Ics M4 Upgraded - I.E. I Broke My Gun and Need Your Help

[Solar]

Hi guys,

I have an ICS M4 which I bought about 4 or 5 years ago now and it has worked flawlessly since then. However in standard fashion I have decided to take something that wasnt broken and have tried to make it better and now I need help.

So the gun is a standard AEG, no MOSFET or Lipos, it has Tamiya connections (which was next on my list to change to deans).

Firstly I added a M110 Guarder spring which ended up being too powerful so I trimmed a few coils and it is now spot on, I tested with 60+ chrono'd shots plus full auto so I am certain there are no problems with the spring.

I also bought an ASG 16:1 high speed gear set and an SHS High Torque motor. Today I have installed the gear set and on test firing without the top half of the gearbox (ICS have split gearboxes in-case you weren't aware) the gears seemed to operate just fine, no issues.

However when I then reassembled the gun (with the standard motor not the SHS one) the gun would fire on auto without issue but on semi it seized up a couple of times. Each time it wasn't clear exactly what caused it to seize but it would then start working again after I took the top receiver off and then reattached it (the split gearbox is so easy for things like that).

After the gun jammed maybe twice I thought I would just try full auto to see if it was only semi causing an issue, and after maybe doing 3 or 4 3-second bursts the fuse went.

So my thought process is:

AEG:

M110 spring slightly downgraded

16:1 gears

"Standard" ICS motor but no idea what the actual rating is of the motor, it has been good in the years I have used it so dont think it is faulty on any way

Tamiya connectors

Standard wiring

9.6 NiMh battery (again has worked flawlessly so do not believe the battery is faulty.

Everything other than gears and spring is stock and has been very reliable up until now.

1 - Gears work fine but I didn't shim them. I have never shimmed gears before and from inspecting the gears they appear to engage well and no obvious issues with them from what I could tell but I am happy to be informed if I am horribly mistaken. For reference there are shims or washes on the gears that were on the old set and I have kept them as is.

2 - The motor is doing more work than before, could the motor just not be up to the task of 16:1 gears and slightly more powerful spring and has drawn too much current to compensate hence blowing the fuse? If that is the case would using the SHS motor fix this issue or just create the same problem?

3 - Damaged wiring - I have not inspected the wiring yet but could it be possible that even some very minor damage caused in my tinkering would cause the fuse to blow? If some small section of the wire has been exposed can I just apply some new heat shrink in the affected area? (I think that any damage to wiring is going to be very superficial so Id rather repair than attempt to rewire if possible).

4 - The battery is just not up to the task: But due to the fuse blowing I d not believe this to be the problem.

Other things - I am aware that deans and perhaps a 7.4 lipo are the way to go but Im not sure that tamiya with 9.6 NiMh should be causing this type of issue...

My next steps are:

1 - Replace the fuse

2 - Inspect wiring for obvious damage

3 - Try the upgraded motor and see if the same problem occurs

4 - Potentially look at rewiring the whole gun which I cant really be bothered to do but I will if necessary.

Soooooo does anyone have any thoughts on this or any words of wisdom, if someone can just say yeah the motor isnt up to it then that would be awesome ?

 

[Sitting Duck]

1 - Gears work fine but I didn't shim them. I have never shimmed gears before and from inspecting the gears they appear to engage well and no obvious issues with them from what I could tell but I am happy to be informed if I am horribly mistaken. For reference there are shims or washes on the gears that were on the old set and I have kept them as is.

2 - The motor is doing more work than before, could the motor just not be up to the task of 16:1 gears and slightly more powerful spring and has drawn too much current to compensate hence blowing the fuse? If that is the case would using the SHS motor fix this issue or just create the same problem?

1 - yes you did shim them, the same as the original set and rarely do gears all shim up the same

2 - the 16:1 set is 17.25:1 compared to 18:1 set is 18.65:1 aprox

in reality next to fuck all difference really

The spring was likely a SP110  =  M120 and the ICS 3000/Turbo was likely a bit tired

worn brushes/dirty commutator etc....

but depending on motor could have just needed a clean up & new brushes

(they are actually not that bad stock motors - even the black ferrite magnet ones)

and if you had silver magnets then even better stronger, but likely the ferrite if it stalled & blew fuse

My main guess is that the new bevel was slightly different and required the motor adjusting

I'll guess the different bevel was cut & shimmed a bit closer to the ICS pinion on motor

which increased the amp draw as the motor was trying to press the bevel into the gearbox casing

thus the amperage rose and with added strain of spring, tired motor, and tight bevel-pinion it struggled & stalled

upon locking up with a higher stress - it blew the fuse fairly quickly

Did this old ICS not have the Anti reversal latch release on the forward assist button ???

(they have tended to cease this feature but as yours is a bit older it should have had this)

if it did you can/could use this to assist in unlocking a stalled box

The fuse is either 20a, 25a or 30a - 20a is a bit low, 25a likely

& if it was a 30a fuse then it really was straining if it blew

I would obtain some 25a & 30a fuses

they could be the mini type (2.8mm connectors like on motor) & 30a is max in mini auto fuses

or the regular type with large spade connectors - but don't go above 30a fuse

if 30a fuses keep blowing then that box is straining way too much

mini & regular automotive type blade fuses...

View attachment 64943

in tight spaces they may often use the mini type fuses

in larger battery spaces they may use the more regular sized ones

or they might use the glass type but often blade fuses are used in decent mid-range guns

(still a lottery if mini or regular sized blade fuses though)

mini/micro 2 go up to 30a max and you should not need any higher

if 30a fuses keep blowing you have really got problems

Once you got fuses, replace and lower the motor height a little, up to say 1 full turn (counter clockwise)

WRITE DOWN WHAT YOU DID, how many turns you backed off etc... so you can reset it to original

if this does not help, you can briefly try the new motor, which will help but if the bevel is shimmed too tight

well then the draw/strain will still exist - just the more powerful motor will force it through so to speak

That sort of gun say M105 350fps even on 16:1 should draw 11~12 amps as it cycles on auto

however a rule of thumb is to double this to 25a or 30a on fuse

lamer guns might have a 20a fuse - usually a 25a is fairly common

BUT on initial firing from stationary the draw is very very briefly 80amps or more

once firing on auto it drops to say 10a rising briefly as spring tension increases the releases

giving an average draw of say 12a

What happened in your case likely tightly shimmed bevel to pinion/motor height

with a stronger spring struggling to cycle on semi, stalled at 80%

so that when you tried to clear it the motor was struggling to pull the extra spring/bevel tension

probably stalling at 100amp or so and blew the 25a fuse almost straight away

Now the shimming "might" not be too bad if you are lucky, a half turn counter clockwise might work

you "could" replace the ICS bevel and in "theory" it should pair up OK still

(remember to return the height back to original position)

The SHS motor "should" pull most things - even on lockup or high pre-cock position

BUT if the load strain is high things will still run warm with higher amps generating more heat

(and draining battery quicker etc...)

As said you "could" try the ICS bevel with ICS motor - which in theory be shimmed OK

(assuming everything went back 101% as before)

and the ICS bevel "should" be compatible-ish with the spur/sector of the SHS 16:1 set

Then if you try the SHS motor then all this could change again coz different gears & motors shim up differently

Another thing - are you sure all them gears shimmed up nicely ???

coz SHS gears are a bit chunky and often need less shims than std gears they replace

I've had the spur/middle/step gear so tight I ended up with no shim on top and had to use a bearing

than a bushing as there next to no room left to shim the spur

(you will almost certainly need a shim on top bevel 0.1 to 0.3mm, but some gears are quite thick)

just saying they is a bit more to shimming than just slapping the gears in - even like for like shimming

and often you change gears - bevel & pinion/motors especially then stuff can get thrown out a bit

If stuff is shimmed too tight then the load increases, amps rise, gun struggles & fuses blow

and as long as this reply is already - shimming is a bit of an art to perfect

and even then doesn't always go to plan - with crappy sounding gears & higher than expected amp draw

Get some fuses, try the motor height a smidge

you change the motor...

split the box

pull the motor out

set fire to auto, pull back the Anti reversal latch forward assist dooberry...

see how the gears spin freely - they should still spin a bit everything is released

if OK - carry on swapping motor but be prepared to adjust motor height on a different motor

Regarding the motor height screw adjustment....

If your ICS has a tiny tiny grub screw (and likely a tiny disc, hopefully installed correctly)

then the thread of the tiny grub screw is very fine - so you may be able to adjust it say 1.5 turns either way

If you have a larger screw (flat head or larger 4mm allen key) then thread is larger

so 1 full turn on a larger screw of 1mm pitch thread is like 1.25 turns on a 0.75mm thread

suffice to say shifting motor height 1mm is not always going to 1 full turn on every gun

as the motor height thread/pitch can/does vary from gun to gun

normally if you are lucky and shimming/motor height was set perfectly

then it would only need a very fine tweak 1/2 turn either way to get perfect sweet spot on less shrill/draw

(much more than that, then the initial setting was a little less precise that originally expected)

So you should not go absolutely nutz winding motor in & out

hence make note where you started from so you can set it back roughly to it

I'd say the shimming is a bit out on a tired motor that stalled & blew the fuse

the bevel "might" be a little tight to pinion perhaps

and also check the gears can spin with box in two halves, receiver open, motor out & AR/Forward assist arm pushed forward

There are few things to try - but get fuses

if all else fails - chuck the ICS bevel or the whole set back in

there really isn't much difference in 16 & 18:1's anyway

and if it is running shit the little tiny gain will be lost as it struggles to cycle

get it so it doesn't blow fuses, drop in the SHS motor ensure it runs/sounds sweet

if it doesn't blow fuses then chuck on deans....

(you'll get same - maybe better performance from deans over tamiya than 16:1 vs 18:1 imho)

BUT GET SOMEBODY WHO CAN SOLDER TO DO IT

(cut one wire on battery at a time FFS, OK you using nimah but avoid shorts & LiPo really goes boom)

hope some of this shit helps to get your gun going again

even if you chuck the ICS gears back in - it is no biggy if 16:1 is causing you grief

 

[Speedbird_666]

Didn't ICS use a different (i.e. not 'TM' Compatible) engagement angle on the bevel and pinion gears for their older models? I seem to remember stories of mulched gears if both were not replaced at the same time.

Personally, I'd put the whole ICS set back in, and return it to 'stock' (spring included). If your FPS is low, check things such as air seal, hop up unit (the ICS plastic ones are brittle and can crack), and consider replacing your hop up bucking and nub.

The stock motor in both my ICS guns are pretty decent on a 7.4v LiPo. I was a naughty boy and removed the fuses when rewiring them to Deans. Gained 1-2 RPS doing that alone.

 

[Sitting Duck]

Didn't ICS use a different (i.e. not 'TM' Compatible) engagement angle on the bevel and pinion gears for their older models? I seem to remember stories of mulched gears if both were not replaced at the same time.

Personally, I'd put the whole ICS set back in, and return it to 'stock' (spring included). If your FPS is low, check things such as air seal, hop up unit (the ICS plastic ones are brittle and can crack), and consider replacing your hop up bucking and nub.

The stock motor in both my ICS guns are pretty decent on a 7.4v LiPo. I was a naughty boy and removed the fuses when rewiring them to Deans. Gained 1-2 RPS doing that alone.

Just compared a ICS Turbo 3000 neodym with a SHS looking bevel...

not quite 90°, maybe 85° (no less)

I've seen worse though

Cyma bevels with the #1 stamped on them don't mesh true 90° with SHS & others pinions

Mind you think G&G pinions are like ICS, not all pinions/motors like certain bevels

& just coz the bevel & pinion mesh perfectly at 90° - does not guarantee smooth as silk meshing

(it will assist a good solid transfer of energy but not a 101% guarantee of smooth as silk rolling if it's rough as shit)

he could try the ics bevel at least - which would be a start to initial pinion/bevel guessing

or

get the fuses & try the shs motor with shs gears/bevel which "should" mesh nicely or better

(but unsure if bevels shim exactly the same as ICS one)

I'd avoid dropping fuses (for now, well I'd avoid recommending this or even mentioning it on the side of caution/safety)

and in hindsight I'd advise to always keep a fuse in there

(even though I don't in some of my stuff but it's my risk & know the draw & wiring condition plus my risk as said)

as OP doesn't know how heavy the drain is

& likely blowing 25a fuses - then the load needs to brought down & fuse kept in there

avoid the urge to bypass the fuse or bodge it - as strong as the urge might seem

many on here have a test meter to gauge what current the gun is pulling

so we can check the draw on auto etc... ourselves

the OP doesn't have this so he should keep the fuses as they are blowing for a good & valid reason

I don't think I have an ICS bevel to hand to compare how bevels are cut to ICS ones

but bevels can vary not just in angle but how high/low they are cut

meaning one bevel might need 0.1mm shim on top & others 0.5mm etc...

so almost impossible or incorrect to assume another gear set - particularly a bevel will shim up the same

see here for differences - though extreme, some bevels are cut very very differently & thus shimming will vary...

(look at that fucker in the center how high them teeth are cut)

 

[Solar]

@Sitting Duck thanks for your very detailed reply, im going to take a much closer look at the gears now and eliminate that as being the cause, i went out and bought some 20a and 25a fuses to replace the blown one.

I did notice the new gears felt stiffer to rotate by hand than the ICS originals so I will remove some shims and see how that goes.

I didnt even know that you could adjust the motor height so I will give that a go too.

Thanks again for your advice I will let you know how I get on...

 

[Solar]

Just a quick update:

I replaced the fuse and had a look at the wiring and I think the fuse blowing issue is now resolved.

A new issue I am having is that firing in semi is very touchy. It appears that my trigger switch mechanism has been damaged at some point and that might be the cause of the problems all along. Basically firing in semi the cut off lever does not seem to engage consistently leading to the gears continuing to spin or spiining in an inconsistent way.

I have ordered a new ICS trigger switch and selector plate but unfortunately delivery is taking ages, Im hoping that this will resolve my problems when it arrives. On a side note all this tinkering has taught me a lot about gearboxes ?

 

[Sitting Duck]

You "could" have damaged the trolley or shuttle part of switch unit

(bit that gets pushed by trigger, into the switch contacts)

Less likely trigger itself is damaged, more likely a damaged trolley

either underneath where trigger lug/sear engages it

or at the ridge/ramp part where the Cut Off Leaver engages & lifts it on semi

(Sector cam raises COL that pops trolley up from the trigger sear & pops back

The other component is a worn Cut Off Lever of COL

Usually made of alloy, non magnetic/ferrous & can wear if you shoot on semi a lot

The COL's often don't appear to be worn at first glance...

until you compare them against a new one - then you notice how worn they can get

When COL wears quite a bit, it hardly lifts the COL via sector semi cam

and thus doesn't lift enough reliably to pop the trolley from trigger sear on semi

Without seeing the issue & test firing to see/feel what the symptoms are

it could either or - worn/busted switch/trolley or worn COL

(possibly both even)

If the trigger ever feels stiff coming from auto to semi

NEVER force it, plop it back into auto & do a quick burst

Then hopefully it will cycle with COL lowered and fire on semi OK

Force it - easy newbie mistake & you risk busting the trolley

PITA these guns, but you get to learn & understand their qwirks

Use them correctly (not forcing crap)

And hopefully they last a bit longer before needing servicing

(Well that is the general idea - don't always go to plan though)

Best of luck - ya getting there bit by bit hopefully

(Hate using my mobile, poxy thing to respond on)

 

[Solar]

Thanks @Sitting Duck yes when you describe “trolley” that sounds like it might be the bit that looks worn/damaged. Part of my issue is I did not have a pristine one to compare to but when the new one arrives it should be easy to spot any discrepancies I think. I was hoping my package would arrive today but it hasnt so that was a bit annoying!

If I can get the ICS working again then this will have been a worthwhile learning experience but waiting around for partsto arrive is irritating, no tracking number either ?

 

[Sitting Duck]

if you get the SAME part/switch then you may probably just need to swap over the busted trolley part

when you get another switch - well things can get interesting with trigger/trolley/switches

as some switches are a little different to others, sometimes they are interchangable

& other times not quite so - not ALL trolleys go in ALL switches

not all switches work flawlessly in some guns/triggers

some triggers (especially cheap flat "speed triggers" tend to be a bit short on sear

that there can be so little metal of trigger pushing trolley at very bottom

it jumps off at full pull etc....

Oh fuck me - trigger/switches & compatibilty can be a PITA if you change lots of shit

plus if you change switch itself - then resoldering required

so if you got an ICS switch or say a SHS trolley is kinda compatible

then just keep it simple & change what's broke perhaps

best of luck

 

[Solar]

@Sitting Duck Hello mate, it took a while for the parts to come but I think the delivery services are struggling a bit at the moment in general, then I didnt have time because of work but... good news! It turns out it was the "trolley" bit (the bit that moves forward to make the connection?).

Basically when I compared to the brand new one it was obvious how worn the old one was and I think during my initial modifications it did get damaged too, but not massively so it was quite subtle. I never would have guessed that such a small part would stop the whole gun from working!

Anyway so I replaced the worn trolley with the new one but kept the rest of the trigger as is (I bought the exact same ICS trigger-switch so its all compatible) and I noticed straight away that the operation of the trigger and the movement of the cut off lever and selector place all felt better somehow (I also tightened the cut off lever which I think was too loose but it wasnt the main issue anyway).

I then had a good look at the new gears and the shimming and all seemed good so I put all back together and it worked without the top half of the gearbox attached. However when I put back in the gun it was struggling to pull the piston back and I was pretty fed up at this point, however just before I took it all apart again I thought that id try a new battery and it worked flawlessly, so basically Ive been testing so much it drained a whole battery lol

Anyway long story short it was the trolley that had worn, I think not helped by me potentially forcing the gearbox back into the gun and not having the selector plate in the right position so straining the trolley even more until a bit has snapped or split off. The new gears are all working well and new motor as well, plus I have learnt a huge amount about teching and working on V2 gearbox. At some point I will still rewire but I need a break now

Thanks a lot for taking the time to write detailed replies and explaining how things work, appreciate that mate! Im a happy bunny now as that gun has been really good and I was gutted that id somehow broken it. Cant wait to skirmish again with it now