terrible grinding sound
 

hiya,

i just bought a mod1 14T pinion for my converted hyper 8, but theres a terrible grinding sound between the pinion and the center diff, and theres a lot of friction. They are both mod1, so shouldnt they mesh? i've set the mesh correctly and there is a fair bit of play in between the gears. I dont know what else to do?


any help greatly appreciated!

there should be very little play between the gears. thats where the sound is most likely coming from.. i mesh my gears by hand. But there should be a very tiny amount of actual play between the gears- just enough to make a small "tink" noise between the gears.

i tried different positions ranging from a lot of play to none at all, and it still grinds really badly no matter the position. is it possible the spur is like mod0.9, or mod 1.1 or something?

Are you sure it isn't the front motor bearing? :oh:

you should be able to rule that out by free revving the motor. --revving it whilst not touching the spur gear--

no- i have run this setup..

check motor bearings, check diff bearings

the motor runs freely. the drivetrain runs freely. the only thing grinding is the pinion and the spur. i might try and make a video of it

Bizzare. Only thing I can suggest really is to remove the pinion, and run it around the outside of the spur with your finger- if it jumps teeth and doesnt stay in constant mesh tehn its not the same pitch as the spur...

metal gears tend to sound like that.. i know my mod 1s do

no- my mod1 gear sare relatively quiet

it seems to fit just fine when i roll it round with my finger.
its really weird lol

i should hav just bought the damn vorza instead of attempting to convert a buggy

Where did you get the pinion? Some pinions are designed specifically for plastic spurs, but will catch and get chewed up when on a metal spur.

hiya i bought this one http://www.modelsport.co.uk/?CallFun...n&ItemID=34365

Hard to tell the shape of the tooth from the pic, but see the pic below. The one on the right is meant for plastic spurs only and roll very rough on steel spurs. The one on the left is meant for any spur, metal included. It's about the shape of the tooth. Not sure if this what you're talking about, but something to look at. Maybe a pic or a movie so we can hear how is sounds would help.

http://scriptasylum.com/forumpics/compare_gears.jpg

oh dang i never realised that! looks like i just wasted money on 2 pinion gears (this is the other one i bought that hasnt come yet http://cgi.ebay.co.uk/ws/eBayISAPI.d...=STRK:MEWNX:IT)

the gear on the left is a clutchbell, can you get pinion gears like that? is there something special that they are called or is the only way of telling by looking at the pic?


cheers

Hmm, the ebay listing says it's designed for 8th scale conversions, so it should work if they're telling the truth.

Yeah, the one on the left is a CB. The right is the kind Mike used to sell a while back before he started selling his hardened steel version shaped a little more like a CB.

Easy way to tell if your gear is ok is to roll it across a spur with the pinion not mounted. It should roll smooth without catching. If it catches, it's the wrong type. Still, a vid showing how it sounds would be helpful. I'd hate for you to go get different pinions just to find out it's something else.

I dont believe they have a special name as such, very much depends where you buy them usually- I know Mikes pinions are super smooth with both metal and plastic spurs. Another thing worth noting is that unless the pinions are hardened steel, they will wear down very rapidly against the hardend steel spurs that are standard on most nitros.

The difference between the 2 pinions shown is the pressure angle I think, BrianG?

Yeah, IIRC, it was the pressure angle. There was a discussion about this a while back where Mike commented at length. I'll try to find it...

Edit: Found it! http://rc-monster.com/forum/showthread.php?t=4383

its strange, when i move the pinion over the spur by hand its smooth as butter, but when i attach it to the motor its crazyness.

i'll try and make a vid tomorrow
or at least some pictures

maybe it's the motor's "notchiness" you are hearing. is it quieter when you are driving the truck at 5-10mph?

well the MMM combo is a decent combo but at slow speeds it does tend to cog. but the grinding noise has nothing to do with the electronics, that i'm sure of

^ +1

Or just set it on the ground and give it a hard shove away from you. If the "grinding" noise goes away but you still hear the gears, and then comes back when the car slows down, then that's it. It's normal for motors with slotted stators to make this noise.

A decent macro photo of the spur and pinion together ( side and front angles) is always handy.

nah i'm telling you for sure its nothing to do with the motor. i'll try and make a vid tomoz

it looks like the RCM pinion also has a flat bit at the top?

http://www.rc-monster.com/proddetail...1pinion&cat=40

ok i've taken some pictures and a video.
im not sure if the video works, it was taken with my phone which isnt that good.

http://i80.photobucket.com/albums/j1...0/DSC01846.jpg

http://i80.photobucket.com/albums/j1...0/DSC01847.jpg

http://www.youtube.com/watch?v=nmGkZ...layer_embedded

I had to download the video with youtube downloader to get it to play, but it did eventually work; dear God, what a racket!

The mesh looks pretty much fine, tiny bit looser than I run mine but perfectly acceptable, and its not skipping teeth or binding up at all either. Its just oddly loud and ratchety sounding. I thought it might be the set screw or something clanking against something else as it spins, but I'd think you'd notice that yourself.

Im stumped really, its just really really loud for some reason; only thing I can suggest is to try those other pinions when they arrive, see if they are any quiter, otherwise look into getting a plastic spur gear, that should quiten things down a bit.

Very odd... :neutral:

That is loud, but it sounds like mostly the microphone being sensitive due to lack of background noise. When the ESC arms, it gives us a little more perspective and doesn't sound quite so bad. Personally, it just sounds like a mesh that is a tad too loose and the notchiness of the motor is making the teeth slap together. You could try a different pinion to get a slight change in gear geometry, but I think you're gonna have some noise like that no matter what, maybe not quite as loud.

My 1512/2d (same kv) sounds much the same way and it has been running fine.

My E-Maxx with a 2200kv from a Revo sounds the same way... I've broken everything else on it, but havent stripped a spur or a pinion yet... Just an annoying price to pay... :mdr:

thanks for all the help guys i appreciate it.

yeah im still waiting for the other pinion to get here its taking ages, probably cos of the snow i guess.

the grinding noise is actually louder than it sounds in the video, its just bad quality recording.

i'd been running the MMM combo in my e-revo and its been fine, smooth as butter so i dont think its causing any problems.

at the moment is has a spider diff on it, and it kinda all screws together. would i have to buy an entirely new one to get a plastic spur or could i just screw one on?

also its not just noisy but theres friction as well, it takes more effort to get it rolling since its not smooth, and when in neutral it will stop quickly rather than coasting for a bit

cheers

Does it roll smoothly to a stop without the pinion meshed to the spur? I'd check that out.

You should be fine to just swap over the spur gear, jusr need to get one the same size & with the same mounting pattern- maybe brand specific, not certain on that.

ok cool i'll try and check out the spur gear. it uses like 6 screws to screw into the diff.

and when the pinion isnt attached its smooth as butter, will coast for ages

well, the 17T pinion FINALLY arrived, after weeks of waiting. As BrianG mentioned on the first page, i expected the pinion to be the same shape teeth as a clutch bell as it says in the description that it is meant for 1/8 brushless conversions. However, its EXACTLY the same as the 14T i already have! i put it in and the grinding noise is still as bad. For some reason, its seems a little quieter going in reverse than it does forward...

here are some pics:

http://i80.photobucket.com/albums/j1...0/DSC01955.jpg

http://i80.photobucket.com/albums/j1...0/DSC01956.jpg

Does anyone know where i can actually find some pinions that have the teeth shaped like a clutch-bells'?

thanks alot

i would try and find a spur that would fit these pinions...

Saddly yeah, plastic spurs are much cheaper than metal pinions to replace, and the noise levels will drop right down at the same time...

its not so much the noise level im concerned about, its the amount of friction. With my e-revo, the gears were mod0.8, and it would freewheel for quite some time. My hyper hardly freewheels at all, theres a lot of friction.

I had a look at the gears on the HPI Vorza, and the pinion's look like what i should be using http://www.hpiracing.com/products/en/100915/

they say 1M, is that the same as mod1?

cheers

Yeah 1M = M1. Don't know why it's shown that way, probably a typo.

Do your e-revo and hyper use the same motor? That may be why one freewheels more than the other. Try swapping them if they are different.

Just to be clear- the hyper will freewheel just fine with no pinion on the motor- and there is no resistance in the motor except for the magnetic cogging, right? Try setting a loose gear mesh and give it a shove across the floor. It should go about 10-15 feet with a firm push.

Could be down to lack of intertia possibly? Buggy is lighter so slows down more quickly than the truck that carrys more weight, thus inertia/ forward momentum...

I personally think all this grinding noise is simply the gears clacking together. That, paired with a notchy motor, can make a decent amount of noise. If the gears are meshed correctly, manually roll together without catching, and the mount is not bent, you probably just have a loud vehicle. Some of my vehicles are louder than others, that's just the way it is.

well the Vorza pinion came, and its the same one as the savage flux. The teeth look more like that of a clutch bell, and it is noticibly quieter and smoother than the other pinions. Looks like its problem solved!