V3 gb issue

[Pewpewpetie]

Hi all, my specna v3 gearbox is causing headaches. Basically when I shim I shim bevel to pinion method, but when I tried I can't even get a 0.5mm shim under the bevel as when motor is installed it is all ready biting on the pinion. I've tried different bushings( low profile) and still the same. Is it a case of getting a new shell?

 

[Adolf Hamster]

0.5mm is a thick shim? normally i'd start with 0.1mm under a gear then add from there.

 

[Pewpewpetie]

0.5mm is a thick shim? normally i'd start with 0.1mm under a gear then add from there.

Meant 0.05mm

0.5mm is a thick shim? normally i'd start with 0.1mm under a gear then add from there.

I'll get a vid up in next hour

 

[Adolf Hamster]

Meant 0.05mm

ahh, that makes more sense.

what gearset/pinion is it?

 

[Pewpewpetie]

View attachment 76567
Tried many different sets, standard, she, rocket all the same

 

[Pewpewpetie]

ahh, that makes more sense.

what gearset/pinion is it?

I think the gearbox is just a lemon, I've noticed wear marks when the shell where the sector bushing isn't sitting flat, next question is the lonex or modify shell the best

 

[Adolf Hamster]

I think the gearbox is just a lemon, I've noticed wear marks when the shell where the sector bushing isn't sitting flat, next question is the lonex or modify shell the best

it could be, it's hard to tell these things from vids sadly

the problem with aftermarket shells is they can have their own issues, for example with the mounting of the motor cage or general fitment of the shell into the gun.

you could try manually countersinking or finding a smaller pinion, although if there's a tooth profile mismatch that can be its own problem.

 

[Pewpewpetie]

it could be, it's hard to tell these things from vids sadly

the problem with aftermarket shells is they can have their own issues, for example with the mounting of the motor cage or general fitment of the shell into the gun.

you could try manually countersinking or finding a smaller pinion, although if there's a tooth profile mismatch that can be its own problem.

Going to try a new shell then if that fails I will try to sink the bushings. Thanks for your help

 

[Skara]

You could also try spur first, you know, there's not only ONE way to do things

 

[Adolf Hamster]

You could also try spur first, you know, there's not only ONE way to do things

i do tend to go spur first, but that's more to place a limit on the range in which i can shim the pinion to (eg if the idler needs say 0.3mm under it then i can't put the bevel lower than that).

problem is when that limit isn't enough, or as in this case even with the smallest possible amount under the bevel it's not ideal.

 

[Pewpewpetie]

i do tend to go spur first, but that's more to place a limit on the range in which i can shim the pinion to (eg if the idler needs say 0.3mm under it then i can't put the bevel lower than that).

problem is when that limit isn't enough, or as in this case even with the smallest possible amount under the bevel it's not ideal.

I've ordered a modify torus v3 shell. I'll update this post if needed when it arrives. Thanks for all the help adolf

You could also try spur first, you know, there's not only ONE way to do things

Wouldn't make a difference as the bevel will still be too close to pinion

 

[Iceni]

The fact it's rocking in the bearing without bottoming out on the shell would imply a badly seated bearing. Is it fully seated? And are the mating surfaces clean and free of marring?

V3 Bushings/Bearings poke out of the shell. If it's sitting flush to the shell then you need to put something that can support the seat like the correct sized socket, then tap the bearing to be flush on the inside of the shell. There's a brief flash of the seated bearing at 7 seconds and to me it doesn't look like it's seated.

 

[Pewpewpetie]

The fact it's rocking in the bearing without bottoming out on the shell would imply a badly seated bearing. Is it fully seated? And are the mating surfaces clean and free of marring?

V3 Bushings/Bearings poke out of the shell. If it's sitting flush to the shell then you need to put something that can support the seat like the correct sized socket, then tap the bearing to be flush on the inside of the shell. There's a brief flash of the seated bearing at 7 seconds and to me it doesn't look like it's seated.

It's as far in and seated as it will go, almost as is the bushing groves on shell aren't deep enough either, also noticed the sector gear is being the shell on oneside, looked at bushing is fine but shell is milled at slight angle. I've ordered a new gearbox shell now.

 

[Iceni]

If you have the tooling you can correct those seats with flat endmills.

If you have access to a milling machine and bits then it's as simple as screwing the shell to something, clamping that to the bed. Find the centres and just do a fine feed to touch it back to square. Takes a couple of minutes with the right tools, without them it's a very difficult task to get right and If I didn't have access  to a mill then I'd be looking at new shells as well. Cyma and JG also make decent V3 shells, Unlike a V2, V3's are generally a lot more robust and don't need to be anything special.

Those modify ones I'm a little sceptical of. With absolutely no evidence I'd be worried about the weight reduction near the spur gear. I'd certainly be thinking about using a piston rack with a few nylon teeth rather than a full steel rack to keep a weak spot.

 

[Pewpewpetie]

it could be, it's hard to tell these things from vids sadly

the problem with aftermarket shells is they can have their own issues, for example with the mounting of the motor cage or general fitment of the shell into the gun.

you could try manually countersinking or finding a smaller pinion, although if there's a tooth profile mismatch that can be its own problem.

So I got my new shell and having exactly the same issue. The bearing are seated perfectly, not risen and still no room between bevel and pinion



View attachment 76688
My guess now is a new motor cage

 

[Adolf Hamster]

is that image flipped?

looks like the bevel is on the right-hand side of the box, it's normally on the left?

also what the hell is going on with that massive hole in the side of the box? looks like dirt city

 

[Speedbird_666]

is that image flipped?

looks like the bevel is on the right-hand side of the box, it's normally on the left?

also what the hell is going on with that massive hole in the side of the box? looks like dirt city

Looks like a Modify GB shell

View attachment 76695

 

[Adolf Hamster]

Looks like a Modify GB shell

View attachment 76695

that just shows another hole for dirt to get in!

 

[Lozart]

So I got my new shell and having exactly the same issue. The bearing are seated perfectly, not risen and still no room between bevel and pinion


View attachment 76688



My guess now is a new motor cage

What sort of play do you get with both sides of the GB on and the motor cage attached properly?

 

[Pewpewpetie]

What sort of play do you get with both sides of the GB on and the motor cage attached properly?

None at all, motor pushes bevel against shell

is that image flipped?

looks like the bevel is on the right-hand side of the box, it's normally on the left?

also what the hell is going on with that massive hole in the side of the box? looks like dirt city

No it's the correct side for bevel to be that way, it's the side without wiring