JG Vz61 AEP FPS Consistency Issues

Discussion in 'Electric Guns' started by FuLL-eFFekT1, Sep 11, 2021.

  1. FuLL-eFFekT1

    FuLL-eFFekT1 Member

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    I WAS getting a fairly consistent 265 FPS
    IMG_2151.jpg

    I had just bought a 9 Ball stiffer spring, I opened up the gear box to install it and discovered that its approx 1” longer than the oem spring...(I could cut it down, but I decided not to at this time).

    I decided to just put it all back together, the ONLY thing I changed was I cut a few coils off the tappet spring (it was under so much tension in its slot that it had actually partially kinked).

    All seemed well until I decided to verify the FPS status. Now its 150ish! But sometimes it jumps up to 220ish. W.TA.F. The tappet plate spring is still over-tensioned (just slightly less so). The other thing I think it could possibly be is there is a small set screw in front of the trigger guard (in the gearbox) that seems to be related to motor adjustment (when screw’d in, presses against a lever...) I tried removing it completely, no change. Screwed all the way in, no change. Tried backing it out, 1/4 turn at a time, no real change.

    Help. Thx!
     
  2. FuLL-eFFekT1

    FuLL-eFFekT1 Member

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    Well, I think I might know what happened.. the hop-chamber is supposed to have a lil metal ring/collar/seal that slides over the inner barrel and into the front of the hop-chamber, up against the locking plate and its missing. It fell off at some point and I totally missed it. View attachment 172511
     
    Last edited: Sep 11, 2021

  3. FuLL-eFFekT1

    FuLL-eFFekT1 Member

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    Well, I’ve learned that shortening the tappet spring was a bad idea. I reinstalled the clipped portion and the FPS has jumped up to 230ish... so the problem isn’t fully fixed, but getting closer.
     
  4. Guges Mk3

    Guges Mk3 Administrator Staff Member Administrator Supporting Member Lifetime Supporter

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    With that...do the tissue test to still see if you have a slight air leak.
     
  5. FuLL-eFFekT1

    FuLL-eFFekT1 Member

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  6. Guges Mk3

    Guges Mk3 Administrator Staff Member Administrator Supporting Member Lifetime Supporter

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    Yep.

    Tissue test will tell you if your issue is with the nozzle or beyond the nozzle. This is a trick from the early 2000's on how to check to see if you have a timing issue with your nozzle.

    Power AEG up. Put it in semi.

    Fire once to set it in case it was in FA before.

    Invert the AEG

    Put a piece of tissue on the feed tube.

    Pull the trigger in SA.

    If the tissue blows off. Your nozzle is off. If it just sits there. It's not a nozzle issue.
     
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  7. FuLL-eFFekT1

    FuLL-eFFekT1 Member

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    Oooh, ok. Thats pretty nifty. And if it is off, how do I reset or fix the timing? I’m assuming the gear that interacts with the piston must be set a certain way?
     
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  8. Guges Mk3

    Guges Mk3 Administrator Staff Member Administrator Supporting Member Lifetime Supporter

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    No, the fix may not be that simplistic.

    Could be any myriad of things...but you don't know where to look until you do that test.
     
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  9. FuLL-eFFekT1

    FuLL-eFFekT1 Member

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    I did that test and it did not blow off.
     
  10. Guges Mk3

    Guges Mk3 Administrator Staff Member Administrator Supporting Member Lifetime Supporter

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    Then the issue is not your Nozzle.
     
  11. FuLL-eFFekT1

    FuLL-eFFekT1 Member

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    I put an o-ring up against the muzzle side of the hop chamber, it seems to have helped, fps jumped to 260ish FPS again, but I realized battery also needed to be charged (decreasing FPS after 4-5 shots)
     
  12. OutlawAirsoft

    OutlawAirsoft Active Member

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    A dying battery will never decrease FPS. All it does is decrease ROF. Think about it. FPS is a result of the spring (among other things), not the battery. Even if you were able to turn the motor shaft by hand, the FPS would remain the same.
     
  13. FuLL-eFFekT1

    FuLL-eFFekT1 Member

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    Wrong. A fully dead/uncharged battery will produce ZERO FPS.
     
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  14. Guges Mk3

    Guges Mk3 Administrator Staff Member Administrator Supporting Member Lifetime Supporter

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    ^My you are getting scholarly...

    ^Zing, Point!...Technically true and thinking big picture.

    just like a broken analog clock is right 2 times a day...
     
  15. aotsukisho

    aotsukisho Well-Known Member

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    Technically untrue, as a 'dead' lipo still has at least 2.5v/cell and a 'dead' NiMH has 0.9v/cell. If the motor can still cycle with the extreme voltage sag typical of a dead battery you will fire a bb. Also keep in mind that in a multi-cell system (which is what we use in airsoft) the battery is 'dead' once a single cell in the pack drops to 2.5v, meaning in a badly matched battery pack the other cells can still be at 3.0v+. ie. a 'dead' 3s at 3.0+3.0+2.5=8.5v vs a 'good' 3s at 2.8+2.8+2.9=8.5v

    You're thinking of a battery that sustained permanent damage from being discharged completely down to 0.0v. I've seen lipos overdischarged to the point of damage in unmodified AEGs, terrible cycle time typical of a dead battery near the end of the game but the guy kept playing with it. When the game was done one of the cells stabilized at 2.2v and the pack was inflated.
     
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  16. FuLL-eFFekT1

    FuLL-eFFekT1 Member

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    Well, I thought I had it fixed-ish.
    Its weird it’ll start at approx 260ish FPS +/- a few FPS for 4-5 shots then cascade down to approx 170ish FPS. With a freshly charged battery too.

    Truth be told I’m not satisfied with the cobbled together tappet spring situo and the o-ring at the front of the hop chamber is just a temporary thing.
     
  17. FuLL-eFFekT1

    FuLL-eFFekT1 Member

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    A small miracle occurred: found the metal collar/seal (could’ve sworn I’d thrown it away, not realizing what it was at the time, lol). Which has seemingly helped stabilize FPS, its still low.. Also, I noticed that the nozzle is slightly “out of timing”.. IMG_1634585499.344169.jpg Circled in pic. It has never had feeding issues, always fires.
     
  18. OutlawAirsoft

    OutlawAirsoft Active Member

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    Interesting, because timing problems often cause feeding issues.
     
  19. Guges Mk3

    Guges Mk3 Administrator Staff Member Administrator Supporting Member Lifetime Supporter

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    Nozzle intrusion into the feed path?

    Um...that should be normal. If that is after a SA cycle.

    If the nozzle retracted all the way all the time...you would have misfeeding issues with to many bbs.
     
  20. FuLL-eFFekT1

    FuLL-eFFekT1 Member

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    Well, I just learned something and that’s not hyperbole. My first aeg/aep.