Tuning Impact MK2PP PowerBlock upgrade blues 🥵

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qball

qball

Member
Apr 13, 2020
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CA, United States
I was lucky enough to score a new power block upgrade kit from a forum member here on AGN. Found some quiet time this weekend so I dived in with great excitement! Turned on Ernest’s power block upgrade video and since I’ve done most of the steps on my impact it went pretty smooth.


First issue I ran into is the front valve stem for the power plenum is very tight into the action. I had to use rubber hammer to gently tap it into place while the old one came right out, odd I thought to myself.

Buttoned it back together and screw on the bottle and Ppppssssssss…..air rushing out of the rear block. What!?!??! Took it apart and a major DOH moment. I must of missed or the earnest’s video didn’t bother say that I need to put those 4 orings into the block. Yes, I’m not the brightest light bulb so warning from a dim bulb: install orings into the power block with extra lube before start the process!!!

Buttoned it back together and screw on the bottle and Ppppssssssss…..air rushing out of the regulator vent hole this time. What!?!??! Fine! Removed the trigger and lubed/sealed the regulator.

Buttoned it back together and screw on the bottle and Ppppssssssss…..air coming out between the front valve stem and action. What!?!??! Disassembled the whole thing and reinstalled the valve stem with extra lube, think I have done the upgrade 3 times by now.


Buttoned it back together and screw on the bottle and Ppppssssssss…..air coming out between the front valve stem and action…..again! Slightly better but still leaking after 90 bars. Frustrated and defeated I put my impact away. Thinking about it I think it’s the valve stem issues because it’s way too tight so the orings probably aren’t working properly.


First thing this morning I called FX service and with in minutes was talking to Chris and yup, tolerance of the block has changed over the years and mine is too tight. Within 10 minutes of that discussion I have a different front valve stem on its way to me from Megan. Two thumbs up to FX’s AWESOME CUSTOMER SERVICE SERVICE!!!




Quick summery on how to avoid frustration and defeat like me:
1. Make sure the rubber(orings) is in place BEFORE you start!!!
2. IF IT IS TOO TIGHT, STOP! (and cal FX immediately)
3. Use more silicon lube than you think you need!
You can thank me later!





Here is the difference of the TP inside of the block between old and new power block:
BFA9CA96-5BDA-4B2C-AB7D-E6F42A3B2EA6.jpeg
 
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hawkeye69 said:
You really have to love the customer service at FX. Let's hope they never decide to change it...
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they are always trying to upgrade as they gi which kinda sucks but would be nice to know these things, fx should let the people know these things so we as consumers know this. im glad they sure do upgrades but for pete sakes we gotta know these things here this fx usa
 
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caesar said:
How’s she running now that you got things squared away qball? I ordered my power block in April, still waiting
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So far it has been great!! The power increase is SIGNIFICANT!!!! I went from shooting 38 grain .22 NSA @860 fps before upgrade (mk2 with original slug kit) to 960 fps and has room for more after the power block and replacing the slug kit with tungsten hammer out of the 700mm .22 barrel. I dialed it back and tuned it to shoot at my preferred range of 920 fps, 75+ FPE in 22 is just ridiculous! The power out of this platform is simply mind bending!!!
 
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douger said:
they are always trying to upgrade as they gi which kinda sucks but would be nice to know these things, fx should let the people know these things so we as consumers know this. im glad they sure do upgrades but for pete sakes we gotta know these things here this fx usa
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I feel you, there are tons of upgrades and information isn’t exactly up to date so they certainly can do better in communication/education department. We need ernest make many more tech videos!!! This is where this airgun community really helps with the know how front.

HOWEVER!!!! Alternative is no grades to worry about like basically everyone else…..I’d rather have the upgrade problems!!!🤔🤨🤣🤣
 
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qball said:
So far it has been great!! The power increase is SIGNIFICANT!!!! I went from shooting 38 grain .22 NSA @860 fps before upgrade (mk2 with original slug kit) to 960 fps and has room for more after the power block and replacing the slug kit with tungsten hammer out of the 700mm .22 barrel. I dialed it back and tuned it to shoot at my preferred range of 920 fps, 75+ FPE in 22 is just ridiculous! The power out of this platform is simply mind bending!!!
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Thats great. Also exactly what I’m getting out of my .25 MKII PP. I shoot the NSA 38.9’s around 970fps. That includes the Ernest TP, slug power kit, NSA pin probe and a Huma hammer weight. 146 on the reg. Ironically my power block arrived today (ordered in April). After seeing the results Ted Bier was able to get in the 1100fps range I’m hoping to find a slug that I can get going that fast. My gun is happiest with the reg around 140 but I can still get good results at 146.

I’d bet you can shoot cans with it out to 300 yards. I do it with the 38.9’s like nothing it’s so much fun!
 
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caesar said:
Thats great. Also exactly what I’m getting out of my .25 MKII PP. I shoot the NSA 38.9’s around 970fps. That includes the Ernest TP, slug power kit, NSA pin probe and a Huma hammer weight. 146 on the reg. Ironically my power block arrived today (ordered in April). After seeing the results Ted Bier was able to get in the 1100fps range I’m hoping to find a slug that I can get going that fast. My gun is happiest with the reg around 140 but I can still get good results at 146.

I’d bet you can shoot cans with it out to 300 yards. I do it with the 38.9’s like nothing it’s so much fun!
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Nice!!! .22 cal 38 grain is much harder to push and why I’m switching back to .25 cal. With power block you will likely get close to 1000fps even with the 38.9 grain with same tune.

The reason factory Impacts are happiest at under 150 bars is because the hammer with is too light, you can keep it that way or add tungsten hammer and use 160 bars which for sure will get you to the 1000 fps mark.

The newer NSA slugs Are so good a soda can isn’t that much of a challenge at 200 as long as the wind is relatively consistent. Where I shoot the wind doesn’t ever stay consistent but I am sure I can still hit soda cans just not very consistently.
 
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Put the kit in last night. My only leak was where the regulator pressure gauge screws in, I sandwiched an o-ring in for now until I figure out a better solution. I used the valve spring from the slug power kit and the Huma hammer weight and spring that I had rather than the weight and springs that came with the gun.

My only real issue is with my C1. I have had a hell of a time keeping it from loosening, so a few months back I ended up putting a small piece of o-ring material at the bottom of the threads inside the C1 and loc-tite. Now when I put the power block kit in my C1 only tightens down to about 6.8mm. I’ll have to remove that piece of o-ring. In my experience that will limit power output. Should be between 5.5-6mm and closer to 5.5, that’s specific to my setup though.

Qball did you retune for a new valve setting or keep it at what Ernest recommended “line 4”. Now that the adjuster uses a metal rod to stop valve travel I’m concerned about damaging the valve stem. I broke the valve stem in my dreamline twice when the regulator was over 140. Don’t recommend doing that. lol

No updates on performance yet, the gun sounds better somehow when dry firing. Almost like the gun cycles and settles faster than it did before and I think that has something to do with the valve stem having a solid piece of metal to prevent excessive travel rather than a rubber ball. Seems quieter too for some reason. Could all be in my head.
 
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caesar said:
I have had a hell of a time keeping it from loosening, so a few months back I ended up putting a small piece of o-ring material at the bottom of the threads inside the C1 and loc-tite.
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It's not a good idea to place any rubber in there. It will make your C1 crooked a little and hammer face will not hit it perpendicular. Blue loctite applied on clean threads is more than enough to keep C1 in place.
 
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caesar said:
Qball did you retune for a new valve setting or keep it at what Ernest recommended “line 4”. Now that the adjuster uses a metal rod to stop valve travel I’m concerned about damaging the valve stem. I broke the valve stem in my dreamline twice when the regulator was over 140. Don’t recommend doing that. lol
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Yes, retune from scratch is needed. The return valve spring from the kit is stronger than earlier spring by a little, my guess is to help with controlling the Tungsten hammer. Even with tungsten hammer I started the retune with valve way pass 4th line and found it to start affecting the speed around 4 line mark already. I left mine just under 4 lines for my tune but yours maybe a little different. The valve return spring takes off a lot of the force striking the valve stem but impact's design is completely different compared to any traditional valve so zero worry around that. Matt dubber and few others have reg at 170-180 bars with no issues......yet. In fact non regulated guns valve stems have to withstand the force to open at 200+ bars.


The Dreamliner isn't designed for high power so the older valve stems are smaller if I recall correctly, the newer version should have a little bigger valve and stem. The crown has much bigger valve and stem so no worries there either.
 
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