Unusual RT Pro Issue. . .Now confirmed as micromag 2k9 problem!

[sniper42]

Alas, I have not yet resolved this. Finals week is approaching for me so I won't be able to work on it until they are over and I'm on break. Rest assured I will be back here for help once finals are over.

[nak81783]

OK. Here's the posts I have from e-mail notifications.

sniper42: I checked to make sure the piston was engaging and I can feel it engage on the reg pin. I checked again for any debris in the valve and I'll get chrono readings tomorrow. I also borrowed my buddy's valve that I can swap springs from to see if that is the problem.

sniper42: Ok I switched the halves for my buddy's valve. Velocity started out at 250. I could turn it up to 260 before the piston leaked. I swapped it for my new piston. I could then get the velocity up to about 270 but then within ten shots I ran out of air. So I need to make a trip to the proshop to get more before I can do any more troubleshooting.

sniper42: Yes my tanks were full and above 1500 psi for all testing.

I started switching the back halves. He is running a level 10 but the valve is relatively new to him so it needs to be tuned still, it had a small leak from the bolt so he needs a smaller carrier. I don't know if the fact the I am running an SHP would make a difference in how his level 10 is setup on his gun. Like if he runs his with a standard tank but then puts an shp on it, the bolt would need to be tuned again correct?

sniper42: I don't know if the fact the I am running an SHP would make a difference in how his level 10 is setup on his gun. Like if he runs his with a standard tank but then puts an shp on it, the bolt would need to be tuned again correct?

athomas: No, the level 10 tuning is always dependent on the size match between the bolt stem and the oring. A properly tuned level 10 bolt should work through all chamber pressures, which are unaffected by the input pressure from the tank regulator.

[OPBN]

Any update on this?

Where did the other posts go? I have e-mail notifications with additional posts that are now gone. Did the Mods delete them?


-Nathan

Apparently there was sort of minor failure and a few days of posts were lost.

[nak81783]

Any update on this?

Where did the other posts go? I have e-mail notifications with additional posts that are now gone. Did the Mods delete them?


-Nathan

[sniper42]

I don't have the marker with me at the moment but I will be able to mess with it tomorrow. I'll give those things a try and see what I come up with.

[nak81783]

I'm following this on MCB as well. I'm not sure if you have the marker with you or not. You stated there is no debris in the reg piston pocket -- good. My next question is does the reg piston slide freely (as freely as a lubricated o-ring should) in the pocket? Also, does the piston travel all the way to the bottom of the pocket, or does it stop short? If you take the regulator valve pin o-ring out (the one that sits in the face of the rear half of the valve), can you see the brass colored reg piston sitting close to the pocket that the aforementioned o-ring sits in? If not, is the reg piston out of round, nicked, gouged, or otherwise damaged? What about the pocket? Is it out of round, nicked, gouged, or otherwise damaged? Do you see anything that would prevent the reg piston from sliding to the bottom?

Other than the reg springs being severely relaxed, my other hypothesis is that the reg piston is jammed up, and when you try to increase velocity, all you are doing is pressing the springs against a jammed reg piston. It's not getting to the reg pin like it should.

A quick way to test this is open the two halves of the valve. Remove the large reg body o-ring (the one on the threads that connect the two valve halves). Screw the valve back together. On the last turn assembling the valve, you should feel some resistance. That's the reg pin hitting the reg piston and compressing the springs. You can feel what it's like when they do not hit by removing the reg pin assembly and screwing the halves back together. If you don't feel the resistance, the regulator can't do what it's supposed to. The reason you take the large o-ring out is so that you don't feel the resistance from that when putting the two halves together. Make sure the reg pin assembly is seated all the way before doing this test. Otherwise, you'll feel a "false positive" when screwing the halves together, because you'll feel the resistance of seating the reg pin assembly.

Even if this is correct, the springs might still need to be replaced. However, if you get the piston to slide freely/bottom out, the suggestion of adding a washer behind the springs should make a difference.

Wordy, but hopefully this helps. Let us know what you find out.


-Nathan

[sniper42]

1. Nope, no leaks.

2. I rebuilt the entire valve. Pretty much all the o-rings were shot when I got it.

3. Double check everything for debris, nothing I could see.

4. I think my buddy has a working valve I can swap for. I'll give that a go.

I will get some chrono readings this weekend when I can test it, as well as get some pics up.

[nak81783]

1. No leaks anywhere, correct? With or without trigger pulled?

2. Did you rebuild the reg pin assembly or the entire valve? What all did you replace?

3. Diassemble the back half of the valve. Check for debris (o-ring segment, dirt, metal shavings, etc.) in front of the reg piston.

4. If #3 checks out, I am still thinking it's the springs. If this thing sat stored for 10 years with the adjustment nut bottomed out, the springs may have relaxed in the compressed state. Or maybe someone put incorrect springs in it to begin with. I'd try new springs.

However, I know it can be frustrating to buy new parts without a guarantee they will work. Does anyone near you have a properly functioning valve you could swap back halves for test? This could help you isolate the problem.

Afterthought #1. You stated you get different velocities with the different bolt springs. Please list starting velocity for each spring. I want to make sure my hypothesis is in line with the data.

Afterthought #2: Do the same debris check as #3 in the pocket that the reg pin assembly sits in. This should cause a leak if there was something in there, except maybe an o-ring, but it's another thing to check. Take a good picture of your reg pin assembly, so we can have a look.

-Nathan

[sniper42]

Both springs are in place.

The reg pin assembly looks good. I did rebuild it when I first got the valve off evilbay and I made sure to put it back together correctly.

[nak81783]

Do you have both springs (inner and outer) in between the reg piston and adjustment nut? If so, consider replacing them.

Also, compare your reg pin assy with the pic at airgun.com. Are all the pieces there? Does it look like the end that is toward the rear of the marker when assembled has been tampered with (e.g. ground/filed)?


-Nathan

[sniper42]

Yup, same issue with all three springs.

[sjrtk]

Are you still using the red spring? Have you tried the gold spring to see what happens?

I ask because my retro valve would cycle at 265 with the red spring one i put the gold spring in it went to 320. I had plenty of room to adjust the velocity down to 270-300 depending on the field.

[sniper42]

I tried that. No change. The gun still won't cycle, even if the nut bottoms out.

[BTAutoMag]

try putting a spacer inbetween your reg spring and adj nut. ghetto but it works

a washer from a hardware store works

[sniper42]

The issue occurs with both my draxus tank (850ish psi) and my ninja shp at 1100psi.