Jump to content


changing out piston


  • Please log in to reply
6 replies to this topic

#1 cellistle

cellistle

    Newbie

  • Members
  • Pip
  • 20 posts
  • Country:

Posted 29 June 2014 - 07:31 AM

Hello. I was running a 11.1 1200 mah 15c lipo for about 6 months. After that I recently had installed a merf 3.2 mosfet to give it a 3 round burst. During the installation my sr10 was rewired with the included low resistance wiring. My tech told me that because of the low resistant wiring and the mosfet I shouldn't run a 11.1 lipo anymore because it will break the stock polymer piston. I was surprised to discover that the stock piston was polymer. The last time I started replacing the piston or any part in my gearbox my gearbox started to have all kinds of problems which makes hesitant to install any other part. (This was on my gun before the sr10). What pistons would you recommend that would be metal and be a perfect fit for the sr10?

I'm currently shooting
Semi/3 round burst with 20 bbps on a fresh 9.6 1600 mah nimh

I want to shoot
Semi/3 round burst at 25 bbps on a lipo. I don't care if it's a 7.4 or or an 11.1 but I know with a 7.4 lipo I'll have to do some other kind of upgrade.

#2 JesseHammil

JesseHammil

    Enthusiast

  • Members
  • PipPip
  • 56 posts
  • Country:

Posted 29 June 2014 - 03:36 PM

Hmm, that is interesting. I have not heard of need to replace the piston due to low resistance wiring...I doubt that you need to... Other guys more experienced than me can correct me if I'm wrong.

I have a RIS that I have had about a year, and been running an 11.1v lipo in it for the last 5 months or so. I recently opened up the gear box to do some work and the piston (and all the other parts for that matter) looked brand new.  

On a side note, I have heard that the piston head slams into the cylinder head really hard so some people put a rubber washer in there...

#3 gcw360

gcw360

    Supreme Guru

  • Super Moderator
  • PipPipPipPip
  • 11,722 posts
  • Gender:Male
  • Location:New Jersey
  • Interests:Airsoft (Especially repair and customizing), Fly Fishing, Fossils (Especially Dino), Snakes, Photography
  • Country:

Posted 30 June 2014 - 11:48 AM

View Postcellistle, on 29 June 2014 - 07:31 AM, said:

Hello. I was running a 11.1 1200 mah 15c lipo for about 6 months. After that I recently had installed a merf 3.2 mosfet to give it a 3 round burst. During the installation my sr10 was rewired with the included low resistance wiring. My tech told me that because of the low resistant wiring and the mosfet I shouldn't run a 11.1 lipo anymore because it will break the stock polymer piston. I was surprised to discover that the stock piston was polymer. The last time I started replacing the piston or any part in my gearbox my gearbox started to have all kinds of problems which makes hesitant to install any other part. (This was on my gun before the sr10). What pistons would you recommend that would be metal and be a perfect fit for the sr10?

I'm currently shooting
Semi/3 round burst with 20 bbps on a fresh 9.6 1600 mah nimh

I want to shoot
Semi/3 round burst at 25 bbps on a lipo. I don't care if it's a 7.4 or or an 11.1 but I know with a 7.4 lipo I'll have to do some other kind of upgrade.
A couple of observations, the wiring in a KWA is low resistance and actually quite good.  And rewiring any gun does not require a piston change. Certainly adding a FET will not mandate a piston change either.  What sometimes can be an issue is if the gun is cycling too quickly to allow the piston to come fully forward before the sector gear re-engages the piston body.  This is pre-engagement and it will quickly destroy a piston.  I would drop in a 1200-1400 mAh 11.1 15C lipo in the gun and recheck the RPS. It should be in the 22-23 range at that point.  From there you can worry about changing the piston if it's even needed.

#4 cellistle

cellistle

    Newbie

  • Members
  • Pip
  • 20 posts
  • Country:

Posted 01 July 2014 - 08:17 PM

Okay, I can understand where you're coming from. I currently have 3 11.1 1200 mah 15c lipos, 3 7.4 1000 mah lipos, 3 9.4 1600mah Nimh batteries. I was warned not to use my 11.1 lipos because due to the mosfet/wiring the increased energy would make my gears slam into the poly piston so hard it'd strip a tooth and then strip the rest very soon within a few cycles. They said it will quickly strip it. It makes sense the reasoning of the gears being spun faster and harder against the piston but I would think the KWA would be able to keep up with the stress of it.
It was never about how quick the cycle rate was but the extra force due to the mosfet and deans connectors of the gears slamming into the piston

Edited by cellistle, 01 July 2014 - 08:18 PM.


#5 JesseHammil

JesseHammil

    Enthusiast

  • Members
  • PipPip
  • 56 posts
  • Country:

Posted 02 July 2014 - 07:00 AM

I suspect youre in the same situation as me. My local "techs" do not know what they are talking about. I decided I'd learn as much as I can about airsoft guns and how they work and do the work myself.

I think tossing 11.1v into your kwa will get you close to 25bbs.

#6 StealthTaskForce

StealthTaskForce

    Enthusiast

  • Members
  • PipPip
  • 246 posts
  • Gender:Male
  • Location:Tampa
  • Interests:Airsoft, Paintball, Sports, My girlfriend, Knives and Real Steel
  • Country:

Posted 02 July 2014 - 09:09 AM

View PostJesseHammil, on 02 July 2014 - 07:00 AM, said:

I suspect youre in the same situation as me. My local "techs" do not know what they are talking about. I decided I'd learn as much as I can about airsoft guns and how they work and do the work myself.

I think tossing 11.1v into your kwa will get you close to 25bbs.

Me and my friend want to do the same thing. Since I have big plans for my gun, I want to be the one to do lol plus it's cheaper that way since I don't have to pay for labor. They hold up a little better than some lower end guns, so you should be fine.

#7 JesseHammil

JesseHammil

    Enthusiast

  • Members
  • PipPip
  • 56 posts
  • Country:

Posted 02 July 2014 - 10:25 AM

If something breaks it can always be replaced!




0 user(s) are reading this topic

0 members, 0 guests, 0 anonymous users