EDgun Leshiy2 "dwell time" tuning?

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bigHUN

bigHUN

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Jan 16, 2020
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Canada/L4G7X4
First the Story:
For over a year I had the FX .22x600 liner mounted on the L2, 0.5+0.7 jets were performing about a MOA pretty consistently with MRD's @ 50 meter rings.
I can safely say the L2 have total exceeding 10K shots, earlier this year I had to replace some worn parts that were effecting the indexing mechanism.
Back in time I was playing more with jets (until I finished my learning curve) and I can recall that 2x0.7 jets @ 140 bars on REPR were the limit that feed the indexing mechanism well, if I increased the jet sizes the mechanism started suffocating.
I am planning to re-purpose the FX liners now to other guns, I have several other .22x500 and .25x500 barrels (clones of AP polygonal rifling in 1:17.7) that I would like to mount now to L2.
The goal is to make this L2 basement friendly for the incoming winter.

Now the Question:
What is a knowledge base about shortening the Dwell timing for a given caliber and barrel length?
What I am seeing the L2 blows too much dust on the floor with .22x500 and jets 0.5+0.7. I have no problem replacing jets but I have problem with degassing many times, because at the moment my YH would need some attention but next time in my hands.
Theoretically 2x0.8 or 2x0.9 jets? can still feed the indexing?
I don't speak Russian but can recognize some random words, I ran into some hacks on YT... what is it about?
 
Disclaimer: Non-L2 owner opinion although I run a valve similar in design.

Larger jet = less dwell.

Doesn't the L2 have a way to choke the transfer port?

If certain parts are worn, no amount of jetting will really cut dwell, I know that much about the L2 pilot valve...if the chambers for the PV rise equal to throat pressure during the shot cycle, you'll basically always be near plateau. So to that, I hope all parts and tolerances are good and well.

(I put about 3~ hrs on my YH when I did the R&D of this valve to adapt to my m-rod, lol)

-Matt
 
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One reason if the L2 PV has poor balances/tolerances and the chambers equal throat pressure why it won't shut fast (short dwell), is because the projectile has to be so far down the bore, and the pressure drop enough behind it at the valve throat for the pressure inside the valve fed by reg to be able to overcome the throat pressure in order to close the valve.

So with improper balance/tolerance you're dependent on pellet position in the bore to decide your dwell.

Choking the TP or limiting the travel of the main poppet are quick fixes to the above.

A slow feeding reg also can make the above worse.

Lastly one could modify the gun to cut dwell by adding more closing force in the throat, present on the pilot, however I cannot recommend this for the L2 personally as I have no clue how it would effect the other mechanism. This would need more attention to detail then I'd like to go through but it is a way.

-Matt
 
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L2 Diagram:

1698456770468.png



#10 is the main poppet that I referred to above in my posts. (limiting its travel somehow will cut dwell)

The circled part bottom left is your jet/check valve

#5 and 6 is your pilot. (Adding more sail effect would assist in cutting dwell)

#41 is a ceramic ball used as a seal against the main. (no comment)

#14 is what your trigger presses against to open the pilot(#5/6) which activates the main (#10)
 
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Stubbers said:
....All I said above applies...
Click to expand...
Thanks Matt
When you said "transfer port" that triggered a spark in my brain.
I have these spare pucks for over two years never measured the transfer hole. Here it comes - 7.25mm . That must be a size for .25 cal ?!

20231027_214429.jpg


Tomorrow I will do some CAD work and design couple sizes, will try to 3d print from resin.
My logic is telling me - for now as I am only speculating - that if I restrict the transfer port size from 7.25 to let say 6mm for example, that may help not suffocating the indexing if I install larger jets - to get a shorter Dwell.
Seem to me a good chance to try something new. :)
 
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bigHUN said:
Thanks Matt
When you said "transfer port" that triggered a spark in my brain.
I have these spare pucks for over two years never measured the transfer hole. Here it comes - 7.25mm . That must be a size for .25 cal ?!

View attachment 400602

Tomorrow I will do some CAD work and design couple sizes, will try to 3d print from resin.
My logic is telling me - for now as I am only speculating - that if I restrict the transfer port size from 7.25 to let say 6mm for example, that may help not suffocating the indexing if I install larger jets - to get a shorter Dwell.
Seem to me a good chance to try something new. :)
Click to expand...

Definitely worth a shot.

7.25mm is without a doubt for .25. This may be the simplest approach in cutting down your valve dwell without impacting the rest of the guns functions.

It will reduce the pressure behind the pellet allowing the main poppet to close faster.

These valves are very finicky and there are a lot of gremlins there. Probably 3-4 other ways to skin this cat.

-Matt
 
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Hey guys - I thought I would jump in here and help out a bit. I've been working on and tuning the L2 since the first batch of 100 made it to the US. I've had the valve apart more times than I can count and have a pretty solid overall understanding of how the L2 operates. Hopefully I can share some of that applicable info here.

First - to Matt's point on the valve. I'd like to clarify a bit of the operation so that you understand how the jets/nozzles control the dwell of the airgun. There are basically two valves in the L2 system. A large outside dump valve which allows a huge amount of air flow. Inside the dump valve is another small valve which controls the operation of the dump valve. In a steady state both the dump valve and the smaller valve are at the same regulated pressure. When you squeeze the trigger you release the air in the smaller valve. Doing so allows the dump valve to move back into that space the air was just emptied from. When this happens, the regulated air starts to fill that small space behind the dump valve back up through the jets. It's the size of the jets which control how fast the air flows in pushing the dump valve closed. Larger jet - refills faster - shorter dwell. Smaller jets - slower refill - longer dwell.

It's mostly the bottom row of parts pictured below. Part 10 is the dump valve.
Screen Shot 2023-10-27 at 10.45.50 PM.png


You can use the approximate total area of the two jets combined to determine the approx change in dwell with different size combos. The tuning concept I use is get the jet size to an efficient dwell for the caliber and barrel length you are using. Then use the regulator to adjust the speed. The nice thing about the L2 valve is that the dwell will remain nearly constant across all pressure ranges because it's the same pressure pushing on both the front and the back on the main valve.

For a 500mm .22 barrel, 0.7/0.7 isn't terrible. I would probably run 0.4/0.5 or 0.5/0.5 if I wanted to tune on the hot side. Going to 0.9/0.9 would be a tamer tune - but you'll need a higher reg setting if you want to get the same fps.

I currently run a .30 600mm LW barrel and I am using 0.1/0.1 jets. I'm pushing JSB 50gr @ 880fps with 120 bar on the reg. I can bump up to 160 bar (personal max I choose to go to baed on number of shots per fill). At 160 bar is pushing JSB 50gr @ 965 and Zan 65gr @ 935 for easily over 100fpe.
Leshiy 2 Nozzle Area.jpg


Second - the little red transfer port discs. Early on I spoke with Brian about using them for tuning and the recommendation from Ed was against it. It's just a teflon plastic disc to seal the air flow between the valve and the magazine with very little friction so the magazine can rotate. It's one size fits all and that's what I've gone with. Other's have written over the past few years about tuning with it, but I don't feel it controls dwell as accurately as the nozzles so I have avoided it.

Third - to the point of reg setting and magazine rotation function. I have run my reg setting all the way from 40 bar to 160 bar with no impact on magazine rotation function. If you are having issues with magazine rotation at lower pressures then there is still something off. Over time I have replaced many parts in the rotation mechanism and eventually I had to send my valve in for Brian to look at as I just couldn't figure out why it stopped rotating. Turns out it was a spring you would have never though it could've been.

We're I'm going with this is that EGW started selling repair kit bundles. They're a bit pricey if you just need one part. But, I think they are worth the value to replace all the wear parts for the rotation mechanism in one shot. I've used them to repair my EAZY fill and the kit was great.

Finally, in regards to moving too much dust on the floor. No matter how you tune it, the valve on the L2 is going to push a lot more than a tuned hammer/spring based airgun. I would highly recommend a good big moderator for it. I find the Silent Thunder Ordinance Falz and Sarissa do a great job. With my .30 600mm barrel I am currently running a Behemoth moderator, with two extra baffle sections, and a full length Behemoth shroud - this setup is indoor friendly and soaks up most of the air output.

Hope this helps out a bit.
 
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bigHUN said:
I see that Edgun is selling these pucks in 1-2-3-full size (7.25) holes, over the weekend I will print some 5.5 and 6.5 to start investigating.
Are you speaking the language from that youtube video? I am very interested to hear the entire story :)
Click to expand...

Heh never seen that video I just reverse r&d'd this valve and made some personal changes to it. Everything I said applies, everything.

@ctshooter You didn't clarify anything I hadn't already fwiw, there aren't two valves (THIS needs clarification because it can easily be misconstrued in the airgun world imo), its a Pilot Valve where a pilot stem (we call them valve stems commonly) controls the main piston, still all together its one valve with a main piston and a pilot 'valve' or stem, and 2 dump chambers, at least in my book, I don't consider poppets/pistons or stems themselves a valve in the airgun world, rather a collection of them all make up the valve.... a properly tuned pilot valve does NOT have to 'dump' or 'move a lot of air'....in fact my design can be de-tuned to 12 fpe or less while shutting VERY rapidly, with very little air moved...I made it clear larger jet = shorter dwell. If you want to get overly technical and scrupulous sure, there are two valves that make up a pilot valve, but that's very confusing to hear/say. Example to that, if someone's poppet fails/breaks, you don't tell them they need a new valve, you tell them they need a new poppet, in a pilot valve, if the main 'valve' fails, you would say you need a new piston, as saying main valve could be viewed as the entire assembly.

Technically regulators are a valve but we don't call them such, would be confusing.

Even what you refer to as a JET is a valve, a check valve. Demanding correction of that from you, Ed or any L2 owner is pedantic.

#10 is more of a piston with an expansion chamber than a dump valve. Calling it a dump valve is rather inappropriate, as a Pilot valve is nothing like a traditional dump valve. All these terminologies can easily be confusing.

I also mentioned many gremlins existing in this valve, from tolerances, balances (which includes springs), to much, much more.

Again, everything I said above applies...and this valve CAN be tamed for very low dwell conditions, although modification of the parts may be required...even if you had to reduce the amount of lift/travel of the main poppet/piston by adding a spacer in front of it.

The fact this valve is trigger actuated is one huge factor in being unable to reduce dwell so easily, but there are work arounds to that...

-Matt
 
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1698467234615.png


1698467266209.png


Those 2 look like different sizes to me.

Leshiy 2 question and different sized pucks...1 mm to 3 mm?

Okay I went to Francisco's EdGunLeshiy.shop to order some things and I see these 1 mm to 3 mm pucks for the L2. I can't find these puck options from anyone else. My understanding is the L2 comes with 5 pucks, 1 puck = 3 joules and then 4 full power, but not 1 mm to 3 mm pucks. If I have the...
www.airgunnation.com www.airgunnation.com

A bunch smaller here:

www.edgunleshiy.shop

Puck · Transfer Port Sleeves

www.edgunleshiy.shop www.edgunleshiy.shop
 
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1698467590377.png


Modifying THIS part in the above diagram to limit the main pistons travel/lift MAY cut flow out of the valve, reducing how much air dumps from the barrel, although I do NOT know how if it will effect the rest of the gun...I'd prefer trying a spacer in the main pistons cavity that runs in front of the main, .02"-.03" thick. This approach would mimic a weaker hammer strike seen in a conventional valve, but again I am unsure how it would effect the magazine cycling.


-Matt
 
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ctshooter said:
....
Click to expand...
Stubbers said:
...
Click to expand...
I agree with both of you.
I replaced the worn parts from the same Brian's repair kit you talking about...I remember measuring new dimensions on the R2D2 spring length...
What is my concern, as I said earlier, if blows the dust on the floor = it blows the pellet as well at-and-away the muzzle. This what I am trying to minimize.
I don't know the current pressure in the REPR I removed the gauge many months ago, I thought that I learned enough to tune by speed only. 16gn Baracudas I can do close to 100 shots at the moment and these would be pretty consistent with MOA @ 50 meter, with the FX .22x600 liner.
Before I replaced the worn parts the indexing didn't work consistent with 2x0.7 jets @ 140 bars and 25gn MRD's, but worked with 16 gn at the same Reg. I have not investigated after I replaced the parts, so far 05+0.7 jets inside for over a year.
I will try next week 2x0.7 and 2x0.8 with a bit shorter barrel .22x500 and I will install back the gauge to monitor.
Wondering how that could be done 2x1.0 I was reading earlier about, but not to exceed let say 150 bars?
 
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bigHUN said:
I agree with both of you.
I replaced the worn parts from the same Brian's repair kit you talking about...I remember measuring new dimensions on the R2D2 spring length...
What is my concern, as I said earlier, if blows the dust on the floor = it blows the pellet as well at-and-away the muzzle. This what I am trying to minimize.
I don't know the current pressure in the REPR I removed the gauge many months ago, I thought that I learned enough to tune by speed only. 16gn Baracudas I can do close to 100 shots at the moment and these would be pretty consistent with MOA @ 50 meter, with the FX .22x600 liner.
Before I replaced the worn parts the indexing didn't work consistent with 2x0.7 jets @ 140 bars and 25gn MRD's, but worked with 16 gn at the same Reg. I have not investigated after I replaced the parts, so far 05+0.7 jets inside for over a year.
I will try next week 2x0.7 and 2x0.8 with a bit shorter barrel .22x500 and I will install back the gauge to monitor.
Wondering how that could be done 2x1.0 I was reading earlier about, but not to exceed let say 150 bars?
Click to expand...

Cutting dwell is just going to be a major PITA on a mechanical trigger actuated valve unless you have the trigger disconnect from the valve upon activation, which the L2 does not.

Won't be a simple approach, but it can be done, even with the largest of jet. An electronic trigger that sends a quick pulse over a mechanical trigger is likely the most IDEAL fix....

-Matt
 
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bigHUN said:
if you watch that video the guy is talking about some 2mm setscrews below the brass bell, I don't have that 2mm hole there. Also I cannot recall seeing this your piece in the image above.
Click to expand...

If that somehow limits the main pistons (#10 in diagram) lift/travel once activated, that will cut the dwell down, that is your best approach outside of an e-trigger, limiting how far the piston can lift from the valve seat. You don't need crazy big jets (although this design relies on them)....my design uses a really small .019"/.048mm vent/jet and still can make down to 16 fpe. Over sized jets are a band-aid approach. You should certainly use them to tune an L2, but by all means, meh.

-Matt
 
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and I forgot to mention it... me in Canada, moderators are a big no-no, not worth the risk.
This is one of the main reasons I lowered the 16gn Hades speed to 800 and want to install the FX shroud with integrated air stripper.
The e-trigger I am tinkering about that for a while, the tricky part is how to replace that long rod inside a plastic housing, not much room for a bracket.
 
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Tbf when you oversize a jet so much to where the magazine stops cycling, you probably could reduce the puck size to get it working again. This is an assumption but the smaller puck should divert air from going down the barrel to...the magazine. Food for thought.

Keep in mind this is for shorter dwell / low power, as you're intending.

These valves aren't balanced valves so to speak but they sure are a balancing act.

-Matt
 
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