Skout Skout Epoch tuning questions?

[Motorhead]

Yes, that’s what I’m talking about.
im running a .177. Not sure that the stock hole size is but what would enlarging it do ?

To understand this "Spool Valve" you need to take one out and look at it ????
The spring that holds the poppet to seat is fairly small & light, so once valve gets opened the speed it has to close would be very long in duration based on Sail effect of air moving past the poppet head and the effort spring is assisting.
* The bleed hole takes air from a pressurized valve throat during the shot cycle, and places the high pressure air on opposing side of piston where the solenoid air opened it.
This HP on pistons back side send the poppet back to seat very quickly !!! Larger the bleed hole faster will piston close chopping dwell duration.
Go too large the poppet will close to fast and you may not be able to make the power required .... There is a balance range here & bigger has limits you will quickly notice.
As to noise .... spool valves don't act like or sound like a conventional knock open poppet. Also the plenum surrounding poppet assembly likely is creating some sonic Ping during the shot.

 

[MSR Workshop]

To understand this "Spool Valve" you need to take one out and look at it ????
The spring that holds the poppet to seat is fairly small & light, so once valve gets opened the speed it has to close would be very long in duration based on Sail effect of air moving past the poppet head and the effort spring is assisting.
* The bleed hole takes air from a pressurized valve throat during the shot cycle, and places the high pressure air on opposing side of piston where the solenoid air opened it.
This HP on pistons back side send the poppet back to seat very quickly !!! Larger the bleed hole faster will piston close chopping dwell duration.
Go too large the poppet will close to fast and you may not be able to make the power required .... There is a balance range here & bigger has limits you will quickly notice.
As to noise .... spool valves don't act like or sound like a conventional knock open poppet. Also the plenum surrounding poppet assembly likely is creating some sonic Ping during the shot.

So what presumably would be that air bleeding sound I’m getting after each shot?
to me it sounds like the sound of leftover air after the shot. For the valve, not closing fast enough.?

 

[Motorhead]

Air sound is emanating from "where" on rifle ?

 

[MSR Workshop]

Air sound is emanating from "where" on rifle ?

To me it sounds like back where that full valve is or Buy the pellet probe.

Here’s an audio clip if it’ll play maybe you can hear the sound

 

[Scotty1]

I’m assuming the second sound is from the pellet hitting the target? Are you just hearing the reg refill the plenum after the shot?

 

[MSR Workshop]

I’m assuming the second sound is from the pellet hitting the target? Are you just hearing the reg refill the plenum after the shot?

Yea maybe that’s it.
I also just discovered a big air leak that im sure is the culprit to my changes In pellet velocity.

I really feel that this part going into the Plenum needs two rings instead of just one since all of that pressure is pushing against a single small O-ring

 

[Motorhead]

At the pressure the plenum operates at ... 1 o-ring is a non issue IMO

 

[MSR Workshop]

At the pressure the plenum operates at ... 1 o-ring is a non issue IMO

Even during the shot?

 

[Motorhead]

Even during the shot?

During the shot plenum pressure DECREASES ... as regulators on PCP's DO NOT supply air for the current shot & only replace what was used for the next.

 

[MSR Workshop]

During the shot plenum pressure DECREASES ... as regulators on PCP's DO NOT supply air for the current shot & only replace what was used for the next.

So why would it be leaking during the shot but not before or after. ?

 

[Motorhead]

Talk with SKOUT

 

[Tricky-Dicky]

I really can't see the block leaking, are you sure it's this that is leaking, what you're hearing could quite easily be the spool valve seal as this is constantly subject to repeated compression during the firing cycle, and may leak until the plenum is refilled and the pressure holding it shut is enough to reseal.

While on the subject of the spool valve is there just the one size of the jet (for lack of a better description) in the end or would experimentation require just buying two or three and re drilling to see how much it affected the closure speed of the valve, and I suspect on an already restricted gun I might run out of dwell adjustment quite quickly as mine is already set to 12.

 

[MSR Workshop]

I really can't see the block leaking, are you sure it's this that is leaking, what you're hearing could quite easily be the spool valve seal as this is constantly subject to repeated compression during the firing cycle, and may leak until the plenum is refilled and the pressure holding it shut is enough to reseal.

While on the subject of the spool valve is there just the one size of the jet (for lack of a better description) in the end or would experimentation require just buying two or three and re drilling to see how much it affected the closure speed of the valve, and I suspect on an already restricted gun I might run out of dwell adjustment quite quickly as mine is already set to 12.

 

[Tricky-Dicky]

Kind of point proven! But it's really difficult to see just where that's coming from? I guess if you have access to a lathe with a four jaw chuck, you may be able to put another small O ring grove in the block, but that could equally be coming from the transfer port/tunnel to barrel interface.

 

[MSR Workshop]

Kind of point proven! But it's really difficult to see just where that's coming from? I guess if you have access to a lathe with a four jaw chuck, you may be able to put another small O ring grove in the block, but that could equally be coming from the transfer port/tunnel to barrel interface.

Yeah I thought of that, but there is so little room to add another O ring

Also I thought that the air might be coming from blowback from the barrel to… and some of it might be, but if you grab the video slider you can see the frame where the bubbles form and it doesn’t look like the bulk of the air is from the barrel.

Also, when I pulled it out of the water and dry fired it again it was spurting residual water from around the cracks where the block fits into the frame.
I’ll call Skout and see if they have any ideas today

 

[Tricky-Dicky]

I can see me dumping my Epoch in the bath next! I will be interested to hear what Skout have to say on the subject, being in the UK it's difficult to talk to them and I also get the impression that they are not particularly interested in the sub 12 market.

 

[MSR Workshop]

I can see me dumping my Epoch in the bath next! I will be interested to hear what Skout have to say on the subject, being in the UK it's difficult to talk to them and I also get the impression that they are not particularly interested in the sub 12 market.

you should try it!
just take the butt pad off
You don’t have to put very much in the water, but I would be curious to see if you’re getting any leaks from that area as well

 

[Tricky-Dicky]

In fact, I am quite fond of dumping my PCP actions in the bath if a suspect a leak, I will post the result when I get around to it.

 

[Tricky-Dicky]

My curiosity got the better of me and I have just tested mine in water and zero leakage! Was yours tested with dry fire or outside with a pellet?

 

[Motorhead]

Figured it out I think ....

Poppet seat has 2 o-rings,
The o-ring closest to the seat see plenum pressure at all times.
The o-ring as viewed at bottom in picture below ONLY sees pressure during the shot when throat and transfer path pressurize.

* SO .... air leaks past this o-ring and exit threw the seat push out hole which looks

exactly the area as video is showing