M4 upgrade threatening my gear box?

[Kingpin665]

Hey guys, I've got a TM M4A1 (New Type) which I believe still runs the V2 gear box. Now I'm looking at getting an upgrade for most of the internals, its the 390 FPS Standard Upgrade about 3/4 down the page (http://www.007airsoft.com/products/htm/upgrades.htm) but after reading a bit about Piston and head sets that it seems to be the part that will give me issues "This (piston head) part is also the one that causes mechboxes to crack, so proper selection is critical." And another quote from Skruface "Aluminum or steel piston heads are generally more resistant to deformation, meaning they'll give you a better seal longer. Unfortunately have a nasty habit of breaking mechboxes, especially on M16/M4/MP5/G3 variants (aka the Version 2 mechbox), and especially if you dryfire alot." Personally, I don't dry fire much so I wanted to know what the risk level was on getting this kind of upgrade without spending the extra $125 for the advanced updgrade with the reinforced gear box. I'm thinking as I type this that for what its worth at $125 its better off to spend it now during the upgrade then to risk it and have to get someone to fix the damage later... but I feel I'm still wanting to know the level of risk without it.

Thanks guys.

Kingpin

The brand of the parts in the kit are as follows if it matters:
Systema aluminum piston and head set
PDI spring
Systema bushings
ICS reinforced gears
Systema shims.

[ILLusion]

I say totally skip the aluminum piston head and get something synthetic - silicon, POM or polycarbonate.

It's been proven that an aluminum piston head with even a PDI 120% piston head can crack your gearbox in the winter.

As for the aluminum piston... I still don't like using them because they tend to wear faster than polycarbonate. Plus the added weight of it is extra stress on your gearbox.

[Kingpin665]

But what if I were to have the advanced upgrade with the reinforced gear box, would I still have to worry about cracking it? Winter play isn't really a big deal for me right now, but I'd rather upgrade and have the option to play in the cold down the road then not be able to at all.

*Edit* I went back to Skruface's thread "Why do I need to upgrade (or not) - with explenations!" to re read some of what he had put about piston heads.

"Aluminum or steel piston heads are generally more resistant to deformation, meaning they'll give you a better seal longer. Unfortunately have a nasty habit of breaking mechboxes, especially on M16/M4/MP5/G3 variants (aka the Version 2 mechbox), and especially if you dryfire alot. This is because it is the piston head that strikes the cylinder head (which is butted up against the mechbox frame), and there is no "give" to the impact. I wouldn't recommend them for use with a high tension spring. They run about $20-$30."

So I suppose in a round about way he said the same thing you did about aluminum. So unless the reinforced gear box is going to save me from that worry I should email Ken at 007 about getting that piston head switched do a softer material.

reinforced mechbox isnt much better...They still crack. You can only slightly improve a flawed design.

Go with a polycarb piston...although, of all the pistons I have used, a stock TM piston is still better then many aftermarket ones.

Its big bucks. For that price, Id look into a systema complete mechbox.

for 390fps, generally, you want an irregular pitch spring, spring guide, bushings, and shims...Reinforced mechbox if you can spare the cash.
Extras. Systema silicone piston head and cylinder head.

Honestly, not to take business away from ken, but ask around for WGC group orders...parts are fantastically cheap. I find canadian retailers offering upgrades isnt worth it...I held out and got in on orders and I built my mechbox for a fraction of the price that canadian retailers were offering.

If you have the money, get a hurricane reinforced mechbox. Not that its essential, but if you crack your mechbox, you dont always know it...suddenly gears are destroyed, parts are snaped and your out a lot of money.

[mcguyver]

Stick to about 360 fps if you want a good balance between performance and durability. The performance difference between 360 and 390 is minimal, but Marui mechboxes are not really built to withstand 400 fps ranges for very long. There are a few guys who've never had a problem with many rounds at 400 fps, but personally I've thrown away a few damaged mechboxes due to an M120 spring.

Silent head sets can help dissipate some of the spring's energy over a larger surface at the impact point point between the heads, but as the cylinder head still makes the exact same contact with the mechbox, it really doesn't do a thing to help out the mechbox.

You may do best as Droc has said to get a Systema complete mechbox with an M120 to give you about 400 FPS. It's overall the best deal and it's pre-assembled. Makes your life easier.

[Identity]

Originally Posted by Droc

reinforced mechbox isnt much better...They still crack. You can only slightly improve a flawed design.

Go with a polycarb piston...although, of all the pistons I have used, a stock TM piston is still better then many aftermarket ones.

Its big bucks. For that price, Id look into a systema complete mechbox.

for 390fps, generally, you want an irregular pitch spring, spring guide, bushings, and shims...Reinforced mechbox if you can spare the cash.
Extras. Systema silicone piston head and cylinder head.

Honestly, not to take business away from ken, but ask around for WGC group orders...parts are fantastically cheap. I find canadian retailers offering upgrades isnt worth it...I held out and got in on orders and I built my mechbox for a fraction of the price that canadian retailers were offering.

If you have the money, get a hurricane reinforced mechbox. Not that its essential, but if you crack your mechbox, you dont always know it...suddenly gears are destroyed, parts are snaped and your out a lot of money.

Nicely said Droc.

[JohnnyDo]

Another option to talk about sitting down at the camp fire is getting a FTK from guarder. They include pretty much every component that can be upgrades inside the mechbox and comes with Super-Lube which many consider to be an excellent lubricant. The Guard FTK's come with (for the M4 variant):

- SP120 Spring ( Oil Quenched/Tempered Si-Cr Alloy Steel Wire )
- Polycarbonate Piston
- Air Seal Nozzle
- Ball Bearings Spring Guide
- Polycarbonate Ventilation Piston Head
- Stainless Cylinder Head
- Lucid Chromium Plating Cylinder
- Original Type Steel Gear
- Enhanced Tappet
- 6mm Steel Bushing
- Shim Set
- SUPER-LUBE Oil X3

This has a polycarb piston and piston head for durability and light weight (less stress on mechbox and faster rate of fire), but also a better then stock tappet plate as they often break, a nozzle with an o-ring inside to help with consistent air flow and better air seal from the cylinder assembly to the hopup. The gears are made of a much harder material then stock and from my own experiance they run and wear very well as long as you shim up your gears correctly.

The only thing is the spring that comes with this kit will make your gun run pretty hot so you may wish to opt out and go for a lower power spring such as a Prometheus ms100 or ms110 (check Illusions spring chart for a better comparison of what springs can give you what results. Link To Spring Chat You can still use the spring which is included in the kit at your choice, however as said above; the stronger the spring, the more stress is on your mechbox.

[Kingpin665]

Thanks so much for all the info John, you've been nothing but great to deal with so far. Can't wait to hear what the comunity has to say aswell.

I have a few more questions myself I'll PM you about though.

[ILLusion]

If I show you a picture of one of my cracked reinforced mechboxes (due to an aluminum piston & piston head set), would that be enough to finally dissuade you from going that route?

[porry]

so you do not recommend an m120 spring in a stock gearbox? what if i cut a few coils off the spring? will that lower the FPS any?

[JohnnyDo]

I totally agree from recent experience. An aluminum piston and piston head can cause all sorts of problems.

To be honest I have yet to see anything documented or made into a theory as to why aluminum pistons and piston heads are made at all. With the ability to mold pieces as well as they do, machining seems to be more expensive and in the end cause more problems then solve. Ok aluminum piston heads may hold their shape better ... but by how much and how much of a performance increase would you see, then weight that against the disadvantages. *shrugs*

[ILLusion]

Originally Posted by porry

so you do not recommend an m120 spring in a stock gearbox? what if i cut a few coils off the spring? will that lower the FPS any?

I don't recommend it with metal piston heads.

Why bother getting an M120 spring if you're going to cut coils off? Why not just get a lower rated spring in the first place?

Originally Posted by JohnnyDo

To be honest I have yet to see anything documented or made into a theory as to why aluminum pistons and piston heads are made at all. With the ability to mold pieces as well as they do, machining seems to be more expensive and in the end cause more problems then solve. Ok aluminum piston heads may hold their shape better ... but by how much and how much of a performance increase would you see, then weight that against the disadvantages. *shrugs*

Systema has documentation on this. It comes with each of their springs and gear sets, although they leave out specific details. Those details are obtained by taking part in "Systema training courses."

Metal piston heads are made for:
a) louder sound on each shot
b) increased feeling of "recoil" on each shot.

Aluminum pistons are made to:
a) slow down the movement of the piston
b) increased feeling of "recoil" on each shot.

[Kingpin665]

Originally Posted by ILLusion

If I show you a picture of one of my cracked reinforced mechboxes (due to an aluminum piston & piston head set), would that be enough to finally dissuade you from going that route?

No, as soon as you mentioned it with the first time I was going to try and stay away from aluminum, I'm just trying to gadge where products like a reinforced mechbox stand. If I don't ask I'll never know, right? Illusion your name on these boards is known by even the newest of us, so your opinion is definitely weighted and I trust what you have to say.

Originally Posted by JohnnyDo

- SP120 Spring ( Oil Quenched/Tempered Si-Cr Alloy Steel Wire )
- Polycarbonate Piston
- Air Seal Nozzle
- Ball Bearings Spring Guide
- Polycarbonate Ventilation Piston Head
- Stainless Cylinder Head
- Lucid Chromium Plating Cylinder
- Original Type Steel Gear
- Enhanced Tappet
- 6mm Steel Bushing
- Shim Set
- SUPER-LUBE Oil X3

What do you guys think about this upgrade package? Now having discussed a few things with John I'm quite confident in him with doing this job for me but wanted the confermation from the comunity as to if they also think I'm making a good decision. Aswell do you think I would still have to worry about cracking my stock gear box with an upgrade such as this? Or any other possible worries I may have.

[CDN_Stalker]

I'll toss in info about my MP5, which might be of interest to the initial poster. My MP5 has a good (meaning a spring made as it should be) PDI 150% spring in it, and it consistantly held 352fps (ok, it varied +/-2fps at times) with everything else stock. Later I added a bearing spring guide, kicked me up to 365fps with 0.20g BBs and hop up set. I added a new stock barrel, 10cm longer (330mm is what I cut it at) and that has me sitting at 387fps now.

Instead of trying to get all your 390fps out of just a spring upgrade, why not go for a medium upgrade (as McGyver suggested, 360fps) and get your fps from other means, such as a longer and/or tighter barrel? With the right choices, you could be sitting at 390fps but your mechbox will be less stressed.

BTW, after I installed the PDI 150% in my gun about a year and a half ago, was December '04, my stock mechbox cracked bad after two months. And that was ONLY from shooting indoors, in my basement. Assume I went through maybe 5000rds. I bought and installed the Hurricane reinforced mechbox and it lasted me all last year, and earlier this year I noticed it was cracking (hairline) as well, but it had been quite a while since I opened it up, could have been from last year sometime and stopped, or fresh. I drilled a small hole at the end of each crack to try to keep it from spreading, then covered the area with aluminum filled epoxy (Metal-Set) hoping it'll reinforce the mechbox enough for it to last longer. Since doing that a few months ago, I've put about 3000-4000rds through it and still running fine.

[Kingpin665]

Info always appreciated. Now I should say that I was also looking to get an M16 6.04mm barrel installed at the same time as the rest of this, now I DEFINITELY don't want a hot weapon. Now 390 was just the FPS count that 007 was quoting for that upgrade, I was hoping to float between 360-380fps after everything is said and done with. The spring I'm looking to use in JohnnyDo's package is the SP100 or maybe the SP110, but the 110 would be pushing it. So other than toning the spring down a bit form the quoted items, as I've switched from using the aluminum piston/head to Polycarbonate as recomended would my Mechbox still be at a large risk within the next year? Lastly, and comments on what John is offering me with that upgrade as a whole? I'm just curious if you guys think its a good choice of parts for my upgrade.