") is a LOT in terms of flow.... I use a lathe to drill my valves, but all I use is a standard twist drill in the tailstock chuck.... HOWEVER, I either use numbered drills, going up one size at a time (0.003" or so) or at the most go only 1/64" at a time.... I have drilled lots of Disco valve out this way in two steps from 13/64" to 15/64" without ever damaging a seat.... but that is NOT an MRod....

Bob

[Motorhead]

FYI ... taking throat on gen II valves to .250" leaves the raised seat intact and actually just touches the inboard edge of seats raised edge.  Gotta ream it tho so it does not go larger or out of round.

[shorty]

You guys made me more comfortable to do the poppet throat. Degassing and tearing it down now. Any last info before I head out to the hardware store for some bits and reamer ?

[shorty]

I am measuring around 3/16" or .1875" on the poppet throat and we want to hit .25". Holy mackerel. I don't think I'll ever be able to keep that hole perfect enough at .25" with out destroying the seat.

What happens if that hole isn't perfectly straight ?

[shorty]

So I know I couldn't get the throat up to .25" so settled on 7/32 or .218". I used drill bits from .1875 and every other number up to 7/32". Can you say nervous. I couldn't get a hold of a reamer from the local hardware store so I hope the bits are going to be Ok.

I reassembled and began putting air in to hear a hiss out of the barrel. I couldn't find a good way to clean up the raised seat perfectly. I open the bolt and same thing. I then closed the bolt and put my finger over the barrel to stop the air until pressure got to around 100 to 200 psi and the removed my finger. Air stopped coming out. I know this might be a stupid question but could this be a little normal when opening up the throat ?

So I am still filling and I decided to put a balloon on the end of the barrel to see if it is still leaking. I am up to 2000 psi and balloon is still empty.

[rsterne]

You probably had a slight burr on the seat, or the hammer spring was holding the valve open (non-issue).... It will either fix itself or get worse.... Best of luck!....

Bob