VFC Scar-l - Gears and motor upgrades

[THE FNG]

Right; done some work since the last post.

Having recharged the battery completely and tried one or two other batteries, I have concluded that the issue was the battery connectors in the stock.

However, having had it firing again, I have encountered another(!) problem.

The issue now is that the tappet plate is bending upwards when the gun is fired. This is stopping the air nozzle from shooting back forward. I have tried it with a delayer chip installed and without. Both give the same results.

Does anyone know a remedy to this?

View attachment 14272

 

[dex]

Does the tappet plate move freely on its rails with the gearbox closed up?

Remove the piston and main spring and then screw the box up. Make sure you can push the air nozzle fully back without obstruction - try this with and without the tappet plate spring - without the spring in you should be able to push/pull the air nozzle in and out fully without it snagging or being obstructed - with the spring you should be able to push it back with a bit of force (smoothly) and it should snap back when you release it.

If the motion of the tappet plate is not smooth, check its seated in its rails properly and the the spring is installed the right way.

I cant see the front of the gearbox in your photo, so its hard to tell if there is some obstruction near the nozzle end.

 

[straffham]

assuming the spring you're using worked fine before it sounds as J.Cheeseright says like the piston is very slightly different somehow. I've known aftermarket pistons to vary and had the same problem you have.

Check the slide rails on side of the piston are exactly the same width as the original piston (as well as the groove between the rails being the same depth and width). Also did you check the piston moves freely and smoothely when you installed it? Simplest way to do this is to reassemble the GB with just the piston/piston head and cylinder in, no spring, screw it shut (don't just hold the 2 GB halves together) and then using a screwdriver insert it where the air nozzle would be and push the piston back and forth. It should move easily and smoothly. Any tightspots indicate something needs sanding down slightly (Spring torque in the equation can make a slight tight spot into a potential jam). Once happy make sure you use good lube on the whole length of the cast rails inside the GB, as well as on the spring guide.

Just another thought, are the battery, wiring and trigger contact switch in perfect condition? Any power loss here can lead to jamming like you describe too. Have you a more powerful battery you can try?

EDIT D'OH my messenger is slow, sounds like you've sorted the jamming now lol!

 

[THE FNG]

Does the tappet plate move freely on its rails with the gearbox closed up?

Remove the piston and main spring and then screw the box up. Make sure you can push the air nozzle fully back without obstruction - try this with and without the tappet plate spring - without the spring in you should be able to push/pull the air nozzle in and out fully without it snagging or being obstructed - with the spring you should be able to push it back with a bit of force (smoothly) and it should snap back when you release it.

If the motion of the tappet plate is not smooth, check its seated in its rails properly and the the spring is installed the right way.

I cant see the front of the gearbox in your photo, so its hard to tell if there is some obstruction near the nozzle end.

Thanks for the replies guys.

I've tried moving the tappet plate in the gearbox it moves fine with both the spring installed and absent.

I have put back together and cleaned it and tried it again. It is still having issues.

What I have noticed is that the air nozzle is staying back after pulling the trigger the first time. It is stuck back; there is no play and you cant push it backwards with a finger, nor can you pull it forward.

I have shone a torch in the geabox without disturbing it and can see that the tappet plate is in fact not beinding; it is in its rails and in line perfectly.

This leads me to believe that the tappet plate is being blocked so that it won't return?

When I fire it, the nozzle stays back. Then, when the trigger is pulled again, the nozzle shoots forward and then returns back.

 

[dex]

How does full auto go? It might be a cut off lever issue if its not cycling properly on semi.

 

[THE FNG]

You may have found the issue!!!

On full auto, the air nozzle does come back!

So cut off lever is my issue then?

 

[Sitting Duck]

Really silly daft question.......

Did you remove trigger switch spring at any time ?

if it was installed incorrectly it can rub or impede the tappet plate whizzing back n forth

(trigger spring needs to be facing downwards - put it on the other way it can rub on tappet plate)

I have made that mistake amongst numerous others - some of which made a bit of a mess inside

if cut-off lever engages and pops the switch - my guess is that as it pops up and flies back to disengage

the tiny spring which "might" be upside down and main body of spring is very close now to tappet....

the spring hits or puts pressure on tappet plate as it pops and thus it don't return properly or quick enough

which means crap/no seal etc......

Well that is my nooby guess - but I've done that (more than once before the penny dropped)

not gonna go on too much but when fitting any new/replacement parts it is very wise to check

and then double/triple check all is moving as it should be, close up box without spring etc... to ensure

stuff like cylinder & head fit correctly inside box as they should, head locates on the lugs, cylinder clicks in place

slide piston back n forth when fitting - quite common there may be a slight burr or blob of plastic from mould

that snags or a little tight when moving all the way back n forth - tiny careful sandpaper

I am a major trainee apprentice noob but from making numerous cock-ups and stuff I have started to gain a tiny

- well microscopic bit of wisdom and now I really take some time checking these new bits all fit together properly

before I fit spring back in there

very often you find some "better" parts still need a tiny little bit of tweaking to fit perfectly

3 types of TM compatible parts:

1st is perfect fit - made to measure

2nd is in need of a little tweak - ahh that's better

3rd - that f**king thing ain't never gonna work and must be for v3 gearbox coz it not going in this v2 box

finally on battery side - you may also consider the 9.9v Life in between 7.4 & 11.1v lipo's

(though size and capacity is more limited - but might be option if you don't wanna pump 11.1v or find 7.4v not enough)

 

[THE FNG]

Unfortunately, I have thrown the towel in

Whilst trying to further diagnose, the connectors to the stock have gone and another wire has split.

It has been dropped off for a techie to fix at JD Airsoft.

Feel like an idiot cus I couldn't fix my own gun

 

[Lozart]

There's no shame in it. At least you tried.