So I installed a power slug kit with the adjustable pin probe and the Ernest Rowe Dual transfer port the other day and finally had time to try and tune my impact. I noticed that there was a pronounced puff of air that hit my cheek after every shot and the gun was louder than usual. I know some people have had this issue but with the "regular" pellet probe being the culprit but this one is adjustable so I'm not sure what it can be.
Tuning Fx Impact Mk2 cheek rest air puff
- Thread starter Tnp
- Start date
The adjustable pin probe is adjusted to where it barely clears the magazine and the o rings on the new transfer port are new and lubed
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If you put your stock pellet probe do you still get the puff? Try that and see if it due to the pin probe not sealing and air escaping.
That will give you a starting point and then you can back track from there.
I had this occur on my .35 when I changed to the NSA pin probe; sounded much louder and I felt air on my cheek. In my case it was the pin probe and as soon as I replaced it with the stock probe the sound changed and no more air puff.
That will give you a starting point and then you can back track from there.
I had this occur on my .35 when I changed to the NSA pin probe; sounded much louder and I felt air on my cheek. In my case it was the pin probe and as soon as I replaced it with the stock probe the sound changed and no more air puff.
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I'll give it a try but what advantages do you get from the pin probe over the stock pellet probe? Does it increase fps?
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Regardless of which probe you install, if you’re still getting that puff of air you may have blown the 1.5 x 1mm o ring on the rear of the valve rod, within your power plenum. Overtravel of your valve rod is the cause of this, and could be a result of installing the lighter valve spring within your valve knob
Make sure and install that rubber ball that was in the kit. If you did not, and your valve knob is out to the 4th line wide open, and depending on your reg pressure, you chance over travel of the valve rod.
By chance before the air started puffing out did you hear a pop? If so, it’s guaranteed you blew that seal out, which will require disassembly of the power plenum, or depending on your skill set and experience, partial disassembly to get to it.
Make sure and install that rubber ball that was in the kit. If you did not, and your valve knob is out to the 4th line wide open, and depending on your reg pressure, you chance over travel of the valve rod.
By chance before the air started puffing out did you hear a pop? If so, it’s guaranteed you blew that seal out, which will require disassembly of the power plenum, or depending on your skill set and experience, partial disassembly to get to it.
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I looked closely at your valve. It looks like your valve rod didn’t spring back out in place, as the hole where the blue arrow is vacant of the valve stem tip. Guaranteed air (black arrows) will blow out with each shot. You may even start seeing a leak in the gun, like 20 BAR overnight
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Here's a better angle. I haven't done anything to it since I posted the picture from yesterday and it looks perfectly normal to me.
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Dry fire the gun with no magazine. Before you do lightly tape a piece of scotch tape or stick on a target dot from one of your shoot and see targets on top of that valve pin and see if it blows off from there when fired.
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Can you verify where the air is coming from? Single load a pellet and put some tissue over that area and see what happens. Shoot one into the dirt if you need to get the angle right.
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I am one that had this problem and had it fixed, mine was a crazy story but ended in a really good way. I have, I guess in a way, been intimidated by the impact, not sure why, but I was. I am glad I did exactly what Glem and Bigragu said and took it on myself to learn it, repair it and tune it. I am still learning, but I have found that learning about it is just as fun as the shooting. The information is everywhere in crazy amounts. PM the guys and they will help you for sure.
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Not understanding- is this last pic AFTER the shot, and you’re saying you draped tissue like Glem advised and that’s what flew off, and that stick on on the valve stayed, or are you saying that the stick on in pic flew off and this pic is PRIOR to the shot?
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The last picture I sent was before I took the shot. The sticker flew off after I dry fired so it looks like I have to replace the small Oring at the end of the valve rod. So it looks like the originally O-ring was 1.5x1mm and Ernest Rowe recommends replacing with a 2.2x1mm but I can't seem to find one. Any recommendations?
**what NO. is it on the schematics?
**what NO. is it on the schematics?
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It might not be listed as it's included on "valvepin complete"
I'd just throw the stock size on unless you can find that one Ernest recommends. 15k+ shots with a mk2 and never had to replace that oring.
Oring store, or orings and more should both carry them.
https://www.airgunnation.com/topic/impact-o-ring-list-corrected-with-links/
Here you go, from the above link
https://www.oringsandmore.com/metric-buna-o-rings-2-2-x-1mm-minimum-25-pcs/
I'd just throw the stock size on unless you can find that one Ernest recommends. 15k+ shots with a mk2 and never had to replace that oring.
Oring store, or orings and more should both carry them.
https://www.airgunnation.com/topic/impact-o-ring-list-corrected-with-links/
Here you go, from the above link
https://www.oringsandmore.com/metric-buna-o-rings-2-2-x-1mm-minimum-25-pcs/
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Not listed on the MK2 schematics but it is on the M3 schematics- E105
https://fxairguns.com/wp-content/uploads/2021/04/F10370-Impact-M3-1.pdf
Here is the o ring-
https://www.oringsandmore.com/metric-buna-o-rings-2-2-x-1mm-minimum-25-pcs/
I highly recommend you go thru the MK2 schematics and pick out every o ring and order them as an impact owner. With almost 60 o rings +/- in this platform you should change out all the o rings within that power plenum since you will have it apart. Trust me, you’ll kick yourself in the arse if you just change out that valve rod o ring, put it all back together and discover you’ll have new leaks elsewhere. Early on I used to be chintzy in o ring replacement and tried gambling the original ones won’t leak, and it bit me every time. O rings take a shape all their own under 3,650 psi of pressure, and depending on how old your gun is, some o rings may be flattened out.
look at it as a great opportunity to learn your gun.
By chance, did you install that black rubber ball that came in that slug power kit?
https://fxairguns.com/wp-content/uploads/2021/04/F10370-Impact-M3-1.pdf
Here is the o ring-
https://www.oringsandmore.com/metric-buna-o-rings-2-2-x-1mm-minimum-25-pcs/
I highly recommend you go thru the MK2 schematics and pick out every o ring and order them as an impact owner. With almost 60 o rings +/- in this platform you should change out all the o rings within that power plenum since you will have it apart. Trust me, you’ll kick yourself in the arse if you just change out that valve rod o ring, put it all back together and discover you’ll have new leaks elsewhere. Early on I used to be chintzy in o ring replacement and tried gambling the original ones won’t leak, and it bit me every time. O rings take a shape all their own under 3,650 psi of pressure, and depending on how old your gun is, some o rings may be flattened out.
look at it as a great opportunity to learn your gun.
By chance, did you install that black rubber ball that came in that slug power kit?
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Big thanks man. I ordered the Fx impact Oring kit and it should be here tomorrow. I installed the slug kit myself and made sure that the black ball is in the spring. I'm definitely going to replace the o rings in the power plenum and will report back when everything is put back together.
*** how do I prevent this happening again?
When I was tuning, I had the regulator set at 110 bar, hammer spring was 5 quarter turns from max and the valve knob was a little above the 4th line. Doesn't sound too crazy to me.
*** how do I prevent this happening again?
When I was tuning, I had the regulator set at 110 bar, hammer spring was 5 quarter turns from max and the valve knob was a little above the 4th line. Doesn't sound too crazy to me.
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