M4 spring vibration noise

traume

Finally finished upgrades on my M4, but now I have new problem - spring vibration noise at the end of each cycle. It is exactly like in this video ( i know its scar, but I have same problem) http://www.youtube.com/watch?v=IhN9N83xjL4&feature=youtu.be
After shimming, motor change, sorbo and bearing spring guide, gearbox is very quiet, just have to solve spring noise. I have no idea about spring noise before, because gearbox noise was much louder.
Any suggestions?

T4RGET

traume wrote: »

Finally finished upgrades on my M4, but now I have new problem - spring vibration noise at the end of each cycle. It is exactly like in this video ( i know its scar, but I have same problem) http://www.youtube.com/watch?v=IhN9N83xjL4&feature=youtu.be
After shimming, motor change, sorbo and bearing spring guide, gearbox is very quiet, just have to solve spring noise. I have no idea about spring noise before, because gearbox noise was much louder.
Any suggestions?

are you sure the spring is the right one? (i.e for a V2?) or if you cut it did you take too much of it, it could be that the spring is too short (this probably would translate into a lower FPS as well though). Every time the AEG cycles the spring just hops around because it doesn't sit properly in the gearbox. If it's a spring that's meant to sit into the piston head make sure it's in properly too. what power spring is in it?

traume

T4RGET wrote: »

are you sure the spring is the right one? (i.e for a V2?) or if you cut it did you take too much of it, it could be that the spring is too short (this probably would translate into a lower FPS as well though). Every time the AEG cycles the spring just hops around because it doesn't sit properly in the gearbox. If it's a spring that's meant to sit into the piston head make sure it's in properly too. what power spring is in it?

I assume, that it is M90. It is the spring which came with aeg when I bought it in Hobbies. Before upgrades it had 308-312fps. Now I have sorbo, but bearing spring guide and better air seal should replace lost fps on sorbo. I'll test aeg fps on Sunday, but I doubt my fps has decreased.
My only explanation is that bearing spring guide lets spring to move it is natural position without effort so causing vibration after spring twists back after cycle.
On the funny side, all I hear from my aeg is - puff - poink (puff-piston head hits sorbo, poink - spring vibrates )
I found out, that if i take upper receiver off and squeeze metal top of gearbox between pillows i can't hear spring anymore, unfortunately in M4 there is not much room for dampening materials.

Southern Dandy

Just sounds like something is catching on return and releasing in that video.

That would bug the crap outa me now that would. I put an guarder M85 into my EBR before and I swear to god it was like a cartoon noise effect the noise the spring made, this big giant imtimadating lump of metal and this ridiculous noise, almost like a lion meowing!

I bumped it up to a guarder M90 which looked alot less flimsy and the noise went. Thank christ......

thermo

I had a gun before with a metal spring guide and a slightly cut spring. When shot it used to sound like a cartoon "boing" kind of noise, to remidy it i put some shrink tube on the spring guide where the spring would touch and it cured the problem.

traume

thermo wrote: »

I had a gun before with a metal spring guide and a slightly cut spring. When shot it used to sound like a cartoon "boing" kind of noise, to remidy it i put some shrink tube on the spring guide where the spring would touch and it cured the problem.

won't it shred after couple rounds?

Southern Dandy

traume wrote: »

won't it shred after couple rounds?

Try putting a rubber washer down, should not be that hard to source I'd imagine, maybe the seal from a washing machine feed pipe to the machine itself, just an idea.

thermo

Southern Dandy wrote: »

Try putting a rubber washer down, should not be that hard to source I'd imagine, maybe the seal from a washing machine feed pipe to the machine itself, just an idea.

Nope as it was coated in a thick silicone based grease.

traume

Cheers guys, after tomorrows game i'll try heat shrink coated with white grease on spring guide, if that wont help - will add rubber washer as well. In worst case scenario I'll just go back to ordinary spring guide.
I'm getting quicker and quicker in taking apart my M4

traume

I'll have to put down the date for this mod until I make my mind for 11.1v or 7.4v Li-Po. If I'll go with 11.1 I have to short-stroke and replace M90 with stronger spring. Couple guys advised that stronger spring would solve my problem with spring vibration as well.

.K.A.L.I.M.A.

Just after looking at you'r post (#3) and to my basic knowledge, installing the like of a sorbo should decrease you'r FPS. This is due to the sorbo taking up space, making the piston not sitting in it's usual place (Which is why one/two teeth have to be shaved off the piston for the sector gear to catch properly). Some people would change their spring out to a stronger one e.g. M90 to M100, to gain back the lost FPS.

Spring wise, I have a ball bearing spring guide and a homemade sorbo and not having a single problem. Even with a M90, it shouldn't be bouncing around due to the spring being pre-compressed in the gearbox before firing.

traume

.K.A.L.I.M.A. wrote: »

Just after looking at you'r post (#3) and to my basic knowledge, installing the like of a sorbo should decrease you'r FPS. This is due to the sorbo taking up space, making the piston not sitting in it's usual place (Which is why one/two teeth have to be shaved off the piston for the sector gear to catch properly). Some people would change their spring out to a stronger one e.g. M90 to M100, to gain back the lost FPS.

Before my fps was 312 with 0.2g bb's. Now it is 260fps with 0.28g bb's. I believe that it is about the same, because I improved air seal and added bearing spring guide.

.K.A.L.I.M.A. wrote: »

Spring wise, I have a ball bearing spring guide and a homemade sorbo and not having a single problem. Even with a M90, it shouldn't be bouncing around due to the spring being pre-compressed in the gearbox before firing.

On Sunday I met a guy who had exactly same problem as myself after exact same upgrades.


As I mentioned before, I have to make my mind for 11.1v or 7.4v. At the moment I have 18rps, with 11.1 it felt a lot more, so just to be on safe side, have to do short-stroking and have to get m120 or even m130 spring.
Just no idea can my raider gearbox handle so strong springs.

Would there be any chance, that shops who are downgrading aeg's would just give me some of the stronger springs for tests?

Southern Dandy

traume wrote: »

Before my fps was 312 with 0.2g bb's. Now it is 260fps with 0.28g bb's. I believe that it is about the same, because I improved air seal and added bearing spring guide.

On Sunday I met a guy who had exactly same problem as myself after exact same upgrades.


As I mentioned before, I have to make my mind for 11.1v or 7.4v. At the moment I have 18rps, with 11.1 it felt a lot more, so just to be on safe side, have to do short-stroking and have to get m120 or even m130 spring.
Just no idea can my raider gearbox handle so strong springs.

Would there be any chance, that shops who are downgrading aeg's would just give me some of the stronger springs for tests?

Correcting AOE can reduce your FPS, it would appear more so if you have a ported cylinder, less with a non ported one, chrono readings to prove it . You are reducing the full swept air volume in the cylinder, so you are bound to get a reduction.

Honestly unless your aeg is fairly upgraded, I would avoid 11.1v lipos, they will shorten the lifespan of your internals. 18 rps is decent, a mosfet, low res wiring, with a 7.4v. Just my 2 cents.

traume

Southern Dandy wrote: »

Correcting AOE can reduce your FPS, it would appear more so if you have a ported cylinder, less with a non ported one, chrono readings to prove it . You are reducing the full swept air volume in the cylinder, so you are bound to get a reduction.

Honestly unless your aeg is fairly upgraded, I would avoid 11.1v lipos, they will shorten the lifespan of your internals. 18 rps is decent, a mosfet, low res wiring, with a 7.4v. Just my 2 cents.

Which of internals have to be upgraded to handle 11.1v?
As for FPS - using online fps calculator i have now the same 0.9J as I had before.

.K.A.L.I.M.A.

Southern Dandy wrote: »

Correcting AOE can reduce your FPS, it would appear more so if you have a ported cylinder, less with a non ported one, chrono readings to prove it . You are reducing the full swept air volume in the cylinder, so you are bound to get a reduction.

Honestly unless your aeg is fairly upgraded, I would avoid 11.1v lipos, they will shorten the lifespan of your internals. 18 rps is decent, a mosfet, low res wiring, with a 7.4v. Just my 2 cents.

Just to add on to Dandy's point, I put a thread up a while back regarding what cylinder I needed. I was recommended a Type C, but after installing it, I actually had a huge loss in FPS with a SHS M90 spring. Installed a non-ported cylinder (Standard one with no holes), and my accuracy and range improved. Still have to get the AEG chronoed to check FPS.

traume wrote: »

Which of internals have to be upgraded to handle 11.1v?
As for FPS - using online fps calculator i have now the same 0.9J as I had before.

Online calculator's aren't the best to check you'r FPS. Again, another thread stating that it can vary in different place's.

Southern Dandy

traume wrote: »

Which of internals have to be upgraded to handle 11.1v?
As for FPS - using online fps calculator i have now the same 0.9J as I had before.

You can never truly tell unless you chrono it with a reliable chronograph, charts are a guideline.

Going by the calculator I found it was

.20g @ 312fps =.90,
.28g @ 260fps =.87.

A different chart showed me a different result. See this post I through up ages ago when the first aeg I corrected got these results. The link on my link has my original post about correcting AOE.

http://www.boards.ie/vbulletin/showthread.php?p=83010207

As for upgrades, decent gearsets to begin with something that is not soft metal. Re-enforced piston that does not have full metal teeth, reason being that if for what ever reason you run into trouble and you have steel gears and a full steel rack the stronger metal will win and more than likely ruin both parts, nylon teeth will just strip, the gears should be fine and all you need to do is replace the piston. Steel spring guide (my own opinion). Depending on what size bearing/bushings your gearbox can take, I would go with bearing for ROF and bushings for reliability (again my own opinion), correct shimming, radius-ing the gearbox shell, correcting aoe.

If anyone else wants to add to this feel free.

traume

Southern Dandy wrote: »

As for upgrades, decent gearsets to begin with something that is not soft metal. Re-enforced piston that does not have full metal teeth, reason being that if for what ever reason you run into trouble and you have steel gears and a full steel rack the stronger metal will win and more than likely ruin both parts, nylon teeth will just strip, the gears should be fine and all you need to do is replace the piston. Steel spring guide (my own opinion). Depending on what size bearing/bushings your gearbox can take, I would go with bearing for ROF and bushings for reliability (again my own opinion), correct shimming, radius-ing the gearbox shell, correcting aoe.

If anyone else wants to add to this feel free.

I have 8mm bearings, sorbo (aoe done), IMO my piston have to be swiss cheesed, reinforced steel gearset.

Why are people so worried about FPS? Is it the pain factor for target or I'm missing something?

BTW good job guys, I'm starting to think about just getting 7.4v I loved great trigger response from 11.1v, but as this is my only AEG, i have to keep it reliable. So I might try stronger spring. Here in shops I have seen only m90's. Have to order.
The brand difference for springs changes only how long spring will keep it's original tension?

Southern Dandy

If you want high speed and a snappy trigger, go for high speed gears with a torque motor, mosfet, low res wiring and deans, as low a spring as possible and with a 7.4v you will get a nice rof and trigger, you could also perform a hair trigger mod if you wanted to.

T4RGET

traume wrote: »

Why are people so worried about FPS? Is it the pain factor for target or I'm missing something?

What do you mean? the limit is 1J, that's a pretty nice value, having it at 1.2J wouldn't bother me too much either but what do you mean what are people's problem with FPS? it's set at 1J, even if you didn't mind the pain of higher limits you legally can't.

traume

T4RGET wrote: »

What do you mean? the limit is 1J, that's a pretty nice value, having it at 1.2J wouldn't bother me too much either but what do you mean what are people's problem with FPS? it's set at 1J, even if you didn't mind the pain of higher limits you legally can't.

In my case by putting in Sorbo I loose probably around 5fps. It is not big deal. Then I hear guys trying to mach exact 328 fps. Is there really huge benefits of +-5 fps?! I had 0.9J, now I have close to that, but possibly smaller J, so is there any HUGE benefit of trying to mach 328fps?! Will my range increase or just live targets will shout sooner - HIT?!

Question - aren't high speed gears (eg. 13:1) on 7.4 Lipo acting the same as 18:1 gears with 11.1v? If 11.1v makes pre-engagement issues, high speed gears are trouble free?

I do have mosfet, I do have deans, I do have torque neo motor.
I don't have 16awg or 14awg wiring as guy who made mosfet said - with these low power springs, motor will never draw so much current to actually have any benefit of having 16awg or lower resistance wires.

Leftyflip

traume wrote: »

In my case by putting in Sorbo I loose probably around 5fps. It is not big deal. Then I hear guys trying to mach exact 328 fps. Is there really huge benefits of +-5 fps?! I had 0.9J, now I have close to that, but possibly smaller J, so is there any HUGE benefit of trying to mach 328fps?! Will my range increase or just live targets will shout sooner - HIT?!

Question - aren't high speed gears (eg. 13:1) on 7.4 Lipo acting the same as 18:1 gears with 11.1v? If 11.1v makes pre-engagement issues, high speed gears are trouble free?

I do have mosfet, I do have deans, I do have torque neo motor.
I don't have 16awg or 14awg wiring as guy who made mosfet said - with these low power springs, motor will never draw so much current to actually have any benefit of having 16awg or lower resistance wires.

The difference between 300 and 328 fps is absolutely tiny. Not even noticeable.


Low resistance wiring, always. Always low resistance wiring, peace of mind. Trust me.

.K.A.L.I.M.A.

traume wrote: »

In my case by putting in Sorbo I loose probably around 5fps. It is not big deal. Then I hear guys trying to mach exact 328 fps. Is there really huge benefits of +-5 fps?! I had 0.9J, now I have close to that, but possibly smaller J, so is there any HUGE benefit of trying to mach 328fps?! Will my range increase or just live targets will shout sooner - HIT?!

Question - aren't high speed gears (eg. 13:1) on 7.4 Lipo acting the same as 18:1 gears with 11.1v? If 11.1v makes pre-engagement issues, high speed gears are trouble free?

I do have mosfet, I do have deans, I do have torque neo motor.
I don't have 16awg or 14awg wiring as guy who made mosfet said - with these low power springs, motor will never draw so much current to actually have any benefit of having 16awg or lower resistance wires.

It's more of a personal preference. Some will keep it at 300FPS, other's will want their AEG around 320-325FPS.

traume

So is there really a difference or there is only personal preference? If it gives extra 4-5 meters on distance, it is good enough reason, but does it gives that extra reach?

Back to topic - spring vibration.
For some reason I think, that if spring guide is made form metal, there is a reason for that, so covering metal with something will make it shred or god knows what can happen.
So, if I'm changing to Guarder sp100 spring and cut down coils would eliminate spring vibration?!

T4RGET

Energy output has no effect on range, especially at those values, Like Ger said the difference between a couple of FPS between 300 and 328 is so small you won't even notice it.
You want range, use a decent hop up, then a barrel, I've started using 6.04-6.08 barrels in set ups with a really good hop up and find the results better than going for a TBB with a good hop up. People may complain about our limits but the limit makes Irish airsofters squeeze every bit of range out of an AEG.

ShRT

Regarding the wider barrels - Have a look over on airsoft mechanics. The trend over there is to go for the looser barrel. The theory is that the bb then rolls along the barrel for longer and keeps its backspin intact. The tbb barrels tend to cause more impacts as the bb exits and so reduces the backspin effect put on by the hop-up

Thats the theory anyways but there isn't a whole lot of testing available

traume

ShRT wrote: »

Regarding the wider barrels - Have a look over on airsoft mechanics. The trend over there is to go for the looser barrel. The theory is that the bb then rolls along the barrel for longer and keeps its backspin intact. The tbb barrels tend to cause more impacts as the bb exits and so reduces the backspin effect put on by the hop-up

Thats the theory anyways but there isn't a whole lot of testing available

Perfect, I have my original cm16 raider L barrel, thought no idea what diameter it is, I'm pretty sure it is not TBB. Have to try r-hop on it and then compare.

traume

I just noticed, that original spring in my cm16 raider is not shs m90. The one inside is linear spring, where shs has non-linear spring.
Will give it a go. Hopefully that will help with annoying vibration noise.

Southern Dandy

I am starting to think that wider bores are just as good, closer range you will defo have a much tighter grouping. But the material they are made of is quite important also brass can be quite ****e being honest.

Also Traume guarder springs tend to shoot fairly high, every one I have installed (4) has given me a much higher reading than avertised. The new Ultimate springs are fairly close to what they advertise though.

thermo

You can get excellent results if you polish the crap out of a "stock" clone brass inner barrel with brasso. Just make sure you leave any residue behind.

Southern Dandy

thermo wrote: »

You can get excellent results if you polish the crap out of a "stock" clone brass inner barrel with brasso. Just make sure you leave any residue behind.

The smell off that crap though is horrendous I get the gawks smelling it , beautiful finish though when polishing your cylinder and buffing it.

thermo

Southern Dandy wrote: »

The smell off that crap though is horrendous I get the gawks smelling it , beautiful finish though when polishing your cylinder and buffing it.

Your supposed to use it to polish the bore,,,,,, NOT SNIFF IT!! Lol