More P90 problems

[Gaffa]

Well, thanks to all those who have given help with my P90 thus far.

It seems like this (may) be an ongoing thread if I have ongoing problems with her, so please bear with me!

This weekend just gone, I had attended an Overnighter airsoft with our Local Team, DT3. P90 worked fine until near the ENDEX on the sunday - where pulling the trigger just span the motor.

Taking the GB apart, I noticed all those metal shards around the gears, and a hell load by the motor, and looking at it, it seems to have been the Motor's Pinion gear that's been stripped... Now, I had been running the P90 with the following specs:
King Arms tappet plate
Classic Army gears
Systema Turbo motor
Guarder polycarb piston
Systema Cylinder
9.6v Nunchuck in stock

The piston is in very good condition, no damage, even when it was firing it's mahoosive 27 rounds per second (which, I understand, isn't the fastest) - which brings me to ask -
Why did the pinion gear get stripped?
What should I do now with regards to getting my P90 back?

If it does mean a replacement of the gearset, I know that you can get some Element High speed gears + piston set for £17 posted - I wouldn't use the piston though; but I've heard their parts are very good.

Any help would be great, thanks!

Regards, Matt.

[Will_0]

Re: More P90 problems

From what I've heard, the pinion gear is a bitch to replace as you need a set of special tools to change it. The best thing to do to get the motor back is to take it to an airsoft shop where they have the facilities to do it as it will probably work out cheaper.

Just to clear up, it's only the pinion gear that has stripped?

I wouldn't know why the gear stripped. Maybe prolonged bursts at 27 rps? Or poor alignment with the gearbox? I'm sure someone on here will be able to tell you.

[Gaffa]

Re: More P90 problems

I wouldn't know why the gear stripped. Maybe prolonged bursts at 27 rps?

Well, I don't think this should REALLY matter, as guns with higher rate of fires, which I have seen, have lasted over 20,000 rounds. This one has only had about 8k I think. If that. But yes, there were some 5 second long bursts (Support gunner - boxmag!)
By poor alignment - you mean shimming?

Regards, Matt.

[Will_0]

Re: More P90 problems

Well there's a screw on the motor cage which aligns the motors isn't there? Like on the bottom of an M4 grip the screw you get? If you replaced the motor from the stock one maybe it wasn't aligned as well and there was extra mechanical strain?

These are all based on theory and I do have a P90 myself just for the record :P I would imagine the 5 second bursts had something to do with it though.

I'm no mechbox genius, but the pinion gear is one of the more unlikely things to go so I would imagine it's unneccesary strain somewhere. Maybe the bevel gear isn't shimmed right?

[sj_asc]

Re: More P90 problems

The Pinion gear is one of the things that lets Systema's motors down, failure is more common with high speed and load setups, something that seems to be more of an issue for U.S players.

What spring are you using, and that is the current rating of the battery pack?
You have to remember that the smaller intolerances and flaws will surface a lot quicker and can have a much more catastrophic effect when you up the speed and or load, things like motor pinion alignment with the bevel gear (motor height) and the shim job.

Ive killed a Systema Pinion in 5K rds @580fps, i couldn't find the cause of the problem, i had the setup running extremely efficiently with a 9.6v, and all of a sudden it just cracked in half, the teeth were still in a good state.
http://i4.photobucket.com/albums/y14...dpinionstu.jpg
All of my Systema pinions have failed in a similar way, i have never had one loose teeth.

On the other hand, i have been using the stock Systema pinion in my SG552 @41rps/340fps for at least 20K now.

For my setups, i run it though at a lower voltage/speed to set the alignment accurately without causing additional damage caused by the higher speeds. When adjusting, you should stop when the gear meshing sound becomes quietest and the cycle rate is highest.

To get the pinion gear off, Systema use thread lock on the grub screw, you need to use a small torch or heat gun to loosen the glue before attempting to remove the screw.

[Gaffa]

Re: More P90 problems

Okay thanks for that. I was told it was an M100 spring, however when I had it chronoed, she was firing around the 300 mark.

I honestly couldn't tell you the rating of the battery pack, all that I know is it's a 9.6v 2000mAh 4/5A Nunchuck.

My motor height might have stripped the pinion gear actually, as the screw at the back could've been a lot tighter. So that might have been the overall problem - does anyone feel that on the P90's with their motors, that the screw needs to be tightened all the way?

How about dipping the end of the motor (ie, the pinion gear) into a small cup of boiling water, would that work too (as I don't have the said tools right now).

[sj_asc]

Re: More P90 problems

A gas cooker flame or lighter flame?

300fps is a little on the low side, unless the piston stroke distance has been shortened.

About the motor adjustment screw, did you remember to put the motor spacer disk back in after you installed the new motor?, or the bevel gear could be shimmed too high.

[Gaffa]

Re: More P90 problems

Ahhh I have access to both of those, thanks (now just need the 1mm Allen bit).

Yeah, I thought 300 was a little low, might need to check the air seal, or get a new spring, or both, and see what that pushes out. It even has a madbull tightbore, so I'd guess it should have increased anyway! (So in actual fact, it may not have been an M100 spring in there, just the stock P90 spring).

The small circular silver shiny thing? Looks like one of those button batteries? Yeah, that's in there.

[magic_golem]

Re: More P90 problems

aye getting a pinion gear off without a pinion gear puller is tricky, ive never been able to do it, so i took it to a hobby show that does rc cars and trains etc..they had the tools and pulled it for free!,,im just about to get a p90 and thinking of trying out one of those acm box mags as the are pretty cheap,do they add mosre weight to the back or the mid secton of the gun?balance-wise?

[Gaffa]

Re: More P90 problems

Although it's slightly off topic, when I had the box mag on, it was a little rear end heavy, but that's no big problem as it is a very light gun anyway. They're pretty beasty though.

Thanks for the earlier comment though, think I might take mine down to a Hobby Shop that specialises in Model Railways and see if they can take it out for me.

Also, to add now, I noticed that the Motor's height adjustment screw was a little loose, so I tightened it up all the way... Does anyone think that this 1mm could have affected the guns operation, and led to the stripping of the pinion gear?

Thanks, regards, Matt.

[Will_0]

Re: More P90 problems

The higher the resistance, the less life it's going to have. If it was in a naff position by 1mm it could have made all the difference, especially if systema's pinions are reputed to be bad. To be honest there's no way of knowing unless someone with a trained eye has it in front of them.