Replacement Parts for V1N Gearbox

[JLiang]

Whoo, boy. Here goes.

Originally Posted by MaciekA

Ha, nice. You should see me when I break a gun these days, usually the first words out of my mouth are "oh boy, I can't wait to open this up".

lol.

Originally Posted by MaciekA

Were you by any chance running the mechbox at a really high RoF on a LiPo battery or anything like that?

Nope.

Originally Posted by MaciekA

Basically the same thing happened to me as you, except for a slightly different reason. In my case, the screw came undone because I had failed to thread-lock the screw after completing the build and gaming it. After a few thousand rounds at 33rps, it finally worked its way out and wham.

Oh. Mine I think was that I just forgot to sorbo it. :woops:

Originally Posted by MaciekA

From what I have read about the Famas mechbox, you should be okay using any v2 piston and piston head. You should google around to make sure. For the cylinder head, things might be a bit more tricky, so if you can salvage what you have, stick with it, because it's already matched to your air seal nozzle.

Yup. V2. The Spring Guide is a V3, though.

Originally Posted by MaciekA

I'm unsure which cylinder type is in the v1 mechbox so make sure to figure out if you need a type 0 / type 1 / etc.

I think it's a Type 0. It's got no holes and it's 74mm long (about)

Originally Posted by MaciekA

If I were doing what you're doing, I'd probably take the whole thing apart and clean all the shattered pieces out (they tend to get into your gears and piston rails and other areas) and regrease with Superlube or some other Teflon (PTFE) grease like the Modify gear grease. If you can get Superlube synthetic grease, get it because it will last you for ages and is superior to almost everything else on the market (and is safe for everything in an AEG).

Already done. I'm using GUNK brand White Lithium for everything.

Originally Posted by MaciekA

Be extra careful when installing a sorbo pad in a gun which beforehand didn't require any angle of engagement (AoE) adjustment. Installing sorbo pads usually requires you to remove a tooth from the piston. If you do decide to go with the Modify ultra high speed piston, it already has the correct tooth removed for an AoE adjustment (hence the name "ultra high speed piston"), but if you go with some other piston, make sure to check this. For example, some of the SHS pistons don't have any teeth removed, so you typically have to go at them with a dremel before running your new setup.

Already been there, done that. Notice the washers in my pics.

Originally Posted by MaciekA

For the spring guide, just stick with the stock one you have. Version 3 spring guides have big fat tabs at the back and I haven't seen them fit in any mechbox other than the V3 so far. Also, it won't really make a big difference for yourself unless you somehow managed to destroy your spring guide -- extremely unlikely.

Oh, okay. What about bearing guides? They might help the spring.

Originally Posted by MaciekA

Finally, when you attach your new piston head to your new piston, be sure to use some threadlocker / loctite on the threads of the screw so that you don't have a repeat of this incident Give it over night to cure so that it holds on real tight.

THAT I didn't do. I'll keep that in mind. Thanks!


/sweat

[JLiang]

Okay, moar pics!

This is the stripping on the screw




**** you, flatspot.

Image of the whole piston. Maybe it won't need replacing...? I'd still like to, however. Notice the AOE mods.



Scratching of the inner cylinder



(It's bigger than it looks)

Moar Cylinder damage.




I think that wraps it up. If you need more, tell me. Also, the cylinder head was NOT damaged, so I won't need to replace that, thankfully.

[Boyso]

The Cyma doesn't have the same gearbox as the TM?

[JLiang]

Nope. CYMA modernized the V1 to the V1N, and it uses more widely-found parts so that when things like this happen, people don't go running back and complaining. The only proprietary parts in the GB are the Tappet and Nozzle.

That's it. Everything else is V2, 3, and 7 parts.

V3 Spring Guide
Type 0 Cylinder
V7 Cylinder head
V7 Gearset
Short Type Motor
M110 Spring Equivalent
V2 Piston/Piston Head

[MaciekA]

Ok.. So far so good, looks like you've got a good grip on this Thanks for the info on the CYMA modernization.. That's a useful thing they've done. On to advice:

Switching to a sorbo pad and ditching the spacers is good for a couple reasons.

First, I've had a couple failures while experimenting with spacers on the piston, one was in a V3, the other in a V2 (on a G&P). In both cases, terrible things happened. In the case of the V3 mechbox, the spacers caused the piston head screw to be attached far less securely, and at a modest power / RoF ( 400fps, 20rps) the piston head flew clean off the piston during testing. Sound familiar?

Secondly, you always want to reduce weight on your piston whenever possible. I have found that the only spacers that can easily be depended upon to not crack are metal ones, and these are heavy. You are trying to ensure the quickest return to home position that you can, especially if you are running at a higher rps. This is to avoid pre-engagement, where your sector slams into your piston teeth before the piston is able to return back home. You probably won't run into this unless you're pushing your mechbox hard (>30rps), but you might as well know, because it can still come up cases of extreme weight, friction, or speed/weight mismatch between gears/piston/spring power.

[JLiang]

Yes, I'm quite happy they did that or I would be in a large pile of poo right now.

And the sorbo is interesting. Where would it go, on the cylinder head, or piston head?

[MaciekA]

Originally Posted by JLiang

Yes, I'm quite happy they did that or I would be in a large pile of poo right now.

And the sorbo is interesting. Where would it go, on the cylinder head, or piston head?

cylinder head

[JLiang]

Okay, thanks.

I'm just worried because I'm afraid the Sorbo might compress over time and I'll lose my AoE, resulting in catastrophy again.

[wind_comm]

oh dude yeouch.

you might be able to save the cylinder depending on how good you are with a polishing tool on a dremel.

what's really interesting is that if you're firing in full auto, sorbo will stay compressed and be thinner (which can screw with piston engagement) than at a resting state.

and if you're going to try and salvage the cylinder, then you might as well take a dremel to the piston at the same time.

[MaciekA]

If you are paranoid about sorbothane squishing, you can do two things..

First, email Duy and ask him what the hardness of the sorbo pads is that he's selling. You're ideally looking for something like 70 durometer. Lower numbers (like 40D) are softer and squish more.

Second, you can install the sorbo pad and assemble your entire mechbox with the spring inside. Let it sit for a while with the spring compressing the piston against the sorbothane. Then do your AoE assessment with the spring in the mechbox. If it is not giving you sufficient AoE, you can always get thicker sorbo pads and shave the 3rd tooth as well. I am using the scatterplot sorbo pads sold at clandestine airsoft.

[JLiang]

I'm planning on buying the V7 Scatterplot as well. Are they any good?

And those tips seem like they'll work. I'll keep that in mind. Thanks!

[wind_comm]

scatterplot's sorbo pads are the best. he's going to start selling neoprene protective mats soon as well.

[JLiang]

Good to know. On recommendation of SHS parts, I have changed the parts list to the following:

SHS V3 Bearing Spring Guide
V7 Scatterplot™ Sorbo Pad - 3/16" - 70 Hardness
SHS Full Type 0 cylinder
Lonex POM Ventilation Piston Head
SHS 14-Tooth Lightened Piston - Full Metal Rack

Any conflicts? Parts to avoid?

[JLiang]

Also, I just noticed this:

Originally Posted by MaciekA

For the spring guide, just stick with the stock one you have. Version 3 spring guides have big fat tabs at the back and I haven't seen them fit in any mechbox other than the V3 so far.

Challenge Accepted. :P

[JLiang]

Triple-post, but I couldn't edit this into anything prior.

I remember hearing people bashing SHS parts; are they high-quality, or parts to avoid? When compared to a company like Modify or Guarder, how do they fare?