[reezo]

Hello everyone,
I've been told from many Tanaka users that the PCS valve has a sweet spot, varying from rifle to rifle, at about 70%-85% open.

The reason seems to be that the PCS valve, when not TOO close on the nozzle, will let the entire gas flow in but will work more as a pressure regulator and not as a limiter. Limiting occurs only when the valve spike gets in close proximity of he metal nozzle itself.

Having the PCS valve too open will actually result in less pressure stabilization rather than more FPS. So it seems (experienced Tanaka field operators may chime in in support, of course!).

I searched and searched for a way to determine what the percentage refers to:

1) to the round rigged screw?
2) to the actual valve spike INTO the metal nozzle?

Below is a picture of my current PCS valve position..the valve spike (that you can see when looking through the rubber magazine-to-bolt o-ring) is WAY far outside the metal nozzle, I can practically barely see the tip of the spike.

I fear this is way too open but I don't know if I should take the round rigged screw or the valve sharp "spike" close to the nozzle as reference..

Thanks for the great insights, as usual,
Reezo

 

[toomanybbs]

^Mine
When the spike gets close to the nozzel it prevents gas from getting in.
If it goes to far back, well all I know is that it doesn't work well.

 

[reezo]

Thanks for the picture! I think mine is pretty close, maybe a little too close to the nozzle, compared to yours..

You teflon-taped the valve..nice. I am going to do that the next time I get the bolt out.

EDIT: It is actually loktite (thanks Cheese Man) but the purpose is the same: sealing the thread between the valve and the main chamber before the nozzle, in order to maximise gas flow towards the nozzle (the only direction it should go to)

 

[toomanybbs]

Thanks for the picture! I think mine is pretty close, maybe a little too close to the nozzle, compared to yours..

You teflon-taped the valve..nice. I am going to do that the next time I get the bolt out.

Thats teflon tape? Didn't know that, the previous owner did it. It seems more of a glue than a tape, but IDK.

 

[reezo]

Yeah after I posted I then realized it might be electrical tape..anyway the previous owner wrapped the thread and then screwed the valve in place..a good idea if you are not going to touch the valve for a long time because it will make it the most air tight possible without damaging the valve (at least, teflon tape is supposed to do that, glue I don't know ).

UPDATE: Done! Teflon taped the thread and carefully placed the valve to look exactly like yours Mine was a little more towards the nozzle although I believe they are both very far from the nozzle itself..

 

[Cheese Man]

That is loctite.

 

[reezo]

Thanks Cheese man!