V2 gearbox locking in full auto

[bob86]

hi all

recently i've starteed to have an issue with my g&p stoner, (good news for the ppl at my local )

it has started to lock up in full auto, its very intermittant, but the only way i can resolve it in field is to disconnect the 8.4 nimh i use, and hook up an 11.1 lipo for a trigger pull to release the box and get everything running again. when it first started happening i put it down to the nimh getting a bit flat, but its been happening more and more recently, plus it now doesnt like firing in semi, woth it locking up a lot, but that i've always been able to clear with a burst of auto.

so with me thinking it wasnt the battery anymore, i've just cracked it open to look in the gb to see if its a gear issue, as previously i had issues and that was down to the notoriously shit G&P gearset shearing, which i replaced with a ultimate 19.1 gearset probably about a year ago now. so my question is...

what is causing it to lock up!!!

-edit-
it always seems to lock with the piston at the rear of the box, so max spring compression

[daladzor]

Re: V2 gearbox locking in full auto

Might be worth checking out your spring.
My G3 kept locking up and requiring the exact same, disconnect the large 8.4, fit an 11.1 to get it free,
In the end the spring had weakened and was just compressing back over itself.
When we got it apart, turned out the spring was in about 4 separate pieces

[bob86]

Re: V2 gearbox locking in full auto

springs perfect and was still consistent at chrono

[Caldymoose]

Re: V2 gearbox locking in full auto

Lack of grease on the piston rails maybe?

What motor is in the gun?

[loki7491]

Re: V2 gearbox locking in full auto

Is the spring in the right way around? (Assuming non-linear spring fitted)

Is there any signs of wear, deformity or damage to any of the teeth of the gears?

Are all the bearings / shims / gear spindles in good condition? One gun we had in has the spindle on one side of a gear snapped off. It all ran fine nice and slowly but at speed went to rat shit

[bob86]

Re: V2 gearbox locking in full auto

rails are nicely lubed

motor is the original g&p m120 as standard with the gun

spring is close coils in the piston, not sure which way it should be. but it has been like that pretty much since i bought and downgraded the gun. and its only started playing up in the last 2 months or so.

theres a slight (and i mean slight) mark on the inside gearbox edge of the spur gear (ie side not touching the casing)

no axles are damages, shimming seems good, apart from a tiny bit of contact on spur to sector.

[Mickydoos]

Re: V2 gearbox locking in full auto

rails are nicely lubed

motor is the original g&p m120 as standard with the gun

spring is close coils in the piston, not sure which way it should be. but it has been like that pretty much since i bought and downgraded the gun. and its only started playing up in the last 2 months or so.

theres a slight (and i mean slight) mark on the inside gearbox edge of the spur gear (ie side not touching the casing)

no axles are damages, shimming seems good, apart from a tiny bit of contact on spur to sector.

Pretty sure the tighter coiled side is meant to be on the spring guide end but I'm not sure if this will cause the issues you're facing.

[bob86]

Re: V2 gearbox locking in full auto

Pretty sure the tighter coiled side is meant to be on the spring guide end but I'm not sure if this will cause the issues you're facing.

seems everyone i talk to can't agree which way round it is lol. but as i say, that hasnt changed in ages, and im only just starting to see issues. i'm wondering if thee motor is at fault

[loki7491]

Re: V2 gearbox locking in full auto

Tighter coils should be to the rear of the gearbox.

The coils are easier to compress at the open end of the spring. This should be in the piston as that is the bit that moves. This allows the motor / gear train to do less work to overcome the inertia of the stationary piston.

The tighter coils at the rear will act as a shock absorber to slow the piston prior to its direction change. This has the bonus of preventing the piston slamming into the back of the gearbox at full speed and prolongs the life of your insides.

It could potentially cause a lock up in conjunction with a worn part as everything needs to work that little bit harder with the spring in as it is. This could force a tooth to skip perhaps.

That aside, the slight wear marks are still a concern as there shouldn't be any wear marks at all.