Tuning FX impact hammer spring adjuster. Understanding the issue.

[Powerbroker]

It's been a year or two since my last post.

This is my first time to encounter the issue.
I have an FX Impact (600mm .25cal with with Power Plenum Kit (old one). Shooting JSB Heavy 33.9gr. 113 PSI Regulator pressure with 225 psi Cylinder pressure.
Whenever I open the Hammer Spring Adjuster way above the 4th line, the FPS goes down to at least 10 FPS. When I close the hammer spring adjuster mid/3rd line, the FPS goes up to 10psi. But if I close it more near the 2nd line, the psi goes down by 20 psi.

I wonder what causes it and how to correct it. I want the fps to go up when ever I open the Hammer Spring adjuster and for the fps to go down when I close it.

Once again, thank you.

 

[Powerbroker]

Does this mean the hammer spring opens up too long that the air pressure towards the barrel will go down? Do I need to change the spring?

 

[nervoustrig]

Try backing out the valve adjuster. If it is turned in too far, the extra hammer spring tension will overdrive the valve, causing the valve to rebound off the adjuster (think of it as a bumper). A strong rebound closes the valve quickly, reducing dwell (how long the valve is open). Less air released by the valve = a drop in FPS.

 

[Powerbroker]

Try backing out the valve adjuster. If it is turned in too far, the extra hammer spring tension will overdrive the valve, causing the valve to rebound off the adjuster (think of it as a bumper). A strong rebound closes the valve quickly, reducing dwell (how long the valve is open). Less air released by the valve = a drop in FPS.

Hi. Thank you for the reply. But what is happening to mine is the reverse. If I dial "back out" the valve adjuster (from 4th line or beyond), I get a drop in FPS. I expect a rise in FPS but it did the reverse. BUT if I dial "back in" the valve adjustment towards the 3rd line, the FPS rise (not normal). And if I dial it "in" further, it will drop in FPS as a normal consequence.

 

[nervoustrig]

What is happening to mine is the reverse. If I dial "back out" the valve adjuster (from 4th line or beyond), I get a drop in FPS. I expect a rise in FPS but it did the reverse. BUT if I dial "back in" the valve adjustment towards the 3rd line, the FPS rise (not normal). And if I dial it "in" further, it will drop in FPS as a normal consequence.

In your original post, you described a down/up/down behavior when dialing the hammer spring adjuster.

In your more recent reply quoted here, you describe the same down/up/down behavior when dialing the valve adjuster.

Is that correct?

 

[Powerbroker]

In your original post, you described a down/up/down behavior when dialing the hammer spring adjuster.

In your more recent reply quoted here, you describe the same down/up/down behavior when dialing the valve adjuster.

Is that correct?

In your original post, you described a down/up/down behavior when dialing the hammer spring adjuster.

In your more recent reply quoted here, you describe the same down/up/down behavior when dialing the valve adjuster.

Is that correct?

Yes. That is correct. Sorry if I was not able to use the right terminology

 

[Powerbroker]

When I dial the valve adjuster towards “backing out,” the fps increases but If I dial it (“backing out”) further towards the end limit, the fps decreases of goes down.

 

[Bigragu]

It's been a year or two since my last post.

This is my first time to encounter the issue.
I have an FX Impact (600mm .25cal with with Power Plenum Kit (old one). Shooting JSB Heavy 33.9gr. 113 PSI Regulator pressure with 225 psi Cylinder pressure.
Whenever I open the Hammer Spring Adjuster way above the 4th line, the FPS goes down to at least 10 FPS. When I close the hammer spring adjuster mid/3rd line, the FPS goes up to 10psi. But if I close it more near the 2nd line, the psi goes down by 20 psi.

I wonder what causes it and how to correct it. I want the fps to go up when ever I open the Hammer Spring adjuster and for the fps to go down when I close it.

Once again, thank you.

I’m confused as well.
The hammer spring adjuster is just to the left of the power wheel dial above the trigger, at left side of gun.

The knob up front in front of the trigger block and under your barrel shroud, with the four lines around its threaded stem is the valve rod throw adjustment, shortly called the valve adjustment.

We’re you accidentally calling the latter the hammer spring adjustment?

 

[bamavet55]

It's been a year or two since my last post.

This is my first time to encounter the issue.
I have an FX Impact (600mm .25cal with with Power Plenum Kit (old one). Shooting JSB Heavy 33.9gr. 113 PSI Regulator pressure with 225 psi Cylinder pressure.
Whenever I open the Hammer Spring Adjuster way above the 4th line, the FPS goes down to at least 10 FPS. When I close the hammer spring adjuster mid/3rd line, the FPS goes up to 10psi. But if I close it more near the 2nd line, the psi goes down by 20 psi.

I wonder what causes it and how to correct it. I want the fps to go up when ever I open the Hammer Spring adjuster and for the fps to go down when I close it.

Once again, thank you.

Try increasing your regulator pressure to 125 bar.

 

[Powerbroker]

I’m confused as well.
The hammer spring adjuster is just to the left of the power wheel dial above the trigger, at left side of gun.

The knob up front in front of the trigger block and under your barrel shroud, with the four lines around its threaded stem is the valve rod throw adjustment, shortly called the valve adjustment.

We’re you accidentally calling the latter the hammer spring adjustment?

Sorry for the confusion. Yes. Hammer spring adjuster.

 

[Powerbroker]

Try increasing your regulator pressure to 125 bar.

Thanks.

 

[Glem.Chally]

Sorry for the confusion. Yes. Hammer spring adjuster.

If your hammer spring is too far you'll get less power as it's hitting the valve too hard and slamming shut faster than it should be.

Normal operation with these guns.