Troubleshooting new build: Opinion requested!

[Flarebrass]

@Pestobanana:

I test each gear to get about a mm play using multiple shim guides online and then test them all together. They turn beautifully multiple times before stopping when they are together (finger flick).

The shim test was done with the bottom 4 screws in each time.

Motor height was adjusted multiple times then reverse gearbox shell adjusted to be the optimal height.

I will double check all my contact and connectors to be sure, but all seems well. Will confirm.

All I have is my phone on me at this time, so when I have a chance Ill try and make a video.

Thanks!

Flarebrass

[pestobanana]

1mm of play is way too much, that's as bad as stock G&P shimming, but that shouldn't cause it to be seizing up.

When you started getting gearbox lockups what parts did you change

[lurkingknight]

check the motor connectors.. they get loose over the course of repeated connect/disconnect cycles when you take things apart. You may need to pinch them tighter with pliers.

[Flarebrass]

@pestobanana: meant .1mm heh sorry for the mis-info. I just checked the connections as you mentioned and it did it again. When I close the box with everything in place, and attach the motor to the connectors without the pistol grip on, the motor spins as it should. However, once I connect the motor to the gearbox, it fired about 5 shots (give or take when the trigger was pulled on full auto) then stopped when i let go of the trigger. I pulled the trigger again and nothing. Not getting the lockup any more which is a bonus i guess heh. I pushed the two contacts at the trigger assembly together further, but it doesnt seem to have made a difference. It seems that it may be a trigger assembly/sled and/or cutoff lever issue. Any dealings with this?

@lurking: double checked those motor connects and all is well. pinched them a bit just to be sure and they connect with no issue (or sign of being loose for that matter). Can you read my bit above and let me know what you think.

Thanks for the help gents. I will be heading to bed and pick this mess up again tomorrow haha.

Cheers,

Flarebrass

[pestobanana]

Test the gun without the cylinder assembly.
See if the gears run smoothly, and then see how semi auto cycles without a piston. If the cutoff lever or trigger assembly is having issues, you will be able to clearly see it like this. You can also feel the trigger sled reset when you release the trigger in semi. If you don't feel that then maybe that is the issue.

Did you recently change the spring or anything? This can happen if the spring has too many coils. This happened to me once last year in my M14, it was because the back of the piston was too big and was hitting the receiver, but that shouldn't happen in a V2 box. Check your piston for signs of jamming anyway.

[Flarebrass]

@Pestobanana: I will give that a shot either later tonight or tomorrow without the piston/cylinder installed to see what happens with the sled. It HAS to be a connection issue somewhere which is why I guessed the trigger sled or cutoff lever. Something is not resetting properly and I just need to find out what it is. Never had this many issues with a gearbox before and its just frustrating to have problems after problems when doing this stuff (i took my other gearbox apart probably 3 times before it all worked right; this one I am probably over 100...).

The spring has been the same one that I put in originally (Lonex M130 w/ short stroke to achieve ~400 fps). It ran before on the current setup, but the tappet plate was too long so I ordered a new one and did some minor changes but now reverted them back other than modding and installing the new SHS tappet plate to match the lonex one (it moves correctly in the box).

I am just a little baffled as I said I had it running but then discovered (see first half of posts on this thread) that the tappet plate was the issue, then when I modded the new one and put it back together, its now having this problem with connectivity somewhere.

Thanks again and let me know if you think of anything else.

Flarebrass

[Flarebrass]

On a side note; think it would have something to do with the trigger sled post? Ill check that as well when I am back inside.

[pestobanana]

Originally Posted by Flarebrass

On a side note; think it would have something to do with the trigger sled post? Ill check that as well when I am back inside.

It shouldn't, if the post was broken the gun would never work properly.
So let me get this straight.

Gun worked with 14:1 gears
Gun would NEVER fully cycle and piston would ALWAYS get stuck in the back of the gearbox with 10:1 gears
Problem persists with 14:1 gears

Was it that it would NEVER fully cycle or would it cycle a few times before locking up? Does it ALWAYS lock up with the piston in the full rear position?

[lurkingknight]

Only jams I have ever had where the gun just became unresponsive like that is the trigger parts interacting in a weird way, the shuttle getting caught mid return cycle or not sitting back down onto the trigger so it floats between everything. That usually only happened after a few normal cycles and then it would jam and never reset so I'd have to take it all apart.

[Flarebrass]

@Pesto: Had it working 100% with the 14:09's but the nozzle wouldn't go far enough back due to the longer tappet plate. I ordered the new tappet plate and while I was at it said "hey, lets try the 10:44's too". Those were the only 2 parts that I replaced at the time. The first time the piston got stuck in the full rear position, the second attempt the gears wouldn't even pull the piston, you just heard the "hum" of the motor trying to turn. I then replaced the 14:09's back in and its now having the sled (or whatever the connectivity issue is) problem (note: the last re-assembly i did last night was the one where it fired once on full auto before i let the trigger go, then would not fire again on either setting; this enforces my statement above that the 14:09's DO work in it and still work). Hope this helps making it a bit clearer.

@Lurking: It could very well be that, but at which point is the question haha. We shall see I guess.

Flarebrass

[pestobanana]

Does the the trigger only stop working when you fire in semi auto? Does it keep working in full auto?

Show us a video of what is happening with just the mechbox and grip, no lower receiver.

[Flarebrass]

@Pestobanana: Negative. It stops working on both. I will try to take a video when I am working on it next.

Thanks,

Flarebrass

[pestobanana]

So when it jams now do you hear the motor moving at all?
Test the trigger with the motor outside of the gearbox.

[lurkingknight]

^ test this when it jams... I bet you it's not the gears causing the jam in this case.

[Flarebrass]

@Pestobanana: Just to clearify, when I put the 14:09's back in, the jamming ceases to exist and the issue is that when the trigger is pulled, it does not fire. It does seem though, that it is a lighter pull which would indicate that the sled might be out of the way some how or stuck somewhere?

I tested the motor outside of the grip last night, and it worked, spun like crazy. But as soon as I connected it into the grip as if installed (no receiver obviously), It pulled once on full auto then stopped and wouldn't fire again.

Flarebrass