Upgrading the USFT HPA Regulator piston

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Offline TexasSteve

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Upgrading the USFT HPA Regulator piston
« on: October 07, 2012, 08:57:51 PM »
I upgraded the regulator that came with my USFT HPA upgrade kit today. The new piston is made out of brass instead of aluminum, has two o-rings versus one on the older piston, and is tapered on the tank end versus square on the old model. Made to eliminate regulator shoot-down. It's easy to do conversion. Just remove o-ring, pull Breville washer stack off and transfer to new piston in same order, then slide the o-ring on to hold the stack in place. Be sure to put a small bit of silicone grease on the o-rings. Don't use oil as always. I might call Tim and get some of his 90 Duro Mil spec o-rings to replace the ones that are on it just to minimize any regulator shootdown. The old piston is on the left, new with washers and o-ring transferred on the right.



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Offline jz2

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Re: Upgrading the USFT HPA Regulator piston
« Reply #1 on: October 07, 2012, 09:22:06 PM »
Did you get the new regulator piston from tim or another source?
thanks

Offline TexasSteve

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Re: Upgrading the USFT HPA Regulator piston
« Reply #2 on: October 07, 2012, 09:57:52 PM »
It a Ninja part #NINJARBK. You might be safer to get it through Tim just to make sure you get the newer piston with two o-rings. Rather hard to find since it's a new part number. As I mentioned above, you might consider having Tim put his 90 Duro Mil o-rings on it. As for the Buna O-ring on the inner seal, which is interesting, I might just leave that one alone. I haven't ran any chrony numbers on it as well, so it's yet to be seen if this is a better way to go for more consistent regulator operation. The original manufacturer seems to think so.
« Last Edit: October 07, 2012, 10:15:20 PM by TexasSteve »
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Re: Upgrading the USFT HPA Regulator piston
« Reply #3 on: October 08, 2012, 01:12:27 AM »
I don't see how the taper can make any difference to the regulator pressure creeping.... the O-ring and the hole in the seat (that the ball seals against) feeding the high pressure chamber are still the same size....

or by "shoot down" do you mean something other than the pressure dropping slightly as the tank pressure drops?....

Bob
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal:
.177 Diana 34, 1750 CO2 Carbine, .177 Uber-Pumper, .22 Uber-Carbine, .25 Discovery, 2260 PCP 8-shot Carbine (Grouse Gun), 2260 PCP Rifle (37 FPE), 2560 PCP Rifle (52 FPE), .22 BAM B-26, .22 BAM B-51, Hatsan AT-4410 Long (70 FPE),
"Hayabusa" Custom PCP Project (Mk.I is .22 & .25 cal regulated; Mk.II is .224, .257, .308 & .357 unregulated; working on the Mk.III, a .410 shotgun, and .458 cal)

Offline TexasSteve

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Re: Upgrading the USFT HPA Regulator piston
« Reply #4 on: October 08, 2012, 02:54:09 AM »
I probably shouldn't have used that word "shootdown" since it applies to rapid fire situations which isn't really a concern on the USFT. I thought it might marginally apply on single shot situations if the new piston design works better in low pressure differential situations, I don't know. What I am ultimately concerned with is the consistency being the same on each and every cycle of the regulator. In my case, my regulator is set up to deliver 1350 psi.

I really need to run a shot string through a chrony and then compare it with a shot string with the old valve will tell me if it improves consistency. I just going to roll with it until I do and assume that the manufacturer did their product development homework and found that two o-rings are better that one, brass is better than aluminum (maybe it's just more corrosion proof than aluminum), and a tapered tip somehow improves consistency over a squared tip or maybe just has some other benefit that I haven't thought of. Intuitively it seems like these changes would, just yet to be proven to be true.

« Last Edit: October 08, 2012, 08:45:47 AM by TexasSteve »
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Re: Upgrading the USFT HPA Regulator piston
« Reply #5 on: October 08, 2012, 05:10:38 PM »
ahhhhhhh.... so by "shootdown" you are talking about the flow rate past the (old) square end, that could definitely be better in a paintball rapidfire situation.... The consistency of the output pressure relative to tank pressure (creep) is another matter.... If you DO find a difference, please let us know as that's a good thing, regardless of "why" it happens....

Bob
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal:
.177 Diana 34, 1750 CO2 Carbine, .177 Uber-Pumper, .22 Uber-Carbine, .25 Discovery, 2260 PCP 8-shot Carbine (Grouse Gun), 2260 PCP Rifle (37 FPE), 2560 PCP Rifle (52 FPE), .22 BAM B-26, .22 BAM B-51, Hatsan AT-4410 Long (70 FPE),
"Hayabusa" Custom PCP Project (Mk.I is .22 & .25 cal regulated; Mk.II is .224, .257, .308 & .357 unregulated; working on the Mk.III, a .410 shotgun, and .458 cal)

Offline TexasSteve

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Re: Upgrading the USFT HPA Regulator piston
« Reply #6 on: October 08, 2012, 06:08:51 PM »
I'm not sure what tapered end vs square end would or wouldn't do for the regulator, it seems that if air does,in fact, flow better around or over it,  it would be good in any situation rapid fire or not. The dual o-rings intriqued me more. My thought was that the second o-ring might have been added to help the piston stop the airflow more reliably on each cycle. It seems that the manufacturer invested time and effort to determine a design change and then believed in it enough to switch their whole regulator line to it. For what it cost in time and money to change, I was interested enough to give it a try. I"ll put it on a chrony and get some objective data just to see if it improved regulator consistency. Otherwise, I might just be PiXXing in the wind once again.
« Last Edit: October 08, 2012, 06:55:23 PM by TexasSteve »
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Re: Upgrading the USFT HPA Regulator piston
« Reply #7 on: October 08, 2012, 06:54:51 PM »
Yes, the air can flow around the end of the stem better.... However, in airgun applications, the regulator can't possibly top up the pressure DURING the shot cycle.... There is no way it can operate in 1-2 mS (the lenght of time the valve is open during a shot).... In paintball, it is trying to top up the pressure between shots, and that is where improving the flow is important....

Bob
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal:
.177 Diana 34, 1750 CO2 Carbine, .177 Uber-Pumper, .22 Uber-Carbine, .25 Discovery, 2260 PCP 8-shot Carbine (Grouse Gun), 2260 PCP Rifle (37 FPE), 2560 PCP Rifle (52 FPE), .22 BAM B-26, .22 BAM B-51, Hatsan AT-4410 Long (70 FPE),
"Hayabusa" Custom PCP Project (Mk.I is .22 & .25 cal regulated; Mk.II is .224, .257, .308 & .357 unregulated; working on the Mk.III, a .410 shotgun, and .458 cal)

Offline TexasSteve

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Re: Upgrading the USFT HPA Regulator piston
« Reply #8 on: October 08, 2012, 11:26:26 PM »
1-2 mS that's a number to note. Just for grins, How fast does a regulator respond? But more to the point for USFT application, I think this new piston might have  the potential to do a better job starting and stopping the receiver fill cycle due to the addition of a second o-ring. I like brass better than aluminum as well.
« Last Edit: October 09, 2012, 01:07:35 AM by TexasSteve »
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Re: Upgrading the USFT HPA Regulator piston
« Reply #9 on: October 09, 2012, 02:46:10 AM »
Quote
How fast does a regulator respond?
Slow enough that you can see the pressure drop on a gauge downstream of the regulator, watch it bounce back almost to the setpoint, and then creep up the last little bit.... Maybe 1/2 second on a 1600 psi reg?....

Bob
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal:
.177 Diana 34, 1750 CO2 Carbine, .177 Uber-Pumper, .22 Uber-Carbine, .25 Discovery, 2260 PCP 8-shot Carbine (Grouse Gun), 2260 PCP Rifle (37 FPE), 2560 PCP Rifle (52 FPE), .22 BAM B-26, .22 BAM B-51, Hatsan AT-4410 Long (70 FPE),
"Hayabusa" Custom PCP Project (Mk.I is .22 & .25 cal regulated; Mk.II is .224, .257, .308 & .357 unregulated; working on the Mk.III, a .410 shotgun, and .458 cal)

Offline MartinDWhite

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Re: Upgrading the USFT HPA Regulator piston
« Reply #10 on: October 09, 2012, 11:56:45 AM »
Two orings could also help with repeatability of mechanical alignment of the small sealing surface over the orifice.

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Re: Upgrading the USFT HPA Regulator piston
« Reply #11 on: October 09, 2012, 02:02:52 PM »
Quote
Two orings could also help with repeatability of mechanical alignment of the small sealing surface over the orifice.
The small O-ring is a lot further away from the larger ones than the distance between the large ones, so I don't see it.... but I assume the change to two O-rings was for a good reason....

Bob
Dominion Marksman Silver Shield - 5890 x 6000 in 1976, and downhill ever since!
Airsonal:
.177 Diana 34, 1750 CO2 Carbine, .177 Uber-Pumper, .22 Uber-Carbine, .25 Discovery, 2260 PCP 8-shot Carbine (Grouse Gun), 2260 PCP Rifle (37 FPE), 2560 PCP Rifle (52 FPE), .22 BAM B-26, .22 BAM B-51, Hatsan AT-4410 Long (70 FPE),
"Hayabusa" Custom PCP Project (Mk.I is .22 & .25 cal regulated; Mk.II is .224, .257, .308 & .357 unregulated; working on the Mk.III, a .410 shotgun, and .458 cal)

Offline TimmyMac1

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Re: Upgrading the USFT HPA Regulator piston
« Reply #12 on: May 02, 2013, 10:51:30 AM »
Quote
Two orings could also help with repeatability of mechanical alignment of the small sealing surface over the orifice.
The small O-ring is a lot further away from the larger ones than the distance between the large ones, so I don't see it.... but I assume the change to two O-rings was for a good reason....

Bob

We've had a dozen or so HPA regulated guns in service now for a year or so and I found the small and large ;piston orings at 1200-1400 psi output or getting saturated by the CO2 component of atmosphere as that gas can leak theuoguyh the 70 Durometer orings used. If yoyu take a gun and degass it after it has sat charged for an extended period the piston orings when removed will ghet real cloudy and stART TO EXPAND. This indicates the oring is not adequetely containing the atmosphere. I'm swapping out the #013 and the #008 oring out for Mil Spec 90 durometers urethanes and the 70 durometer seal degradation issue is gone. Ray at Ninja said he had made a similar swqith to a 90 durometer on the twin oring pistons but his 90 is Buna, The two orings on the piston won't change alignments so much as they are a back to the leading poring should it fail. I'm leaving the 70 durometer as the second oring but as long as the leading one does it's job the trailing oring never sees the pressure dif.
The Ninja HP Regs are now Orange Anodised so they can keep the high pressure regs from finding their way into painball service. The switch to a twin oring piston was probably a year or so ago but I see no reason to worry if you have a single oring. You can always chuck it and cut another but it is belt and suspenders. Not neccessary but doesn't hurt anything.
The more we use these the more we learn. They overcharge the after reg chamber during filling so know that. It is best to set reg to the peak speed /pressure range for the gun so when the gun comes off the reg at 1250 it still shoots to POA till the vessel pressure gets down to 1100 PSI. I've got mine working better than ever right now. And I've upgraded all the CASA guys except LD and friends which will do at the Temecula challenge. If you have an HPA regulated Gun give me a call and we can figure out what you need to get updated.
The Gas saturation of the Piston seals does not seem to be an issue on the 800 PSI standard Ninja Regs but it is again no sweat to upgrade to Mil spec 90's and an upgradede seal can't hurt the situation. Only improve longeivity of the soft goods. All the Ninja Reg Pistons take a 013 and 008.

TimmyMac1
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