Jump to content
Sign in to follow this  
Jonathon Gillham

Noisy 2wd?

Recommended Posts

So I finally got around to fitting the new motor in the *cough* Ultima *cough* and noticed it is really noisy and there seemed to be quite a bit of vibration in the rear end.  This car was running well (other than dodgy electronics) last time it was raced which would have been November I think.  It has a ball diff and 3 gear standup transmission and a slipper eliminator.  The only change was I took out 2 screws to allow more flex at the rear of the chassis so I put those back in which didn't really change anything, and of course the new motor.

The noise sounds like a rattle and it happens when the car is coasting after you come off the throttle - is this normal for a car with a ball diff?  I can't say I've noticed it before.

Checked the pinion/spur mesh - this did a bit to quieten it down but its still noisy when its about as perfect as I'm capable of making it.

Took the pinion off and rolled the car along the ground and it doesn't make the noise at all which makes me think its to do with the spur/pinion mesh.

With the pinion off ran the motor and that sounds fine

The spur is a bit worn, nothing major (ie it still has nice sharp gears) but its certainly not brand new anymore.  Pinion looks like new still.

 

Any ideas?  (hopefully one where I feel a bit stupid but its a really easy fix, don't say rebuild the ball diff as I hate doing that and have to ask someone to adjust it for me)

Share this post


Link to post
Share on other sites

It could be the motor. I've a couple of brushless motors that make noise, like you describe, when they are turned manually - by pushing the car along for example.

  • Like 1

Share this post


Link to post
Share on other sites
4 minutes ago, Peter_B said:

It could be the motor. I've a couple of brushless motors that make noise, like you describe, when they are turned manually - by pushing the car along for example.

That would be great if it is.  Its the new Surpass V4S which have much stronger magnets than my other motors and are near impossible to turn by hand.  Just tried it with another one (as in, tried turning it by hand) and I have to hold really tight and then spin the can.  It may have done this with the old motor too but I really can't remember.

 

Share this post


Link to post
Share on other sites

Best chuck another motor in and see if its noisy too... preferably a motor that is easy to spin by hand, then you'll know it's that tough new motor and nothing to worry about with the rest of the car.

Or, rebuild the ball diff ;)

  • Like 1

Share this post


Link to post
Share on other sites
4 minutes ago, Jason1145 said:

Best chuck another motor in and see if its noisy too... preferably a motor that is easy to spin by hand, then you'll know it's that tough new motor and nothing to worry about with the rest of the car.

Or, rebuild the ball diff ;)

Hmm, changing motors is easier than rebuilding the ball diff, and this is a good idea.  I should chuck the old motor in and see.  Only thing is I am rubbish at soldering!  I will have a chance to give it a go this week.

  • Like 2

Share this post


Link to post
Share on other sites

Have you changed pinions while changing motors? sound like a silly thing but... maybe the *cough* Ultima *cough* runs on 48P Spur and you accidentally put in a 0.6M pinion?? that sound awful, 48P with 48P is so silent... while 0.6 and 0.6 arent so silent.

  • Like 2

Share this post


Link to post
Share on other sites
Just now, Fabia130vRS said:

Have you changed pinions while changing motors? sound like a silly thing but... maybe the *cough* Ultima *cough* runs on 48P Spur and you accidentally put in a 0.6M pinion?? that sound awful, 48P with 48P is so silent... while 0.6 and 0.6 arent so silent.

Same pinion as before, and I've swapped all my race cars to 48p (well Kyosho come with 48p, but I have 2 Tamiya race cars which were .6 and .4), except the nitro which runs mod 1 or something?

I haven't mixed and matched gears before but have heard they sound awful, and its easy to get caught out as shops descriptions aren't always the best...

  • Like 1
  • Confused 1

Share this post


Link to post
Share on other sites
49 minutes ago, Fabia130vRS said:

Have you changed pinions while changing motors? sound like a silly thing but... maybe the *cough* Ultima *cough* runs on 48P Spur and you accidentally put in a 0.6M pinion?? that sound awful, 48P with 48P is so silent... while 0.6 and 0.6 arent so silent.

This was my immediate thought, but seems not to be the issue 

  • Like 1

Share this post


Link to post
Share on other sites

Ball diff shouldn't make noise unless it is loose/broken.

The noise a brushless motor makes when you turn it manually is called cogging. Typically you should only hear that noise while the car is moving under it's own power when it is going very slow - typically below 5-10% of top speed. Coasting at high speed should be smooth and not sound like the drivetrain is full of rocks.

I would check backlash of the drivetrain by holding the spur stationary and attempting to turn the wheels. It should not slip or make a loud clunk when turned either way. Check that the new motor is mounted straight so the spur and pinion aren't angled relative to each other - gears will be noisier if they are on a slight angle even if you set the spacing correctly. Dust covers installed after setting the gear mesh may flex things enough to throw out the meshing - you may need to set the gear mesh slightly looser or tighter to mesh just right when the covers are installed.
As a last resort, swap a totally different spur/pinion gear set in, even if it isn't the ideal ratio it would at least tell you if the issue is that or something else.

 

 



 

  • Like 1

Share this post


Link to post
Share on other sites

The only way is as people have said, swap known parts in and out. There's no need to resokder the old motor in. If it makes the noise on the bench then Jerry rig the motor out of another car whilst it's still attached to the other buggy. Just lay it on top of the ultima or something. That then eliminates the entire electronic side of the ultima to see what's what. 

On my TRF211 I found it being loud after a few runs and it turned out the spur gear had warped slightly. Eventually turned out the tiny 840 bearing at the other end of the top shaft had failed causing the spur gear to whirl. Keep at it. You'll figure it out. 

  • Like 1

Share this post


Link to post
Share on other sites

So after more research I'm thinking the motor or idler gear. Apparently idler gears are known to wear on these. I will hopefully get some time today to check it out.

Thanks everyone

  • Like 1

Share this post


Link to post
Share on other sites

Hi Jonathon, I have the surpass V4 in my new built Xray XB419 and have had the same problem, its very noisy when off throttle or coasting along, I was of the opinion that I had built the diff wrong but on inspection it is just the Magnets on the rotor, I have a 17.5 in my B6.1 and it is the same.

I must say that they are a great motor, heaps of torque and speed.

IMG_4711.jpg

  • Like 1

Share this post


Link to post
Share on other sites
47 minutes ago, OOZZEE said:

Hi Jonathon, I have the surpass V4 in my new built Xray XB419 and have had the same problem, its very noisy when off throttle or coasting along, I was of the opinion that I had built the diff wrong but on inspection it is just the Magnets on the rotor, I have a 17.5 in my B6.1 and it is the same.

I must say that they are a great motor, heaps of torque and speed.

IMG_4711.jpg

Thanks for confirming that.  I'll still pull the gearbox apart (and rebuild the diff while I have it out) since its been a few months since I last inspected it, but I'm 99% sure its the motor.

Good to hear that they are good motors too.  This weekend will be my first use of it.  If I like it I'll be putting one in my Lazer too, I have it sitting here all ready to go.  That has a near new Orca Blitreme in it which is a good motor, although I'm pretty sure I have cooked it pretty badly, hence the second Surpass.

 

Nice looking XB4, is that a clay car?

Share this post


Link to post
Share on other sites

pretty much, its going to be used @ Chargers RC in Brisbane, its a great track with heaps of traction

Share this post


Link to post
Share on other sites

My surpass motor would cog under load (at full throttle) and make a horrible racket, it was noisy rolling too, after trying to fix it for awhile  I ended up ditching it in the end as it simply didn’t work properly. However it sounds like this isn’t the problem, the cogging I experienced felt like the car was jumping teeth in the gearbox under full throttle.

Share this post


Link to post
Share on other sites
15 hours ago, Jonathon Gillham said:

Same pinion as before, and I've swapped all my race cars to 48p (well Kyosho come with 48p, but I have 2 Tamiya race cars which were .6 and .4), except the nitro which runs mod 1 or something?

I haven't mixed and matched gears before but have heard they sound awful, and its easy to get caught out as shops descriptions aren't always the best...

They do? Dunno if they changed their gearing system for the re-res, but top-end Kyoshos always used to come with .6 module gears.

Share this post


Link to post
Share on other sites

I just had to look it up to check I wasn't losing my mind, but no, Kyoshos did run on .6 module gears. I did double take when various forums claimed that the Lazer ZX-R ran on 48dp, as I ran mine on .6 module for its entire racing life with no problems, but according to the manual it seems there were either two versions  – one with 48dp and one with .6 module – or there was a kit to convert one to the other. I know we would have used the .6 module version as we still had all the pinions from the Mid.

218243141_ZX-RGearChart.jpg.62d88948350c1dd34d2451d872c78129.jpg

  • Like 1

Share this post


Link to post
Share on other sites
58 minutes ago, Yalson said:

I just had to look it up to check I wasn't losing my mind, but no, Kyoshos did run on .6 module gears. I did double take when various forums claimed that the Lazer ZX-R ran on 48dp, as I ran mine on .6 module for its entire racing life with no problems, but according to the manual it seems there were either two versions  – one with 48dp and one with .6 module – or there was a kit to convert one to the other. I know we would have used the .6 module version as we still had all the pinions from the Mid.

218243141_ZX-RGearChart.jpg.62d88948350c1dd34d2451d872c78129.jpg

Interesting, I thought they were all 48p.  I have a Mantis EP from the 90s and that has 48p gears in it, and my Lazer ZX6 and Ultima RB6.6 both run 48p.  The Ultima has an exotek slipper eliminator so that has an exotek spur gear, but I've got a bunch of spurs for the Lazer in their Kyosho packs which are 48p.

 

I wish everyone would use the same, it would make life so much easier.  I run 48p in my onroad as well even though most run 64p as I can mix and match pinions.  Also, when I tried to order 64p gears I got it completely wrong because they are physically so much smaller for a given tooth size that I ended up with the pinion not touching the spur in my TRF102...

  • Like 1

Share this post


Link to post
Share on other sites
8 hours ago, Jonathon Gillham said:

 

I wish everyone would use the same, it would make life so much easier.  I run 48p in my onroad as well even though most run 64p as I can mix and match pinions.  Also, when I tried to order 64p gears I got it completely wrong because they are physically so much smaller for a given tooth size that I ended up with the pinion not touching the spur in my TRF102...

what did you do?

I run a 64P 80T spur in my F103 and a 64P 35T pinion. the spur is almost the size of the diff itself.

Share this post


Link to post
Share on other sites
15 minutes ago, Fabia130vRS said:

what did you do?

I run a 64P 80T spur in my F103 and a 64P 35T pinion. the spur is almost the size of the diff itself.

I run a similar FDR to that, but now have around 73T spur and 30T in 48p. When i bought simialr to that in 64p the gears were too small and didn't touch when mounted...lucky gears are cheap

Share this post


Link to post
Share on other sites
9 hours ago, Jonathon Gillham said:

Interesting, I thought they were all 48p.  I have a Mantis EP from the 90s and that has 48p gears in it, and my Lazer ZX6 and Ultima RB6.6 both run 48p.  The Ultima has an exotek slipper eliminator so that has an exotek spur gear, but I've got a bunch of spurs for the Lazer in their Kyosho packs which are 48p.

I can't say what format gears Kyoshos ran in the first half of the 80s, but Mids definitely came with .6 module gears, as did the Ultima Turbo II I briefly had. I seem to recall that the original Optima came with 32dp gears, but I might have imagined that entirely or confused it with a coarser metric pitch, so don't take it as truth without further research. The Lazer ZX apparently also ran .6 module, while the ZX-R was a changing point, as it appears it came with either .6 module or 48dp. It could be that this split was either along market lines (maybe Europe and Japan came with metric .6 module, while the US came with imperial 48dp) or it could have been simply that they didn't have enough of one so they filled the rest of the kits up with the other. I honestly don't know.

What does seem to be the case is that after the ZX-R, Kyosho standardised on 48dp, so your Lazer ZX-6 and Ultima RC6.6 defintely would have been 48dp from new.

The picture for Mids, Ultima IIs and ZX-Rs is likely to be murky these days, though, as so many of them will have been fitted with aftermarket spurs or run with the wrong pinions by owners ignorant of the difference between the two standards. From reading some of the forum posts, I can tell you that A LOT of people either don't know the difference or didn't even know there was a difference.

We tried running 64dp on the Mid for a while, as we bought some second-hand equipment that included a lot of 64dp Mid spurs and pinions. I loved the smoothness of the drive and the fact it was so quiet, but ultimately the motors we used tended to be too much for the fibre the spurs were made out of and they tended to chew the teeth up. It was also a bit hard getting the amount of play between the pinion and spur right with such small teeth on the Mid. Too tight and it would chew the spur teeth up, too loose... and that would chew the spur teeth up, too.

  • Like 1

Share this post


Link to post
Share on other sites

Check the amount of droop on your wishbones.  If there is too much the dogbones rattle at the extremes of travel and cause lots of vibration.  You say it is noticeable when coasting.  This could be because the weight of the car moves forward and the back end raises up.  When you accelerate the back goes down, levelling out the arms.  Try lifting the car off the ground and running it with the wishbones pushed level with the chassis.  Might help.  If that is the problem just shorten the dampers a bit.

  • Like 1

Share this post


Link to post
Share on other sites
2 hours ago, Jonathon Gillham said:

I run a similar FDR to that, but now have around 73T spur and 30T in 48p. When i bought simialr to that in 64p the gears were too small and didn't touch when mounted...lucky gears are cheap

Well, doesnt that make sense? 48P would be 48T on 1inch.

so would be 64P, 64T on 1inch 

while the metric pions have a 0.8, 0.6, 0.4mm gap beetween teeth. 

 

So for example 80T in 64P and 48P would be a significant difference in diameter.

had the same problem with a 80T 64P spur on my TA05. It would not touch the spur with a 0.4 36 pinion or smaller.

but that way I could reach to much lower FDR. 

My F103 with 80T 64P spur uses 12x 2.8mm balls instead the    Standard 3.12mm balls. Something like that. I know I had to buy smaller balls for the spur and use 12x instead of 6x

how does your perform with such a FDR?

mine has a bit of a less impulsive start and on full throttle gains speed steady but slower..

As for the sound...

can you hold the car in your hand and get it to make that sound? Or on a car stand where the wheels spin freely?

keen to hear what was it

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  

×
×
  • Create New...