Nothing but problems with my Custom G&P M4

[Katana]

So I get this G&P M4 v5 at the beginning of the year and it came with some lovely problems out of the box like the hop up didn't work, the gun would overshoot almost stupidly and externally I could see that it was a lemon (things like the receiver pins were misaligned). Email this particular LONDON dealer 3 times with no reply (yes I should have called) and so I just go "screw it" and start chucking a load of upgrades at it which I was going to do anyway so it wasn't the end of the world.

So at the moment, here is the run down of my gearbox:

G&P 8mm Bearing Gearbox

ASG Ultimate Trigger Contacts

SHS 13:1 gears (short-stroked by 3 teeth)

Sector Delay chip (Can't remember brand but doesn't matter anyway)

SHS High-Torque Motor

Lonex Cylinder Head

Lonex Air Nozzle

SHS Tappet Plate

SHS 14 tooth piston (AOE Correction and Swiss-Cheesed)

ZCI Steel Full Cylinder (this should of been ported but I'm a tit, should I switch this out???)

Nuprol M130 spring

Lonex Spring Guide

Gate Merf 3.2 (hard wired)

Running on 11.1v 25c LiPo's

Hop up setup:

Prometheus TB 6.03mm

G&P Hop Up Unit

Prometheus Flat Hop Nub

G&G Green Bucking (Flat Hopped)

Spring to push against gearbox

FPS with a 0.2g bb is around 330-335

Now when this thing performs, there is a small child inside of me that jumps with joy because it's just perfect. Trigger response is pretty much perfect and Full Auto is very fast but not to that point where it is ridiculous but I don't ever really use full auto anyway. Range is...just...yay.

Problem 1) Fully auto cuts out after random amounts of shots. I'm pretty sure its me trying to push the mosfet down into the buffer tube to make room for the lipo and it's crimping the wires in some way so I am planning for an external battery pouch.

Problem 2) When I load any brand mag at all (usually use mids), the first 30 bb's will shoot about 50 feet and the range will slowly improve until I'm hitting shots at around 250+ feet. I feel that it tends to happen if I fill say a 130rnd Mid Cap with 100 bb's than if I loaded 50.

Problem 3) Trigger sticks on semi but returns on full auto which I am guessing means that the trigger spring has snapped.

Problem 4) If i shake the gun, the motor starts turning until it cycles (even on Safe). I also don't have to shake it for this to happen. Basically, I had a problem today where it started shooting by itself and accidentally shot someone on the other team without touching the trigger.

I keep thinking that the Lonex air nozzle and the G&P hop up unit don't like each other but I could be wrong. Mag compatibility is a right pain in the ass. G&P though so....

I'm at my end all with this thing. It's been in and out of shops longer than it's been in my hands and so could I get some help at all from you kind folk. I don't think my wallet can take much more.

 

[Lozart]

Certainly sounds like there's a short somewhere, I would get the whole thing apart and check the wiring because the last thing you need is a shorted out LiPo going bang.

 

[Katana]

Certainly sounds like there's a short somewhere, I would get the whole thing apart and check the wiring because the last thing you need is a shorted out LiPo going bang.

Have you got any takes on problem 2? I took it apart but didn't open up the gearbox. Just checked around and couldn't find any areas where it might have shorted. Maybe it's inside the mechbox and maybe I should replace all the wiring with 14awg? Also, should I switch out that cylinder?

 

[Lozart]

Have you got any takes on problem 2? I took it apart but didn't open up the gearbox. Just checked around and couldn't find any areas where it might have shorted. Maybe it's inside the mechbox and maybe I should replace all the wiring with 14awg? Also, should I switch out that cylinder?

Sitting Duck is your man for gearbox/short stroking things but if all the advice was to have a ported cylinder then yes, I'd say swap it out.

There's every possibility that the wiring that may be damaged is around the bottom end of the gearbox where the motor comes in. It's a pretty standard place for it to get mashed by gears or nipped between the halves of the gearbox casing. Without taking it apart you'll never know.

With regards to the 14awg - what's it wired with now? If you mean the trigger wiring then no, it doesn't need it.

 

[Sitting Duck]

uhhm ergh my take but at best we are kind of calculated guessing if your description is correct

(we don't have gun in front of us and I'm still learning)

Problem 1) Fully auto cuts out after random amounts of shots. I'm pretty sure its me trying to push the mosfet down into the buffer tube to make room for the lipo and it's crimping the wires in some way so I am planning for an external battery pouch.

&

Problem 4) If i shake the gun, the motor starts turning until it cycles (even on Safe). I also don't have to shake it for this to happen. Basically, I had a problem today where it started shooting by itself and accidentally shot someone on the other team without touching the trigger.

deffo wiring problem as Lozart said - might be mosfet's onboard thermal fuse cutting out or very likely an iffy connection to cut out

but then motor creeping and firing in prob 4 - that is a short

unless an iffy unit - check wiring and good clean solder joints etc.....

Problem 2) When I load any brand mag at all (usually use mids), the first 30 bb's will shoot about 50 feet and the range will slowly improve until I'm hitting shots at around 250+ feet. I feel that it tends to happen if I fill say a 130rnd Mid Cap with 100 bb's than if I loaded 50.

This could be a not so great piston compression issue but 50ft ???

OK to Good compression is where the first few tests are not awesome but after a few pumps you get better solid compression

GREAT piston compression is where you get "bloody hell" compression first pump every time

This is a bit of a stab though but sounds like good compression on piston but not GREAT compression

you might have a slight air leak somewhere (might be piston but could be hop/nozzle) if using a m130 equating to say 425fps ish on 0.20's

then SS 3 teeth would no way drop to 330fps - you would "normally" lose about 15fps per tooth or 6% or multiply by 0.94 for each tooth removal

please note this maths crap is only a ROUGH ROUGH guide at best but 90 to 100fps is larger than expected drop in expected fps

though the fps will vary anyway depending on barrel length/creep and springs actual power will vary a bit from manufacturer - dunno what a Nuprol M130 pushes out

Real test is to chrono a lot of shots to confirm the possible piston seal/compression/air loss ......

them short shots must produce really low fps to drop so short at first then climb in fps/range

pity you not got stock hop/barrel & new hop/tbb to quickly test if same issues on both to narrow it down a little

but you said you had issues before so could be hop related....

But the poor start of mag fps then improvement after some shots sounds like not a great piston compression at first but builds after a few pumps

TBH - think it could be 2 or 3 things - seals - hop/nozzle even alignment perhaps - it is all guesswork on screen

Ported cylinder - would be wise to select correct cylinder / volume even on a short stroke setup

Ideally the stroke port should allow a couple of last teeth to draw in & fill cylinder asap even if piston/o-ring is operating at full effectiveness

on release it won't matter if it starts to travel with open port for a tooth as speed is just building up

you didn't mention how long barrel is so going to suggest that SS 3 teeth your barrel should be no more than about 363 - could stretch to 380 but not if want to lift .25 or .30's I feel

If you are on 300mm you could drop a ported cylinder in there - port position will depend on barrel

I'd say if it is shooting ok then leave it

though atm you got inconsistency on range n stuff........

bloody right nightmare at present it seems and would suggest trying just one or two things at a time atm than everything all at once

"what - I've gotta open it up again" - yup but often this is a good thing anyway to check early wear or often just adjust the bevel height a smidge

sounds good - low amp but found the pinion sat lower/higher than expected so I've adjusted shimming a 0.10 shim in past

compression test on piston - jeez that's not great as I first thought.....

ooh hold up, that wire behind motor looks a little chewed....

regrease blah blah blah......

phew...... Think I'll stop there coz most peeps have probably fell into a coma about 15mins ago......

Problem 3) Trigger sticks on semi but returns on full auto which I am guessing means that the trigger spring has snapped.

Yup possible issue or cut off lever isn't quite lifting trolley upwards enough to lift it off sear and return

The trigger switch is best tested in a partially assembled box (no piston/cylinder/tappet)

by pull trigger in semi, ensuring the cut off lever is under the trolley's lug

roll sector backwards in direction it takes when retracting piston, just as gears would release piston it should simply pop the trolley & fly back

relatch and repeat a few times - all dandy - switch/trigger/trolley passed operation check

well that is how I check for trigger switch crap for v2's

on higher speed builds you don't want contacts too tight or too much contact length - means it remains closed for longer or struggles to release asap - on mental guns it can increase risk of overspin or even double firing if it is slow to disengage - very tight contacts can grab switch so much she just fires all the time

though if she fires ok on full auto then contacts are not grabbing switch that much

(bloody whooooaaaaaa when ya gun just carries on full autoing when ya released the trigger - sorry sorry sorry sorry - bash bash bashing receiver - wtf is the deans connector..)

oh and Lozart is correct as per usual 14awg - not worth it

16awg Alpha Eco wire is my favourite - 22/24awg any stuff will do for mosfet signal but Gate would have supplied the signal wires

16awg slicone is 3mm fat and needs a bit of dremel work to fit

Alpha is 2mm but same csa stuff - should not need any modding to fit

over this and you won't see much difference at all - you are only drawing 20-25amps I would say on that setup unless you are using a very very fast and very hot motor or your shimming is quite crap

phew - if anyone is still awake - that is my possible take on some stuff

tbh I just forgot what crap I just spewed out - got on a roll, then got called away, cuppa tea, some lunch then came back and carried on spewing out more crap

so excuse any typo's, or if I repeated myself again, or pointed you in wrong diagnostic direction coz I forgot yonks ago the reall issues you might have been having as I lost us all in a sea of type

hope some of this helps - off to get some deep heat for my wrists & fingers - ooouch

 

[Katana]

Thanks a bunch guys for giving me the time of day to help out. I'm not gonna lie Duck, you made me chuckle quite a lot through that

Upon closer inspection of just outside of the mechbox on the motor end, there is an exposed bit of wire on la red side that's making contact with the motor so it could be possible that it's interrupting the connection or something of the sort. However, no doubt that SHS High Torque has chewed up all kinds of colours inside of the gearbox and such

To do today:

Order a Lonex 4/5 Cylinder to go with the Lonex Cylinder Head.

Order a Lonex M120 Spring (will this be okay to get me under 350 whilst not allowing pre-engagement)

Order some of that 16awg Alpha Eco wiring

Play the waiting game

Also, I have active-braking turned on, should I turn it off?

 

[Sitting Duck]

There 2 main ways to wire in mosfets - either using existing wire

or

rewiring it with dedicated wire and have a supply & return signal wire back to fet

on a rear wired gun it is worth seeing if with a small mod at back of gearbox have both motor wires pass into grip

this means only two very thin mosfet wires pass behind the motor collar

these can be placed in thin tiny heatshrink and drop of superglue to hold it firmly in place

(the glue is optional but if you shrinked it it will be fine to do any future work/removal of wires)

pic says 1,000 words:

yes there is a spare piece of thick mofo wire holding the fet wires down but I still shrinked & glued them behind motor to make 101% they stayed in place behind motor - it was a build for somebody so I wasn't taking any chances

they little white bag tie was just to hold them mofo wires together whilst I worked on the box

before anybody says sector looks scratched - that was me smoothing the very edges as it seemed a tiny bit sharp so ensured it wasn't scraping on tappet plate but thought I'd smooth the very edge just in case

the rubber on cylinder head is my latest thing I'm using to increase tappet travel to feed better at higher speeds - more agro

swiss cheese piston - ohh bollox I'm not looking for marks out of ten or justifying what/why I do stuff

it was just to show the routing of wires - jeez I'm getting carried away again.....

this build is using crazy mofo wire that requires quite a lot of dremel adjustment to get mofo wires in there

don't usually take pics of everything but was more to show the guy and now you how it was assembled and routing of wires

yes you may need a bit of active braking on 11.1v but try turning it down in the settings to reduce heat/strain on motor

I don't AB fets myself so I'm not best person to ask but plenty others do use them

main thing with wiring get it as neat & tidy as you possibly can, good connections and insulated of course

how you route them damn wires makes a big difference.....

but each gun is different and depends on orientation or polarity when fitting motor

rear wired - normally positive is laid first, then negative this keeps the positive held down if it is to run underneath/behind motor up to switch and then back to motor/pistol grip on a non fetted rear wired standard gun

Like most stuff - it is really down to planning/time & care assembling stuff etc....

if it helps my first few attempts did not work out well at all and my first mosfet was an abortion and didn't last long before she popped her clogs

each install by various people will be slightly different - google up some mosfet install pics - do not take mine as gospel

I keep learning, trying/changing stuff - the thick mofo wire is a ball ache to do and don't actually offer any big noticeable difference for all the work to squeeze it in there - Alpha 16awg eco is damn good stuff for an easy life install - better than some silver low resistance wire I have used

Your cylinder port - as a min take inner barrel length eg: 300

divide by 10 - yeah tricky stuff I know.... 30

now add 15 to that = 45mm

(15mm is about where the piston head would sit in cylinder once you correct AoE)

your port tip needs to be about 45mm for a 300mm inner barrel

the volume or real stroke does kind of correlate to the barrel

or just work out volume ratios of cylinders and barrels n stuff if you wish aiming for a 1.6 to 1.8 for most guns or 2.0 if lifting heavier bb's

or 2.25 ratio say for dmr/snipers

this is really only a rough guide to help when throwing together a build - helping to choose a barrel - cylinder combo match

you have some give either way though I wouldn't go much under the 45mm figure

originally I said 12mm but upped it to about 15mm - yup it really is about 11 or 12mm but you need a few mm on release of piston to seal and build compression - wtf - call it 15mm & add a 10th of ya inner barrel length:

http://www.airsoft-forums.co.uk/index.php/topic/25386-some-easy-simple-airsoft-maths-that-i-think-work/

I'm no expert or write any rules - I'm still learning as I say

I have learnt a lot in the study of breaking guns - fixing them - argh yeah that bit is proving a bit more trickier than I first thought

best of luck

 

[Sitting Duck]

Thanks a bunch guys for giving me the time of day to help out. I'm not gonna lie Duck, you made me chuckle quite a lot through that

Upon closer inspection of just outside of the mechbox on the motor end, there is an exposed bit of wire on la red side that's making contact with the motor so it could be possible that it's interrupting the connection or something of the sort. However, no doubt that SHS High Torque has chewed up all kinds of colours inside of the gearbox and such

To do today:

Order a Lonex 4/5 Cylinder to go with the Lonex Cylinder Head.

Order a Lonex M120 Spring (will this be okay to get me under 350 whilst not allowing pre-engagement)

Order some of that 16awg Alpha Eco wiring

Play the waiting game

Also, I have active-braking turned on, should I turn it off?

OK - to avoid PE you need to not take the pi$$ too much - despite what stupid stuff I still to this day do

Now you 13:1 & SHS Torque so I am going to go out on a limb and guess you are hitting rps on 7.4v of about 22 to 25rps

easily 20rps or something is up but that m130 could slow it down a fair bit

This is the steady tester bit - on 7.4v

now you can get over 30rps on a 7.4v with a super speed motor on a m115 but that motor will get hot if spammed

The point I'm trying to make is your test speed on 7.4v is important - coz you will hit a good 50% more when going to similar 11.1v

so if you are hitting 30rps on 7.4v you will hit 45rps on 11.1v

This fine for US higher fields but I would be careful if you are going to hit over 35rps in the UK even on a SS 3 tooth build

you will probably be fine up to 40rps but I'd rather underquote this figure when you could Pre Engagement....

Now you say you have a M130 in there - think you may have a leak tbh like I said

barrel length can adjust figures 50 fps too on a really short/long barrel

plus bearing spring guides, piston spacers - I'd avoid piston bearings as they add weight or loctite them bastids on coz they love coming undone

anyway they add to springs final compression

so a std true m100 @ 328fps could put out around 300 to 350fps depending on two different builds/guns it is fitted to

so any spring's rating is at best a guide - yup some techs know what to expect from a certain brand of parts so they prefer to stick with what the know

I would fix up your seals first - you should be hitting:

first and foremost you should hit a more constant figure and this should be 350 but no biggy if she creeps over a bit

you can use the m120, or remove another tooth is barrel is say 300mm or under, reduce spring compression by remove bearing/spacer inside piston etc....

but you need to chrono them bad shots coz that is a leak of some sort or nozzle or alignment

nozzle could be scraping inside hop but the low start & build up on fps is what makes me inclined to check/improve the sealing inside gearbox perhaps the piston head

Piston heads & o-rings - jeez you think you got a good seal but when you swap crap around a bit and you get a GREAT seal

this mofo you really feel the seal ergh sealing - no really it is not easy to describe in words

but when it seals it really seals asap and you really can't push that piston very far plus it bounces back nigh on to the port or where you closed the seal off

Some piston heads are good and some are not so good/crap even trying a few o-rings with silicone blah blah blah

Spend a bit of time trying a few o-rings - some slightly stretched or brand new it can make a big difference

this will help loads making gun efficient and more constant

the seal on cylinder head - ptfe

if you think you still got a leak and sure if it cylinder head/scratched cylinder/piston head - test the cylinder head for leaks in a bowl/sink of water - you will see the air escaping by dipping front half of cylinder in there - no bubbles - then it is piston head not sealing in cylinder too great

air nozzle - yeah it will seal well rammed against cylinder head but how does it seal when in use ??

easy way is place say a bit of tubing/spacer something say 8-10mm to push nozzle foward....

do compression test in sink again - you will get some bubbles coz you will never get a 101% leak free nozzle

99% but if it sealed that perfectly you would not be able to move it back n forth very easily/quickly when in use

so you will not get a truely perfect seal on the nozzle but nigh on is what you hope to achieve

(there are some nozzles that have double o-rings but still you will never really get true perfection)

Phew... - you get them seals as best as you possibly can so gun is running as efficiently as it can

these seals will wear even soaked and greased etc they don't improve over time like fine wine

but we aim to get this crap as near as damn it - then we shouldn't need to compensate for leaks with much higher springs than we really need

so less stress and more fps so to speak

As said - final fps will depend on gun & setup

a 120mm mp5k or FireHawk will need like a m115 or m120 to hit 350fps

a full size AK may only need a m95 to hit 350fps - down to creep

order your m120 in case as a backup - but check n fix any leaks that I'm suspecting could be improved in ya box

best of luck

 

[Katana]

So I have a 363mm barrel / 10 = 36.3mm and the +15 = 51.3mm which is the distance from the front of my cylinder to the tip of my port.

Now there is a ZCI stainless steel 3/4 Cylinder which has a "vent distance" of 52.16mm. That's pretty dang close if you ask me.

On AirLab, there is a sized cylinder for a "301-400mm barrel"

https://airlab.parts/products/lonex-cylinder?variant=1144584339

This might marry up quite nicely with the Lonex CH rather than mixing and matching although the ZCI one I had before fit very snugly on the Lonex CH so it isn't too shab but what do you think I should go for. My gut tells me the Lonex but I guess as long as the type is right, the brand might not matter provided that they line up well.

Edit: A quick search turns up no results for the Lonex vent distances. Also, I think I will give it a rewire because the wire itself is starting to look and feel a little worn from all the movement.

 

[Katana]

OK - to avoid PE you need to not take the pi$$ too much - despite what stupid stuff I still to this day do

Now you 13:1 & SHS Torque so I am going to go out on a limb and guess you are hitting rps on 7.4v of about 22 to 25rps

easily 20rps or something is up but that m130 could slow it down a fair bit

This is the steady tester bit - on 7.4v

now you can get over 30rps on a 7.4v with a super speed motor on a m115 but that motor will get hot if spammed

The point I'm trying to make is your test speed on 7.4v is important - coz you will hit a good 50% more when going to similar 11.1v

so if you are hitting 30rps on 7.4v you will hit 45rps on 11.1v

This fine for US higher fields but I would be careful if you are going to hit over 35rps in the UK even on a SS 3 tooth build

you will probably be fine up to 40rps but I'd rather underquote this figure when you could Pre Engagement....

Now you say you have a M130 in there - think you may have a leak tbh like I said

barrel length can adjust figures 50 fps too on a really short/long barrel

plus bearing spring guides, piston spacers - I'd avoid piston bearings as they add weight or loctite them bastids on coz they love coming undone

anyway they add to springs final compression

so a std true m100 @ 328fps could put out around 300 to 350fps depending on two different builds/guns it is fitted to

so any spring's rating is at best a guide - yup some techs know what to expect from a certain brand of parts so they prefer to stick with what the know

I would fix up your seals first - you should be hitting:

first and foremost you should hit a more constant figure and this should be 350 but no biggy if she creeps over a bit

you can use the m120, or remove another tooth is barrel is say 300mm or under, reduce spring compression by remove bearing/spacer inside piston etc....

but you need to chrono them bad shots coz that is a leak of some sort or nozzle or alignment

nozzle could be scraping inside hop but the low start & build up on fps is what makes me inclined to check/improve the sealing inside gearbox perhaps the piston head

Piston heads & o-rings - jeez you think you got a good seal but when you swap crap around a bit and you get a GREAT seal

this mofo you really feel the seal ergh sealing - no really it is not easy to describe in words

but when it seals it really seals asap and you really can't push that piston very far plus it bounces back nigh on to the port or where you closed the seal off

Some piston heads are good and some are not so good/crap even trying a few o-rings with silicone blah blah blah

Spend a bit of time trying a few o-rings - some slightly stretched or brand new it can make a big difference

this will help loads making gun efficient and more constant

the seal on cylinder head - ptfe

if you think you still got a leak and sure if it cylinder head/scratched cylinder/piston head - test the cylinder head for leaks in a bowl/sink of water - you will see the air escaping by dipping front half of cylinder in there - no bubbles - then it is piston head not sealing in cylinder too great

air nozzle - yeah it will seal well rammed against cylinder head but how does it seal when in use ??

easy way is place say a bit of tubing/spacer something say 8-10mm to push nozzle foward....

do compression test in sink again - you will get some bubbles coz you will never get a 101% leak free nozzle

99% but if it sealed that perfectly you would not be able to move it back n forth very easily/quickly when in use

so you will not get a truely perfect seal on the nozzle but nigh on is what you hope to achieve

(there are some nozzles that have double o-rings but still you will never really get true perfection)

Phew... - you get them seals as best as you possibly can so gun is running as efficiently as it can

these seals will wear even soaked and greased etc they don't improve over time like fine wine

but we aim to get this crap as near as damn it - then we shouldn't need to compensate for leaks with much higher springs than we really need

so less stress and more fps so to speak

As said - final fps will depend on gun & setup

a 120mm mp5k or FireHawk will need like a m115 or m120 to hit 350fps

a full size AK may only need a m95 to hit 350fps - down to creep

order your m120 in case as a backup - but check n fix any leaks that I'm suspecting could be improved in ya box

best of luck

Just saw your new post...

I'll pick up a lonex M120 spring then and get at those when I open it. Looks like I may be befriending some o-rings and teflon tape. :lol:

I understand now that having a full cylinder in a gun that doesn't have a long enough barrel reduces your fps because the air can't get up behind the bb and supply all that air fast enough because the spring hasn't reached a speed where it can dump all that air fast enough and so the bb has left the barrel before all of the air can get behind it? I think that's right.

An air seal leak would definitely make sense anyway and I have no idea why I didn't think of that earlier :blink:

When it arrives, I'll test and see where it's leaking. I just ordered a ProWin Hop Up chamber to replace the crappy G&P one because I can't tighten it down enough so that the wheel won't move.

Let's hope that ProWin chambers enjoy the sight of a Lonex Air Nozzle eh? :lol:

 

[Sitting Duck]

Just saw your new post...

I'll pick up a lonex M120 spring then and get at those when I open it. Looks like I may be befriending some o-rings and teflon tape. :lol:

I understand now that having a full cylinder in a gun that doesn't have a long enough barrel reduces your fps because the air can't get up behind the bb and supply all that air fast enough because the spring hasn't reached a speed where it can dump all that air fast enough and so the bb has left the barrel before all of the air can get behind it? I think that's right.

An air seal leak would definitely make sense anyway and I have no idea why I didn't think of that earlier :blink:

When it arrives, I'll test and see where it's leaking. I just ordered a ProWin Hop Up chamber to replace the crappy G&P one because I can't tighten it down enough so that the wheel won't move.

Let's hope that ProWin chambers enjoy the sight of a Lonex Air Nozzle eh? :lol:

BLIMEY - you didn't have to quote ALLLLLLL OF MY CRAP

normally people just quote - stuff....

(think it saves the whole internet from crashing and not sure what the forum's bandwidth allowance is - )

yeah people go on about all this over/under voluming stuff

most manufacturers over volume a little bit and tbh on most guns a bit over volume is fine or better than under voluming

serious over volume is when you chuck in a long full cylinder into mp5k's then the ratio goes way way over the range of 1.5:1 to 2.5:1

(often this goes silly like over 4:1+ ratio on really small inner barrels and full cylinders)

it is just a rough guide that maths crap like the way of working a gear ratio by seeing the amount of turns of bevel to rotate sector

eg: your 13:1 set is likely to be a 13.65:1 actual ratio

so it would take about 4.5 turns of bevel to rotate sector 1 full turn

multply by 3

4.5 x 3 = 13.5 simple stuff unless you want to count up all the teeth n crap

yup std gears take 6.25 x 3 = 18.75 for a 18:1 set of gears

anyway - a 3 tooth SS setup would be fine for a regular m4 carbiney type barrel

i'd avoid the urge to remove any more teeth

on a full cylinder the volume would of been alright - your stroke would be about 51mm

you removed 3 teeth so you got 13 left x 3mm is what the pitch is = 39 but before you panic

you have a bit more than what is on the rack with pick up & slipping off the last tooth on release

so the total travel of that is about 49mm actual stroke instead of a full stroke of about 58mm aprox

(measuring this by marking piston at rest & at full retraction - may vary a smidge on different guns)

So do NOT take any more teeth off

the cylinder should be 51mm min - no lower really

you can go up to about 56mm and it might just show the o-ring in port to help it fill quickly

over 60mm position and it is likely the piston/o-ring won't pass the port inb use so may as well go with a full cylinder or whatever seals best

realistically the o-ring should be a little thinner than the piston head's groove coz it is designed to slip forwards as piston retracts and allows the air to slip past filling cylinder with air, then fall back on piston's release to seal the chamber blah blah blah

the port just helps it make sure that cylinder is refilled easily and also to the correct volume blah blah blah....

Thing is all this maths crap sounds all great but in reality if a gun shoots crap it still shoots crap

and these poxy toy guns are famous for producing very odd weird what the f*ck results even if you have done your homework to A+ standards like these teching gurus....

if you want to read really clever well written stuff then you MUST read this:

http://www.airsoftsociety.com/forums/f10/legacys-guide-building-high-speed-aeg-87504/

some of it is a little bit different - we can't really use m130 springs on full stroke pistons coz we have lower limits than USA

so don't take every single thing as complete 101% gospel for UK use, but most of it really explains a lot in very easy to understand stages than my rambling bollox

 

[Katana]

Yeah I don't really know why I posted that big ass quote haha

I read that post a while back actually, really informative stuff. I was tempted to go DSG until I read that it's basically hell if not done to perfection. It also doesn't really meet my playstyle as I'm more of a semi-auto kinda guy. 40-50rps is just funny to have and a real head turner. Also, when someone's cheating.......

I feel like the length of my posts are kind of pale in comparison to yours so I'm sorry if I'm coming off a little...short :lol:

I have to read your posts at least 3 times before I start understanding it because of my tiny/tried brain but it's all slowly making sense so thanks for the explanations because I actually feel like I'm learning something.

I'm gonna go for that Lonex Cylinder and get ready to take the gun apart a billion times until its right. When it gets here, I'll open err up and test for compression before to see if that was the problem but I'll still throw in that ported cylinder anyway because it should work better. I won't switch the springs immediately because I don't know how those Nuprol springs are either in terms of performance to rating. Wasn't my choice to put it in there anyway, that was a local tech. I suppose springs don't really matter but I prefer to stay away from Nuprol as their quality isn't the best. One of the "we do it all" brands rather than the "we don't do much, but what we do sell... it's good."

Have I already SS too much then or is that just for the full cylinder?

Will a ported cylinder mean I get more bang for my buck in terms of distance that the piston is travelling and the speed at which the compression takes place?

If the compression happens faster, that would mean that the fps would rise right because the force being exerted on the air being compressed is much higher? Unless of course that there isn't enough air to get that BB to travel the length of the barrel and fill that larger barrel volume. But for me, 363mm isn't on of the larger barrel volumes so I'm good for the so called "suckback" effect which apparently isn't a suck but more of a lack of air pressure?

Man, I'm tired and when I wake up tomorrow I bet I'll realise that I've totally botched this up and had no idea what I was talking about?

 

[Sitting Duck]

A SS 3 tooth is about the lowest I would go for a 363 setup

some might say a SS 4 tooth may be ok but I'd rather not go lower

It will be fine - your full cylinder would only be stroking about 49/50 and you may have pi$$ poor seal somewhere

So you was losing a fair bit of compression at start or something - well you wasn't always getting 101% efficiency

So the zci or lonex ported cylinder should be fine - it might lower the volume a little depending on port position but if port is about 50 to 55mm from front of cylinder it should still allow the piston & more important the piston's o-ring itself to show a little in port window to help it breathe so to speak

Don't worry - even if it shows for a little while say another tooth or so it will help to fill the cylinder - the compression doesn't begin straight away on release even in a full cylinder - the o-ring has to settle back, the vents in piston head start to fill with air and push the o-ring against the walls to help sealing plus the piston was static and is now going to accelerate rapidly generating the compression as it thunders down towards the cylinder head....

So a little gap or piston head/o-ring showing is not going to end the world or throw all these maths out of the window

(I thought I overthought stuff way too much)

What you need to do is do it all as best as you can......

A number of stock guns have at best so-so to crap seals & compression so they often will chuck together stuff that works ok for stock builds

Often the piston head or compression is not great - sometimes very little compression but they chuck in a slightly stronger spring and even they over volume a bit, the poor seal means the real volume of compressed air should probably work out about right once you add in a slight leak at cylinder head & std non o-ring nozzle

If you feel you have improved the seal/compression by a good decent amount and you are very pleased with great seals and bloody hell compression

(remember to grease that o-ring on piston & the cylinder's spout or nozzle, polish cylinder with silicone oil blah blah blah)

if you got great compression then I'd perhaps suggest using the m120...

this should get you very near 400fps then due to SS you should be dropping back to around 350 or maybe a touch over if all is great

I'm sure you won't be like 30fps lower than your current chrono readings on a m130 with possible bad seals

The ProWin type hop unit can either work great or not so great and need a bit of mod/adjusting for some builds

often they work a charm but a few have had problems - usually not so great at feeding for some builds but you got a delayer maybe so it could/should be fine. If you have problems with hop = tbh you ain't having much luck with std hop it seems...

but if you do get a bit of agro then watch this for hop problems:

The great thing about the prowin or the prowin type clone hop units - they are lot less pita to strip down and change buckings/nubs etc... than the bloody std M4 hops with poxy circlips that fly off and never can found again or refuse to come off/go back on and stay on etc.....

(plus they usually behave themselves in use than some basic M4 hops that lose the setting you just dialed in on the hop - yes a shim behind the adjustment dial/screw will help but some can be ok to use but other hops can just end up driving you nutz if they decide to wind off in game)

You could lose any bearings off from the piston head to make the complete piston lighter

this will help piston to return a little more rapidly as a light piston should return faster than heavier one - this may knock fps up a tiny smidge too but I have not nor can be ar$ed to study and present exact findings based upon piston's weight etc......

just if you still got bearings on piston head loctite the scew/bolt holding them all together coz they like to come undone a scratch & muller the cylinder

don't worry reckon a good-great seal box with be fine with m120 especially if you got a decent long 363mm tbb and hop/bucking is also sealed up nicely

google up some more guides n tips on getting great seals/compression and think you will get proper more constant results and see/understand it a bit more than read my sea of typing crap

 

[Katana]

Thanks a lot for your help man. Will crack err open this Sunday and see what I can do.

 

[Katana]

Still gonna split it open this Sunday but I decided to take it down to the shell today just because I was bored basically

Found this lil bastard hiding up the ol' chimney pipe...aka devils canyon...aka...yeah I can't actually think of any more. The motor insert basically.

Just see for yourself.


http://imgur.com/a/FUnGV

 

[Sitting Duck]

what the hell - shredded posi wire ???

Found this lil bastard hiding up the ol' chimney pipe...aka devils canyon...aka...yeah I can't actually think of any more. The motor insert basically.

" motor entry point " or something like that - the thingymajig bit where da mota goes init

G&P looks like turnigy silicone wire - 3.1mm fat bastid wire

you can use Alpha eco and run both down the back without hacking box to bits like I had to on a G&G FFR A2:

I'm sure I posted my hacking adventures getting thick mofo wire in

pita - having to keep grinding away and check box closes up ok with that mofo wire in there

then the grip too - tbh quite a bit of work for not a big improvement considering at the pi$$balling about

but yeah run both Alpha wires down back, fet wires behind motor and you shouldn't have such nightmares

Can't remember exact model - a certain G&G M4 - seems to come to mind but had both wires running down back grip

ahh yes that was it....

the 2 wires went down the left/right but the positive wire didn't go straight down but back straight away just above motor itself

then both wires went down rear of pistol grip then connected to motor

like this:

bloomin' weird ???

anyway - see if you can get both wires down the back using Alpha without too much file/sanding

bet it would make for a much easier stress free install

 

[Katana]

The only thing I haven't yet ordered is that wire. I was going to but when looking for it, I couldn't find anywhere that would sell such a small amount of it. Where do you get it from that won't do a massive quantity? I'll keep scouring. I'll do the wiring later in the week when I...you know....have the wire. All that turns up is uk.farnell and some other mass distributors.

 

[Sitting Duck]

The only thing I haven't yet ordered is that wire. I was going to but when looking for it, I couldn't find anywhere that would sell such a small amount of it. Where do you get it from that won't do a massive quantity? I'll keep scouring. I'll do the wiring later in the week when I...you know....have the wire. All that turns up is uk.farnell and some other mass distributors.

yeah unless you buy in bulk nobody seems to sell it in small amounts

best just get this:

http://www.ak2m4.co.uk/internal-parts/misc-internal-parts/gearbox-silver-wire-2-metres

shoot him a pm for any other bits

if you need a trigger spring:

http://www.ak2m4.co.uk/internal-parts/misc-internal-parts/zci-gearbox-spring-set-v2

(this set comes with a trigger spring)

the other things....

G&P - not 101% sure but they might connect to motor with eyelet connectors

so you need to check if you can re-use or need to buy these again or the 2.8mm spade motor connectors

if as it seems you used the existing wiring loom with thick mofo silicone wire

then you would of used the single wire mosfet wire connector to the Gate Merf

it should have come with 1 wire and 2 wire connector

So you should be able to use the 2-wire Gate connector if running dedicated wires to motor & the supply + signal wire to switch

if not you may need this:

http://www.ebay.co.uk/itm/AIRSOFT-GATE-DUAL-SIGNAL-PULSE-REPLACEMENT-WIRE-AIRSOFT-MOSFET-/322066478684?hash=item4afca8765c:g:6n4AAOSwjMJXBnqt

All you need to do is carefully plan the wiring/routing

mosfet wire(s) first, then positive, then negative on top

as said that first pic was using the 2 wire Gate connector in a bit of shrink by motor & the shrink glued in placed to ensure she stays put behind motor

check that box closes easily running both motor wires down the back - they will be at least 1mm thinner than the silicone's external diameter.

Rest is down to just taking your time and doing it all to the very best of your ability

replace or investigate the trigger spring issue, remove cylinder test switch by pulling in semi, rolling sector back in the direction of travel and it should pop the trolley off trigger sear and relatch blah blah blah....

 

[Katana]

I'm all good for springs. Bought a pack of Lonex springs. Went for the Lonex 3/4 Cylinder because according to AirLab, that's the one for my barrel although I don't know if the short stroke will have affected that and whether I should of gone for the 4/5 but I guess only time will tell. I've got an Lonex M120 spring too which I'll just throw in there because the phrase "I have Nuprol inside my gearbox" just raises all kinds of alarm bells in my head and on top of that I picked up a new piston o-ring because why the hell not...it was 80p and the one that's in there is probably too tight and isn't sealing properly. I've had two opinions on this..whether the piston o-ring is supposed to be slightly too big to create a better seal or whether you're supposed to leave it tight so that the air doesn't have any trouble getting back into the cylinder when the piston retreats to draw air. I think the former makes sense being that the piston is ported to allow air in anyway and I don't think it would affect it that much.

The motor connectors have already been switched to gold plated connectors so that's all good and I do have some spare for the new wiring because..again the originals look too worn for a re-use. The gate wires have been squished and completely flattened in some places so that's yet one more thing that looks like it needs replacing. The trigger returns by itself on both fire modes unless the gun is live with battery (in which case, as I said before, semi doesn't return and must be pushed back) if that changes anything.

Only thing I will say is that the gun is filthy and I took it to a tech less than a month ago and only skirmished once since then and I was by no means getting down any dirty with the gun. I mean inside that motor insert...entry point..thingy there is so much crap that I'm not so persuaded to ever take it to that tech again..hence why I'm doing it myself for once as I don't need anything much but a soldering iron for the wiring. A bit hard to short stroke a gear with some sandpaper and a screwdriver kit. :lol:

I'll pop over to halfords tomorrow and pick up some of this stuff:

http://www.halfords.com/motoring/engine-oils-fluids/grease/3-in-one-professional-white-lithium-grease-400ml

Looks alright but not all too sure. Got some silicone spray that might be a bit lighter for the cylinder but I know for a fact that everything inside needs a bloody good wash. I'll order some of that wire tonight, a new charging handle spring because holy shit mine is tired out and it's £3 off that website and the new gate wire. I'm gonna spend some time on this, try to make it look as neat and tidy as I can.

I'll try out that trigger test as well.

Thanks again.

 

[Sitting Duck]

All that I know - normally you might have a few even half a dozen o-rings in front of you - nope nope hmmm nope nope yes f*ck me that's the one

then grease/polish/grease again that lot and that is about it....

Grease wise a decent grease LM2 for gears/bushings etc...

Some say a Molly grease but use slicone for o-rings I'd say

I use a slicone grease for up top piston runners, tappet plate as it is lighter for items that move only once each cycle so free easy gliding

found that other grease like LM grease was a bit thick and certain grease can degrade the rubber/silicone in o-rings etc.....

(even tried a weird silicone grease that was too thick but reduced the viscosity with silicone oil - yet seemed to dry out and went back to the thicker stuff - another idea out the window of mine)

In the end I'm using this stuff as I've given up experimenting on changing thicker grease viscosity

http://www.ebay.co.uk/itm/18g-SILICONE-GREASE-O-RING-RUBBER-GREASE-PLUMBING-LUBRICANT-HANDY-MINI-TIN-/130890762171?hash=item1e79b287bb:g:GQYAAOxy1klRbXUO

well something like for o-ring seals and stuff on top

LM or Molly for lower half of box

remember to smear a bit of grease to the motor pinion when you finally come to install motor

you don't cover it all just smear some on bushings/axles - a little bit if the teeth of some gears, smearing excess over face of gears but remember that poor pinion when all the power first comes from

yup you get a bit of dirt build up - but most will probably from gears n stuff running themselves in

if you have spent a good while pi$$balling about with shimming - then it has had a little running in

though never hurts to clean up the surplus crap & re-grease - bit like a car's first 500 mile oil change if you like

Look I'm no expert, I'm still learning and changing stuff as I go

try to plan and do stuff to the very best of your ability - that little bit you think oh wtf - that will do

very likely that will be the bit that gives you trouble further down the road

most of it is planning, taking your time getting it as close to perfection as possible

if it goes crunch then find out why & learn from it - it is just a poxy toy gun meccano set with a basic bit of electrics

How hard can it be ????

uhm ergh yeah - not quite as easy as most of us first thought but hopefully not quite as difficult as we later found out the hard way