2240 Valve mods
Printed From: Kiwi Airgunners
Category: Technical
Forum Name: Pauly's Technical Area
Forum Description: Technical information, Modifications and DIY projects are all in here
URL: www.kiwiairgunners.co.nz/forum_posts.asp?TID=1208
Printed Date: 17 Jul 2025 at 1:43am
Software Version: Web Wiz Forums 10.14 - http://www.webwizforums.com
Topic: 2240 Valve mods
Posted By: Kris
Subject: 2240 Valve mods
Date Posted: 29 May 2025 at 12:55pm
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Hello all, With a 10inch Barrel, are there any mods I can do to the valve itself? Cheers Kris |
Replies:
Posted By: kruzaroad
Date Posted: 31 May 2025 at 8:58pm
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There will be. I know from 1322 (pump up) that the valve can have a few threads cut off and inside of the valve can loose some metal. I think you can slightly change the angle of where the air leaves the valve so its not a hard turn for it. You can drill out the port too a small amount. There will be stuff on site and the web about how to do it. |
Posted By: Pauly5
Date Posted: 01 Jun 2025 at 10:09am
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Yea, I think that smoothing off the path of the CO2 by taking a dremel to the transfer port will help a bit, but don't think there's a huge gain in power, still an increase is an increase. Kruz, cutting the threads and boring out the valve works well for the pumper because it increases the volume of the plenum, or the stored air for each shot. With the 2240 its a direct path from the capsule to the poppet valve.
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Posted By: Microbugs
Date Posted: 01 Jun 2025 at 2:37pm
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Yes, port the valve, remove the right angle that feeds into the vavle into the connection to the barrel. You can also thin down the valve stem to allow better gas flow out of the valve, but don't go too far or the stem with break after a while (been there). ------------- Benjamin Discovery Modified Crosman 22XX PCP Build Cometa 400 restocked Zorali HP01 |
Posted By: Kris
Date Posted: 05 Jun 2025 at 1:37pm
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Thanks KrisNZ |
Posted By: Kris
Date Posted: 05 Jun 2025 at 1:38pm
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Makes sense Thanks KrisNZ |
Posted By: kruzaroad
Date Posted: 09 Jun 2025 at 3:14pm
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So i been looking at 2240 valve on line out of curiosity, It would seem you can buy a better flow valve from boss. A better transfer port to barrel, up to 25% increase in volume flow claimed. Also a stronger hammer spring to keep valve open longer or weaker valve return spring. Seems the longer barrel is the number one thing to do. Im assuming as co2 will only pressurize to a certain pressure (not taking heat and cooling affect into account) that goal would be to get enough co2 into the barrel to keep it expanding for the duration of the pellets travel along the barrel. Thus there will only be so much that can be achieved in actual power gain and that max power is created by having a long continuous push that doesn't stop till after the pellet leaves the barrel. Not a get the pellet going and let momentum carry it the final part of barrel, or a weaker push as the co2 slows its expansion due to decreasing expansion pressure. Only issue i see would be the gas flow around the pallet as it left the barrel. Your crown would want to be in good nick to encourage even distribution of escaping gas so as not to upset the pellet. It would also seem you can actually take some metal out of the head of the valve to help volume. Also the thinning of the valve stem as mentioned above. Nut as i say, this is from web research. Hopefully the ppl on here who pull these co2 pistols apart can verify this |
Posted By: Pauly5
Date Posted: 09 Jun 2025 at 3:21pm
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I will agree with the longer barrel and from experience heavier pellets. Mintie is a CO2 wizard.
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Posted By: kruzaroad
Date Posted: 09 Jun 2025 at 3:28pm
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If you want to the math for the volume of your barrel here's a blurb on expansion rate The liquid-to-gas expansion ratio for CO2 is approximately 535:1. This means that for every unit of liquid CO2, it expands into 535 units of gaseous CO2 when vaporized at room temperature and normal atmospheric pressure. Heres a pipe volume calculator which you can get an approximate volume off. Due to rifling its not going to be exact but should get you in the ball park. It will take mm and inches at the same time so you can do the pellet in mm and barrel in inches https://www.servicetitan.com/tools/pipe-volume-calculator |
Posted By: Kris
Date Posted: 09 Jun 2025 at 11:21pm
| Thanks, there's plenty to think about. |
Posted By: Kris
Date Posted: 09 Jun 2025 at 11:24pm
| I think a 12-14 inch barrel is the best to use with the modded valves, |
Posted By: kruzaroad
Date Posted: 10 Jun 2025 at 12:06am
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The question would be, i think is it putting out enough power as it is to do what you need it to do? Power for the sake of power isnt always the best move. My 1322 doesn't have great power, but its a bird gun. For tree shooting and at that it excels. A longer barrel and steel breech,scope and really thats is enough. Have a rifle for further distance larger critter. It will never be a primary weapon for hares or possums and doesnt need to be. It fills it role very well. |
Posted By: Kris
Date Posted: 10 Jun 2025 at 2:03am
Yes, your dead right. So in my case modifying the valve would be of no real use. Thanks Kris |
kruzaroad wrote:Posted By: kruzaroad
Date Posted: 10 Jun 2025 at 9:42am
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There is one more mod that i had done which seemed to me made difference and that was a hollow probe bolt. ( Its such small and non intrusive mod i forgot about it) Pauly5 was kind enough to turn one up for me. I had replaced the original bolt with a extended probe version allowing the pellet to push past the transfer port, I worked fine but the hollow probe really ended up being a good move. It's contact point is wider and sits better against the inside of the pellet skirt, but i think the main thing is it directs the pressure strait to the back of pellet which means the pellet has to start moving before the gas can keep expanding and as the pressure is directed to the inside of the skirt it flares the skirt better or quicker than having the small amount of space to start expanding around the probe first. What ever it is, i noticed the difference at the time i installed it and wont be going back to a standard bolt or extended probe bolt for any pump or co2 air gun i get in the future. A small and subtle change that im glad i made. |