Losi 8ight-T Electric - Loud grinding noise near pinion/transmissions gear

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Mr_Pinkster

RC Newbie
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Hello everyone,

First time posting and hope you RC guru's could help out. I just purchased a Losi 8ight-T Electric 3.0. A custom built buy from eBay.

First run, it has a loud grinding noise where the motor and transmission gears meet. The seller suggested a fresh battery. I charged up, went to the park, even with the loud grinding, I gave it a little go and broke a pinion gear. I just got some new ones in, and still the same, just really loud. I've tried to adjust it, but still loud. W/o the motor mounted, no sounds, so I'm thinking it's those gears. I'm literally on hold with Losi support, been about 30 mins, so I'm not hopeful with them :(

I've out of RC for a while, so these newer cars are a bit foreign to me.

Any help is mucho appreciated!

Cheers all!
 
First thing you're going to need to do is make sure you have your gear mesh set properly between the pinion and the spur gear. You should be able to crinkle a strip of paper between the two gears without tearing or poking holes in the paper. So far it just seems like its a bad gear mesh.

This is why I dont recommend used kits for beginners. Half the time (or more if they come from ebay) the person you're buying the kit off of has developed a problem that they can't figure out how to fix so they just sell it on ebay and then when you buy it you better be willing and able to do a full tear down of rebuild of the kit to make sure everything is right with it. However since youve already bought it lets try making sure the gears are meshed properly and go from there. Pics and vids of the issues usually help a lot if this doesn't fix your issue. :)
 
You need to make sure the pinion and spur have the same size teeth. Called the gear pitch or module. If they arent matched the gears will never mesh correctly and you instantly get a grinding sound.

Just to be clear did the gear on the motor break or the spur gear on the center diff?
Is the spur gear steel?
If you replace the pinon and spur at the same time you are sure to get a matching set.
 
Sounds like mesh to me also.
On a positive note, taking it all apart you will learn a lot about it.
 
stock pinion pitch is mod 1 .. like said above Id check that pitch could be different Id ask seller whom built along .with did they know of pitch change?
 
Looked and the plastic gears all say mod 1. There is a steel spur gear upgrade made. It's mod is not listed anywhere, doesn't state you need a new pinion though.
Usually the little gear eats the bigger gear. I thought it was strange that a pinion broke first.
 
Thanks for all the info everyone! The gears are 32P, and matched on both sides. I did the paper trick, and still it seems that it's stripping my pinion gear down a bit, as I see small parts of metal shreds inside. I've mounted motors before and never had this kind of issue. I also tightened up the pinion gear as best I can, and during some tests, it comes off. Does this need Loctite? Thanks!
 

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mod 1 and 32p can be similar but they are not Id put a mod 1 in that and test it. betting pinion doesn't get eaten.I've used blue lt for 1 pinion gear
 
I only put another 32P in, since this was the one that came with the Truggy itself.
 

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All the Losi pinions for your car I see on the internet are 1 mod. More broken gear teeth are in your future.
 
All the Losi pinions for your car I see on the internet are 1 mod. More broken gear teeth are in your future.
Ah geez, most likely this was built with the wrong pinion :( Time to order them off of Amazon, thanks, you've been most helpful friend! Cheers!
 
Are the nitro and electric spur gears the same mod?
Depends. Nitro is almost (if not always) Mod 1. Heavy 1/8scale elctrics and 1/5 scale tend to use Mod1. Lighter 1/8 scale & heavier 1/10 scale tend to use 32P. Lighter 1/10 scale and some minis tend to use 48P. Even smaller kits tend to go 64P but theres a lot of variation possible in there too. As far as I've seen Nitro is always Mod1 though.
Thanks for all the info everyone! The gears are 32P, and matched on both sides. I did the paper trick, and still it seems that it's stripping my pinion gear down a bit, as I see small parts of metal shreds inside. I've mounted motors before and never had this kind of issue. I also tightened up the pinion gear as best I can, and during some tests, it comes off. Does this need Loctite? Thanks!

Ah geez, most likely this was built with the wrong pinion :( Time to order them off of Amazon, thanks, you've been most helpful friend! Cheers!
Sounds like this is indeed your problem. Here are the stock specs for the Losi 8ight-T E 3.0 pulled straight from their website.
Capture.png
 
Depends. Nitro is almost (if not always) Mod 1. Heavy 1/8scale elctrics and 1/5 scale tend to use Mod1. Lighter 1/8 scale & heavier 1/10 scale tend to use 32P. Lighter 1/10 scale and some minis tend to use 48P. Even smaller kits tend to go 64P but theres a lot of variation possible in there too. As far as I've seen Nitro is always Mod1 though.



Sounds like this is indeed your problem. Here are the stock specs for the Losi 8ight-T E 3.0 pulled straight from their website.
View attachment 128024
Thanks ! I'm looking at Amazon to get some ASAP!
 
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