Im having a crack at opening up gearboxes and trying to fix stuff myself and could use a bit of direction if someone is happy to steer me straight.
I have an SRC SR4 blaster which has been great but recently the FPS dropped right off, so much so that I was getting gels stuck in the barrel. Tried several different gels of varying sizes to check that wasn’t the issue, couldn’t see anything obvious with the barrel or t-piece, nothing broken there.
I’ve been following this video in the hopes that one of his solutions could have been my issue but it doesn’t appear so, at least to me.
While pulling it apart I figure its probably a good opportunity to clean it up and regrease? If anyone knows of a good gel blaster or air soft “servicing” video they’d recommend I’d certainly appreciate a link.
One thing I noticed is allot of metal shavings under where the bevel gear sits. Is this normal? The blaster has been sounding slightly, er, grindy lately. Not bad, but a noticable change from when it was new.
I’ve pulled the cylinder, pistols and air nozzle out and pushed them together to test the air seal, and well the air seal its almost non existent if Im doing that test correctly.
Couple of pics
The teeth on the gear look a little flattened out, or worn?
Relaxing main o-ring, and clean and grease does wonders sometimes! I’d start there.
That bevel does look a bit worn, the catch is SRC motor use an o type pinion, which isn’t bad apart from being pricks to replace but the tooth profile is noisy at best, to horrifically noisy… but they are annoyingly tough and will last seemingly forever
Unfortunately means the bevels don’t. Decent motor, just pinions let them down. Good grease on the bevels are a must
I had this issue before a couple of times…once it was because the tappet plate wasn’t going all the way forward (somehow ), leaving space between the nozzle and barrel. The second time, it was because the o-ring had somehow stuck to the front of the o-ring groove in the cylinder head due to an excess of grease.
From what i can see, the metal filling may comes from the bevel teeth, since it has been rusted but the teeth where it makes connection with the pinion gear from the motor aren’t.
The gears are all rusted, so i suggest you change them out.
Fps loss can come from a lot of parts not sealing correctly, so you might want to check your compression kit, starting from cylinder, piston, piston head, cylinder head and nozzle:
put the piston, piston head into the cylinder with cylinder head first, keep the nozzle out since we don’t need it check now, and try to push the piston in the cylinder while covering the cylinder. If the piston is hard to push, then your cylinder, cylinder head, piston, piston head have good air seal and proceed to repeat the process with the nozzle attach in. If it travel easily, then you have poor airseal and will need to check on and maybe change those parts, especially the orings since they play a huge part in keeping the air sealed.
I notice there iisn’t any black rubber on your nozzle. I’m not familiar with this model so i’ll leave that to the pros here, but most gel blaster i’ve had all have the rubber on their nozzle to push the gel into the t-piece and keep the air sealed in the t-piece, too.
I’ve tested the air seal with just the cylinder and piston, nozzle left out. I set it up as shown in the photo, a house fly landed on the piston and it started to go down, is that bad?
You need to test the seal at speed with the cylinder head attached.
The o-ring on the piston head should be a loose slide when orientated the way you have it sitting, but should compress almost immediately if you punch it fast into the cylinder.
The o-ring is designed so that it has very little air seal that will create a hard vacuum when it’s being cycled rearwards, and yet is able to expand and seal fast when accelerated forward.
That’s the job of the Air Holes in the piston head, to force air to the inside of the o-ring to make it expand and seal on compression, yet able to quickly shrink back into place when the direction is reversed, allowing the o-ring to move forward enough in the groove to allow air to flow back around the o-ring and the holes in the piston head to prevent it from vacuuming.
Always make sure that the groove in the piston head allows for some forward/rearward movement of the o-ring and that the holes in the piston head are large enough and shaped properly to direct the air to the inside face of the o-ring itself.
I haven’t had an SRC on my bench yet.
That SRC nozzle looks like an LDT or CYMA nozzle, probably interchangeable with one of those.
The tip looks the same at least.
), leaving space between the nozzle and barrel. The second time, it was because the o-ring had somehow stuck to the front of the o-ring groove in the cylinder head due to an excess of grease.
