Some G36 issues, looking for advice

Stonewolf

I have an Ares G36, spring downgraded.

The cylinder head cracked and had to be replaced, I had a brass one convenient so I used that, it has a rubber pad on the face to reduce stress when struck by the piston head.

Some time afterwards the piston head shattered and the gearbox locked up, as the piston was a one piece unit I had to replace the whole thing and what I had handy was a polycarbonate piston with a stronger aftermarket head. This piece was a little on the long side though so it caused gearbox locks, to counter this I removed the last tooth (the removable one closest to the head) on the piston.

The performance of the gearbox was particularly poor (120-150fps) after this and the sound was strange (deeper and more thuddy). I opened it the other day to find the front half of the rack on the piston had been completely worn down to a smooth surface by the gears with signs of damage on the other teeth. Two of the shims on the gear that drives the piston were also buckled.

I dug out an old star G36 piston I had and after checking the seal installed that. I also cleaned and regreased the gear and replaced the damaged shims. Everything else looked to be ok.

The gearbox now works and sounds correct. The gun fires at 300-310 fps. I am however concerned that this piston will go the same way as the stock one. Essentially I feel like I'm treating the symptoms but not the cause but I don't really know what the cause might be. I suspect it might be the spring but I'm not sure how. It's a symetrical one, short and easily pushed into the gearbox.

glicster

if the last tooth on the piston that the last tooth on the gear was catching(hope that makes sense)was not steel but polycarb then inevitably it would get wore down and each tooth after would suffer the same fate in time due to the resistance from the spring on the piston against the gear.
as for the buckled shim i cant really say,maybe problem above caused a wobble in the gear?
hope ive explaned tthat ok:o

Stonewolf

glicster wrote: »

if the last tooth on the piston that the last tooth on the gear was catching(hope that makes sense)was not steel but polycarb then inevitably it would get wore down and each tooth after would suffer the same fate in time due to the resistance from the spring on the piston against the gear.
as for the buckled shim i cant really say,maybe problem above caused a wobble in the gear?
hope ive explaned tthat ok:o

Ok, so that explains the shredded piston, thanks.

On to the bigger problem of a cracked cylinder head and shattered piston. I reckon the shattered piston is because the replacement cylinder head is much stronger than the stock part so the big question is what's wrong that's causing so much stress on those parts (above normal that is, I've only had this gun for a bit over 6 months, don't get out to play much and generally wouldn't get through a hi-caps worth of BBs in a whole day).

glicster

i cant really comment on the cracked cylinder head coz i dont know
but for the piston head, id have a look at the brass cylinder head and see if its one of those for a silent head set,you know one that the p'head has, for use of a better word, a 'nipple' and the cylinder head has a funnell like shape to accomodate it, and your using a flat p'head.
the sorbo pad on silent c'heads are not the same size as on normal heads so your p'head would be taking most of the impact on the outter edges.

this is just speculation lad coz its never happened to me b4.
maybe someone else might have a better explanation for ya later on?

Stonewolf

No, it's a standard flat shape on the inside with a rubber ring on the face.