Impact Reg, save tip.

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Drumsnguns

Member
Jun 14, 2016
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North Carolina, United States
I had to recently replace my regulator piston because of the dreaded "dimple" caused by the tip of the reg adjust screw digging in. I don't know why it was dimpled as I read the manual and know never to turn the adjust screw clockwise while the system is under pressure. When turning clockwise and under pressure you are "forcing" the sharp edge of the adjust screw into the delrin piston, pushing against 120+ bar of push-back.

So why was it damaged? I'd say because even though you are unscrewing away from the force of the piston, (and the manual says this is OK), the piston is still pressing very hard against that small sharp circular edge of the adjust screw as it turns and cuts into the delrin. It only gets worse as you up reg pressure. 

Because of this I have taken a tip from Ernest and anytime I need to turn that screw (which I'm doing a lot when trying to find that perfect tune), I unscrew the bottle and evacuate the pressure "anytime" I turn that reg screw. 

It's a pain but I checked the piston not too long ago and it's still smooth and flawless.

Just passing some info along in hopes of saving some one from inadvertently damaging that $30+ part.

Cheers, KP
 
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I don't yet own an Impact and may never get the chance, but you just now uttered what seems to me to be the best advice that I've yet heard about regulator adjustments of the Impact. Make no regulator adjustments until first evacuating the system. Oh how that advice will soon be valued by Impact owners. Plus one for you my friend!

BeemanR7
 
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A dimple in the regulator piston doesn't necessarily mean that the regulator will creep or doesn't seal.
As long as the regulator stays on the right pressure, you are good to go. And a minor readjustment every now and then is also no disaster :)
To each his own, but I even turn the pressure DOWN while pressurized with a little trick.
It seems a big PITA to depressurize for every adjustment, in that case there isn't much advantage anymore for a externally adjustable regulator IMO.
 
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To each his own. I've adjusted my regulator many times and have not needed to release all the pressure when going upward.

Also, it is not a good idea to release all the pressure from the orings constantly. That's why the case went from one where you were constantly unscrewing the bottle to a case where the bottle could stay on all the time. Constantly having to re-pressurize the system will cause the orings to lose their ability to seal, causing you to have to replace them often. 
 
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Weatherby, I don't think I claimed that the dimple causes creep. But AOA says it voids your warranty and I think that it can contribute to it. My reg crept up when the gun was a few months old; it went above 150....while I was shooting a string. The velocities just kept going up. Until then I didn't really mess with the reg. I did set it up to 140 up from 125 following the manual to get up to 860 fps with heavies. When I tore it down...there was a very significant dimple and AOA and Ernest said that it needed to be replaced. At that point Ernest suggested always adjusting without a pressurized system either down OR up. I trust his word, it makes sense, the tip if that adjust screw is "tiny" and sharp. That amount of force in pounds per square inch on that small surface area is quite large. Basic physics. Yeah, it's a pain in the butt.... but it's no longer wearing on the piston like before. 
So, if this is of any help then great, if not....still OK.......... We all have our own ways of doing things.

Also to answer Trailryder....Someone on this forum has sanded down the tip of the reg screw on 1200 grit 3M paper and said that it really helped. But I'm not touching that one. You would need some sort of squared off jig to keep the tip exactly flat or its toast.

K
 
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Thing is, luckily we don't adjust our regulators that often and so we aren't depressurizing the system repeatedly otherwise I'd agree. All I know is I got a severe dimple on the reg piston while adjusting following the manual procedure. How it got there I don't have a definitive answer but, I got a new piston and I'm now depressurizing before turning the screw and my reg piston looks brand new after 6 months. The only reason I know is tore it apart was to polish the piston and belleville washers in an attempt to decrease extreme spread and standard deviation. 
Anyway, there you are.
 
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Bucketboy, I might not have explained correctly but you remove the bottle then empty the plenum of regulated pressure so the gun is COMPLETELY empty before adjusting the reg screw. That way no pressure against the piston and no marring of the piston surface by the sharp reg screw as is on my Gen 1 Impact. So far it's working and my reg has no creep whatsoever.

Cheers,

KP
 
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Bucketboy, I might not have explained correctly but you remove the bottle then empty the plenum of regulated pressure so the gun is COMPLETELY empty before adjusting the reg screw. That way no pressure against the piston and no marring of the piston surface by the sharp reg screw as is on my Gen 1 Impact. So far it's working and my reg has no creep whatsoever.

Cheers,

KP
Click to expand...

Got it!



thanks



Bb
 
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I trust his word, it makes sense, the tip if that adjust screw is "tiny" and sharp. That amount of force in pounds per square inch on that small surface area is quite large. Basic physics.
Click to expand...

If the regulator seals properly there should be barely any force on the tip of the regulator. It's a balancing act between the pressure on the bottom of the piston and the counteracting force from the belleville washer/disks. When the pressure stops rising (aka the regulated pressure is reached) there should be zero force on the piston tip against the inlet nozzle (in reality there will be some force to seal it completely), if it starts leaking the piston will keep pushing against the inlet nozzle until it seals, this is what happens when you see reg creep.

Therefore a regulator needs it's break in period to form a sealing surface on the top of the piston and if you wan't to keep it sealed you shouldn't adjust it anymore. If you keep adjusting it it will start to leak after some period of time because it will become harder and harder for the nozzle to create a sealing surface on the piston due to a lot of small deformations.
 
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Hello everyone. I am new in pcp airgun but i have research enough not to damage the regulator when tuning the gun or increasing or decreasing the regulated pressure. I never turned the regulator clockwise while under pressure. I tired to digest your discussions to find a solution to my issue but was lost in translation. I have an FX Impact X with 600mm 25 cal. My issue: After constant tuning and slowly increasing the pressure to 160 bar to get the desired speed, i decided to lower the regulated pressure and unscrewed the bottle to depressurized. I am expecting to depressurized the regulated air pressure in the valve tube by turning the regulator counter clockwise. BUT after removing the bottle, the regulated pressure in the valve tube was depressurized immediately right after the bottle was removed. Was the regulator damaged already? If yes, what type huma regulator to buy?

I have depressurized the plenum twice before with no issues until i went beyond the 150 bar or 160bar.

Thank you.
 
Upvote 0
Hello everyone. I am new in pcp airgun but i have research enough not to damage the regulator when tuning the gun or increasing or decreasing the regulated pressure. I never turned the regulator clockwise while under pressure. I tired to digest your discussions to find a solution to my issue but was lost in translation. I have an FX Impact X with 600mm 25 cal. My issue: After constant tuning and slowly increasing the pressure to 160 bar to get the desired speed, i decided to lower the regulated pressure and unscrewed the bottle to depressurized. I am expecting to depressurized the regulated air pressure in the valve tube by turning the regulator counter clockwise. BUT after removing the bottle, the regulated pressure in the valve tube was depressurized immediately right after the bottle was removed. Was the regulator damaged already? If yes, what type huma regulator to buy?

I have depressurized the plenum twice before with no issues until i went beyond the 150 bar or 160bar.

Thank you.
Click to expand...

The piston bottom is not necessary damaged. When removing the bottle sometimes the pressure drops on its own, depending on how the hammer spring tension is adjusted.

If you have a warranty, you should contact FX for a replacement piston and o-ring. They will mail your replacement.

If you are out of warranty, or if you have the ability, the bottom of the piston can be fixed by cutting and polishing the end. It doesn't take much effort to do, with a (spinning) drill and a sharp razor blade. A (careful) steady hand and good eye... View attachment MTU3NDYyMjgwOF80MjE5OTIyNDVkZGFkNjU4NDE4MjUwLjQ1NDg5ODc1X0lNR18yMDE5MTEyNF8xNDA0MDM1NDB+Mi5qcGc=
 

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  • 1574622808_421992245ddad658418250.45489875_IMG_20191124_140403540~2.jpg
    1574622808_421992245ddad658418250.45489875_IMG_20191124_140403540~2.jpg
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Upvote 0
Hello everyone. I am new in pcp airgun but i have research enough not to damage the regulator when tuning the gun or increasing or decreasing the regulated pressure. I never turned the regulator clockwise while under pressure. I tired to digest your discussions to find a solution to my issue but was lost in translation. I have an FX Impact X with 600mm 25 cal. My issue: After constant tuning and slowly increasing the pressure to 160 bar to get the desired speed, i decided to lower the regulated pressure and unscrewed the bottle to depressurized. I am expecting to depressurized the regulated air pressure in the valve tube by turning the regulator counter clockwise. BUT after removing the bottle, the regulated pressure in the valve tube was depressurized immediately right after the bottle was removed. Was the regulator damaged already? If yes, what type huma regulator to buy?

I have depressurized the plenum twice before with no issues until i went beyond the 150 bar or 160bar.

Thank you.
Click to expand...

The piston bottom is not necessary damaged. When removing the bottle sometimes the pressure drops on its own, depending on how the hammer spring tension is adjusted.

If you have a warranty, you should contact FX for a replacement piston and o-ring. They will mail your replacement.

If you are out of warranty, or if you have the ability, the bottom of the piston can be fixed by cutting and polishing the end. It doesn't take much effort to do, with a (spinning) drill and a sharp razor blade. A (careful) steady hand and good eye... View attachment MTU3NDYyMjgwOF80MjE5OTIyNDVkZGFkNjU4NDE4MjUwLjQ1NDg5ODc1X0lNR18yMDE5MTEyNF8xNDA0MDM1NDB+Mi5qcGc=
Click to expand...

Hi! Thank you. But today, the pressure in the air cylinder and valve tube are gone. Zero air pressure. I am lost and i do not know where to start. I emailed fx for warranty and replacement of the regulator. I will replace it myself because shipping it to fx from where i live ia not an option. The tech guy of the distributor seems to be new with fx. Wish me luck.
 

Attachments

  • 1574622808_421992245ddad658418250.45489875_IMG_20191124_140403540~2.jpg
    1574622808_421992245ddad658418250.45489875_IMG_20191124_140403540~2.jpg
    416 KB · Views: 6
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