Exploding piston head?

[GrieverX]

Originally Posted by dontask

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

I had an aluminum piston head come off my AUG after 3 highcaps the first time I didn't use loctite. But it may have been because I didn't tighten it as hard as I could because my M4 piston head has no loctite and has been going strong for more than 3000 rounds.

[dontask]

Originally Posted by GrieverX

I had an aluminum piston head come off my AUG after 3 highcaps the first time I didn't use loctite. But it may have been because I didn't tighten it as hard as I could because my M4 piston head has no loctite and has been going strong for more than 3000 rounds.

dang I'm scared now
oh well I'll make a trip to Crappytires tomorrow
which loctites do you guys recommend? the purple ones?

[GrieverX]

I don't remember the color, but just make sure you don't get the one thats permanent LOL. The weakest one should be fine.

But yeah don't worry too much, if your piston head gets loose you will know right away because ur gun will still sound like its "cycling" but the BB's will just roll out. Just remember to stop firing right away then or else you may lose some piston teeth.

[eel one]

Originally Posted by 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?

There are plenty of room to both having a bearing in both the piston head and on the spring guide, hell you can even fit a spring tensioner on the spring guide to with out running in to problems. In the 8 years I have done airsoft mechanics I have never seen a case where a failure was caused by inadequate room for the spring under the piston backward stroke.

You do however only need a bearing in one end of the spring, to allow it to rotate freely under compression and decompression. Leaving one of the bearings out of the system will leave less tension on the spring while it is fully compressed resulting in less muzzle velocity. The effect is the same as making a short stroke setup with 2 teeth removed, in terms of velocity sacrifice. By leaving the piston head bearing out, you get a lighter piston assembly, resulting in less stress on the gearbox from the pistons forward stroke. Also the lighter piston assemble also results in a slightly increased ROF. However do note that for low power setups you gain muzzle velocity from a light piston assembly where as the effect are the other way around for high power setups where the hard rapid compression of air in the cylinder puts so much resistance on the piston that you need a heavy piston assembly to achieve maximum muzzle velocity due to the pistons higher inertial energy. The turnover point is around the M130 springs mark. Practical experiences with high power setups shows, that passing M160 does not result in better accuracy or range and the wear on the gearbox gets so extreme that it is not worth playing with (at least when it comes to ver.II boxes). Personally I have only used M150 springs so the experiences are of others.

[mcguyver]

Originally Posted by dontask

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

If you ever noticed, Marui uses Loctite on their guns with stock head and piston. Use the blue, let it set for 24 hours, then re-assemble the mechbox. You don't absolutely need to let it set, but it will be fully cured guaranteed.

[TokyoSeven]

I use a this blue thread locking stuff, I wish I could remeber the name, but its in a small blue tube with black cap, its not super strong, and not permenant either, I started thread locking my piston heads to my piston after one upgrade where after 2 locaps my m4 stopped firing during a game, after opening it up, I noticed my piston was in the full back position. The screw had seperated from the piston head and had fallen back and jammed up the whole set up making it go belly up and all quagmire. Now I thread lock all the time just to be sure.

[Buds and Suds]

I never used thread lock before, mostly cause im just finding out about it. I dont think it would have made a difference in my case, the piston head was still secured tightly.
This has been one of the more informative threads for me in awhile. Can always learn something new with airsoft.

[mateba]

Originally Posted by 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.

I'm just relaying read info on this one. Besides can we ever expect to get as good of results out of our guns as you have Illusion? Your right about the o-ring making differences.

+1 loctite on almost all screws. I use the blue stuff, which allows for easy screw removal with tools.

[hutch1970]

Buds an Suds- I noticed you said that the motor pinion gear lost 2 teeth. CA motors are notorious for their grub screws on the motor pinion shaft for working loose. That' the reason I've removed them from all of my CA aeg's. HELL, THE MOTORS OUT OF MY utg MP5'S ARE BETTER MOTORS. If your motor gear worked loose, then it will cause your rifle to jam. As for the piston head shattering, I havn't had this happen to me yet. Check that motor gear, I bet you'll find it loose.

[Buds and Suds]

Originally Posted by hutch1970

Buds an Suds- I noticed you said that the motor pinion gear lost 2 teeth. CA motors are notorious for their grub screws on the motor pinion shaft for working loose. That' the reason I've removed them from all of my CA aeg's. HELL, THE MOTORS OUT OF MY utg MP5'S ARE BETTER MOTORS. If your motor gear worked loose, then it will cause your rifle to jam. As for the piston head shattering, I havn't had this happen to me yet. Check that motor gear, I bet you'll find it loose.

I dont doubt what your saying, as time goes on ive noticed that CA seems to make thier guns full metal by the lowest bidder (so to speak). But in this case, its on there good. Im sure the piston head broke, locking the piston and causeing the gears and pinion gear to seize. The pinion gear was the weakest link so it broke. I think if the head had not failed, id still have a pinion gear.