Very Loud Drive Train

[Greatscott]

Given what this RC is, I wasn't too sure where I should post this, so it landed here.

Here is a video of my latest creation, Project: RC4WTH.

I like the way this thing turned out, it has a RC4WD Mojave body, hinge mounted to a Axial Dingo chassis, powered by a Losi Night Crawler drive train. My problem, the drive train is VERY loud, is this normal, or is there something not right here?

I have played around with the pinion mesh, and swapped out motors with no real change.

https://youtu.be/EBBmECyqtrw

[grayspm]

Grease is your friend, young grasshopper ;) fill the gearbox and diffs, and smear some in your u joints. Things should quiet down some.


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[Loehdingc]

Something is slipping for sure. If it's off, can you spin the tires without the motor spinning? Maybe your pinion is slipping? I know the little grub screws, the 1.5mm for me, will only tighten so much before it strips sometimes.

[JatoTheRipper]

Did you use lube? If so, what kind?

That just might be the noise that you're going to get from that worm gear drivetrain.

[Greatscott]

The worms are packed with hi-temp bearing grease. There is no place to put grease in the transmission, which is where the bulk of the noise seems to be coming from, the gears are open, the only thing inside of the transmission is just the through-shaft.

There is nothing slipping in the drive train, the whole thing is solid. All of the power is making it to the wheels, and climbs well, and the axles lock up when power is removed, as expected. With the motor removed the drive train is free-rolling and no sign of binding.

This is my first experience with a Losi drive train, I was expecting it to be different, just not LOUD...

[Ditchrat]

I never see this talked about on this forum, and maybe for a good reason, however....

Noisy gears can generally be quieted down by lapping them.

For those unfamiliar with the term lapping, from the ye olde interweb...

By running mating pairs together in a gearlapping machine and feeding a liquid abrasive compound under pressure into the gear pair, small amounts of metal are removed as the gears rotate, thus refining the tooth surface and achieving the desired contact pattern.

[Greatscott]

Originally Posted by Ditchrat

I never see this talked about on this forum, and maybe for a good reason, however....

Noisy gears can generally be quieted down by lapping them.

For those unfamiliar with the term lapping, from the ye olde interweb...

By running mating pairs together in a gearlapping machine and feeding a liquid abrasive compound under pressure into the gear pair, small amounts of metal are removed as the gears rotate, thus refining the tooth surface and achieving the desired contact pattern.

Overall, it is just not practical to do this at this scale. In this particular case, the main culprit of the noise are the plastic gears in the transmission, which would not take to the lapping process at all.

The Losi NC drive train is noisy to begin with, not having any experience with it, I am trying to figure out if there is something funky going on, or if the amount of noise in my truck is normal.

[Ditchrat]

Practical at this scale? It is done all the time in ho scale, in that scale the improvement to gear mesh is noticable due to small reduction in friction making a huge difference in speed.

Lapping plastic gears is easily done using toothpaste.

Or are you saying the any improvement would be insignificant and not worth the time?

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[JeremyH]

You need a set of the HD Worm Gears.
Losi: HD Worm Gear Set, 21T (2): CCR, NCR: Losi (LOSA3187)

MUCH quieter than the original gears.

Also, to help diagnose problems with the drivetrain, just disconnect the driveshaft and hook up a drill. Pull the trigger and see if the noise is present. You can do this on the axles or trans.

[84yoda]

Its just the lnc drive train. My losi is super loud and sounds like something is wrong. I get strange looks a lot. I run brushless and always add grease before every run. I would definitely get HD worm gears, new fast eddy bearings in axles, and always add grease (dont worry about over greasing it, the worms eat grease like crazy). Yours does sound a little different but I think after hd gears, new bearings and always adding grease, it should help with the noise.

[EeePee]

Normal, noisy Losi.

[shiftauto]

That sounds terrible!!! I wouldn't even have run it that long with the way it sounds. It reminds me of a jet boat making a ton of noise while not going anywhere.lol. Have you checked your gear mesh? It definitely sounds like something is slipping to me.

[Greatscott]

Originally Posted by EeePee

Normal, noisy Losi.

I have went through everything with a fine toothed comb. All of the bearings and gears are good. I have swapped out the motor, the one in the video was a 20T Novak, I went back to a 27T HPI, and switched pinion gears (26T to 25T). The changes seem to have calmed down the noise a bit, it is still noisy, but doesn't sound like it is going to rip itself a part.

[finewayne]

sounds normal man

[Greatscott]

I spun both axles and the transmission with a drill, it turns out that the noise was coming from the transmission. Saw the same thing as I did when it was driven with the motor, it does ok until about 40% throttle, then it makes a god-awful noise. I have taken it apart (again), checked all of the bearings, and can't find any smoking guns. Put it back together and still have the noise.

Along with the noise, it is also boggy down the drill when it is at speed, which explains my high motor temps.

For now I have put the Axial SCX10 transmission back in it, geared at 66/35, on 3S it does ok, but not a speed demon by any means. I still have the classic sound of the worm gears, and that is it.

I was thinking about going brushless, looking at the SV3 7700. I am wondering if that is too high of a motor for this. Normally a sensored system would be the go-to option, but I am thinking that it would be unnecessary in this rig because of the high RPM it will be ran at.

[Natedog]

That seems like too high kv for crawling imo, however the LNC is very slow and low geared. Sensorless shouold be fine on Night crawler, because it it worm gear axles, don't need special drag brake or anything fancy for esc.

I did a search and this seems like a good thread.
Losi night crawler trying to pick the rite motor combo