Concerns after upgrading spring in G3

[Lee, T]

So I just finished upgrading the stock tm g3 mc51's internals to :

Metal bearing spring guide,
Modify s100 spring,
Metal bushings,
New shim job,
New piston and bearing piston head.

Now this is the first time I upgraded any aeg, so I followed mechbox.com to the tee. After I reassembled the gearbox and tested how it works, I have just a few concerns.

1. Obviously the noise level is much higher than stock, but I am hearing this much prolonged winding sound coming from the gears/motor and I have never experienced any grinding of the gears so I don't know if it sounds ok. What type of sound should I expect if I did it right or wrong?

2. I read some of the faqs in this forum about what to upgrade and what not to. For the modify spring I had supposedly it gives around 320-350 fps which was what I was looking for, and the various guides did not say I will be required to upgrade to better gears or whatever. So is it safe to say that even stock internals with the s100 (claimed to resemble the m100) with just the upgrades I had suffice?

3. Should I use 9.6v nimh's from now on or stick with my old 8.4v nimh's which I was using while the gun was stock?

4. Could it be possible that I should stick with the old TM stock piston with 1 metal tooth or the new one with 7 metal teeth?


My main concern is that after the upgrade, the gun its 3x as loud and the vibration from the gears/motor is so much more prominent that I am starting to think I messed up big time.

[ThunderCactus]

a high pitch grinding whine indicates the motor is grinding against the gears, whereas a high pitch whine without the grinding indicates the motor is too far from the gears
adjust the motor height until you cant hear any whining at all
Now if you keep adjusting it and you cant get rid of the whine, it means you put the bulk of your shims on the wrong side of you bevel gear and its just not sitting far enough away from the motor, or it's too close. I usually put a .5mm shim against the left side of the shell and put the rest on the other side

Now at 350fps, the gearbox shell will eventually fail. My G3 broke the front of the mechbox off, but nothing else broke and it only lost 10fps. I'd say it's a much better gun to have a mechbox break in than a TM M4 lol

If your 8.4v gives you the kind of rate of fire you want, then keep using it

and you should keep the old stock TM piston, they're TANKS. FYI pistons with 7 metal teeth are designed for REALLY high FPS (well above 400fps)
But if you want a new piston, I'd suggest the modify or systema piston

[Lee, T]

I'll try to adjust the motor and see if I can get rid of the noise. I have a feeling it might be a poor shim job as well.

Oh and in order to use the tm stock piston with a new spring i'd have to destroy the head, which I have some qualms, but will probably do it because it really is a solid piece.