New piston required, any recommendations?

[Nickos225]

Stripped down the Evo this morning and notice the plastic teeth are worn on the piston. Does anyone have any recommendations for a full metal? Also looking at a head and new hop up/tight barrel

[sj_asc]

Re: New piston required, any recommendations?

Will you be making any other changes to the internals?
What spring or you currently running in there, or FPS?

[Nickos225]

Re: New piston required, any recommendations?

To be honest I'm not sure what its using at the moment spring wise, on the can test it came out at around 350 which is the max as my local site is 350 limit, although I have just bought .25g bbs now as they're supposed to give a better range which means the FPS will be lower

[Nickos225]

Re: New piston required, any recommendations?

And yeah I'm thinking full overhaul

[Sitting Duck]

Re: New piston required, any recommendations?

Lonex / ASG / Ultimate piston
a few plastic & aprox 11 steel teeth piston

I always like to have a little weak point on a few plastic teeth to shred just in case of PE
if teeth still stripping you have a problem - check shimming AOE etc.... and the smooth action
coz you are not really solving the issue just by shoving in a full teeth piston straight away

[Nickos225]

Re: New piston required, any recommendations?

So I'm thinking red ASG piston with the red ASG poly head, ASG ultimate cylinder head, kanzen 8mm bearings, 16:1 gear set not sure which is best shs/ultimate, original cylinder for now, and then I'm thinking replace the hop rubber but unsure which is best

[wilko129]

Re: New piston required, any recommendations?

That all sounds good but I would save your money on the cylinder head and just PTFE tape the cylinder-costs next to nothing and has the same effect as a shiny upgraded one.

I have used both SHS and ultimate gears and they both seem just as good as each-other but the SHS are a fair bit cheaper. As long as you don't get version 2 SHS because the bevel gear will break very quickly due to a flawed design.

As for hop rubbers the top few drop-in rubbers are, in no particular order: Tokyo Marui stock, Madbull blue (sometimes too thick/tight but great air-seal), G&G green (cold-resistant), Firefly soft (expensive and harder to find) and prometheus purples (never used these myself but many have/do and rate them).

The best hop up rubber (sorta) is the R-hop by HunterSeeker, however this requires modification to your bucking and a bit of work to get working (even the 'easy-install' Z-kits need some work). When set up correctly these give you incredible range, however it isn't that much better than a good setup rifle with one of the above drop-in rubbers so up to you how much time you want to spend.

[Sitting Duck]

Re: New piston required, any recommendations?

don't bother getting 16:1 shs gear set....

according to some info on another site that I probably can't link to........

This is the newest SHS 4th Generation 2014 Gear Set. This Gear Set has a true ratio of 17.28:1 and a nominal (advertised) ratio of 16:1. This gearset runs slightly faster than most stock gears, so it's a perfect replacement if your old gears are worn or broken.

so in effect you pay for a 16:1 set and get only say a 5% increase in rof/trigger response !!!!! not an expected 10%

may as well leave stock 18:1 or get 14:1 set if ya build is up to it

if you can get good seals then most stock stuff is fine, new piston o-ring or one that fits/seals well, polish cylinder
check nozzle replace with o-ring nozzle etc....
tape on stock cylinder head works great - often got great seals on old stuff if new head isn't performing as expected
(a lot of "must have parts" are a bit of a myth tbh - especially if fitted badly - some old parts can perform great if fitted properly)

[wilko129]

Re: New piston required, any recommendations?

Sitting Duck-That is true for all 16:1 gear sets mate, not just the SHS.

OP-If you dont want a mental ROF you can either use a 7.4v lipo and high torque with 13:1 or 14:1 gears or just leave the gears stock at 18:1 and use a fully powered high lipo and high torque motor.

[Sitting Duck]

Re: New piston required, any recommendations?

OP was thinking of 16:1 set and though usually sets are +.65 the 16:1 is nearly double that actual amount

12 = 12.65:1
13 = 13.65:1
etc.....

but 16:1 sets being 17.28:1 is robbery - why they are not called 17:1 I don't know

just pointing out how a 16:1 set is not quite as good improvement over stock 18:1 gears
you would expect say 12% improvement but you probably only get just under 8% due to getting mugged a bit

Not all sets are the same though - most have 10 teeth on bevel but there are variations eg: 9 teeth for torque
or over 10 - seen mental 13 teeth bevel but that is probably ultra high end seigtek sets

I ain't gonna bother counting teeth & maths n stuff though
normally count the number of turns the bevel gear takes to rotate sector gear eg:
6.25 bevel gear turns to rotate sector
multiply by 3 then, 6.25 x 3 = 18.75

sorted - 18:1 gear set in ya gun
(unless you love counting all the teeth on all gears)

stock gears are fine for most builds tbh.....

best rof I got so far is 24.8rps on 7.4v stock 18:1 gears @ 355fps but that is ultra mental thick wires etc... soldered direct to v3 motor/gearbox

[dave38x]

Re: New piston required, any recommendations?

Given that all the SHS gear-sets are exactly the same price one is hardly being mugged by selecting a different ratio.

These days I tend to recommend SHS pistons (the 7 steel tooth ones), gears (not sure what these version two SHS gears are, I've had one failure in all my time airsofting of an SHS bevel gear), cylinders, cylinder heads BUT NOT nozzles or piston heads - I prefer the guarder polycarb piston head, and if you can get them deepfire nozzles

[Nickos225]

Re: New piston required, any recommendations?

Who knew it would bring up such a discussion LOL any this is the offending piston, shimming seems OK

[Sitting Duck]

Re: New piston required, any recommendations?

Given that all the SHS gear-sets are exactly the same price one is hardly being mugged by selecting a different ratio.

Well kind of coz the 16:1 sets are compatible with G&G & SHS dual sector gears which are for the range 18:1
though you can use slightly different ratios - in particular the DSG's by the above two are designed for 18 or 16:1 sets

So I used a 16:1 set and still quite pleased but it appears the slight improvement wasn't quite as good over the HC05 stock set as I was lead to think

So anybody choosing a 16:1 set should be aware they are not 12% quicker but just under 8% over stock gears
with that in mind spending £15-£20 on a 16:1 gear set is not such a great improvement as we might think or lead to believe


OP - jeeeez wtf has caused them teeth to shred like that ????

last teeth 16,15,14 & 13 are metal
then 12,11,10,9 & 8 have worn mentally ????

before anyone says spring tension - then explain 8 9 & 10 have more wear than 11 & 12th teeth ?
surely - stop calling me Shirley
you would of thought 11 & 12 would have same if not more wear as spring tension increases

too late for that piston - but next piston deffo check it slides back n forth freely and no snagging
(pop just the piston inside box shell without sector cylinder etc... and it should move back n forth freely holding box upright/downwards etc...)
had to sand a piston's guides/runners slightly recently that was just binding a tiny smidge coz I noticed it sticking a tiny bit when building

So my guess it could of been binding or snagging a bit or something like that to cause that weird isolated wear in middle - 2/3rd of piston's teeth

I'm no expert but the more I break the more I learn and still to this day I often learn something new each box I work on

[wilko129]

Re: New piston required, any recommendations?

These days I tend to recommend SHS pistons (the 7 steel tooth ones), gears (not sure what these version two SHS gears are, I've had one failure in all my time airsofting of an SHS bevel gear), cylinders, cylinder heads BUT NOT nozzles or piston heads - I prefer the guarder polycarb piston head, and if you can get them deepfire nozzles

The SHS gearsets have been re-made four times with different designs for each version. The version 2 spur and sector were fine, but the way the bevel gear was designed means that the motor pinion meshing-teeth break very quickly, even under small amounts of load. You have probably only had the one version 2 set or have run them in builds which are not very intensive if only one of yours has broken.

Manufacturers don't usually say which version the gears are so I think most people assume there is only one.

[Nickos225]

Re: New piston required, any recommendations?

Anyone reckon the Evo could take 13:1 gear set? I've seen one done but it had also been short stroked