ATI NOVA LIBERTY LEAKY POPPET and VALVE connection

[Bob Pratl]

duy, you are a gentleman, thanks for the measurements as I also want to fabricate a new poppet valve.

 

[FuzzyGrub]

if someone is making a poppet. they really need to tear it apart. besides its so easy. degas, undo the barrel and unscrew the regulator and its right there. the only thing hard about this rifle is the valve. getting to the valve meant everything needs to come apart, almost.

stem od: 3mm or .116
stem length: 1.7695
poppet od: .353
poppet spring seat: .2785
poppet shell length: .298

the shell lengh can be shortened for less preload on the valve spring.

Thx for posting.  I agree that will need to dive in before making, but wanted the right diameter stem and poppet material to be on hand, before doing so. 

Thx again for dimensions and pictures.

[Wayne52]

Mine is leaking very slowly, I did top it off this morning and went hunting with it, what a great shooting rifle it is, blasted a red squirrel in the head this morning with one of my 19.6grainers.

[darkcharisma]

Mine is leaking very slowly, I did top it off this morning and went hunting with it, what a great shooting rifle it is, blasted a red squirrel in the head this morning with one of my 19.6grainers.

ill be searching for your hunt pictures in the hunting gate

[wll2506]

From the looks of the photos, the small black washer is the only thing blocking air, and it looks like a small "WASHER" can be made and the black piece taken out, replaced and that's it ?

Am I wrong ?

wll

[darkcharisma]

From the looks of the photos, the small black washer is the only thing blocking air, and it looks like a small "WASHER" can be made and the black piece taken out, replaced and that's it ?

Am I wrong ?

wll

i think the crush washer can be taken out to remove the shell. you can then replaced the sealing material. you may be able to use the crush washer again, or fabricate something similar.

[FuzzyGrub]

I had four different poppets, after measuring, none can be easily made to fit.   

Being at home, able to enlarge the photos.  It looks like a metal can holds the poppet material.  A different style of poppet than I am use to.   If you still have the poppet out, a pic of the sealing side/poppet stem side would be appreciated.  Also the ID of the inside of the can, would be great. 

3/8" OD Peek or Delrin rod seems easily available.   For the stem, is that a hardened steel? 

Duy, you might be right and need to dis-assemble before ordering. 

[FuzzyGrub]

FWIW: Ty did respond to the email and link.  He was not aware of the issue yet, and will be forwarding the info, assuming to NV. 

[wll2506]

Another crazy question, is near the size the Crosman uses in many of there guns ?

If you can find an American made poppet valve, you are home free !

wll

[FuzzyGrub]

Another crazy question, is near the size the Crosman uses in many of there guns ?

3 of the 4 I measured were crosman poppets.  The closest was the Fortitude, which had a head OD of 0.350".  The poppet stem is too large OD (but could be turned down), but is not long enough. 

[darkcharisma]

there is a picture on post 25 now. yes the stem should be hardened. if you have access to a lathe you can just turn down a peek poppet.

[nervoustrigger]

Just in case it's a question still up in the air, there is no reason the replacement poppet needs to be a metal shell with an embedded seal.  A solid cylinder of Delrin or PEEK will be both more durable and easier to make.  The only negative is the seating surface must be flat and uniform to seal properly (compared to the OEM poppet).  That's where the lapping jig comes in if you're making one with caveman tools.

Regarding the stem, indeed it needs to be hardened to withstand the constant pounding.  Otherwise it will mushroom.  Turning down the diameter of a 3rd-party one therefore isn't in the cards...could grind it down but that would be tough to do with sufficient precision.  More practical options would be salvage and reuse the existing stem if possible, or buy a piece of hardened rod.  https://www.mcmaster.com/hardened-rods

If dead set on using a 3rd-party valve stem, it's much easier to modify the valve body to accept it than the other way around.  In other words, if the stem is large, enlarge the hole in the valve body to accept it.  If the stem is too small, get a piece of brass tubing and make a bushing to reduce the hole in the valve body.  A drop of threadlocker will bond the bushing in place forever more.

[FuzzyGrub]

there is a picture on post 25 now. yes the stem should be hardened. if you have access to a lathe you can just turn down a peek poppet.

Duy, Thx again, sorry for being a PITA with questions. 

[FuzzyGrub]

I assumed the can was there to prevent the softer material from mushrooming out.  The Sumatra poppet has a metal wrap, something like that.

From the pictures, it looks like the stem goes all the way through the head, so "if" it can be encouraged to come apart and you can get the softer material out of the can, to just turn down the Delrin or peek to fit the can.  Then using the spring side as a pilot, drill the hole for the stem.  And still use your method to true it up.   Lot of if's. 

So, looks like I can go ahead order the material.   3/8" Delrin and Peek, and find some 3mm hardened steel rod.  Thx for the info guys. 

[darkcharisma]

or get rid of the shell and just drill through the delrin or peek and put the crush clamp washer back. done. of course you need to machine the spring seat and profile the poppet to the corect OD

[FuzzyGrub]

Is there a particular hardness I should be looking for in the stem?  The reason I ask is, I have a spent crosman mrod poppet, that I use to protect the barrel when I'm drilling out the port.  When I do that, I incrementally go through number drills to the right side.  Very little pressure is needed.   That poppet stem has numerous places where the drill has bitten into the stem.  So, its not as hard as tool steel.   

Also, what is the best method for cutting?  Dremel cutting wheel? 

[AVS Stephen]

Hello All,

Good News...at least I think. Here is Nova Vista's Kee Keat General Manager's response to my call for help with the leaky Poppet. I just sent a photo of the poppet and valve. Lets see what they do about it.

Hi Stephen,

First of all thank you for your interest on Nova Liberty and appreciate all your videos about our airgun, there are excellent! But Apology for late replay due to public holiday in China, and I just back to office today.

We are very concerned on the leaking issue. Immediately we have a meeting this morning with our engineer and production team and look into the problem. But now we have to make sure we understand which part cause the problem. Can you please take a picture or video and send us clearly. Here attached with our assembly instruction included the parts name and number for your reference.

Once we are clear on the problem, then we will immediately send the spare parts to our distributor (ATI) and all of you can get the parts for replacement. For your information, all of our airguns will have tested before we ship it out. We have done the accuracy test, leaking test and so on. I understand that most of you will modify the airgun, if some of them are not as expert as you, the process of modification might cause damage for the parts too, so I will leave this (after sales maintenance) to our distributor to handle their customer. Hope you understand.

Here is the latest publish about this gun by Hard Air Magazine for your reference:
https://hardairmagazine.com/reviews/american-tactical-nova-liberty-pcp-air-rifle-review-22-caliber/ 

Lastly, I really like you in person as you are very passion on airguns. And I love your "Lady Liberty", she is sexy! Again really appreciate all your efforts towards this gun.

Feel free to keep in touch with us about any of your ideas and comments. No one is perfect, but we will keep improving and try our best to produce good airguns with very affordable price, so that many people can own a PCP and have fun on it.

We look forward to a wonderful relationship together with you.

Thank you.

Regards,
Kee Keat

[darkcharisma]

Fuzzy just use what you got. dremel or hack saw. go slow then square off with a grinder. i usually heat treat my stems to roughly 60hrc then temper it to 50hrc. hard enough but not so bittle...but i dont think that stuff matter much just as long as it doesnt mushroom.

Stephen, thats some dedicated email. looking forward to improvements from manufacturers side.

[Hawkeye51]

I had the same slow leak at the poppet seal. About 1000psi over night.  Caveman tools only!  Took the stem & chucked it up in my drill, carefully filed a very small amount of the can away from the edge of the seal with a "mini" diamond encrusted file.

Very crude methodology, but functional. Just enough material removed to allow poppet to make full contact with the valve face.  If the poppet material is too soft for the hammer spring, then this will only be a temporary fix. However if the tolerance of manufacturing was just a little too close, this might get me by for a year or so. We'll see.

Man do I wish I had a mini lathe, and the training to use it.

[Bob Pratl]

Very nice reply from the manufacture which I find to be VERY rare.