Gear Problem / Decision
 

Hey everybody, I recently upgraded my TM M4 RIS with a PDI 150% spring, new bushings and shims, and a ball-bearinged spring guide. After I got it in, it wouldn't run, so I tried a more powerful battery. I used an Intellect 9.6V 4200 mah battery, and while it did finally run, after about half a magazine, it made an incredibly awful, loud whining sound. Upon opening up the mechbox, I found that my spur gear had lost an entire tooth, and the 2 surrounding teeth were ground down to very little left.

What I want to know is, would you recommend upgrading the entire gear set to like a torque up set? Or a different type of set perhaps. Or should I just replace the spur gear with a better made one. Thanks.

Sounds like it wasnt shimmed right since stock TM gears should pull back a PDI150% easily unless u got one of those defect ones and was way higher then 150%... U shouldnt mix gears, buying a complete torque set would be your best bet.

I'm no expert but I think it would make mechanical sense to at least upgrade them all at once to a better quality metal, perhaps getting a torque up set. Though I wouldn't go with the torque up set unless my motor was fast enough to still give me the ROF I desired (I personally, wouldn't want my M4 able to spew BBs even at the rate it does in stock form).

What can improper shimming do? And so you would recommend a torque-up as opposed to a standard ratio set?

http://www.mechbox.com/site/

If you're going to be running a stiffer spring, you'd want the torque-up gears, they'll compress the spring easier. Watch some videos on mechbox.com and they'll show why proper shimming is important.

You should answer that question, from what I understand, a 150% should be able to handle the stock gears.

That leaves the choice to you; do you want to trade some rate of fire for the peace of mind that you can be sure you aren't stressing the gears?
Or do you want to slightly lower the rate of fire from stock(due to the new spring) to keep it higher than you would with the torque up gears?

buy a systema torque up gear set, you want to keep all your gears the same type of metal because tough metals wear down pot metal

OK, thanks for all your help guys. Since I'm running a powerful battery, I'm probably going to go with a torque-up set. This battery turns it over pretty quickly, if I was using full-auto it would cause a lot of stress. I'd rather sacrifice the ROF for safety of mind that I won't have to open the gear box again for a while... It's a pain to work on. Thanks everyone.

Improper shimming causes gears to break, more stress on your motor, your mechbox to lock up and all that jazz. It takes a bit of time to shim a gearbox correctly.

I recommend just torque up systema as well, nice set of gears as long as you shim it right/get a gun doctor to shim it you wont have to worry about busted gears.

With one torque up level above standard torque using a battery as big as yours, you won't notice the loss in ROF.

Most PDI springs these days are defective ones. The ideal length of a PDI 150% is about 6 3/8" long, and the wire is a blackish brown colour. If the spring you bought is shiney jet black and longer, losing just your spur gear's teeth will be the least of your worries.

I am no master at airsoft mostly a noob but i think that airsoft surgeon springs are the best

If you are going to upgrade your gun send it to an expert, i made the same decision and almost wrecked my gun.

well some people don't have mechanical talent (no offence), but we gunsmiths have to start somewhere lol anyone should be able to just open up a gearbox and change a spring, especially with..... www.mechbox.com

*Should* is the key word - unfortunately, some people are all thumbs and have absolute zero mechanical dexterity, nor have a grasp of certain physics, mechanics, pneumatics and electricity - all of which are core skills for a good understanding of the inner workings of any of these electro-mechanical-pneumatic devices that we use.
The ones that do have that learned skill (or in some cases, an inate understanding) are the ones who move forward with confidence to service other user's guns.

No I'm capable of upgrading, I've done it before. I'll check my PDI spring to make sure its the proper one. And I will go with the SystemA torque-up gear set.

Now for another question: helical, or flat? If I go helical I suppose I'd have to change the piston to work properly. Any opinions?

Flat if you want less gear whine, flat if you want to save a couple of dollars. Helical gears are much more sensitive to proper shimming.

And what makes you think you have to change the piston to "work properly"? That's 100% false.

the helical parts of the gears are between the bevel and spur, and the spur and sector, the part meshing with the pinion gear on the motor and sector gear meshing with the piston is still the same. The only time you'd need to change your piston is for unlimited torque gear sets which require you use a half tooth piston. Hope that clears it up for you :)

Oh, that's odd. I thought I had read somewhere that there was some difference in the pistons while using a normal vs. helical set... Oh well, thanks though. I've ordered a flat type torque-up SystemA set off the WGC. Thanks for all your help guys, its very well appreciated.

Those posts are only half-truths. Only *certain* gear sets require the half-tooth pistons, and those gear sets just so happen to be helical. Those torque levels are only available in helical setups.
It's NOT to say that all helicals require the half-tooth piston, though.

It's kind of like... an apple is a fruit, but a fruit isn't necessarily an apple.

Okay, that makes a lot of sense and clears it up for me. Dear lord you are ridiculously smart..