Exploding piston head?

[Buds and Suds]

I recently added some parts to my CA M15A4 SPC:

Deepfire pistonhead with super O ring and bearing
Metal spring guide with bearing
Deepfire 1/2 tooth polycarb piston

My gun has a M120 spring in it and was running fine but I wanted to add some more durable parts. After I added the above parts I played a 4 hour game and it was fine. Following week I played I got through 100rnds and it just froze. upon taking it apart I found 2 missing teeth from my pinion gear on my motor and my piston head had all but desintigrated. My piston was in the full rear position when I took out my mechbox. What could have caused this??, and what parts should I purchase to prevent this in the future? I was reading and from what I gather aluminum piston heads could cause damage with an upgraded gun. So i kinda need a nudge in the right direction.

[The Saint]

Piston in full rear position could just be because you didn't fire it a few times on semi after firing it on automatic.

You shouldn't be using a 1/2 tooth piston unless you've got the proper gears for them. Do you see any piston teeth wear or damage? If you do, the teeth on the sector gear might have meshed with the 1/2 teeth in such a way as to retard the movement of the sector gear, which increased the stressed on all the gears and damaged the pinion.

I was told that Deep Fire only makes good piston and their other parts are rather unreliable. You might want to avoid their piston head in the future. A good polycarb piston head should be able to handle a M120, or at the very least not fail so rapidly and disasterously.

[Buds and Suds]

Originally Posted by The Saint

You shouldn't be using a 1/2 tooth piston unless you've got the proper gears for them. Do you see any piston teeth wear or damage? If you do, the teeth on the sector gear might have meshed with the 1/2 teeth in such a way as to retard the movement of the sector gear, which increased the stressed on all the gears and damaged the pinion.
.

My stock piston is also a 1/2 tooth. And I was told to buy 1/2 tooth from someone who I can now not remember. There is very little wear on the piston itself.

[The Saint]

1/2 tooth piston in a stock CA gun? I've never heard about that before, it's very surprising. That's all I can say.

[ILLusion]

Some pictures of this disintegrated piston head might help.

Was the motor height adjusted properly? Did you check for bind-free movement of the piston before closing the gearbox up? And what battery are you using?

[Buds and Suds]

Well, here is the damage.
This was what the piston head looked like original
http://www.redwolfairsoft.com/redwol...l?prodID=17954
There was no real solid pieces that came off, it was like it just shattered.
I am using a 8.4V battery. And yes the piston moved freely before reasembly. I used it for a whole game. Then my 2nd game it broke.

[Jugglez]

That piston head in particular was discontinued a couple months ago by Deep Fire because of some reports of premature failure. They are releasing a new version with better materials come 2008.

A half tooth piston in that gun doesn't sound right to me either. Was this gun bought new or used?
Generally you want to be using full teeth pistons with CA gears.

[Buds and Suds]

Sorry, feel like a moron, its a full tooth im using. Been awhile since ive shopped for a piston, should have double checked before I posted.

So is there a recommendation for a good non-aluminum piston head? I was going to play it safe and get a systema with bearing.

[TokyoSeven]

I rock the aluminum systema piston head but Ive got everything upgraded in the top half as well, no issues yet, but if your in the line for something non metal , try the systema duracon one.

[eel one]

Your gearbox shell will thank you for choosing a systema silent head set. The soft rubber softens the blow from the piston forward stroke and the conic shape of the cylinder head gives you a better and less turbulent airflow from the cylinder to the inner barrel.

[mateba]

Don't expect the SystemA Silent head to decrease decibels though. It will make your gun sound more like a "thud" instead of a "thwap" and you'll loose 10-20FPS. It's still a good choice for a durability upgrade though.

Do you have a reinforced MB? CAs can handle 400FPS out of box. Some even use a large 9.6v but it just speeds up the inevitable, the gears strip.

[ILLusion]

I haven't noticed velocity drops like that with Systema silent head sets that I've installed.

Realize that they do require some working-in of the oring and proper lubing to get a good seal out of them. Many users fail to do that and that's when claims of reduced velocity output are made.

[mcguyver]

Buds, did you remember to Loctite the piston head screw? Infamous cause of failure right there.

[GrieverX]

I remember reading somewhere that you are only supposed to have bearings on one end of the setup, either the spring guide or the piston head or else your gearbox might be prone to a lockup/piston losing teeth.

Not sure if that is applicable in your situation, but can anyone tell me if there is any truth in that idea?

[dontask]

Originally Posted by mcguyver

Buds, did you remember to Loctite the piston head screw? Infamous cause of failure right there.

mcguyver, how important is this step? I recently upgraded my piston head too but I haven't put any loctite on the screw