Yah, the highest it reached was 115m/s!
I bought another Angel spring today as I realized the choppa is for short stroke so I bought a regular pitch spring and will install it this evening.
Thanks for everyone's help.
Can you give the Joule output instead of the m/s please ? I'm not sure I follow the result >_<
Ycare,
before I changed the spring I was getting from 1.3 Joule to 1 Joule readings.
After changing the spring I was getting .7 Joule to .77 Joule.
Yesterdays speed downgrade resulted in a broken selector plate (the one that selects safety, auto, full auto) a ground out piston
So much for my first attempt at shimming...gotta learn from my mistakes and figure it out.
Will any version 2 piston and selector plate do the job or should I order a G&P so it is all by the same maker?
(01-10-2009 11:04 PM)dstole Wrote: [ -> ]Ycare,
before I changed the spring I was getting from 1.3 Joule to 1 Joule readings.
After changing the spring I was getting .7 Joule to .77 Joule.
Dude that's crazy, I was getting the exact same thing with a 1J spring, while yours was a 0.9, right ? Almost the same. If you're ok with 0.7 thank stick with it, but to me it was too much of a drop, and you will seriously feel it on the field... cutting the old spring is in my opinion the best course of action.
(02-10-2009 07:57 AM)dstole Wrote: [ -> ]Yesterdays speed downgrade resulted in a broken selector plate (the one that selects safety, auto, full auto) a ground out piston
So much for my first attempt at shimming...gotta learn from my mistakes and figure it out.
Will any version 2 piston and selector plate do the job or should I order a G&P so it is all by the same maker?
I think the G&P is completely standard, but you might want another confirmation... echigoya will tell you worst case scenario, they know that shit.
(02-10-2009 07:57 AM)dstole Wrote: [ -> ]Yesterdays speed downgrade resulted in a broken selector plate (the one that selects safety, auto, full auto) a ground out piston
So much for my first attempt at shimming...gotta learn from my mistakes and figure it out.
Will any version 2 piston and selector plate do the job or should I order a G&P so it is all by the same maker?
If it's a standard V2 box, should be any V2 selector plate. The only exception to this rule is VFC's SCAR which has a proprietary selector plate.
BTW, I still have a personal recommendation of changing the cylinder to a matching ported one for that stubby killer. Changing springs and power is all good but if you really want some
consistency in your m/s or J, then matching cylinders to inner barrel length is almost a necessity.
Thanks for that Q,
I will see which cylinder is best for the 166 mm length. A ported cylinder will further reduce power won't it?
If I am getting just under 90m/s (or .8J) with the downgraded spring and then add a ported cylinder won't the fps potential go down further? I don't want it to go too low
In my testing shots have been fairly consistent though, constantly within 1 or 2 m/s. What is acceptable in terms of consistency? Every shot the same every time?
Really appreciate everyone's willingness to share tips and advice. Thank you.
If you're getting 1-2m/s variation, then that's fine...that's accurate enough from a power perspective. Then don't really need to change the cylinder. I'm surprised though that you're getting that level of accuracy for a mismatching cylinder/inner barrel combo.
Changing to a ported cylinder to matching barrel, you will get a change in power. However not always necessarily a power down. I know this sounds illogical at first, however if you consider that with a non-ported, the piston may not have achieved max acceleration but the BB has already left the barrel....it -is- possible (and has been observed before for other circumstances) that a ported cylinder may result in a power increase.
Back to you, if you're getting consistent power....and (better check that you do) get consistent groupings (i.e. no BB wobbles from excess "air"), then you don't have to change cylinder.
For a barrel that short I think you should get the Prometheus Type F or the MP5K cylinder of Systema.
For shimming, try this:
1. Remove all shims from all gears and try to group the shims according to thickness.
2. Take the sector gear and put a shim (any shim) at the underside (opposite the side that pulls the tappet plate).
3. Put the sector gear in its bushing, put the cylinder in its slot, place the piston inside the cylinder, and simulate the sector gear pulling the piston by turning the sector gear by hand.
4. Check if the teeth of the sector gear catch the teeth of the piston rack at the non-beveled parts. If too high use a thinner shim. If too low use a thicker one. Usually a good measure of this is the metal tooth of the piston as they are usually not beveled. The metal tooth and the sector gear teeth should be perfectly aligned when in contact. TIP: when you find the "perfect" shim, use a bit of grease to stick it to the gear.
5. For now remove the cylinder and piston (you won't need them at this point)
6. Close the gearbox without screws (hold it closed with your hand), pick it up, and turn it over - right side facing down.
7. Using a very small flat-head screwdriver, push the shaft through the bushing holes (alternately, you can reach in the gearbox using the screwdriver to move the gear) to get a feel of how much shims are still necessary.
8. Open the gearbox and add (or remove) the necessary shims on top of the gear .
9. Repeat steps 6-8 until the movement is minimal AND there is no visible gap when you close the gearbox.
10. When the state in step 9 is reached, tighten the screw(s) closest to the gear
11. Using a very small flat-head screwdriver, reach inside the gearbox and turn the gear. The gear should turn with little effort. If not, repeat 6-11.
12. Open the gearbox, take the sector gear out, take the spur gear (middle gear) and put a shim (thin is recommended) on the underside (behind the large gear, opposite the small one) and put it in its slot.
13. Put the sector gear in its slot and check the gap between the sector gear and the spur gear. The gap should be as small as possible without touching. Make sure both gears are firmly seated in their bushings when doing this. Add or remove shims when necessary.
14. Take the sector gear out of its slot and do steps 6-11.
15. Open the gearbox, and with the spur gear still in place, take the bevel gear and place a shim on the small gear (opposite the actual bevel gear), and put it in its slot.
16. Check the gap between the spur gear and the anti-reversal notches, adding and removing shims as necessary. Usually, the smaller gear in the bevel gear assembly is thicker than the (big) spur gear so put as many shims as possible until their undersides are almost aligned, the bevel gear assembly's small gear should be lower. As in step 13, make sure that both gears are firmly seated in their bushings.
17. Take the spur gear out of its slot and do steps 6-11.
18. After shimming all gears, put all gears in, screw the gearbox closed, and with a screwdriver reach in and test the meshing of the gears. There should be no screech-like sounds and the gear train should be fairly easy to turn.
19. Grease the gears, making sure that every tooth has a thin film of grease and assemble your gearbox as normal.
Sometimes you won't get the exact shim you need. The ones you got are either too thick or too thin. In this case, some sandpaper helps.
If I get to open up my MP5 I'll take some pictures for this.
Wow! Thanks for that Hazard. I will give that a go this evening.
Back again with an updated and request for some more help.
As suggested I bought the ported cylinder, a spring, a piston, and a new sector switch.
I installed them and gave them a few rounds, and I am having a new issue...
Every 2nd shot the piston will stop half way through the cylinder. The tappet plate doesn't seem to be catching on the gear and the gear is over rotating, causing the piston to travel part way through a 2nd shot, even though I have only pulled the trigger once.
Also, the sector plate is very tight and I am having trouble going from safety, to semi, to full. Some times I can't engage full at all, some times it stays stuck on full. I think the spring mechanism is having trouble pushing it.
I counted the teeth in the piston and it was the same as the initial piston that came with the Zomie Killer. I am not sure if I should buy a new tappet plate, or if at this point I should throw in the towel and just have a store rebuild it for me so I can start using it again. Any suggestions?
Please see photos for a better idea of what i am talking about.
Thanks.
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attachment=106]
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attachment=107]
Can't really tell from the photos but I'd say mis-installation/mis-alignment. Tappet plate is guided so shouldn't "slip" off the sector chip/in thingi. Same with your selector plate...seems like mis-alignment if it's so tight.
I think it's virtually impossible for the tappet plate to not move with the sector gear since there is no space for it to escape the cam on the sector gear. Maybe it's just came to look like that after you opened the mechbox. If the tappet plate does not move with the sector gear, your BBs will not be loaded into the chamber.
Regarding excess movement of the sector gear, that's normal. Especially for guns with bearings and strong springs as there is a considerable amount of momentum behind the gear when it released the piston. If you want your sector gear to be at a specific spot everytime, you will need to install a MOSFET.
Regarding the selector switch, you may need to do some modifications to something. Check if the selector is not rubbing into anything (specifically the mechbox).