G&P upgrades?

[Dime]

I have a G&P m7a1 Troy Industries replica and wanted to know what should be upgraded or replaced,I have been told the G&P gears are garbage,what are the best options[make/model]and what else can I do to improve the quality and longevity of the rifle?

[Squirrel]

The gears in a G&P box are not garbage. My G&P has been running with a 5000mah 25c 7.4v LiPo for 2000+ rounds and show no sign of wear. The G&P m120 high speed motor that came with it is pretty high speed (25-27 rps) with an m110, light piston and head, and sorbo AOE adjustment. It was shimmed pretty decent from the factory, but a shim job really meshed it up a bit nicer, and it runs smooth and pretty quiet.

It should be a very reliable setup in stock form. I've taken apart 3 G&P gearboxes of various ages, and none of them had signs of wear to the gears or piston teeth.

[ctres]

The gears are supposedly hit or miss, and maybe they've fixed the issue by now, but for a while it was not uncommon for g&p gears to have the axles shear off under stock or mild loads. I've never worked on a G&P box but it's been a fairly common thing and that is probably why you have heard that the gears are junk. Personally though, if I were you I would just runnit stock until something goes wrong. If you have to ask everything that needs to be done to the gearbox then you probably aren't ready to dig into it.

[Caboose]

Don't replace anything until it breaks. As Squirrel said, a G&P box is pretty good in stock form and can last a while on a 7.4v lipo.

The parts most likely to break are the gears and the piston, but some standard XYT's and a Lonex piston would be fine, not to mention cheap, replacements if/when the original parts go.

[Squirrel]

So if axles are sheering off, that means something is either misaligned or binding. I did have trouble with one of the G&P boxes having a bearing that would not fully seat and stay in, which theoretically could cause a little uneven torque to occur on the axle. (The selector plate was actually pushing on the bearing) This was an older gearbox though. On my new gearbox it seems like this issue has been taken care off.

I'm guessing another thing that could help that issue would be torquing down the shell evenly. The trigger / motor wires in the G&P are fairly large, so seating them properly will help you get everything snugged up right.

Seriously though, don't dig into it till you know a bit of what is going on with the gearbox and what needs to be upgraded. A lot of people say things suck, but you later find out they are the one that caused the failure.

[ctres]

Whatever it may be, G&Ps are indeed notorious for axles snapping, just do a google for G&P gear axle and you will see what I mean. I believe most of these happened straight out of the factory, but that doesn't necessarily rule out the explanations that squirrel mentioned since those could also happen in the factory. Either way, I say just run it until it breaks or until you are proficient with gearboxes and ready dig into it.

[Squirrel]

Feb 20, 2014 8:53:33 GMT -5 ctres said:

Whatever it may be, G&Ps are indeed notorious for axles snapping, just do a google for G&P gear axle and you will see what I mean. I believe most of these happened straight out of the factory, but that doesn't necessarily rule out the explanations that squirrel mentioned since those could also happen in the factory. Either way, I say just run it until it breaks or until you are proficient with gearboxes and ready dig into it.

With some further thought and more clarity, I have the following to add:

I'm by no means a mechanical engineer, but there really should be very minimal friction on the axle itself due to the bearing mounts, so snapping from binding in the case of perfect alignment should be pretty much ruled out.

You would really have to have a misaligned gearbox or off center / off perpendicular machining of the axle to cause a bind to snap it off. If replacement gears do hold up in the gearbox without a bearing change, the likelihood of a poorly machined gear axle would probably be the culprit of the failure.

Some more research:

I did a little google searching and found it is mostly the sector gear that is the problem. The people I saw that had the problem were still running the stock piston (white), which I did initially notice had some problems with gear meshing on the second and third tooth. An AOE sorbo adjustment did seem to fix the engagement issue. Poor gear meshing could cause enough off center force that leads to the eventual failure.

I did not run my gearbox without the AOE adjusted, which may be the reason I have not seen wear or failure.

[Dime]

Thanks guys,just making sure I'm not going to have any unforeseen problems on the field.Is there anyone near Ann Arbor that could offer their tech skills for a fine tuning?