AOE/sorbo possible issue

[paulwes83]

Hey folks,

I'm rebuilding a V3 gearbox and am going for proper AOE to make it as nice of a build as possible.

I added a fairly thick sorbo+neo pad to the cylinder head and now my piston is sitting fairly far back. So much so that the first tooth on the sector gear is engaging the 2nd tooth on the piston rack (2nd tooth after the gap) at the 12 o'clock position. I'm using the an SHS 14 tooth piston.

If I remove part/all of the 2nd tooth I will get proper engagement, but it will be beyond the 12 o'clock position for the sector gear. Is that ok, or should I try and smaller sorbo? I'm still getting full contact with the first tooth on the sector gear.

If it's ok, then will the piston and piston head being so much further back affect my air volume significantly? It's a full size cylinder with no windows.

This is for a full size AK with a 455mm inner barrel, so I'd like to keep as much air volume as possible as this is an outdoor field build.

Thanks for your time!

[Spike]

Removing part of the second tooth is usually necessary for proper AoE correction.

If you're worried about under voluming, bump up to a full cylinder.

Also, be sure to glue that piston rack in place very securely, the 14 tooth pistons don't have much holding them together.

[lurkingknight]

typically you need to remove the existing rubber pad on the cylinder head if you use the 3/16th sorbo pads. In the states clandestine and scatterplot sell varying thicknesses so you can glue them right onto the rubber pad, if you bought the sorbo from airsoftstore, they have only the 1 thickness, which will fit lonex cylinder heads with the rubber pad removed (and should fit most other metal cylinder heads and some plastic.)

This will put the engagement at 12'oclock on most setups. If you are beyond that is too far, you want the pickup tooth of the sector to meet the pickup of the piston as flat as possible with as much contact surface as possible.

You will also need to take about half of the first normal tooth on a 14t piston off in order for the sector to engage properly. on a 15t you take a whole tooth off and part of the next. 14ts have the first tooth missing already.

[paulwes83]

Awesome, thanks guys. I am already running a full cylinder and did remove the rubber pad from the Modify cylinder head before gluing on the Sorbo pad. I picked the pad up from Airlab, so hopefully it's good quality. I'll be sure to properly glue the piston rack on once I've removed part of the 2nd tooth.

Even though the pick up tooth isn't at the 12 o'clock position, it does seem to be making full contact with the pick up tooth on the piston at point of contact. I might try slicing off part of the neo pad cause it's about 3-4mm thick at this point, so halving that might give me all I need for perfect AoE.

Thanks for the help guys, much appreciated!

[Spike]

3-4mm neo pad? On top of the sorbo pad? Holy crap that's huge.

[paulwes83]

Originally Posted by Spike

3-4mm neo pad? On top of the sorbo pad? Holy crap that's huge.

I know, I saw it and thought it would be good, but foolishly glued it in place before seeing how it fit. I guess Airlab designed it to be used in REALLY high stress builds.

[Stealth]

Be sure to check the AOE with the spring installed.

Word of warning: verify that the piston glides freely. SHS 14 tooth Pistons have crooked rails which causes them to bind.

[paulwes83]

Thanks for all the tips guys. That sucks about the SHS piston, maybe I'll have to swap it for a Lonex/Modify.

Also, turns out my whole issue was that the pad wasn't sitting properly. I'm using a Modify cylinder head and it has a raised concave portion where the air passes through. It's a funnel rather than a straight hole and the opening is raised from the back surface of the cylinder head, so any sorbo pad has to have a MASSIVE hole in it to accomodate this feature. My sorbo was sitting on top of the funnel portion rather than around it which added a good mm or so.