Really, Evanix?

[Bullfrog]

Yesterday I was all decked out and ready to go for my first filmed coon hunt of the 2015-2016 hunting season. I was shooting groups with my .357 Stormpup to make sure I had hunting-acceptable accuracy. During the third or fourth shot my gun let out an awlful "woosh" and my entire tank dumped itself during the shot.

I took the gun apart and found this...



The valve stem broke. That's garbage. There's no good reason for that to happen. Even my mods to the gun shouldn't cause that to happen. I'm only using a factory spring and hammer with little preload and I'm using prescribed fill pressures.

I'm not a happy camper. I've found too many problems with this gun since I've had it that are clearly manufacturing problems. A misaligned barrel port, a bad lever pin, and now this. Although I bought my gun refurbished through PA, I do not believe abuse from any past owner would cause these issues. Its simply the fact that Evanix used cheap metal for some parts and was sloppy with their drill work at the factory.

I can't sell this gun with a clear conscience, not for all the problems it has. They'll become someone else's problems. I'm going to try to get the gun working again but after that its probably going to get given away to family who will only shoot it occasionally. I'm going to start saving for a Slayer.

I'm having a hard time reconciling the positive word-of-mouth that Evanix generates with my experience with this gun. I bought this gun because of how so many people rave about the Korean guns and it seemed like good value for the money to get me started in big bores. Now I feel cheated.

So now that's out of my system, any solutions? Rkr, I found an old thread where you observed the same issue, but I didn't see what your solution was. I have access to a lathe now. I can probably make a stem. I just don't know how to make the plunger. Any drop in plungers out there that would work?

[rkr]

That is a rather common occurrence with Evanix valves, you are certainly not alone with this issue. Another problem is that the seal material is poor and will likely chip at some point causing another dump shot.  Check the rear of your breech, that dump shot may have caused it to stretch at the lever bolt hole.

Now to fix this I would suggest making your own valve. Mine was made by local guru but it's not that hard to DIY. For a stem you could use a 4mm HSS drill bit cut down to appropriate length. It might need annealing so check it after some use, new drill bits are cheap if you need to replace it. Then a piece of Ertalyte (PET-P) to make the seal. Drill a hole that's 0.1mm smaller that the stem to a roughly formed seal and push the stem in with some epoxy to aid in attachment. Put that on a drill or lathe from the stem and start shaping. Make it the same shape as your original valve end if you are still using the valve spring. Finish the mating surface with 400-800 grit sandpaper and you should be good to go. On high power guns that stem o-ring is not needed and as you noticed the groove weakens the stem considerably.

For the price those Evanix guns are indeed rather poor quality, sure they shine a lot but that doesn't make for a good gun. It is quite often that you here people recommending one brand because it has so nice bluing and so nice stock and it must be quality work. How many of those people have ever opened up their gun and checked for the assembly quality and parts quality? Not to mention the design itself but I guess giving a fair review of that is beyond most. Sorry, had to vent a bit. I just noticed a small but to me very annoying design problem in my BSA, heard JBs comments on that and it isn't his fault but BSAs who didn't listen to him. Why on earth can't those companies make things properly?

Edit, I believe Air Arms valve stem is the same diameter and has threads on the poppet part if you prefer using that http://www.airgunspares.com/store/product/13365/Air-Arms-S410-Firing-Valve-FAC-Part-No.-S370H/

[TleVta]

Read this thread yesterday right after I started thinking about a .30 RS II. Bummer, since these rifles are within my price range.

[Bullfrog]

PA sold me another valve stem. It seems that the new factory valve stems don't have the oring grove that the older stems had.

I'm retuning the gun now. It seems like the new valve stem moves a lot more air than the old stem did. It doesn't take as strong of a hit to open it up. I'm going to try a 14 pound Marauder spring in place of the factory spring to see if I can get it to full power with the advantages of the shorter spring. I'll report when I have something to report.

[Bullfrog]

I hate, hate, HATE this gun. The new valve stem leaks and has lowered my max velocity with JSBs from the 950s to the 850s on a bell curve or the 880s without a bell curve. Air usage has went up dramatically per shot, even taking into account the slow leak at the poppet. I'm not having good fortune with my airguns lately.

The gun is also ALOT louder. I can't square that with the lower velocities unless its just major hammer bounce.

[Nomadic Pirate]

Funny how the same exact gun can go for years without any probles and good accuracy ( several members of this very forum have the .357 rainstorm and are very happy )

than you have that one gun that just don't happen,....like cars,some lemons just are never right no matter how much you try fix them,Mind boggling

[LEE IN VA.]

Travis,  I know you always work on your own guns but I'd send it to Will Piatt.

[C.ALLS]

I hate, hate, HATE this gun. The new valve stem leaks and has lowered my max velocity with JSBs from the 950s to the 850s on a bell curve or the 880s without a bell curve. Air usage has went up dramatically per shot, even taking into account the slow leak at the poppet. I'm not having good fortune with my airguns lately.

The gun is also ALOT louder. I can't square that with the lower velocities unless its just major hammer bounce.

I'm willing to bet you called PA and asked for a replacement valve stem and they sent you an "updated" stem without the o-ring grove? See the problem is the valve stems without the o-ring grove are 2mm wider at the head which restricts air flow in the smaller valves used in the RS platform. The bigger stems are used in the Max ML which also uses a 2mm larger ID on the valve body.

I have owned 5 different Evanix. 357 rifles and have never had a failure and I believe it's because I didn't try to turn it into something it was never ment to be which is a 150 ft/lb gun. I did strip them all down and basically rebuild them so all the ports aligned and smoothed out the air path but never enlarged them. I was always rewarded with a super flat 7 shots and great accuracy after a spring swap.

[Bullfrog]

I hate, hate, HATE this gun. The new valve stem leaks and has lowered my max velocity with JSBs from the 950s to the 850s on a bell curve or the 880s without a bell curve. Air usage has went up dramatically per shot, even taking into account the slow leak at the poppet. I'm not having good fortune with my airguns lately.

The gun is also ALOT louder. I can't square that with the lower velocities unless its just major hammer bounce.

I'm willing to bet you called PA and asked for a replacement valve stem and they sent you an "updated" stem without the o-ring grove? See the problem is the valve stems without the o-ring grove are 2mm wider at the head which restricts air flow in the smaller valves used in the RS platform. The bigger stems are used in the Max ML which also uses a 2mm larger ID on the valve body.

I have owned 5 different Evanix. 357 rifles and have never had a failure and I believe it's because I didn't try to turn it into something it was never ment to be which is a 150 ft/lb gun. I did strip them all down and basically rebuild them so all the ports aligned and smoothed out the air path but never enlarged them. I was always rewarded with a super flat 7 shots and great accuracy after a spring swap.

That is correct, PA sold me a new stem without the oring groove. The thicker stem at the base would explain my loss in power, although it shouldn't have anything to do with the valve not sealing or dumping a lot of unused air during the shot. I am wondering if the poppet has to have a break-in period. To that end, I shot it a lot today hoping that the slamming action of the shot might beat it into place, but it didn't work. During the 20 minute trip between the farm and home it leaked about 2500 psi. When it shoots, it sounds like its dumping its air each shot, like the valve stem has broken again even though it of course hasn't.

Objectively, I do not believe the breakages in the gun have much or anything to do with my power mods. When my valve stem broke I was using a factory hammer, factory spring, very little preload, and 3000psi fill pressure. Those should all be within factory parameters.  It must have been a problem across the platform or Evanix wouldn't have done away with the oring stems. Furthermore, the level pin breakage most certainly didn't have anything to do with my power mods. That is dealing with nothing but mechanical forces within the lever and it broke within the first few days of me having the gun and putting few shots thru it. Of course the misaligned ports had nothing to do with my mods.

The failures seem to be related to whatever metal they make the valve stem and lever pin from. It seems like a brittle material.

The only feature that I think *might be caused by the power mods is the issues I'm having with accuracy. Accuracy is spotty even with JSBs. After cleaning the barrel I can usually stack pellets after several shots, and then after 20-50 shots the groups open up. Tonight because I figured I have nothing to lose, I tried a new bore brush I've always been afraid to use. Its made of steel loops and it scrapes the barrel instead of brushing it. Steel onsteel seems like a bad idea to me, but I said "what the heck" and gave it a whirl. I'll shoot groups this weekend to see if it made a difference. Bore most certainly looks cleaner than it ever has.

Before the valve stem broke, I was getting two clips in the high 800s and low 900s or one clip in the mid 900s at 100psi per shot. That was amazing compared to what I normally see for the platform. I can live with reduced power but not reduced efficiency. I'm not going to tolerate a 1:1 ratio of fpe to psi, not where it was doing 100psi to 150fpe before the valve stem broke.

I'm going to get it going again just because I'm not going to let this gun beat me. Then I'm getting rid of it. I've already got a friend who wants it. He doesn't care if its doing 800fps or 950fps, just so long as it gets working reliably. Looks like that .30 FLEX is going to be happening sooner rather than later.

My objective now is to get the valve to seal. To that end, I've reinstalled the valve spring (I was running it without one). I'm going to try to get it to sit under pressure all night and see if that won't press the poppet good into the seat.

[Bullfrog]

Well the gun won't hold air. I've also tried dry firing it and air is blowing out the valve stem hole during the shot cycle. PA's going to have to replace this valve stem, as the one they sent just isn't sealing.

[rkr]

I'd guess that your valve stem does not move freely in the valve block. That causes slow opening and slow closing making for low fps and lots of air dumped out after the shot. It could also be a reason for your leak. Why don't you just make your own valve? You can do it in a bench drill, no need for a lathe. There are instructions for making one somewhere on this forum, drill bit for the stem and PET-P for the seal. Alternatively if your valve is binding put it in a drill and take some material off the stem with 400-600 grit sandpaper.

[Bullfrog]

I did what you suggested and sanded the valve stem down... and it worked! The valve is sealed now and holding air, and the gun sounds more like it should when it fires and is using a reasonable amount of air when it shoots. This weekend I'll chrony it to see what my shot strings look like.

I'm willing to consider that I possibly just got the dud of all duds. But it just stinks to be the person who gets it for the money you spend. However, if I can get the accuracy problem solved and if the gun will continue to hold air as it should, my buddy who will be happy with it. My gut feeling is that by the time everything is said and done, the gun will be shooting JSBs accurately in the mid 800s.

[Bwalton]

Sorry to hear that I enjoy your videos, hope it all works out....

[rkr]

I did what you suggested and sanded the valve stem down... and it worked! The valve is sealed now and holding air, and the gun sounds more like it should when it fires and is using a reasonable amount of air when it shoots. This weekend I'll chrony it to see what my shot strings look like.

I'm willing to consider that I possibly just got the dud of all duds. But it just stinks to be the person who gets it for the money you spend. However, if I can get the accuracy problem solved and if the gun will continue to hold air as it should, my buddy who will be happy with it. My gut feeling is that by the time everything is said and done, the gun will be shooting JSBs accurately in the mid 800s.

I have pieces of one factory valve where the stem was made of too soft material. The stem expanded by hammer hitting it, got hang up and the hammer hit snapped it on o-ring groove. If your's is that way you may experience the same. Alternatively it may be just poor tolerances and it will work fine.

[oldpro]

Travis send it to me I can fix the valve and seat in my mill and Ill cut you a break bro.

[Bullfrog]

Hey Travis, I appreciate it, but its sold and gone. Its making way for something better. 

Here's my final report on it. I got the new valve stem sealed after sanding down and polishing the stem There is a small blast of air that comes out of the stem hole when the gun shoots, but it cannot be felt or noticed unless the gun is out of the bullpup stock. Annoying for sure as I'm sure its part of the reason for my continued power loss, but its acceptable under the circumstances.

Of course the gun had to do something else to me. The trigger linkage kept coming undone at the bullpup trigger. There is a small pin-clamp that holds the linkage on the trigger and the pin kept wanting to pop out of place. I finally had to red loctite it in place and after that it held well.

Accuracy was restored when I scrubbed the barrel out with the tornado brush. I forgot to report this a few posts ago, but when I scrubbed it I got a piece of rubber out of the barrel. I couldn't figure out whether I was mistaken about it coming out of the barrel until I remembered that I shredded a bunch of breach orings when I was doing a lot of ammo testing. A little piece got wedged somewhere in the barrel. Now the gun is a consistent tack driver with JSBs as it should be, so I can't fault the gun there. Interestingly, JSB bore paste and a bronze brush did NOT get that rubber out. Only the tornado brush did.

I had the most fun shooting that gun to date the day I sold it. I was blowing caps off of milk jugs at 20 and 25 yards with it, which is fun with such a strong projectile.

Here were my final numbers:
3000psi
JSB Kings
844
841
847
859
860
849
848
Approx 2300psi

That's not near as good as it was, but its at least a full clip that exceeds factory performance with good accuracy. My buddy who was aware of the gun's history was pleased with it.

I wouldn't own another one. Yet I think it ended up better than how it started. I'll service it for my buddy for a lifetime if it needs it. Hopefully I've fixed everything in the gun that has a tendency to break.