anyone have any experience upgrading their JG Works Sig 551?
any recommendations on the max spring size compatible without destroying the internals?
any other simple performance upgrades available that I could look at doing?
1 Like
I have had some experience with them. A few warranty jobs and a handful of upgrades, and a couple of unfortunate gearbox replacements.
I wouldn’t go anything over an m100 without touching more inside. They are cast gears so always bit of a lottery, some will handle an m130! Some will strip stock… most handle m100-m110 but it’s a cast gear lottery you just can’t know until you try.
but the gears aren’t why… The gearbox can be the problem. They are not radiused, and can break.
Now here is the fun, they are quite a dick to pull apart and put back together. So unless you are willing to go through with it I would keep to an m100 maximum.
They can be pretty nasty performers, with not alot of parts if you are willing to change a couple of parts and put in the work.
Piston head, o-ring, nozzle, and motor are good to go… provided you got a motor with a blue end bell as they have neo magnets. Most had these. Some had a weak ferrous magnet with a black end bell. Not many though… if any 
The cylinder head is good, I always put a 2mm “aoe pad” on them, more to help prevent gearbox failure but the aoe correction is a nice byproduct. Also a quick gearbox radius job on all corners of the cylinder opening is highly advised.
Piston is okay, but a nice SHS piston is worth doing if you are in there. Then a set of 16:1 gears will get a slight boost in rps and semi response, if you are like me, send it on 13:1 gears and should have about 25rps on the stock neo motor with a very tasty semi auto, paired with an m100 and the long barrel it is good for 350+fps! (Depending on brand of m100 some are 370fps!). M110 will see about 380fps on most brands.
In short, aoe pad, radius, m100, 13:1 gears, and a piston is all they need to rock hard.
…But not as annoying as the mag terminal block. Video and photo the hell out of that when you pull it apart, and to add to this the whole build is easier if you un solder the trigger block and remove the trigger switch and wires.
In fact, photo everything. The ambi selector and wiring can also give you grief when putting it back together.
The can go really hard, and a long titan 11v stick is a good fit for them and lasts ages. Even seen a few people just dangle the charging wires out the handguard so they never have to pull the battery out. Though I don’t advise leaving batteries in blasters.
Cool blaster, and plenty of potential with few parts and a little work. Be gentle though as external spares almost don’t exist and need to be imported.
Gearboxes are still available, so that’s a plus.
2 Likes
awesome write up. just the information I’m looking for. thank you
I’ll start small with the m100 and see where the road leads from there, will definitely be taking a lot of pics n videos so I can put it back together again if I decide to go further, definitely want to be able to keep using it lol
I definitely like it, it’s a pretty nice rig
They are a decent blaster, pretty reliable and decent performance stock. Like all JG blasters, the internals are pretty good, don’t need alot to really pump gels out, and the externals are good but not great.
I shoehorned a JG sig box into my old abs plastic wells G36. Also has all the mods listed in my guide but is short 4 teeth. Nice sturdy gearbox with good semi and rate of fire and an old blaster revived!
1 Like
Might be a Well ABS blaster but from memory those G36s had a pretty thick shell on them. 
I had one years ago, painted it up, gave it away to a mate… I should have kept it. 
No G36 on my wall now, and I’m not up for dropping a monkey on an LDT from WAT or X-Force. 
1 Like
For an abs blaster they are pretty thick and sturdy. I originally got it just to have a G36C because same reason… LDT one was expensive, and with the proprietary mosfet and such I was not keen.
I did see a Jin Ming G36, J15 I believe but never seen them sold. I think opforcedelta had them but didn’t have mags so again thwarted my desire of ownership. Also I think it was the longer G36 not a “C”
That was a fair step back in time, and would definitely be very rare and collectable model Gelbasters today… right down my alley 
2 Likes
I had the very first G36 with the clear shell. Which is why it got painted up.
There’s a Well M401 with clear receiver for sale up on the Sunny Coast for $40… if only it was a G36, I’d be all over it like stink on fish. 
Plenty of those clear G36’rs down this way they sold like mad. Probly in landfill now Nothing better to do with wingfield…turn it into a dump
does anyone know what spring comes standard in the JG works SIG 551?
RJ at xforce thinks it’s got an m100 or the equivalent in it already and therefore wouldn’t be any point installing one
any further insight would be appreciated
cheers
RJ knows his stuff. If he’s right, the advice is it’s pretty much maxxed out already.
What sort of FPS are you getting out of it with the stock spring now?
Reading what RokSolid said about being a difficult disassembly, are you sure you want to go to the trouble? The gain might not be worth the pain. 
wouldn’t be my pain except pain to my wallet at this stage I’d rather pay to upgrade it properly rather than F it up myself.
turned out the part the hammer hits in the Kublai p4 I tried to upgrade was installed upside down by me 
whoops. he fixed it up for me no charge as it took him a whole 60 seconds to correct pretty much
there was a customer in there today who said he’s got a sig 552 I think he said that he put an m130 or m135 in it, piston cylinder head, brushless motor and something else and was getting 330fps out of it which confused RJ as he expected more from the upgraded spring to which old mate said it’s got an air leak in the t piece, but my point was its apparently quite capable of more than then standard ootb performance
I’m going to run it through the chrono tomorrow and see what it’s currently putting out, I’ll try with a couple different gels n see what mine is currently putting out
1 Like
Found the same sort of results years ago where fitting some pretty stupid sized springs in the old Little Pig Gen8 didn’t exactly give a linear output as would be expected.
My thoughts that the springs at those sizes simply had too much weight and the windings, although much stronger, obviously couldn’t release all that energy as fast as a thinner and lighter spring 
I’ve got a Sig 552… not a JG though, it’s a LeHui.
An M100 spring in that gives me an FPS consistently in the high 290s to low 300s
I’m happy with that… It’d be easy to upgrade to an M110 which should give me around 330, but I’d prefer to accurately hit sub-300 than spray all over the field at 330 anyway.
2 Likes
yeah the JG sig’s are advertised as 280-290fps ootb. RJ didn’t hold the lehui sig in high regard when I asked about it a couple of months ago
as it is, my JG sig 551 straight ootb, accuracy is pretty shithouse anyway, most of the gels kept curving to the right upon leaving the barrel, I’ve only been using AusGel armour tech yellows as recommended. might try the super pinks n see how they go when I get around to brewing them
2 Likes
Curving to the right sounds like high FPS pushing your gels around. Or maybe a hop up that needs rotating.
I dunno, we used to aim for 270-280FPS because that gave us the best accuracy… I still maintain it does.
That was evident the other day when we put BME’s Thompson on the chrono. With upgrades it was up around 330-340FPS… it was hitting hard for sure, but so randomly inaccurate, almost impossible to hit a tree half a metre wide from about 15 metres away. Gels curving away in different directions, a spread of nearly a full metre at that distance. Push it out another 5 or 10 metres and the grouping would have doubled. Granted no hop up, but still…
I can hit the same tree from the same distance every trigger pull with any of my 280 FPS blasters
I’ve never understood why peeps want to trade accuracy for hitting power. If you can only hit your target with 1 in every five gels with a 1 metre grouping, I just don’t get the point.
But that’s just my opinion.
3 Likes
probably cuz that one out of 5 high fps gel, hits hard and stings just that little bit more lol… I dunno. they’re probably hoping for several close to, or flat out point blank range hits
there is no stock standard hop up for the JG sig 551, from what I read you need to change to a longer barrel to install a hop up
The JG spring is like an m100, but shorter so closer to an m90. JG has good seals and longer barrel, most I tested stock were 300-320fps. Old mate with an M135 probably has an ASG M135 spring, which I always found was really an M110 in power. ASG springs M-ratings are wank, they NEVER do what they say they are, and I have no idea how they rated them.
I wouldn’t change a JG piston head or cylinder head an nozzle as I always found them to be good sealing and capable of higher FPS and RPS no problem. Honestly, if I could buy JG piston heads and o-rings I would use tons of them! They are, good. Better than most aftermarket piston heads actually.
An actual M130 like an SHS would not end well for a JG v3 gearbox. Would also be well over 400fps. Way too hot. Biggest spring I would use would be an M110, and in a longer barrel blaster like you 551 will be likely be around 380fps, too much IMO, hence why I recommend the M100. Also M110 on stock piston and cast gears is a mega gamble.
There is no need for such a big spring in a full stroke setup in gel. Gel is so light it looses all that extra speed pretty quick. Even if it is pumping out over 400fps, it only gets maybe 5 meters further than 300fps, and it does it inaccurately, and the feeling at 20meters is pretty much the same. Loads of diminishing returns.
M120 is the biggest spring I have ever needed, and it is only for stupid high ROF with 4 (or 5) teeth missing. Even then on a short barrel and 4 teeth off gets close to 350fps. Again a bit hot for what I prefer, 5 teeth off is closer to 330fps but you start needing a 22cm +/- inner barrel.
I have a couple of M130 and M140 springs, but I have only used them for stress testing and giggles in my own blaster. Vector CNC gearbox with M140 and 4 teeth short got some pretty nasty fps, again, was only testing my build for giggles. Now running an M110 cough ASG M135 (at the time was the only M110 spring I had, will be an SHS M110 when my next parts order comes). It does a nice respectable 320fps with its short barrel and M110(ish) spring which is perfect
Also there really is only so much fps you can gain from a big spring. I think gel deforms and fills the barrel creating friction and loosing acceleration. Pub talk theory, I have no need for such high fps so really not tested it much.
Enough ranting on springs…
The 552 has a normal 14mm ccw thread… the 551 and 550 have a 14mm cw thread. Which always found stupid. If you want a hopup for your 551, the old DK LH AUG hopups thread on and work alright as they were also clockwise threads. Not the best hopup but an easy option.
For now if your gels are curving right, the inner barrel is not really glued or stuck in the tpiece rubber, put a pen mark on it for reference and rotate the barrel so it spin upwards, might be like a inbuilt hopup effect!
Bingo! I call it the “You can’t fight physics” theory.
You can throw all the FPS you want at a gel but it won’t fly any further than it’s mass and momentum will carry it. It just becomes erratic in flight.
You have a higher frquency of your targets saying “ouch” more often if you focus on accuracy rather than hitting power.
The sweet spot for me is powerful enough to be efficient with hard gels but accurate enough to guarantee a lot of hits. For me that is usually around 280 with a standard length barrel. Goes out the window with the shorties… the MP5K being a great example of that.
1 Like
