Broken Piston

Discussion in 'Gun Building, Modifications & Repairs' started by Psych0_S0ldier, Sep 13, 2012.

  1. Psych0_S0ldier

    Psych0_S0ldier New Member

    121
    0
    Bloomington
    Hey guys, you may or may not remember my JG G36C upgrade project from a couple months ago. Well, I ended up completing the upgrade and the gun was working really well. Then, after about 1,000 rds, I heard a sickening CRACK from the inside of the gun. I opened it and found this:
    the Super Shooter piston I had installed had totally broken. Did this break occur because of my error, or was it merely a bad piston? Any help is appreciated. :)
     

    Attached Files:

  2. Batman

    Batman New Member

    1,554
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    Wichita
    Did you correct AOE?
     

  3. IHOP

    IHOP New Member

    5,426
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    Rockton
    Looks to me like AOE was corrected. If it was a problem with AOE, I'd imagine it would have broken off the pick up tooth, not the entire front of the piston.

    Adman234's SS piston did this same thing, albeit, his was on a 55rps DSG, it broke very similarly.
     
  4. Psych0_S0ldier

    Psych0_S0ldier New Member

    121
    0
    Bloomington
    I corrected the AoE to the best of my abilities, so it probably wasn't that. I really don't know what to think. The gun was running on a 9.6v at the time with a Deep Fire m100 spring. Not that stressful of a set up. I also used a rubberish washer from a sink kit to adjust the AoE.
     
  5. Thestig

    Thestig Some say... Supporting Member

    1,263
    1
    Colorado Springs and Southern California
    That is weird... I have never seen a piston break there...

    How hard was the washer? It could have broken off sheer force. And lastly, what piston head were you using?
     
  6. Psych0_S0ldier

    Psych0_S0ldier New Member

    121
    0
    Bloomington
    The washer isn't very hard, it bends fairly easily. The piston head is Dream Army.
     
  7. IHOP

    IHOP New Member

    5,426
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    Rockton
    Get a nylon piston like a SHS 14/15 tooth and try it out. The the AOE was fine, there's not much else that could be done, except maybe reduce the force of the piston hitting the CH (Which would only be decreased minimally by swiss cheesing and sorbo if spring rate remains.)
     
  8. Thestig

    Thestig Some say... Supporting Member

    1,263
    1
    Colorado Springs and Southern California
    Is it heavy? Do you have another piston head to compare it by?
     
  9. Psych0_S0ldier

    Psych0_S0ldier New Member

    121
    0
    Bloomington
    The dream army head is probably about 2x the weight of the original head. I'll probably get the SHS piston you mentioned IHOP.
     
  10. Thestig

    Thestig Some say... Supporting Member

    1,263
    1
    Colorado Springs and Southern California
    That could be your problem. Also, how tight was your compression, and what type cylinder do you have?
     
  11. EDI1st

    EDI1st New Member

    2,062
    3
    Fountain Valley
    Those clear piston, they crack easily simply because their structure is like crystal instead of nylon.

    Punch a piece of glass and then punch a shirt, examine the differences.

    The area where the piston broke off is the place where the piston takes most of the energy.
     
  12. Lefse

    Lefse Well-Known Member Supporting Member

    4,743
    159
    You should definitely remove that ball bearing and metal washers, they add alot of weight. And I agree with EDI, this is probably a polycarb piston, they are very brittle, I don't get why so many manufacturers produce pistons out of such a brittle material, nylon is much better. An SHS 15 teeth piston with a light swisscheesing should do much better.
     
  13. Psych0_S0ldier

    Psych0_S0ldier New Member

    121
    0
    Bloomington
    Ok, so my questions are: Should I get a new piston head or should I just get rid of the ball bearings and washers? Should I get an SHS piston with one metal tooth or one with more metal teeth? I probably won't swiss cheese the piston. btw, thx for the help everyone!
     
  14. Star_folder

    Star_folder New Member

    1,056
    1
    Lexington
    Your set up isn't a strenuous one, I would just get a new piston and have the AoE corrected on it. It will hold up fine. Any of the dark blue SHS pistons should do fine, as would any lonex piston. With your set up, you don't really need to worry about PE or anything of that nature.
     
  15. Psych0_S0ldier

    Psych0_S0ldier New Member

    121
    0
    Bloomington
    Sorry, but what is PE? Should I keep the same piston head with the new piston I get?
     
  16. Star_folder

    Star_folder New Member

    1,056
    1
    Lexington
    PE = Premature Engagement. It's when the gears are spinning faster than the spring can return the piston to the front of the gearbox. This generally only happens when you start getting above 30rps on low powered springs.

    I would save a few bucks and keep the piston you have now.
     
  17. Psych0_S0ldier

    Psych0_S0ldier New Member

    121
    0
    Bloomington
    You mean piston head right? ;D My piston is just a little bit obliterated atm. Should I keep the ball bearings and washers on the piston head when I install it tho?
     
    Last edited: Sep 14, 2012
  18. Star_folder

    Star_folder New Member

    1,056
    1
    Lexington
    lol, oops, yeah, the piston head. You can just chunk that piston.
     
  19. Mystery43_4

    Mystery43_4 New Member

    1,307
    1
    Santa Barbara
    No, remove the bearings/washers, you want the piston assembly to be as light as possible. If you don't have a bearing'd spring guide then pick one up.
     
  20. Psych0_S0ldier

    Psych0_S0ldier New Member

    121
    0
    Bloomington
    Sweet! thx for all the info! Fortunately I, already have a ball bearing spring guide. thx everyone for helping!