need advice on how to address weird x-valve behavior

[nicholas70]

Just recently I noticed my x-valve would go full auto when it is first charged with air while the trigger is depressed. I've only run about 4 or 5 cases through it up to this point and this is the first time I've noticed this. At one point when being charged today it rapid fired a few times a dumped air into the barrel. Once I let up on the trigger and fire it it seems to start working normally, at least for the most part. While trying to see if I could get it to go full auto by holding the trigger down I did notice a slight bit of air escaping down the barrel but this stops after about half a second while the trigger is held down. Once the initial air up process is completed the only things I'm noticing are somewhat inconsistent velocities. About 60% to 70% of the shots are running between say 278fps and 290fps but a few outliers will push up to the 300fps mark or down around 260fps. I noticed a couple of dimpled paintballs in the batch I had today but I wouldn't think that paint alone would generally cause this kind of fps deviation.

I tried checking the on off assy removed and visually inspected o-rings and wiped them down. I also inspected the sear which I installed a month after I got the x-valve and it appears to be in good condition and a gap is present between the trigger and the trigger rod when gassed up. (note I played with less gap prior to the start of this problem.) I also removed the regulator seat holder and regulator seat oring wiped them down and they also appear fine upon visual inspection. After doing these things I tried putting everything back together put more oil in the system and gassed it up and in rapid fired a few times and started dumping air into the barrel. Let go of the trigger fired it once and it seemed fine. Tried holding trigger down to check for full auto and all that happens is a bit of air escapes for about 1/2 second. I should also point out that I don't have access to chrono to know if the inconsistency has issue has been effected by the actions taken so far.

[athomas]

Check your on-off top orings first. Then check the regulator valve pin oring at the back. If any of those orings are leaking, then they let air into the front chamber, even when the on-off is closed. This can cause full auto issues.

[nicholas70]

Ok so I took apart the entire on/off removed every oring and wiped every oring down all orings appear fine upon inspection. I also removed the reg valve pin assy and wiped down all those orings. .( I did notice a very small amount of debris which looked like tape from the air line threads around the reg valve assy) When I first regassed the gun with the trigger depressed I got huge air dump into the barrel which was stopped by re-engaging the trigger. I fired a few shots to get the oil I added into the gun and retested it. The 2nd test went much better then the first as the gun only fired one time when initially gassed up no full auto and no air dump. I fired a few more shots and it seems the short leak that occurs for about a second when I hold the trigger down though still present is not quite as noticeable as before. One thing I did notice is a slight persistent leak down the barrel that occurred during a few of these tests which would usually stop after a brisk pull of the trigger but is encouraged by a slower pull like one might use in attempt to sweet spot the trigger. Note I was unable to see if the consistency issue was impacted but I'm optimistic and will check back on that when I can get to a chrono.

I considered trying to fine tune the level 10 as from what I've been told you usually have to change the carrier size once the orings wear in which I have not had to do up to this point, but I thought I should check back here first in case you think there could still be an issue in the on/off.

[Cyco-Dude]

could be time to move to the next smaller sized carrier.

[athomas]

Remove any shims that may be installed in the powertube first. They can contribute to the slight leak down the barrel when the trigger is held in, and to random leaking out the front.

Teflon tape debris can definitely cause issues when it gets into the valve. I try not to use tape for any of my air joints. I use high pressure sealant instead. It works much better and you never have to worry about pieces breaking off.

[nicholas70]

I removed all the shims after having put the first 1000 shots through the valve to address a level 10 leak. The only thing left to do at this point as far the the level 10 goes would be to change the carrier size which has not yet been done to this valve.

[nicholas70]

Well I switched out the carrier I was using to the smallest one I had and I can no longer create the leaking problem even when the trigger is pulled and held down no air can be heard escaping. I added additional oil fired multiple times and checked level 10 reset and it is working as intended. I did about 6 or 7 disconnect and reconnects of the air source while holding the trigger and all but one of the times the gun only fire once when the initial air connection was made. During one of the early tests,I think it was the 2nd, it fired 3 times and then stopped so I guess the problem is 90% solved. I really do wonder why it is firing when the air is connected like that as I don't remember it doing that before and I know the classic valve I had never behaved that way. Hopefully in the next two weeks I'll be able to chrono it to find out if it is shooting a bit more consistent and if so I'll probably just opt to leave it as is and chalk the fires once when gassed up as a mystery.

Edit add: it did occur to me that my on/off brass is getting a bit chewed up by my old school standard feed mainbody and I have to sometimes use a dental pick to get it to clear the mainbody when installing the valve. (Had to do this day one when first installing the valve) I didn't think this could really cause a problem as long as the on/off pin is in good shape which it appears to be but I figured I throw this out there in light of this experience.

[Cyco-Dude]

Edit add: it did occur to me that my on/off brass is getting a bit chewed up by my old school standard feed mainbody and I have to sometimes use a dental pick to get it to clear the mainbody when installing the valve. (Had to do this day one when first installing the valve) I didn't think this could really cause a problem as long as the on/off pin is in good shape which it appears to be but I figured I throw this out there in light of this experience.

what? the on/off bottom should be in the valve; it should not even touch the body when installing the valve.

i would check your on/off top o-rings and make sure they are seated correctly. you may need to get a different power tube o-ring; as some are smaller than others and when putting the valve pin o-ring inside, can snap apart and unseat. i usually try a bunch until i find an o-ring pair that sits flat and doesn't pop apart.

[nicholas70]

The on/off bottom does make contact with the mainbody and as I said before it actually came to me that way from AGD and was a bit puzzled at first when the valve didn't slide into place like the classic valve did. After using the dental pick to get it to clear the mainbody it seemed fine, and this issue only remerged after I removed the on/off the other day while troubleshooting these issues I've been having. I will try reseating it a couple times and if still no go try a few different top on/off orings to see what happens.

[nicholas70]

So I reseated the on/off top o-rings and the on/off assy and while doing this I noticed what appeared to be another small piece of debris deep in the on/off housing. I managed to fish the offending item out of the valve which appeared to be keeping the top on off o-rings from sitting completely flush against the valve body in the back of the on/off housing. When I finished removing the item I had to do a double take as it wasn't just a piece of debris it was what appears to be a 'very' small shim which had been bent slightly by the on/off pushing it against the valve body. The shim is totally round with what resembles an open crown on one side. I double checked the x-valve schematic located at http://www.automags.org/forums/showt...ith-emag-valve and I do not see the part there anywhere. I do however notice this same part is included in my x-valve parts kit. I decided to go ahead and put the on/off back together and sure enough it seems to be sitting flush against the valve body now. I retested everything several times and the marker still fires once when being gassed up but otherwise seems fine when dry fire testing.

I'm starting to wonder now what if any impact this out of place part might have been having on the operation of the valve up to this point. I'm not even sure how long it has been like that as I could have missed it the first two times I removed the on/off when I first started troubleshooting this issue.

[Cyco-Dude]

sounds like you had a lvl 10 shim in there (or, a ult shim). either way, it wasn't supposed to be there.

have you replaced any of the on/off o-rings with new o-rings?

[nicholas70]

I have not actually replaced the on off orings yet. I will try replacing the on/off top orings later this afternoon to see what happens. Also here is a picture of the strange object I found in the on/off housing that appeared to be causing it not to sit flush against the valve. I put the two unknown parts next to a level 10 shim to give you an idea of the relative size. Based on reading what parts came in the x-valve parts list I'd say the unknown part is either reg valve pin spacer or reg valve pin c clip. How it got to that point in the first place I don't think I'll ever know, and I'm guessing it isn't too important since I'm not noticing any major issues without it being in there.

[athomas]

They look like the tiny C-clips that go on the regulator valve pin assembly.

Well, that part isn't supposed to be in the on-off area. It would definitely change the ability of the on-off to seal properly, which would cause your double firing. Hopefully the orings weren't damaged by it being there.

[Cyco-Dude]

yeah, answered this in chat late last night; what athomas said.

[Laku]

I suppose they aren't missing from your valve pin?