This may have been a bad idea but...

[FoxOfHall]

Afternoon! Long story short, have a Maverick Strada evo MT, burnt out the brushed motor, so upgraded to http://www.hobbyking.com/hobbyking/store/__41129__Turnigy_TrackStar_Waterproof_1_10_Brushless_Power_System_3000KV_80A_UK_Warehouse_.html

 

My transmitter had died in the steering department too so had to replace that so decided to go for http://www.modelsport.co.uk/carson-reflex-pro-2-lcd-3ch-2.4ghz-fhss-combo/rc-car-products/368278

 

Parts came today after Easter weekend non post. Installed the parts and on the turntable at least, everything seemed fine. So it's a nice day go outside and see how it runs.

Put the truck down on the floor and now when I touch the throttle grinding noise. First thought I've not set up the pinion to the spur, I've been tweeking it for the past hour now, just can not get it so there's no grinding noise, tried loosing the grip so the gears are wider apart, and then tried tightening them, but no joy. So just to see if it was only at low speeds it was doing it, I did a quick run up the garden (about 8 meters) ease onto the throttle and the speed is immense and the grinding noise goes away, but the brakes which were working awesome on the turntable now seem to have little effect. Brought it back in to have another look and I've messed up at some point because now the spur gear has been chipped and bitten away by the pinion. It's the stock one so at this point I'm guessing time to get a metal spur? Or have I overlooked something like a complete newbie.

 

Spur and pinion are stock to the Maverick.

 

http://www.modelsport.co.uk/maverick-strada-mt-evo-rtr-monster-truck/rc-car-products/38122

[FoxOfHall]

Looking at the pinion side of this situation, would these help with the power or even just stop the grinding? http://www.modelsport.co.uk/traxxas-differential-ring-gear-pinion-gear/rc-car-products/31672

[smeghead28]

First off when you put in the new radio gear did you recalibrate everything?

If the spur is chipped them something has gone wrong somewhere.

Ideally you dont want a metal pinion and spur gear,you need a failure point such as the plastic spur gear otherwise the whole lot might just jam up and burn something out if they are both metal.

Those parts listed will probably not change the situation.

Since fitting the brushless system have you had one succesfull run?

There is a chance that fitting the brushless system might have stripped or damaged something elsewhere,in the front or rear diffs maybe.

[Noj]

The braking on that set up is poor, don't expect too much....

[FoxOfHall]

Radio gear all calibrated in, just needed a bit of fine tuning. Successful brushless run, not as yet no as today I've installed, like I say, once you accelerate it seems to stop grinding. But yeah the msot of the spur is chipped away now.

[smeghead28]

Is it actually grinding though?

On some brushless systems you can get something called cogging.

It is related to the construction of the motor and not an actual fault.

When you drive away slowly you can get a noise that can sound like something is grinding.

Remove the motor all together and see if you can feel anything grinding in the drive train by just pushing it along.

Edited April 7, 2015 by smeghead28

[Tamiyacowboy]

Yep as smeghead says 

 

 

pull out the motor, pop the truck on a nice HARD surface, and with your ears nice and close run the truck back and fourth ,

if the grind sounds like its in the rear of the chassis, we have a rear diff problem ( most common) , sound from the frontal area gives us a front diff problem ( more rare)

and if it sounds like the noise comes from where the motor would be sitting, its a center diff problem - center drive shaft play ( usually a small grub screw works loose)

and thats sounds like a rakey grinding noise

[FoxOfHall]

Thanks both, have done a bit more tweeking, and got a couple of runs out of it, low speed grind as if the teeth aren't gripping then all of a sudden they grip and the truck is gone (so gone it almost took me out on a return run), shall take the motor out now and see what's what

[mike anderson]

Had the same on a helion dominus,

got bored, threw a 5kv and wp8 in it, 3s, and took it out, first few runs were immense, then grinding under acceleration. Tried everything you did, then pulled front diff out, still noisy, swapped rear diff with the front one, noise gone,

ordered a new complete diff and centre shaft gear, fitted and all is fine, just sticking to 2s from now on though.

rear diff looked okay visually, but clearly wasn't.

[FoxOfHall]

Ah should have mentioned my batteries too, they're 5.0ma 2s.

 

Also the pinion on there at the moment is a 13t, would going up to a 21t cure the grind?

[FoxOfHall]

Update, stripped the truck down, (no motor, decking taken off) noticed a knocking noise, turns out the centre shaft is bent ever so slightly, one thing after another with this truck. Going to strip it down a bit further to see if there's anything else that needs replacing. Thanks Maverick! (Y)

[Noj]

Ah should have mentioned my batteries too, they're 5.0ma 2s.

 

Also the pinion on there at the moment is a 13t, would going up to a 21t cure the grind?

It would cause serious heat issues!

Gear up/down in two tooth increments, not 8!!

[capri-boy]

Connect the program card and up the breaking a little - not too much though - My Strada SC can lift it's back end with this set up (though I do have an older can so might have changed since).

 

As for the Maverick - it's perfectly capable of running this BL system - all metal drivetrain - mine has run it for a long time know with no issues.  I serviced the diffs recently and there was zero signs of wear (and very little play so didn't shim them).  I suppose it's possible for your to have a bad diff that the extra power is showing up.  13t pinion is too low, I found the SC ran quite well on the stock (23t iirc).

 

I've never bent the centre shaft, though I have bent the uprights many many times, and the upper deck once - it fit together fine, ran fine but was obv when the angle the centre shaft met the front cup was seen.  Quick straighten and all fine.  A CF upper deck was on the cards but I've no got round to it yet.  bent shaft would certainly mean a grinding noise but have you triple checked the motor mount?  Make sure the mesh is et and the motor screws are tight in, and check the mount where it fastens through the chassis.

 

I've recently swapped towers to some CNC ones, yet to run them though as somewhere have misplaced a dogbone.  Biggest weak are has been the front knuckles - the axle extenders put a lot of strain on them when jumping, and they've been pulling the screws from the carriers through.  I've also just swapped these for alloy ones, as M3 threadleacked screws should cope fine - carrier may well fail next but alloy carrier is on route too

[FoxOfHall]

Sounds like a plan, I've tried a few things you guys have said here, and I don't think I've explained this well (probably my newbishness) but I've maade a quick video showing the noise under acceleration.

 

https://youtu.be/-omOpiZUko4 < It's currently only in two wheel drive as I needed to make sure it wasn't the centre shaft causing the noise, the pinion kept slipping just before I shot this so it's tightened right up so at least that doesn't move anymore.

 

Is this noise normal for a brushless? I slotted in my dead brushed earlier that came stock and that noise you hear it does not make at all, I'm completely stumped.

 

(Tis fun driving RWD again though, have not done for many years )

[FoxOfHall]

Just a guess, but would it be because the motor doesn't have much torque low down? So it's harder to move off the line? Been running it a couple of times since that video, and when it gets going all seems to be well, it's just initial starting from a stop.