MP5K gearbox & upgrades?

[Hugo03]

Re: MP5K gearbox & upgrades?

ok, thanks but with the systema would i be best using helical standard gears or flat standard gears?

[sj_asc]

Re: MP5K gearbox & upgrades?

The stock MP5K comes with an EG700 motor, that should with the 8.4v stick battery should be getting you around 15rps standard. Swapping the 700 out for a 1000 wont make much of a difference at all. With either of the above motors + an M100 spring, you would be looking at an absolute max of 20rps with a 9.6v stick.

The Turbo has it's flaws, but they are easily fixed, in this type of setup it will easily out perform the other motors in discussion. The biggest drawback is that it will draw a lot more current which would require you to think ahead with the limitations of electrical assembly and battery - which can be very costly if you count the cost of the motor its self, as such i wouldn't recommend it.
As for the ICS motor matching the Systema's performance, that would be more the Magnum (for torque) than the Turbo. I am going to recommend the G&P M120 Motor for this one - remember that you need long type.

What id do for parts,
Piston - Keep the stock one by all means
Piston head - Stock
Bushings - Systema 6mm oil less, don't get ones with oil wells
Motor - G&P M120 (long shaft)
Cylinder - Stock 1/2 ported
Cylinder Head - Stock
Air nozzle - Stock
Spring Guide - Anything metal with ball bearings - Systema, Guarder etc.. (remember it's v3)
Spring - Systema M100
Gear set - Systema Original type flat cut gear set. If you want ICS, keep the TM bevel gear
Gearbox shell - Stock, its rock solid, absolutely no need to replace it
Battery - Intellect 1600mah 9.6v Stick Type

Other things that i would throw in there, would be Deans connectors, Low resistance wiring e.g. 16awg and a MOSFET

Modifications i would highly recommend, Ports for the piston head, Weight reduction for the piston, Teeth 2 and 3 removed (from the pickup side) from the piston, Spacer between piston head and Piston body to correct angle of initial engagement. There a fe

[Hugo03]

Re: MP5K gearbox & upgrades?

nice, but sounds expensive ...

[sj_asc]

Re: MP5K gearbox & upgrades?

No,
It really doesn't have to be at all. I should have set the post out differently. The majority of the parts can remain standard, if you really wanted to go cheap, you could just get a steel sector gear, the steel bushings, Spring and 9.6v battery, that would still be faster than the stock setup and give you decent FPS.
The Modifications suggested cost nothing more than a drill and a bit of elbow grease, and they seriously will prolong the life of the piston more than any other part could.

Getting to and sustaining 25rps isn't that difficult and it really doesn't have to cost a fortune, in fact a lot of "supposed" upgrade parts out there are inferior to some standard parts in this type of setup.

[Hugo03]

Re: MP5K gearbox & upgrades?

I wouldnt know what i was doing if i tried to install these upgrades myself, could you tell me of any instructional/how-to videos that show how to do all this?

[sj_asc]

Re: MP5K gearbox & upgrades?

I wouldnt know what i was doing if i tried to install these upgrades myself, could you tell me of any instructional/how-to videos that show how to do all this?

Sure,
There are a few disassembly videos out there, but those are probably more helpful for specific gearbox versions, the ones that cover normal MP5s will not be accurate to the take down of the K as it uses a different gearbox. Ive dug up some pics from a few years ago back when i had one, so i will get right to the point and try to make it easier to understand.

MP5K take down to the gearbox.
Unfortunately i don't have as many pictures as i would have like to, but i will do my best to explain it, in no particular order.
Remove all receiver pins (the two that hold the end cap and the one near the mag well. Take the two screws out of the bottom of the grip, the cap should spring out with the removal of the final screw, and a small metal disk will fall out (keep this safe), you will be able to see the motor from this point.
Disconnect the wires from the motor and pull it out - put it to one side.
Inside the grip there will be two screws, take these out and put them to one side.
Next step, IIRC there is a small screw under one of the fire selector switches, take this out and pull the selector lever off, and the opposite one out and put these to one side.
The upper and lower receiver should be free now, the lower receiver will slide down an off if i recall correctly, then the gearbox will slide out the back of the upper receiver, the two wires clipped to the upper receiver will need unplugging.
Be aware that the selector cam may fall out of the lower receiver (the small piece of plastic that guides the other fire selector and interacts with the selector plate), if it does put it to one side.

(the pic is about 4 years old now, so apologies for the mess)




To the Gearbox,
Put the Motor to one side, start by removing the motor guide, take the two screws circled in red out and slide the piece off.
http://i4.photobucket.com/albums/y14...0Tech/v3k1.jpg

Next, take the stopper rail off, it will probably want quite a lot force for the first time.
http://i4.photobucket.com/albums/y14...0Tech/v3k2.jpg
http://i4.photobucket.com/albums/y14...0Tech/v3k3.jpg

Now take out the screws and plastic wire clips
http://i4.photobucket.com/albums/y14...0Tech/v3k4.jpg

Opening the GB, there are many ways of doing this, but i find the tidiest way is to place force with one thumb down on the cylinder holding the cylinder and piston assembly into the other half, with the other hand place a small screw driver into the back of the spring guide holding that down and pop the upper half of the shell off, then gently lift up the spring guide and release the spring tension.
http://i4.photobucket.com/albums/y14...0Tech/v3k5.jpg
http://i4.photobucket.com/albums/y14...ch/v3kopen.jpg

Starting with the Piston assembly, the stock main spring is hooked inside the piston head base screw, it catches some people out who try yanking it out.
http://i4.photobucket.com/albums/y14...0Tech/phr1.jpg
In order to get it out, you will need to remove the piston head, this done by Gripping the Piston body tightly and unscrewing the piston head, it will require some force.
http://i4.photobucket.com/albums/y14...Tech/tmphr.jpg

With the piston head removed, the spring will pull right out, most if not all aftermarket springs don't have this hook, so you upon reassembly you just need to put the piston assembly together without the main spring.
http://i4.photobucket.com/albums/y14...0Tech/phr2.jpg

Sometimes the piston head will turn to no avail, in this case you will need to open up the small hole in the center of the piston head to avail the screw which you will need to take out.
Heres a pic of the screw, the piston head has also been ported.
http://i4.photobucket.com/albums/y14...ech/porttm.jpg

Bushing installation is straight forwards, just remove the old ones and pop in the new ones. Shims will come later.

Shimming
http://pageproducer.arczip.com/daedalus03/workshop.html

Piston Head Porting, Angle of Engagement (AoE) and Weight reduction or "Swiss cheesing"
I will run through these briefly cause i'm tired, if you want any clarification please do say.

Porting the piston head
Porting allows air to pass through the backside of the piston head on the back stroke which prevents resistance caused by vacuum, during the compression stages the air comes through the ports to force the o-ring tight against the cylinder walls and the lower half of the piston head for better air seal (potential FPS), the majority of aftermarket piston heads are ported, but the modification is straight forwards, costs nothing and is just as effective.
http://i4.photobucket.com/albums/y14.../systmport.jpg
A small template,
http://i4.photobucket.com/albums/y14...Tech/tmphp.jpg


Angle of Engagement correction,
Standard AoE
http://i4.photobucket.com/albums/y14...0Tech/aoe1.jpg

Corrected AoE
http://i4.photobucket.com/albums/y14...0Tech/aoe4.jpg
A cheap and effective modification that involves adjusting the piston so that the first sector catch tooth meets the first piston catch tooth with as much surface area contact as possible so that the initial impact and load from the sector tooth is evenly distributed to reduce wear that would be greatly accelerated when the system speed/load is increased. It is more of a necessity for setups 30rps and above, but it will help regardless.

You will need to space the piston back until it is corrected, washers between the p.head and piston (like pictured below) will sort it, though if you are fussy about weight the Cylinder head buffer pad can be replaced with something thicker.
http://i4.photobucket.com/albums/y14...0Tech/aoe3.jpg

Teeth 2 and 3 will also need to be shaved down so that they clear the pickup tooth, complete removal is fine.
http://i4.photobucket.com/albums/y14...0Tech/aoe5.jpg
http://i4.photobucket.com/albums/y14...0Tech/aoe2.jpg

Downsides are reduction in usable cylinder volume due to the spcaers, but it wont apply to a 1/2 ported cylinder (MP5K) if the spacers go on the piston assembly.

Weight reduction,
Reducing the Piston assembly weight, the TM Piston typically weighs 13g, the more you can cut this down, the better, you will get a faster return time (less chance of out of time engagement), and less load on the drawback. Weight reduction works particularly well with ported cylinders. Basically remove as much material as you can without sacrificing the structural integrity of the body. The example below (piston and p.head) weighs just 14g, and it could probably go lighter.
http://i4.photobucket.com/albums/y14...h/beanpole.jpg

New Spring installation (often over looked)
A large number of aftermarket springs are non linear (variable pitch), Systema and Guarder springs are just a few examples. If you do get one, remember that the end with the tighter coils goes towards the spring guide.
http://i4.photobucket.com/albums/y14...ch/nlinspg.jpg
http://i4.photobucket.com/albums/y14...h/spsetout.jpg

Oh yeah whilst i was digging out the old folders i came across a few tests i did some years ago which i thought were relevant.
EG700/8.4v 1100mah
http://s4.photobucket.com/albums/y14...&current=8.flv
EG1000/8.4v 1100mah
http://s4.photobucket.com/albums/y14...urrent=8-1.flv
EG700/9.6v 1400mah
http://s4.photobucket.com/albums/y14...urrent=9-1.flv
EG1000/9.6v 1400mah
http://s4.photobucket.com/albums/y14...&current=9.flv

Hope this helps

[Hugo03]

Re: MP5K gearbox & upgrades?

ok, thanks very much!! :D