Piston Issues ICS M4

[Zep]

Just wondering why the piston keeps cracking on the sides where the first tooth is. I have shot about 4000 rounds with this piston.

I have added a picture to show where.

the piston is a StormTech MAX Impact Polycarbonate Piston

I have upgraded almost everything on the gun except adding a tight bore. But im still running the stock spring.

Not sure why it keeps cracking, I was told it might be the gears doing the damage, but not sure how to check or find out.

King Arms Helical Torque Gear Set. does it also with the regular gears.

Motor is a G&P M170



Also if you have any suggestions id appreciate it thanks. Maybe another type of piston or whatnot.

[iKliiu]

I've heard that torque helical gears need half tooth pistons, try looking into that.

[Zep]

Originally Posted by iKliiu

I've heard that torque helical gears need half tooth pistons, try looking into that.

Thanks, i'll look into that.

It did the same with the original gears, so thought id put the king arms one in, thinking it could be that but nope, same result with both gear sets.

Motor is the G&P M170. not sure if that matters LiPo etc..

[Kos-Mos]

Do you use a bearing spring guide? If so, it might be the spring that is too long and puts pressure on the last teeth when the piston is all the way back.

[Sha Do]

Originally Posted by iKliiu

I've heard that torque helical gears need half tooth pistons, try looking into that.

Unfortunately this is not the issue here.
If the half tooth piston theory was indeed the issue, the piston would not cycle at all, or at least without damaging all of the teeth on the piston or sector gear. I've recently had this same issue with a G&G box.....but never with a VFC, Systema, TM, or King Arms box. Spring guide may be the culperit...though I use a bearing spring guide in my Systema and King Arms mech boxes.

SHA DO

[Kos-Mos]

Originally Posted by Sha Do

Unfortunately this is not the issue here.
If the half tooth piston theory was indeed the issue, the piston would not cycle at all, or at least without damaging all of the teeth on the piston or sector gear. I've recently had this same issue with a G&G box.....but never with a VFC, Systema, TM, or King Arms box. Spring guide may be the culperit...though I use a bearing spring guide in my Systema and King Arms mech boxes.

SHA DO

ICS upper mechboxes are about 1/4" shorter than regular mechboxes... that is why that would be the probable cause.

[Zep]

Yeah that might be the issue i will put the old one back on..

I have actually put 3 different pistons on, piston heads etc and i can't seem to think of what it can be. hop up rubbers etc, the gears seem to catch fine no damage to the piston or anything, so i will try changing the spring guide, it does have bearings on it so yeah lets try that.

Right now with all the changes i made, i can only get it to fire MAX 337fps with the S110 spring. Should be more shouldn't it?.

I also replaced the gears with the King arms torque gears, and put the full tooth piston back on. i have more parts for that just incase i break something.

I'll put the normal spring guide on then make a post if anything changed.

Cheers.

[Zep]

Nope Still nothing. It's even worse with the stock spring guide on. It actually lowered the fps by 50fps Weird.

[THe_Silencer]

Maybe you should just switch to a different piston? If it's only happening with the stormtech piston then there's your problem right there.

[Zep]

Originally Posted by THe_Silencer

Maybe you should just switch to a different piston? If it's only happening with the stormtech piston then there's your problem right there.

Oh i did that. I actually put the new Modify Quantum piston that i got today and made it worse. It lowered my fps to about from 337fps ish to 290fps with the S110 spring this is weird.

http://www.airsoftparts.ca/store2/in...oducts_id=1812

Can the hop up unit be the actual problem? i can cover all holes and blow into it and i can hear air coming out of the actual unit. Not sure if thats normal or nothing should be coming out at all..

If that it, ill get the G&P hop up unit. I have changed the hop up rubber and everything. Not sure what else to do.
I tested the cylinder and cylinder head with the piston the compression seems great. no leaks there.

[THe_Silencer]

Originally Posted by Zep

Nope Still nothing. It's even worse with the stock spring guide on. It actually lowered the fps by 50fps Weird.

One way to get a bit of FPS is to use a spring guide with bearings and have bearings in the piston head. The the thickness of the bearings and washers will keep the spring under more compression and will increase your FPS as a result.

[Zep]

Originally Posted by THe_Silencer

One way to get a bit of FPS is to use a spring guide with bearings and have bearings in the piston head. The the thickness of the bearings and washers will keep the spring under more compression and will increase your FPS as a result.

already have it man.

[Con Murder]

I do suggest you keep using the stock spring until all is worked out Zep, maybe measure it next to another. If it is for some reason the culprit the size may give that away.
More than anything I hate it that you keep shredding pistons when testing... So hard to tell what happened in the mangled plastic, its like car forensics.

[HKGhost]

I have installed several Stormtech pistons in ICS split gearboxes without any issues. If you're having problems even with different pistons, then you're installing them wrong or not paying attention to the little details that makes it work. You can buy the best of the best parts, but if you don't install them right, then it's just a POS. Check the angle of engagement.

[CerberusNet]

Originally Posted by THe_Silencer

One way to get a bit of FPS is to use a spring guide with bearings and have bearings in the piston head. The the thickness of the bearings and washers will keep the spring under more compression and will increase your FPS as a result.

Bearings where already suggested to be causing the problem. If it turns out the bearing are the cause, adding more would likely destroy the piston.

I agree with Con Murder in installing the stock spring untill the problem is solved. Actually I remember reading you are still using the stock spring..

If your FPS is decreasing, it may be a problem in the seals, either with the piston head, or wherever it is, it seems to be causing excess friction.

Possibly the cylinder may be too large or small for the piston, or the spring may be to long for it. I'm assuming the spring guide is stock, if not try installing the stock, the bearings could be taking up room necessary for the spring to fit when compressed.

With so many upgrades, any one of them being misaligned or improper fit could be causing the issue. If you still have your stock parts, I'd try reverting back to stock and replacing one peice at a time to see how they react with each upgraded part.

I know it'll be a lengthy and repetitive procedure but I honestly can't come up with a better solution.
Good luck