Brainstorming for a Marui M14 rebuild

[Sentenced2Burn]

So I smoked-out my old CYMA trigger contacts and wiring the other day on my Marui/CYMA M14 hybrid after years of hard skirmishing.

I decided that I would take it as a blessing in disguise and finally get around do rebuilding it in a more "complete" sense. I have quite a few of the specific part-groups already selected/available, but there are a few key things I'm looking to change on it. Having said that; it's a version-7 setup; which I am minimally familiar with (aside from the basics and how to disassemble/reassemble the gearbox).


TL;DR
The one thing I have little to zero experience in is modifying the cylinder/piston group with aftermarket parts. I want to replace the Cylinder Head, Piston, and Piston Head with a good, solid setup. I'm happy with both the CYMA and Marui cylinders as they offer quite a good seal and show little sign of wear.

Some fundamentals of my rifle that may be helpful in deciding which parts to go with:

-Running a Prometheus 120 spring; shooting approximately 435 FPS
-Stock CYMA motor that offers low RPS (due to the heavy spring), but going to change to a high-torque
-Prometheus 6.03 TBB
-Stock CYMA gears
-Tokyo Marui stock trigger contacts
-Silver low-resistance wiring (newly installed post-smokeout)
-Tokyo Marui stock hop-up unit with Baton Ryosoku flat-hop
-SHS springset
-Still using the CYMA gearbox shell; but may swap back to the original TM shell. Can't really tell the difference in quality between the two, to be honest.
-Currently the primary motor-connection is deans, leading to standard small-tamiya at the battery-connection end. I only had one pair of each available in my spare-bin, so for now it will have to do (interested to try it out though as I honestly prefer tamiya's on the battery end anyway, for convenience's sake)


Not looking to go with a high-speed setup; only thing I might change aside from this new cylinder grouping is a high-torque motor for better response on the 120 spring.


Sorry for the wall-o-text; but anyone who is even casually interested in spitballing on an M14 project is encouraged to throw their feedback in.

Any and all expertise is welcome, of course. I'm a huge fan of the platform, but unfortunately, I haven't had the time or money to explore the performance of all the different aftermarkets for the Marui V7 types.

Thanks for reading.

[Styrak]

What kinda battery are you going to be using? Might want to throw a mosfet in there while you're at it.

[-Shade]

My 2cents

• Learn about and use a LiPo battery if you aren't. (Massive performance boost)
• Get a high TPA torque motor. ZCI makes a good 28tpa one. Make sure you get a SHORT motor if it's a Socom-16 or regular M14. LONG motor for the EBR.
• The Cyma shell is built like a tank.
• Cyma gears are good, but you can get faster ones by SHS and Prometheus. Pair those with the motor and you're great for trigger response.
• SHS makes a cylinder head and nozzle for the Marui style M14 as well - make sure your compression is good
• Obligatory: Polish the cylinder, correct AOE, shim, etc (DIY youtube videos)
• Make SURE when you take apart the gearbox you put every screw back where you found it. There are two in particular on the right side of the gearbox that, if switched, will extend into the gearbox and jam your gears.

Sample List:
Mosfet/Lipo (NukeFet is bestest - GATE fets for an arguably easier install)
ZCI High torque motor
SHS/Rocket M14 nozzle
SHS/Rocket M14 Cylinder Head
SHS/Rocket blue piston
SHS/Rocket POM piston head (or Lonex POM if you want to spend more money)
Any V7 ball bearing spring guide
SHS or Prometheus high speed gears (if you want)

You may want a weaker spring as all of this may increase your fps

Hope this gives you some ideas.

[Sentenced2Burn]

Originally Posted by Styrak

What kinda battery are you going to be using? Might want to throw a mosfet in there while you're at it.

I had a TriggerMaster MkII Mosfet in there at an earlier point and ran 11.1's occasionally, but usually kept it to 9.6. The following year I yanked out the MOSFET and old wire harness/fuse and re-wired it again, plain-jane style. Ran 7.4 LiPo's and 9.6 NiMH after that (9.6 NiMH give me great response for the setup, but I know I can do better).

I will probably reinstall the TriggerMaster again when I finally have everything in front of me ready to go. I have half of my new wiring assembly ready, but I will need to put new contacts in for the MOSFET if I'm going to use it again.

Originally Posted by -Shade

My 2cents

• Learn about and use a LiPo battery if you aren't. (Massive performance boost)
• Get a high TPA torque motor. ZCI makes a good 28tpa one. Make sure you get a SHORT motor if it's a Socom-16 or regular M14. LONG motor for the EBR.
• The Cyma shell is built like a tank.
• Cyma gears are good, but you can get faster ones by SHS and Prometheus. Pair those with the motor and you're great for trigger response.
• SHS makes a cylinder head and nozzle for the Marui style M14 as well - make sure your compression is good
• Obligatory: Polish the cylinder, correct AOE, shim, etc (DIY youtube videos)
• Make SURE when you take apart the gearbox you put every screw back where you found it. There are two in particular on the right side of the gearbox that, if switched, will extend into the gearbox and jam your gears.

Sample List:
Mosfet/Lipo (NukeFet is bestest - GATE fets for an arguably easier install)
ZCI High torque motor
SHS/Rocket M14 nozzle
SHS/Rocket M14 Cylinder Head
SHS/Rocket blue piston
SHS/Rocket POM piston head (or Lonex POM if you want to spend more money)
Any V7 ball bearing spring guide
SHS or Prometheus high speed gears (if you want)

You may want a weaker spring as all of this may increase your fps

Hope this gives you some ideas.

Definitely, I was pretty happy with the higher-output LiPo's back when I rocked them in the M14 but ultimately took the MOSFET out to make more space as the wiring was a big spaghetti-mess. 9.6 NiMH's still give pretty snappy response, so I'll probably keep rocking those unless I decide to incorporate my TriggerMaster back into the setup.

Thanks for the heads-up about the CYMA shell; I might end up rolling with that one since all my other CYMA guns are rock-solid too.

Was thinking about picking up an SHS set of gears for the M14; and since I poached my CYMA sector gear to replace one in my CYMA AK (yes, they are in fact identical), I might just go ahead and grab the SHS set. I was very happy with their V2 set.

Definitely going to grab a new cylinder since the old ones have taken a bit of a beating. I think I'll go with a dull-finish though so the o-ring and lubrication have some texture to keep the seal alive. I have found that polished cylinders are fabulous for a time, but once the grease-barrier between the cylinder and oring "pops", your compression is all over the place until you re-apply fresh.

Have you had luck with the SHS pistons? I've used one in my AK and while it was constructed well, the rails were very fickle and it would often torque in the cylinder. Eventually ditched it and went back to my Lonex red. Will definitely look into their piston-heads though as I don't want to go hunting for another Lonex one. I have a Guarder V7 nozzle ready to drop-in so here's hoping it works well with what I end up buying.

Excited to check out the motor you mentioned, too. Thanks for the suggestions; gives me a few things to start checking out for sure. Ty Ty

[-Shade]

The M14 cylinder is a different length than normal ones. So if you upgrade that, be sure to get one specifically for an M14. Maybe you're using the wrong grease/oil for the o-ring, lol.

SHS and Rocket (same OEM) are very good and I use them in almost all my builds. They can have fitting issues, so you should always check by putting the piston in an empty shell, screwing it together, then tilting it back and forth to see if it slides freely/easily. If it does, you're golden - if not, then file the rails down/inbetween, little by little, so it can slide without a problem. All that being said though, the lonex red is still the better piston. In terms of the heads, everyone has the lonex POM piston head in stock nowadays I think.

Stay awaaaaaaaay from the guarder nozzle. You want one with an internal o-ring for a better seal. This is KEY. If I recall, the guarder doesn't have one. If I'm wrong and it does, then use it - not sure if they've updated them or not. SHS M14 nozzles are about $5 or less. Don't forget to add a drop or two of silicon oil to that little o-ring either, lol.

And no problem. Glad I can help.

[Sentenced2Burn]

Nah, correct grease but I have had much more consistency with the semi-dull finish cylinders over lifetimes. That's just me though, I know there are many who swear by full-polish. Our mechanic friend (and master gun-tech) actually explained the process behind it and it seems logical enough, but who knows.... there's tons of "voodoo superstitions" in airsoft haha.

I'll still give the guarder a try just for shits, I've had some pretty unassuming parts surprise me sometimes with how they fit (LCT parts come to mind). If it turns out to be total garbage I will definitely snag the SHS though as I have had luck with their nozzles in the past (just thought I'd try the guarder one I had in my toolbox haha).

I will keep you abreast of the situation as it unfolds.