M4 Air Nozzle Issue?

Discussion in 'Gun Building, Modifications & Repairs' started by M4Ever, Jul 17, 2012.

  1. M4Ever

    M4Ever New Member

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    San Antonio
    Hey guys, need a little help here. Not quite sure what's wrong. I have an M4 and I was putting in a new cylinder head and air nozzle. Everything seemed to go back together just fine, no problems at all, sounds normal, looks normal, the air nozzle moves back and forth on shots, It's all good.
    Then shooting, the first shot of the mag shoots normal. Then it skips a few and then will shoot another normally. Did a little investigating and I think it's an air nozzle problem because after a shot, the air nozzle is sticking about halfway into the hop up system feeding tube (I can see it through where the mag feeds). I'm really not sure what to do. The gearbox looks fine, the tappet plate looks normal to me I guess, it could be something with that, but it seems normal. I'm just not sure what it is, and I've been fiddling around with it for a while now, and I'm out of ideas. Any help would be appreciated, thanks.
     
  2. BRTSoloWing

    BRTSoloWing Well-Known Member

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    China Grove
    Look and see if your cylinder nozzle is to long. Your air nozzle should be going back flush with the cylinder head. If this is the case, carefully file down the cylinder nozzle untell the air nozzle goes back flush like its suppose to. I had this same problem, and this is how I fixed it
     

  3. M4Ever

    M4Ever New Member

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    Yeah, I looked around here on the forum and found some other guy with the problem and someone suggested cylinder head height. And considering I had a new cylinder head I thought that might be my problem. So I threw the old head in there and it works great, and I compared the two and that's what it is. I will file it down tomorrow. Thanks for the help.
     
  4. BRTSoloWing

    BRTSoloWing Well-Known Member

    1,517
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    China Grove
    No problem, when you file it, do it in smooth slow strokes to take a little off at a time and be careful not to deformed it and you'll be okay
     
  5. M4Ever

    M4Ever New Member

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    Cool, thanks. I'll tell ya when I'm done and when it works, otherwise I might need more help.
     
  6. BRTSoloWing

    BRTSoloWing Well-Known Member

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    All right just let me know
     
  7. M4Ever

    M4Ever New Member

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    If my air nozzle slides
    All the way down onto the cylinder head, then that means either my tappet plate isn't pulling back far enough,
    Or my air nozzle is too long right.
    Am I right? I am thinking of just shaving down the air nozzle.
     
  8. BRTSoloWing

    BRTSoloWing Well-Known Member

    1,517
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    China Grove
    That won't work, stand your new one up beside the old one and see if its longer, can you post some pics?
     
  9. Mystery43_4

    Mystery43_4 New Member

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    Santa Barbara
    Explain what's happening.

    "If my air nozzle slides all the way down my cylinder head"

    You air nozzle should slide all of the way down your CH. I'm not sure of what the problem is, or what you're trying to explain.
     
  10. BRTSoloWing

    BRTSoloWing Well-Known Member

    1,517
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    China Grove
    I understand it, but some pics would be more helpful
     
  11. M4Ever

    M4Ever New Member

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    All this originated from a newb mistake I made a while back. I had this problem with my new cylinder head and so I shaved off some of my stock cylinder head, unfortunately from the back. (I know I know, stupid stupid)
    So as you can see there is slight difference in the height from the front lip of the tappet plate holder thingy. Not sure if you can see that, it's apparent when you hold them. It's small, we're talking a mm here, maybe a little more. But when that's a 1/6 of the bb, that could be all that it needs. Idk. I'm not doing anything till I'm sure about it.
     

    Attached Files:

  12. BRTSoloWing

    BRTSoloWing Well-Known Member

    1,517
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    China Grove
    The red is a m4 nozzle right? I'm sure it is, can you get me some pic of the cylinder heads the same way you have the air nozzles?

    EDIT: can you get me a pic with the new air nozzle on the cylinder head ?
     
    Last edited: Jul 18, 2012
  13. Mystery43_4

    Mystery43_4 New Member

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    Santa Barbara
    I still have no idea of what you're asking.

    What is the actual problem? Are you misfeeding, is your tappet plate binding because it can't retract far enough, etc.?
     
  14. BRTSoloWing

    BRTSoloWing Well-Known Member

    1,517
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    China Grove
    The problem is that the air nozzle isent being pulled back far enuff to allowe the mag to feed the b bs. So were trying to find out if the cylinder nozzle or air nozzle is to long
     
  15. M4Ever

    M4Ever New Member

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    San Antonio
    The stock is on the right, new G&G on the left, slightly taller. And as you can see, the nozzle does reach all the way down to the base of the cylinder head. So I don't think its the cylinder nozzle height.

    @ Mystery: yeah, it's a misdeed type thing. Tried mid caps and high caps, and it won't shoot properly. It'll shoot the first round, and then not shoot for about and then weakly shoot another and repeat. I think it's because the air nozzle won't get back all the way, but it doesn't explain why it'll shoot even one out of three.

    I will be away from my house for a few hours, so no pics for a while, just answering questions. Thanks for the help.
     

    Attached Files:

  16. M4Ever

    M4Ever New Member

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    Mystery . How do I know if my taper plate is binding, what are the symptoms? That could be it.
     
  17. BRTSoloWing

    BRTSoloWing Well-Known Member

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    China Grove
    From what I'm seeing, you cylinder nozzle is too long, it don't take much
     
  18. M4Ever

    M4Ever New Member

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    San Antonio
    Ok, I'll file it down some and get back to ya. Thanks.
     
  19. M4Ever

    M4Ever New Member

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    San Antonio
    Ok guys, thanks for bearing with me.

    Good news: it shoots every time.
    Bad new: it has almost no power. Like 30 feet pathetic.

    I shaved down the cylinder head (I used the old stock one as a ginny-pig in case it ruined it I would save the new one) I dont know if it's enough. As you can see in the pic, it's a fair deal lower than the other, at least more so than the original pics.

    Do I need to go farther? Is it something with the tappet plate? Or do I need to shave down the nozzle too? What's next?
     

    Attached Files:

    Last edited: Jul 18, 2012
  20. BRTSoloWing

    BRTSoloWing Well-Known Member

    1,517
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    China Grove
    Okay I see your filling isent too straight, that it self could be the problem now, don't do any filling on the air nozzle, that will just mess it up and youll have to get a new one. Try to straighten the end of the cylinder nozzle, and if you have a fine piece of sand paper, use that to sand the rough edge a little and try that

    EDIT: Sorry I looked at the wrong cylinder head, yes file it a little more, but not to much, and try the sand paper trick as well. Also check the compression before you put it back together as well
     
    Last edited: Jul 19, 2012