Evanix Tactical Sniper

[dogwood]

Took the gun apart 


the receiver looks beautifully done

found more burrs and this:


either the port was drilled off center or the o-ring groove was machined in the wrong spot
You can't see it in the photo but there are more burrs inside the valve and the o-rings had a bit shaved off

[dogwood]

Stem broke right at the o-ring groove, I couldn't find the other half 

[rkr]

Stem broke right at the o-ring groove, I couldn't find the other half 

Also look at the valve seal, it has been compressed almost to the cup part. I bet you'd be having a leak in a hundred or so shots had the stem lasted. That valve housing outlet hole being offset is also a familiar thing. although my gun had that hole in place while the transfer port was offset. I can't help but wondering what the heck is wrong with Evanix? They have a nice bigbore concept here and they are just wasting it with some poor design choices and poor QC.

[dogwood]

is your valve seat flat? mine has small lip around it, almost like an insert was put in, metal color is different 

[rkr]

is your valve seat flat? mine has small lip around it, almost like an insert was put in, metal color is different 

The seat has a lip but it's all blacked out so I don't know of material differences.

[Rescue35]

Why is there an oring on the stem? It just weakens the stem and is not necessary if the valve is made properly. In fact, an oring will hinder performance here...I've tried it.

[dogwood]

I have the feeling that I will end up making my own valve
And once my lathe is back in shape and probably a new valve assembly

[dogwood]

cleaned my barrel again while waiting for the new valve, was finding small metal shaving on the patch, assuming it was lead.
Cleaned up the edges on the transfer port, smoothing out the transition
Lead in looks like it was cut with a chisel, spent some time polishing that up.

Will spend some time polishing the bore where the hammer rides as it still feels a bit gritty and rough. 

popped in my de-pinger since I have the gun apart.

[dogwood]

spent an hour or so polishing all the moving parts, cocking action is now much smoother

Valve arrived today, hope to get it and try it out soon, 2 1/2 feet of snow on the ground right now though 

putting in a lighter valve spring and trimmed the hammer spring down bit added delrin washers in hopes to let the spring move freely

[rkr]

spent an hour or so polishing all the moving parts, cocking action is now much smoother

Valve arrived today, hope to get it and try it out soon, 2 1/2 feet of snow on the ground right now though 

putting in a lighter valve spring and trimmed the hammer spring down bit added delrin washers in hopes to let the spring move freely

You could even leave the valve spring out if you want it real light. If you have dremel you could smooth the edge at the valve housing where air turns from valve stem tunnel to the outlet. That's the worst bottleneck in a stock gun. 

[dogwood]

Thanks rkr

pumping so no valve spring at all is out  the spring I'm putting in is lighter ad shorter

Actually I already did that, have a nice diamond ball burr and rounded off and smoothed the port as much as I could, then sanded and polished and well

not as smooth as I'd like it ( hard to get in there) but huge improvement over stock.

I had also added some more holes in the block around the inlet, thinking of getting a conical spring and really opening up that portion

[rkr]

Thanks rkr

pumping so no valve spring at all is out  the spring I'm putting in is lighter ad shorter

Actually I already did that, have a nice diamond ball burr and rounded off and smoothed the port as much as I could, then sanded and polished and well

not as smooth as I'd like it ( hard to get in there) but huge improvement over stock.

I had also added some more holes in the block around the inlet, thinking of getting a conical spring and really opening up that portion

I've been thinking of a conical spring as well but you would have to make one yourself as ready made ones do not fit. Instead I've considered making a cross shaped support from a plate that holds the spring in the middle while still allowing a larger hole to be used for more flow.

BTW, can you actually pump up that thing from zero psi? I tried it in my blizzard and the gun didn't seal.

[Nomadic Pirate]

I've pumped several Evanix from zero, just have to cock the hammer.

[dogwood]

I've pumped several Evanix from zero, just have to cock the hammer.

Good point about cocking the hammer. 

Guns 2/3rds back together and holding air (no hammer spring  ) got it to 100 Bar before calling it a night

[dogwood]

I've been thinking of a conical spring as well but you would have to make one yourself as ready made ones do not fit. Instead I've considered making a cross shaped support from a plate that holds the spring in the middle while still allowing a larger hole to be used for more flow.

BTW, can you actually pump up that thing from zero psi? I tried it in my blizzard and the gun didn't seal.

Yeah the conical springs I've found so far would need some "massaging" to fit.

I've also been thinking of a way to support the spring after removing most if not all the material the blocks the path

was thinking of drilling a small hole just before the threads for a small rod and printing up a spring guide, something that would hold it without blocking the path too much.

[rkr]

Well, my pressure test without the valve spring is failing, down to 80 bar now. It seems that PEEK really needs some additional pressure to seal. When the gun gets empty I'll make a spring support and post some photos in the 9mm tuning thread.

[dogwood]

Finally got chance to finish pumping it up, still only partially together, decided to shoot a few more Lap rounds through it and want to be able to clean the barrel properly

Fire 5 round, 5th stuck in the barrel about 2" from the muzzle, made an odd sound -  the air was slowly escaping around the bolt

had to hammer it out with my cleaning rod, pumped it back up and fire one more, not sure what happened.

I am running a lighter spring on the valve and trimmed the main spring a couple of loops.

[rkr]

Finally got chance to finish pumping it up, still only partially together, decided to shoot a few more Lap rounds through it and want to be able to clean the barrel properly

Fire 5 round, 5th stuck in the barrel about 2" from the muzzle, made an odd sound -  the air was slowly escaping around the bolt

had to hammer it out with my cleaning rod, pumped it back up and fire one more, not sure what happened.

I am running a lighter spring on the valve and trimmed the main spring a couple of loops.

Does your pellet probe (the thick part) actually reach the barrel o-ring? Sometimes the barrel is too far ahead or probe too far back and there's no proper sealing at the breech end of the barrel.

Also, the problem you have sounds a bit like mushroomed valve stem end which prevents the valve from opening fully. If I were you I'd open it up to check that stem. The new stem I got was like that and it eventually locked the valve open.

[dogwood]

Bolt seals nicely in the barrel o-ring.

I'll take a look at the valve stem, hope that's not the case - I will be most displeased 

[rkr]

Well, it took me 8 shots to lock it open - you've fired 6 now. The speeds were all over the place with those 8 shots so that might be your problem. There's at least one bad batch of Evanix valves out there and some of the replacement valves are bad as well.