Valve lock?

[DanoInTx]

I know Bob asked about this a few weeks ago, but I hadn't been shooting much so I didn't have anything to answer.  I left the QB out in my garage last night (about 101F) and tried some penetration tests and noticed a significant loss of power.  I just did my very first CO2 tune on this thing so I thought maybe I did something wrong.  The gun went back into the house, into my closet for the night.  I just got home from work and took it out to the garage to see if I could figure out where I went wrong.  I did a couple more penetration shots into some pine I have laying around and ...poof, power was back up again.  Now the house is air conditioned to about 76F, and the gun was in the house all day.  I only took it out for maybe 5 minutes while I did my test shots, where as last night it sat for many hours in the hot garage before I took anymore shots.  Does this sound like valve lock?  Like maybe the heat has given enough extra pressure that the hammer spring is having trouble openning the valve?  Just a thought, I only recently got into CO2 guns so I'm not sure, but it makes sense to me.  Anyone else?

Also, while I'm here... While doing my tune I left the cottony filter inside the valve.  Bob's tune guide said I could remove it, but it didn't say anything about that washer that sits on top of it except to mod it to look like a star.  I'm pretty new at this and was wondering if I remove the filter is there any reason to keep the washer?  Seems to me it just keeps the filter flat?  Also is there any real reason to keep the sleeve inside this thing?  The sleeve doesn't seem to serve a purpose except taking up space that could hold more CO2, maybe it's a guide to keep everything centered?

Dan

[mikeiniowa]

Anything over about 90 degrees will slow the rifle down, if a very light spring is installed in the valve you may be able to use the rifle up to about 95. Or install a much heavier spring for the hammer. these have a tendency to smash the end of the valve stem and bend stems but if you need it.........
If you are using bulk fill you can remove the pin ,cotton and washer they are not needed for bulk. If using cylinders you can remove the cotton and small screen, keep the washer as that is what the spring pushes against to close the valve. I have used a conical spring from Mcmaster-carr I'll see if I can dig up the part number, washer can be removed with this spring as it's just a tad bigger than the ID of the tube and holds the pin just about perfectly in the middle without the washer. It's also lighter than the OE spring so can give more FPS in the right conditions but will aalso use more gas per shot.

[mikeiniowa]

The Mcmaster-Carr part number for the conical spring is #1692K36 should help hot weather shooting. It may cause a valve leak when first piercing the cylinders, pop the cylinder then open the bolt right away so the pressure can close the valve.

[DanoInTx]

Thanx Mike, I'll give it a shot..  I really never noticed this with my Crosmans, but they aren't modded at all maybe that has something to do with it.  I did however notice my shot count go through the roof one afternoon with my 2300, but I never noticed much of a velocity drop.  Maybe the 2300 doesn't have enough barrel for how much air it eats, huhm, more things to ponder:)  Again thanx for the help with this AND the free floating barrel advice, I think I'll just play around and see what happens.  One thing I know for sure is that I need 2-3 more QB's, these things rock.

Dan

[DanoInTx]

Chronied the QB yesterday, but it's hard to say what it'll do still.  It was about 101F outside and the first shot was at about 610fps with cheapo Daisy wadcutters.  Then I dry fired it once or twice and shot up around 640.  I continued with very little time between shots and watched the fps climb with each shot.  Hard to say if the gun was heating up and giving me more speed, or cooling off and getting less valve lock.  Will have to do it again when it's more like 70-80F, but it was still good to see that I wasn't way off at like 200FPS or something.  Still have more work to do on this thing, but it does shoot pretty nice for my first CO2 tuned gun.  Picked up a 24" .22 barrel for my Crosman 2240 yesterday too, time for me to get grinding on that valve too!!!

Dan

[mikeiniowa]

I'd say it was cooling off and letting the valve open some more with each shot, when it gets down to 90 try again should be about right for max FPS.

[DanoInTx]

I was thinking that sounded right.  Gun cools, valve opens easier, more air, faster pellet..nice!

Thanks for the prior advice, I still have to go order some springs..

Dan