[Ben3721]

I need a photo of the pinion too.

Keep in mind not every pinion fits every bevel. But something else is off by a lot. The tips of the bevel teeth aren't as worth. Suggesting the motor height is way too high. A pinion with fatter teeth basically needs to sit edge to edge with the bevel. Thinner teeth pinions will set higher where you can't see the edge of the pinion teeth. After than you shim the pinion bevel tight but with a .3mm to .5mm gap.

If the shell bottom is ground improperly it can seat the grip off. The grip should be sanded so it doesn't rest all its pressure on the lower receiver and sits flush on the gearbox, unless the receiver is a better fit than the gearbox, which happens. The grip hole should not touch the motor tower first, the motor tower should contact the gearbox hole first. This will screw up the motor angle checker tool.

Another thing, a ton if gearbox shell manufacturers modified molds to make their 6mm or 7mm gearboxes into 8mm gearboxes. Because of this some brands poorly centered the hole and the bushing or bearing will sit off center, making the pinion wreck the bevel as it's not lined up. Even some high end cnced gearboxes such as the beloved retro arms shells have improper 8mm bearing holes due to inability to properly design a gearbox for some reason. So if your bushing/bearing is off it would cause insane wear like this, and the gearbox/motor grip would clamp down on the angle tester giving a false impression its passing the test.

The gearbox itself could also be sitting back tilting. Either due to fitment or other issues. If the grip is resting on the lower but the gearbox is tilted back from fitment issues or tightening the stock screw first it will cause alignment issues.

Best of luck.

Oh and this wear has nothing to do with the spring, rps or anything. I have plenty of high rps builds running every weekend that have very little wear on the bevel and pinion. You will likely see a rps improvement once you fix this issue and the aeg will become super quiet.

 

[Ben3721]

Well keep in mind, some motors don't fit the same at all and will push the motor way to high regardless of how much you lower it. Shimming the motor armature or sanding the endbell of the motor can help, but you need to know what your correcting if you do this. Some grip caps fit weirdly with some motor endbells too. The motor tower also needs to be shimmed snug into the gearbox hole. If its sloppy it will wear things out.

I shim completely differently than anyone else. So it's hard to recommend how to check shimming without literally writing a guide on how I do it. But you have something way off and it's screwing you over. I'll give it more thought and post back here if I can think of anything else.

 

[Ben3721]

The half shell shimming method is flawed. It let's the bevel tilt on its own and the shell will not sit the same in the grip.

 

[Ben3721]

M130 short stroked 3 can hit like 38 with a long 6.01 and 42 with a long 6.03 with a .28 bb. Lighter bbs or shorter barrel means even higher pme ceiling.

This isn't pme wear. Pme wear is mostly on the piston then sometimes a broken shaft or tooth. But not the part that touches the pinion.

 

[Ben3721]

Pme sounds horrible, pellets hit midair infront of you, the piston rack breaks the supports or itself in half and the sector pickup tooth gets rounded off.

 

[Ben3721]

Well when it comes to shimming no guide applies to any given aeg, part mix and what-not. Steps 1-10 guides for airsoft will always miss things you can clearly see with your own eyes that no one else here can. Aegs can vary batch to batch, maybe the assembly line lady for the gearbox shell sanded too much of the casting line off the bottom of the shell where the grip attaches, or the factory converted a 6mm shell mold to a 8mm shell mold with some poorly centered mold inserts to save on money. (rather than make new expensive molds) Or maybe the factory worker ripped the plastic grip out of the mold while it was still cooling to save time, warping it's fitment. Or the grip has a tail to it that with some receivers causes it not to sit flush so it ends up bending/pulling the grip back without you knowing. (Yeah ive seen all this crap) This kinda stuff screws so many new techs and players up, you cant have someone help you when things like this happen as they can predict it, even testing tools can fail to detect this stuff, but your eyes and ears sure can. Airsoft teching is like trying to mix MEGA blocks into a lego build.

So to shimming...
First you MUST find a pinion and bevel that are compatible, so you must find a pair. Same brand doesn't mean anything half the time.

To "pair" a pinion to a bevel you actually must test them by hand and roll them together. You literally take the pinion and hand roll it against the bevel, You'll find where it wants to seat in the bevel as it rolls and how smooth it feels, that might be higher up than another pinion, you then must check at that meshing point if the pinion is seated at 90ish degrees to ensure its truly meshing with all the metal of the tooth, if not find another pinion. I tend to avoid pinions that sit high, its easier to work with ones that are near the edge to edge of the gears. Keep in mind pinions and bevels mesh roughly, the tooth profiles will have high and low points as each tooth makes contact.

For my shimming I used a tiny precise drilled hole in the gearbox top shell where the bevel and pinion meet and in the right side of the grip im using to see EXACTLY where the pinion seats into the bevel. This tiny view hole lets me set the motor height perfectly to where i know it should be at. When I shim, i have the motor tower shimmed snug'ish into the gearbox hole. Like near zero slack using ptfe tape, I slide the motor in and look into the tiny gearbox hole to see when the pinion meshes with the bevel edge to edge then see if the motor free hangs at a 90 degree angle while the height is exact, I shim until its at that 90 degrees then take out .3mm of shims.

You need to make sure the motor armature isnt sloppy, and shim it if you need to as well, you also need to be sure the grip and grip endplate isnt doing something funky to the meshing angle as much as you can.

To me this is the easiest way to get a good shim job every time. It also allows you to set motor height easily on the fly as well.