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What did I do wrong? Bucking suggestions! Prometheus Tightbore & M120 spring


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#41 rawfuls

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Posted 15 July 2013 - 08:17 PM

Took it apart moments ago- tighter coils were in the back near the spring guide.
However, I did notice some rubbing on the side of the spring coils, hopefully you can see it.
Not sure if this is standard, but I definitely have the compress the spring like crazy to get it into the piston without it flinging up into my face.
Spring: (Regular color is green, rubbing off, looking a little copperish)
Posted Image

Now, I went ahead and grew a pair and took a deeper look.
Definitely looks like the compression is bad.
I assume the ORing is supposed to seal the piston and the Cylinder, which would trap the air between the cylinder and piston, forcing out the air nozzle- thus creating a powerful push of air- right?
This can't be done if the ORing is very loose!

As you can see in this picture, the ORing is totally moveable, and manipulate, definitely no seal-- if any, here.
Do I just need a new ORing that will puff up and create a seal?

ORING:
Posted Image
Posted Image


Bucking & Hop Up looks fine...
Posted Image
Posted Image

#42 EzDeezer

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Posted 15 July 2013 - 08:41 PM

To test your compression, put the cylinder head on the cylinder and place the piston with the piston head on it into the cylinder as it would be normally, then place your finger over the cylinder head nozzle (not the actual air nozzle) and move the piston into the cylinder, once the piston head moves past the port it should become quite difficult to push the piston further, ensuring good compression.  If you do not get good compression (the piston just moves right through without difficulty when your finger is covering the nozzle) you can stretch out the oring that you have (it is actually fine that the oring moves around on the piston head, just make sure that it gives good compression once inside the cylinder), or buy a danco #14 at a hardware store, stretch that a bit, and replace it with that.

Could you also give me a picture of the back of your hopup unit?

Edited by EzDeezer, 15 July 2013 - 08:43 PM.


#43 rawfuls

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Posted 15 July 2013 - 09:15 PM

Did as you said!
First time (didn't touch oring), dropped it in, and it sunk right in past the port, no compression whatsoever.
Stretched out the oring, did it again, and it definitely took some pressure to push it down, however not as much as I feel is best?
Could I buy a new danco #14 at Home Depot, soak it in shock oil (silicone?), wrap some teflon around the oring trench then put the oring on top to provide the best compression?
EDIT: I take that back- none of the hardware stores around here carry the Danco #14.

Personally, I don't think the compression right now is TOO great- however, this is again my first time.

What do you think?

Hopup: (Hopoff off!)
Posted Image
Posted Image
Posted Image

Edited by rawfuls, 15 July 2013 - 09:29 PM.


#44 EzDeezer

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Posted 15 July 2013 - 09:42 PM

Bucking is definitely installed correctly from what I can tell.  The Orings do not have to be danco, but just #14 orings I think.  You can try using teflon tape around the cylinder and cylinder head to improve that seal, but as long as the piston is fairly tough to get to move, you should be fine.  I would put it all back together with the stretched oring and see how it goes.  If you still have problems, take it into your shop as you said it is open now.

#45 rawfuls

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Posted 15 July 2013 - 09:46 PM

View PostEzDeezer, on 15 July 2013 - 09:42 PM, said:

Bucking is definitely installed correctly from what I can tell.  The Orings do not have to be danco, but just #14 orings I think.  You can try using teflon tape around the cylinder and cylinder head to improve that seal, but as long as the piston is fairly tough to get to move, you should be fine.  I would put it all back together with the stretched oring and see how it goes.  If you still have problems, take it into your shop as you said it is open now.

Would soaking it in oil, making it expand be beneficial at all?

Edited by rawfuls, 15 July 2013 - 09:48 PM.


#46 EzDeezer

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Posted 15 July 2013 - 09:52 PM

It could, but stretching it or replacing it should be fine, and I don't know if you want oil inside your gun and possibly getting into the nozzle and barrel.  (not sure if this will actually happen, but better safe than sorry I suppose)

#47 rawfuls

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Posted 15 July 2013 - 10:11 PM

View PostEzDeezer, on 15 July 2013 - 09:52 PM, said:

It could, but stretching it or replacing it should be fine, and I don't know if you want oil inside your gun and possibly getting into the nozzle and barrel.  (not sure if this will actually happen, but better safe than sorry I suppose)

Sounds good!
Going to wrap some teflon around it to raise it a tad bit.
Will grab a new oring tomorrow morning and throw it in.
Anything else I should check out while I'm in here?
Or to take pictures?

#48 nbv386

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Posted 15 July 2013 - 10:19 PM

Before you put the new o-ring in you should heat shrink the o-ring. Now I know I'm not saying it right and I can't seem to find the vid but if one of the mods could chime in doing this will also ensure you have good compression. I think Gwc made the vid sorry if I'm way off but they should know what I'm talking about.

#49 EzDeezer

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Posted 15 July 2013 - 10:31 PM

I don't know if you should wrap teflon tape around the O ring or not (sounds like it could cause issues) I would only use teflon tape to create a better seal for the cylinder head and cylinder, and as nbv has said, there is a post somewhere on the forum about heating up the oring while it is wrapped around the cylinder to make it stretch a bit more, I just use the method of leaving them around an old cylinder over time allowing them to stretch.

Edited by EzDeezer, 15 July 2013 - 10:31 PM.


#50 rawfuls

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Posted 15 July 2013 - 11:27 PM

When I mean Teflon, I mean I would wrap in the oring channel, which would allow the oring to sit higher (stretched a tiny bit) which would push the oring outward creating a tighter seal.
The Teflon would technically be under the oring, and not over. The only issue I could see is wrapping too much, forcing the oring to push outward in the port, which would crush and inevitably rip the oring.

I've seen this work with great success on green gas pistol mags that were leaky.

I will leave the oring stretched around the piston for now (on top of one of the teeth- to stretch it more) and reassemble it in the morning to see how it shoots then. Hopefully everything will be a-okay!

#51 rawfuls

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Posted 16 July 2013 - 07:35 AM

I stretched the oring, made sure there was great compression (no teflon), reassembled with the 120 spring- still same thing.
Won't pierce a coke can (even at point blank, muzzle to can).

Now..starting to get frustrated.
Going to take it apart and try the stock spring and see where we're at.

#52 rawfuls

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Posted 16 July 2013 - 09:09 AM

I assume you mean this thread?
http://www.kwausa.co...8177#entry96197

#53 rawfuls

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Posted 16 July 2013 - 09:13 AM

I assume you mean this thread?
http://www.kwausa.co...8177#entry96197

#54 EzDeezer

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Posted 16 July 2013 - 10:58 AM

Yeah that thread, surprised you still have the same problem :cry:
Only thing left is to check with a stock 2gx bucking, but in my experience the G&G green never reduced FPS, let alone by that much.  If switching to the stock spring fixes it, you just got a bad spring or something (I have never seen that happen before except with Matrix brand springs), in the future I recommend Guarder springs.

#55 vanevery

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Posted 16 July 2013 - 02:11 PM

rawfuls:

- Do not attempt to fill the Piston Head O-ring channel with teflon tape or anything else.
The teflon tape will eventually become unseated and just fall out somewhere in the cycle of the Gearbox.
Thus will force you to have to open up the Gearbox again.

- The O-ring is intended to be loose.
It is not meant to be sturdy, just sturdy enough.

- A new #14 pack of O-rings is what you need.
They are in the Plumbing section at Hardware stores.
If your local hardware stores don't have them. you cam order them online. Just do a Google search or even advertise on another Forum that you would like to buy some Danco #14 O-rings and I am sure you will find all the O-rings you could ever need.

- Main Spring:
Get rid of that spring you have.
Pick up a brand new m110 or m120 spring from the KWA Pro-Shop or get a Guarder, Systema, MadBull, or Prommy Spring from another online Vendor.
Never buy a Matrix Spring.
Their Quality Control is horrible.

#56 EzDeezer

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Posted 16 July 2013 - 02:43 PM

He did not buy a matrix spring Vanevery, it is a Prometheus.  But Rawfuls you should follow Vanevery's advice, just replace the oring if you can with some #14s, and as I said before if you still get the problem, try a 2gx bucking or take it into your local airsoft shop.

As a side note, never buy matrix anything, I hear their motor is alright, but I still do not trust their quality control, their tightbore barrels are the equivalent of using a bendy straw as a barrel from what I have seen.

#57 gcw360

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Posted 16 July 2013 - 06:25 PM

View Postrawfuls, on 15 July 2013 - 08:17 PM, said:

Took it apart moments ago- tighter coils were in the back near the spring guide.
However, I did notice some rubbing on the side of the spring coils, hopefully you can see it.
Not sure if this is standard, but I definitely have the compress the spring like crazy to get it into the piston without it flinging up into my face.
Spring: (Regular color is green, rubbing off, looking a little copperish)
Posted Image

Now, I went ahead and grew a pair and took a deeper look.
Definitely looks like the compression is bad.
I assume the ORing is supposed to seal the piston and the Cylinder, which would trap the air between the cylinder and piston, forcing out the air nozzle- thus creating a powerful push of air- right?
This can't be done if the ORing is very loose!

As you can see in this picture, the ORing is totally moveable, and manipulate, definitely no seal-- if any, here.
Do I just need a new ORing that will puff up and create a seal?

ORING:
Posted Image
Posted Image


Bucking & Hop Up looks fine...
Posted Image
Posted Image
I have a few questions and some observations that might help.  Why is there a sorbo/rubber pad on the end of the piston head (second picture down)?  Does the cylinder head nozzle move or are there any cracks in the cylinder head itself?  A picture of the cylinder head would be helpful, I'm guessing it's damaged.

Also, that cylinder (based on what I am seeing in the picture) is not optimum for the lenght barrel you are using.  You need either a type 1 or type 0.5 cylinder for 363mm.  These would have a smaller port placed further back giving you more volume of air for each piston stroke.  By better matching the cylinder to the barrel length you will optimize FPS produced.

#58 rawfuls

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Posted 16 July 2013 - 08:01 PM

View Postgcw360, on 16 July 2013 - 06:25 PM, said:

I have a few questions and some observations that might help.  Why is there a sorbo/rubber pad on the end of the piston head (second picture down)?  Does the cylinder head nozzle move or are there any cracks in the cylinder head itself?  A picture of the cylinder head would be helpful, I'm guessing it's damaged.

Also, that cylinder (based on what I am seeing in the picture) is not optimum for the lenght barrel you are using.  You need either a type 1 or type 0.5 cylinder for 363mm.  These would have a smaller port placed further back giving you more volume of air for each piston stroke.  By better matching the cylinder to the barrel length you will optimize FPS produced.

To answer your sorbo question: I have no idea?
I thought this is how they came from stock?
I didn't think the owner before me had opened it up.

Can I remove the pad? If so, I definitely will.
The cylinder head nozzle does not move (the aluminum part, right? not the air nozzle), nor do I see any visible cracks.
HOWEVER.
Upon compression, if I cover the nozzle, and push a bit harder, it still goes through, and I can hear air leakage from some point.
Where? I honestly cannot tell.
I figured it was the oring letting some air by as the air compressed harder and harder it eventually gave and had a small crack through the oring- once pulled back it reset itself?

The gold barrel is the stock KWA CQB barrel.
If I can get away with a type 1 or type 0.5 (which is the best?) cylinder for the stock barrel- I'll do it.

-----

I bought new orings, heat expanded them, stock spring.
muzzle to coke can, BB will pierce.
Back up an inch, bb will no longer pierce.
I'm guessing it's now a little under 300- making some headway.. I guess

I'm about to chalk it up to sending it to the shop, though.
Plop it down on their table, tell them it was a DIY Spring change gone bad, and give them the prometheus 120 spring. (Unless the guarder is THAT much better). [The outdoor field about 1hr away is field limit of 400, the CQB field about 25 mins away, is 350... so I don't want to go TOO hard.) I'm aiming for the ~370 area.
What do you guys think?

P.S. I'm now debating whether or not my sight actually picked up ~360 at the first chrono w/ stock spring, or if it was something much less.

Thanks!

Edited by rawfuls, 16 July 2013 - 08:04 PM.


#59 EzDeezer

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Posted 16 July 2013 - 09:28 PM

Gcw, you make a good point about the cylinder, but even with his stock barrel (300mm) he is still getting FPS issues, so I do not think that is the case anymore.  However, it is odd that there is sorbo pad attached to the front of the piston head, that might have been added by a previous owner or it pulled off the back of the cylinder head and got stuck on the piston head creating issues.

#60 rawfuls

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Posted 16 July 2013 - 09:37 PM

I just pulled the sorbo pad off- and will be trying it shortly.
Here are the pictures of the cylinder and cylinder nozzle/head.

Posted Image
Posted Image
Posted Image
Posted Image




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