Piston grinding

[zone 69]

Originally Posted by byblos

i didnt clean off the grease but it does feel greasy... is it suppose to be drenched?

No, it just look's a little dry in the pic. it could of bin the cold that broke it, how cold was it the day it broke.

Could you take another close up pic of the piston teeth looking right strait down at it.

[byblos]

ok ill do that Zone, and the temp was -5ish..

[zone 69]

Well i had a bb jam on me once and i had a gear tooth land on the middle or top of one of my piston teeth like you have on the 5 tooth. the bb jam slowed the piston down so the gear ingaged it in the middle of the piston. some thing mite be slowing down your piston make sher you lube it good and i don't mean drenched just a little more then you have it now. Lube the, piston rail giude,s & piston head & bushing & gear's all thess thing's look a little dry to me in the pic's. also do you have a vented bearing piston head? Anyway go for a new Modify piston since most of your upgrade part's are Modify.

[Nova316]

Piston grind is usually caused by teeth misalignment, Try grinding down your second tooth it'll help with alignment issues

[byblos]

http://www.airsoftparts.ca/store2/in...roducts_id=758

or

http://www.airsoftparts.ca/store2/in...oducts_id=1173

[CDN_Stalker]

Originally Posted by byblos

sorry yes m/s...

for the record, i am using 8.4V, and my FPS is 320

What i understood from you stalker is that:
high speed gears + low spring = not recommended?
when,
high speed gears + high spring = recommended?

The other way around, high speed low fps.

What mAh is your battery?

[byblos]

1400mah

[byblos]

Originally Posted by byblos

http://www.airsoftparts.ca/store2/in...roducts_id=758

or

http://www.airsoftparts.ca/store2/in...oducts_id=1173

.. ... so which one should i order?

[Crunchmeister]

I'd say the second one, since it's designed for high speed setups. That's the one I had suggested back in post #2 in this thread. Once you get this gun working, it SHOULD be high speed since you have a high speed gear set.

[byblos]

ok thank you very much, thank you all for the help. and hopefully this will help others in the future.

[CDN_Stalker]

Originally Posted by byblos

1400mah

Pretty low for the spring you are using, should get a larger celled battery of at least 2000mAh, but 3000mAh would be best.

[Flatlander]

That's a modify piston, correct? If so, I would suspect that's one of your main problems. I had one of them crack and spider all along the front end from about 1000 rounds of use. THey're made from a very brittle plastic and I'm sure the cold added to it's brittleness. You want a tough piston over a hard piston, really. I like the Deep Fire poly's and even stock TM's are great.

All of the piston's I've replaced so far were stripped because of BB jams. I think your piston just sucked combined with the cold which is why it chipped rather than stripped.

As for your ROF, are you using a cheap battery that came with the gun? The pack that came with my clone m14 was garbage and the ROF was terrible. It fired great after I put one of my quality packs in it. Also personally I'll never put in a high speed gear set ever after what I've seen; I just get a better motor and/or up the voltage on the battery... usually just a higher voltage battery.

[byblos]

edit* yes that a modified piston.. basically everything there is modify*

I am using modified AK47 mags on my aks74u, i had to file the bb catch (plastic lever that holes the bb's down before putting into the magwell). im not 100% sure but when jamming comes to mind, i did experience bb jamming before the piston got stripped...

and for the batteries, i am using Tenergy 8.4v 1400mAh.. i got 2 of them, im going to ask my local hobby shop if they can merge the 2 together (to increase the mAh.. right?)

[Flatlander]

Copy/Pasted from another post of mine on Jamming:

My gun is jammed, what do I do!?

Another sort of common problem is BB's jamming in the barrel/hopup. Tightbores are particularly prone to this and you may find your gun likes/dislikes certain brands of BB's.

You can tell if your gun is jammed by the fact when you pull the trigger and nothing comes out but the gun cycles and there is also a distinct lower pitched 'thud' rather than a 'snap' when you shoot.

- Clearing Jams: Fire the gun upside down in SEMI AUTO several times to try and clear the jam. Upside down so that gravity helps feed the BB. Semi auto slowly so that the air has time to leak out and the piston has time to return to the forward position. If it doesn't unjam in several shots you'll probably need an unjamming rod to clear the BB. I always take the mag out trying to clear the jam, not sure why I started doing that but its just what I do, haha.

- DO NOT TRY TO CLEAR IT IN FULL AUTO! Here's why:

- BB jams in barrel
- Air is now trappped and/or cannot escape fast enough therefore the piston is now stuck mid-stroke
- The gears now come back around and try to rack the piston teeth but don't always mesh properly causing wear on the piston and a gross grinding noise.

I had to replace Megaman's piston a little while ago because his gun doesn't like Madbull BB's and would frequently jam. He tried to clear it in full auto and it would sometimes cause a grinding sound (which was the piston teeth not meshing). He switched to KSC's and they give him no trouble. Madbull's work in my gun fine and most others I've talked too who use them. If jamming is a frequent problem, switch brands right away.

Sorry, I'm not familiar with Tenergy battery quality. You can get them to wire the two in PARALLEL to double the capacity. If they do it in SERIES, they will double the voltage.

EDIT: Wiring them in parallel will not mean you get more ROF as they'll have the same discharge rate - well whichever pack has the lower discharge rate is the limiting factor but they should be very close as they're the same battery - it will just allow you to shoot more BB's before having to change batteries. Wired in series will definately give you a huge ROF boost but would probably be way too much voltage and bad things will ensue!

[byblos]

i am using .28 bb's, should i change?