Hatsam Vortex Type 1 Ram..What Am I Missing??

[Ronno6]

I opened up a defunct Virtex typr 1 ram.
I found NO piston...unless I dropped it,and I don't think I did.
There ia a rod with a small button headscrew at the inner end, holding an O-ring of some sort..
But the ram is certainly not large enough to act as the piston.

What am I missing here??

[Back_Roads]

 Yup that's about it, you should see the tiny piston O-rings on a Shoe Box Compressor.

[Ronno6]

So, the increase  of pressure inside a gas ram is only due th the volume taken up by the untrusion of the rod?

NO piston contactine the wallsof the cylinder?

Is this the how come degradidion of the O-rings in the nose are reponsible for the demise of the ram?

Wow........

[Airnut]

Ya throu me for a loop the first time I took one apart. Like you I was expecting to see a piston with orings. I am still not to sure exactly how it works but most failures I have had was the oring in the head that seal the shift.They are inside the end cap
And can be a bugger to replace.

[mikeyb]

I opened up a defunct Vortex type 1 ram.
I found NO piston...unless I dropped it,and I don't think I did.
There is a rod with a small button headscrew at the inner end, holding an O-ring of some sort..
But the ram is certainly not large enough to act as the piston.

What am I missing here??

Nothing, that is exactly the way they work. Button screw with small washer at inner end of rod is there to keep it from flying OUT when pressurized. Replace the 2 o-rings inside the shaft bushing. That should stop most leaks.

High pressure works on the END AREA of the rod ONLY.

Gas STRUTS/LIFTS have a kind of piston head, but it is there to SLOW DOWN the action of the strut. That is why you DON'T want to use an NP1 to lift your toolbox lid (WAY too FAST). It it also why you can't use the heavy duty tailgate lift struts in an air rifle (WAY too SLOW).

So, the increase  of pressure inside a gas ram is only due to the volume taken up by the intrusion of the rod?

NO piston contacting the walls of the cylinder?

Is this the how come degradation of the O-rings in the nose are responsible for the demise of the ram?

Wow........

YES! That is why compressing an NP-like air/gas spring starts at 140lbs and only climbs to 180 lbs. The rod volume causes the increase in pressure.
Similar energy coil spring would start at 80lbs and finish at 240lbs. Both power an air rifle to about 17fpe.

[Ronno6]

Geez...who woulda thunk it??

I have net been able to remove the shaft bushing. Is that normal?
Can both O-rings be replaced from the same end of the bushing?

[mikeyb]

Geez...who woulda thunk it??

I have net been able to remove the shaft bushing. Is that normal?
Can both O-rings be replaced from the same end of the bushing?

Shaft bushing threads probably have a good dose of thread locker. It didn't move for me until it was "smoking hot".

I don't think it is necessary to unthread the bushing to change both shaft o-rings, but it may be easier(?)
There are fine tools for o-ring removal called o-ring picks. They look similar to dental tools. Search Amazon or Harbor Freight for "o-ring pick set".

Even with these tools I found the process of removal and replacement quite challenging. Hope you find it easier than I did ;-)

Edit: I frequently need to modify existing tools to work BETTER on my air guns. Some days I need to make special air gun tools from scratch!

[H95Kidd]

Guys, H95Kidd here--- Remember my recent posts about my 95 Vortex and the "fun" I had replacing the Type1 ram? Happy to report she's shooting well now. Like you, I was also curious to see what was actually inside that defective ram. I was amazed as well about the lack of a "piston" but that internal rod has to go somewhere when the pressure is released. Pretty much acts the same as a piston I would guess...  Regarding replacing the o-rings, a better way may be to soak the brass cap in some solvent (carb cleaner, maybe?) that will serve to SWELL the o-rings, and thus make it easier to pluck them out. It's VERY easy to scratch/damage that brass or the grooves where the rings reside, and possibly affect the sealing ability of the replacement o-rings. Ask me how I know If you can get the existing o-rings to swell and get somewhat "proud" of the grooves, it will be much easier to get ahold of them with an o-ring pick or other suitable tool, and hopefully avoid any damage to the grooves/brass cap. As an aside, does anyone know the correct material (buna-N, silicone, or what) and the correct durometer rating of these o-rings? If my Vortex ram decides to fail again I might consider a repair. That is, replacing the o-rings and a recharge to 130 or so bar. The ram says a MAX charge of 150 bar, not sure what they contain when new from Hatsan.

[Ronno6]

I believe mikeyb has spec'd 90durometer Buna-n
8mm x 12mm

From what I saw in one online test, carb cleaner and acetone really swell them buggers up...........

[H95Kidd]

I believe mikeyb has spec'd 90durometer Buna-n
8mm x 12mm

From what I saw in one online test, carb cleaner and acetone really swell them buggers up...........

8mm ID, 12mm OD, but what thickness? Also, 90 durometer is pretty hard, but guessing it is a toss-up in terms of the right combo of sealing ability AND decent  longevity. Also, does anyone know what "bar" the Type 1 ram should be pre-charged to? Verbage on the ram itself says 150 bar MAX. Is there a rule of thumb to use, like a 10% reduction when initially charging (maybe use 135 bar, or less?). Just curious is all, as to what others have done here when rebuilding Hatsan type 1 rams.

[avator]

Wait...
If the ID is 8mm and the OD is 12mm would the thickness not be 2mm?

[Ronno6]

Wait...
If the ID is 8mm and the OD is 12mm would the thickness not be 2mm?

Sharp as ever,Mr. Bill!

I wonder if quad rings would be a benefit in this application........

As for ram initial pressure, seems to me that I have read somewhere that 125 bar was typical.

[avator]

If I'm not mistaken, quad rings are designed to reduce friction, such as a seal for rotation, whereas orings are better suited for holding pressure.

[H95Kidd]

Wait...
If the ID is 8mm and the OD is 12mm would the thickness not be 2mm?

Duh... This is what happens when someone (ah, that would be ME) starts typing before engaging what little brain matter God gave them (me). I call it brain fade, and the older I get, the more I seem to experience it...  That's my excuse and I'm sticking to it

[avator]

Wait...
If the ID is 8mm and the OD is 12mm would the thickness not be 2mm?

Duh... This is what happens when someone (ah, that would be ME) starts typing before engaging what little brain matter God gave them (me). I call it brain fade, and the older I get, the more I seem to experience it...  That's my excuse and I'm sticking to it

Trust me, I just got lucky.   

[Ronno6]

Once I replace the O-rings, should I put silicone oil in the ram?
How much?

[Ronno6]

The front O-ring went in no problem.
The inner O-ring was a different story....
I made tools and lubed things but no dice.
Finally removed the gland (heat, vise and 18mm wrench..) and found a chunk of the old O-ring still in the groove.......grrrrrrr
Got that out, cleaned ir up and the O-ring went in without incident.
A drop or 2 of oil, re-assembled and airet it up.
We'll see if it holds......

[H95Kidd]

The front O-ring went in no problem.
The inner O-ring was a different story....
I made tools and lubed things but no dice.
Finally removed the gland (heat, vise and 18mm wrench..) and found a chunk of the old O-ring still in the groove.......grrrrrrr
Got that out, cleaned ir up and the O-ring went in without incident.
A drop or 2 of oil, re-assembled and airet it up.
We'll see if it holds......

Ron-- following this with great interest. How much pressure (bar) did you apply on the initial fill? If your "rebuild" is successful, might try to do mine as well. Still have my "defect" type 1 ram on the shelf, just begging for some attention. As an aside, happy to report that the replacement g-ram that Hatsan provided for my 95 (free of charge, BIG thanks to Hatsan ) is performing perfectly. Fingers crossed that I get more shots out of the replacement g-ram than I did with the original unit.   

[Ronno6]

I put about 1800 psi or 125 bar
Also did a type 3 (?) from a Striker......

The old O-rings were rather brittle and broke when being removed.....

My SCUBA tank gettin' kinda low.....

[mikeyb]

Several of the Vortex air springs i own have "max velocity @ 125 bar" printed right on the tube. I have tried the "150 bar max pressure" on a couple rifles and I DID NOT LIKE THE RESULTS!! Velocity plateaued or went DOWN above 125 bar and both rifles needed TWO hands to cock. Shot cycles were HARSH and almost knocked the fillings out of my teeth! Accuracy also went DOWN because the rifles bucked like a mule and I FLINCHED in fear on every shot.

But... go ahead and try for yourself! You may be one of the few who like an air rifle that has maximum energy and minimum accuracy ;-)