Tappetless gearbox review and build

I’ll try and join all my posts together once I am finished :rofl:
So received my renegade tappetless gearbox today same day as @Cruise. Figured I would start the thread and he can join in.
The box itself has no brand markings but the packets with a gears,screws ect: are SD

First impression.
Lower half;
is quite light and obviously cast there is a few parts that need to be cleaned with a dremmel it. Not super important as it is just the peep hole for the bevel gear. The cover for on of the bearings wasn’t set in properly but managed to get it in place with my nails and push it down tight.

Top half/cylinder;

Looks like the same cast material and has me wondering if it will stay in place properly when fully assembled. It is ported on the top side ending about where a regular cylinder would start also if the nozzle is screwed completely closed the holes for securing are at the top and bottom.

Was worried about that but realised I shouldn’t need to use them as there is nothing in the receivers that would do that.(obviously just copied the design from the a**soft equivalent)

There is also a grove on the outside about 2/3 from the back but isn’t actually visible from the inside. At first I thought it would in screw there as you need a little bit of force to push the piston out of the front as I couldn’t get it out the back.

Looking inside the cylinder assembly it has the guides to hold the piston in place which I was a little worried it wouldn’t actually have.

The way the tappetless nozzle works is the Oring in the center of the piston pulls the nozzle back and about half way through the travel it is released. The piston head also has a spring so it stretches away from the actual piston aswell. Looks like a standard polymer piston with the first and last teeth half size

Also can with all the bit and bobs to have a functional gearbox. Shotty cast gears and a pink safety latch and selector plate (cute?) the spring is a 1.2 unequal. DIDN’T COME WITH SHIMS! The T piece looks really short compared to most of the v2 style ones i have but that could just be me

I’ve been trying to decide which blaster I want to put it in and I’ve decided that it will replace the nylon box, going to swap the Leviathan v2 and shs gears out, but for all you guys that want to see it complete with what it came with I will be doing that first. I am very intrigued like the rest of you what the air seal, FPS and feeding will be like. Starting the assembly now


Your the real MVP :ok_hand::heart_eyes:

One thing I have noticed looking the the lower part it doesnt seem to be very flush. I’m hoping once everything is screwed closed it closes them up abit.

I can squeeze the top part together with a little bit of force but can’t close the bottom.
I wonder if it is a defect on all of them or just a few.

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Ok so the trolley system need a minor modification so it would go in properly which was the little nib the help keep it straight need to be cut off.

(don’t know how to draw on the photo with my phone but it’s the little one one the top left corner.

One of the mag terminals wires also had to be taken off and soldered back on as it was set so the wire went into the gearbox and not out.

I’ve put the sector gear in amd closed the box up and the gaps have gone

Bear in mind I haven’t shimmed the spur gear at all yet but one slight problem I have found is that the gear seems to be rubbing on one or more parts of the gearbox. It is incredibly close to the wall. Might have to get the dremmel out and either file down the teeth or perhaps the walls around it a touch. I am going to shim the gear first and see if that helps and if it doesn’t I’ll try the shs gears and shape the gearbox to the gears I actually want to run

Pretty sure it’s the one with the X. I’m going to shim and if it is still doing it use a sharpie to see where it is rubbing off.


So I’ve finished shimming and the grinding on the box has stopped. I had to put 0.38mm of shims on the bottom of the spur gear anything less and it grinder. Sector and bevel both needed more then 1mm of shimming. I’ve have also found out that once the box has been screwed together the cylinder is actually quite tight fitting and it looks like once the Body pin and buffer tube screw are in it probably won’t move.
It’s late and the hardest part is don’t. I’ll finish it in the morning (always a good day off work when I’m tinkering :hugs:)


I’ve been wanting to try one of these as soon as I see it go up, just been waiting for pay day. If all goes well it should run pretty well in my stubby.

I’ve finished assembling the internals now and greased with molygreas (NOTE: There was no anti reverse spring) and have found 2 small easy fixes. First off is the cheap cast trigger is actually tiny bit to short and doesn’t brace onto the trolley properly. It still works but not sure for how long as you can hear a loud click when it slips down. I’m not worried as I was going to use an adjustable speed trigger. The other small issue is one of the mag terminal wires is a tiny bit to short the other way too long. As I am going to be using a leviathan I’ll be a little bit dodgy and cut a little off the long one and put it one the shorter one also need to change the direction of the wires so they go into the plate properly.

While I am changing the mag wires I’ll change over the shite JST connector for a XT30 mainly because I don’t own any jst batteries anymore.


Inching ever so close to the fabled FPS testing.
The gear box was a tight for for the kublai k3 nylon reciever but once the back of the cylinder was in it lined up perfectly. There has been a couple things I’ve found one was that the body pin the hold the cylinder in was quite tight after it passed through the cylinder loop. Only happened once in the receiver. Experienced the same problem when I put a ldx in to my metal kublai/wat receiver so used a rubber mallet.

The other is that only GEN 8 mags will fit amd actually lines up perfectly with the T piece. I’ve tried my kublai/cyma/ldt mags and none work because of the latch placement don’t have and jm gen 9 maps to test but from memory the lock grove is still in roughly the same place as my others

But I am running into a slight problem with the actual Tpiece. It is actually quite thick and a snug fit into the cylinder head which I was thinking is to help keep it stable . The problem is it will not fit into the outer barrel adapter. I could use a warinterest Tpiece because the nozzle fits in nicely, The but then it’s not a tight fit into the cylinder head. I was thinking about sanding down the outer diameter to make it fit (which is about 6mm) But want people’s thoughts on what I should do before I do something irreversible. I’m going to test both by just holding the barrel in by hand first to give me a better idea of if I need the original Tpiece

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Ok so I’ve tested the FPS reading with the standard nozzle and a warinterest.
Bear in mind there is no buffer tube and I was holding the t piece on to the cylinder head by hand and all I have done to the cylinder is put a tiny bit of the blue silicon oil in that came with it. Running a

motor + battery;
DOG 26tpa motor and 11.1v 3s turnigy
Aka v2 (orange packet.not a fan but that’s all I had ready)



Are you guys as surprised as me that the warinterest actually performed better?
I am going to wait to see what people suggest to do with the t piece before I continue.

maybe need to modify the outer barrel adapter have you a picture of it ?

It is a single piece battle arms outer barrel so would prefer not to duck around with it :slight_smile: someone suggested getting an adapter and new outer barrel set but I’ve just tested completely assembled and I’m pretty happy with it.

oh ok good review thanks for taking the time to do this appreciate it

if its going ok leave it the other option may be to take a bit of the t-piece if you don’t want to hack into the outer barrel

without the buffer tube on does it open up when you drop the rear pin out ?

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So I’ve completely assembled with the ldt Tpiece and the emptied 2 mags with out it missing a beat at 13rps, would be really interested to see if the piston nozzle Combo can keep up with higher speeds. considering the oring and spring are just stock the FPS reading where really surprising to me. Whole thing on full auto consistently hitting 240-250 with the occasional drop or breakage and no difference on semi.

Going to strip it back down and replace the Orings and a bigger spring (maybe 1.5🤗) really want to try and push it now

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It’s the same as the ldx boxes you can take it off but it’s a tight fit and if the sector gear is showing teeth at all you need to either push the piston down a little bit or a lot/ cycle gears.

From what I here these tappetless systems , high rate of fire are where they excel apparently the new one from azreals they predict it will feed upwards of 90 rps

I can see how that would be the case. The only thing I would worry about is that the oring inside the piston could possibly stop gripping at some point Are azrael armoury selling the piston head aswell and does it also screw into the cylinder? I looked at their website the other day and couldn’t find it. because in all honesty after putting 2 mags through it I would consider making all my blasters tappetless.
I am more impressed with how this gearbox has worked then I was with the ldx advance


yes just goes into a stock cylinder

this is the right vid


Make me wonder how different it would be as that nozzle is pushed forward by air and therefore the piston will have already started to travel. Wouldn’t that mean you loose a little bit of FPS as the air seal wouldn’t be perfect until enough pressure had been created to push it forward. Unless it is super sensitive,

Interesting stuff.
It would have to work against a spring strong enough to push the nozzle back at the rps.

Really ? Like the tapetless system that much ?