Jump to content
esmuz

Pinion gear mystery

Recommended Posts

Hi, it's me again with the **** Shadow 4WD. 

After my niece used it for a few times, I noticed the spur gear, is almost totally worn out.

Captura de pantalla 2020-12-04 a las 19.22.30.png

 

 

Initially I thought it could have been because the system to adjust the distance between the pinion and the spur is really weak  in this model, and a couple of times I could hear how it got loose and the pinion started to "eat" the spur.. You know this scary sound right? 

WelI, I  found a spare spur in ebay, which cost me a finger... (and I hope it lasts more that the original one or the car will end up in a shelf for ever).. but checking the original instructions I found a chart in which it recommends using a 16T pinion for the Le Mans stock 05 motor.. 

 

Captura de pantalla 2020-12-04 a las 18.25.37.png

I was shocked because the pinion in my motor is a 13T one made of aluminum I think it's an OT-50, which also seems to be quite worn out.

 

Captura de pantalla 2020-12-04 a las 18.42.33.png

 

Do you guys think this might have been the reason why the spur was worn out? A too small pinion for this engine's torque? I don't remember ever buying a pinion for this car, so it's very weird it came with a 13T and the maker recommends an 16T. 

I want to make sure the new spur gear lasts as much as possible, do you think I should get the 16T? Should I go for the original OT-52 or  can I get something newer, steel made with the same 32 pitch? 

Thanks!

Share this post


Link to post
Share on other sites

Aluminum pinions will wear out faster than a steel one. When they wear, the teeth get sharp and pointy. If the gear mesh isn't right with a pointy pinion, it will eat up spurs. It looks like the gearbox may have been over greased too. I suggest going with at 16T steel pinion and really getting the mesh right.

Back in the day, when we couldn't see the mesh on a certain car, we would drill a hole in the gearbox on the other side to set the mesh and cover it with tape or a really short chubby screw.

  • Like 2

Share this post


Link to post
Share on other sites
30 minutes ago, RichieRich said:

Aluminum pinions will wear out faster than a steel one. When they wear, the teeth get sharp and pointy. If the gear mesh isn't right with a pointy pinion, it will eat up spurs. It looks like the gearbox may have been over greased too. I suggest going with at 16T steel pinion and really getting the mesh right.

Back in the day, when we couldn't see the mesh on a certain car, we would drill a hole in the gearbox on the other side to set the mesh and cover it with tape or a really short chubby screw.

Thank you, actually there is a hole to see the mesh but the system is not exactly precise, it's very close or very loose.

So you think I should go for the 16T? I am actually not use it fits the hole.. maybe in this chart (in swedish) the black dot means "not recommendedmended"?

In regards to grease, I think I over greased it you are totally right.. The nylon bearings are in really bad shape so I tried to lubricate the shafts a bit too with shock oil.. Probably a bad decision.  

This car is a total ruin it was never a good design and it will never be.. a pity because I find it quite nice looking. 

Share this post


Link to post
Share on other sites

Yes, I just googled the manual for that car. It looks like they suggest a 15 or 16 tooth pinion for the LeMans 05 motor. Also, if you're still using the nylon bearings, that will massively contribute to excessive wear. A ball bearing upgrade will definitely help you. That way you won't ruin the new spur gear you paid for with a finger. :D So, clean out the old grease, install bearings, lightly relube with proper grease, use recommended steel pinion. DONE!

  • Like 1

Share this post


Link to post
Share on other sites
1 hour ago, RichieRich said:

Yes, I just googled the manual for that car. It looks like they suggest a 15 or 16 tooth pinion for the LeMans 05 motor. Also, if you're still using the nylon bearings, that will massively contribute to excessive wear. A ball bearing upgrade will definitely help you. That way you won't ruin the new spur gear you paid for with a finger. :D So, clean out the old grease, install bearings, lightly relube with proper grease, use recommended steel pinion. DONE!

Yeah! I Know.. bearings will improve it a lot you are totally right!  

That's the thing with old cars.. specially entry level ones like this, every time you fix something you have to spend a lot for pieces and after you fix it something new gets broken hahaha... Same with real cars actually.

In any case, I'll think about it, because whatever I do, nothing will improve the absurd steering system of this car.. 

I should probably get a DT-03 for my niece and stop spending money!

  • Like 1

Share this post


Link to post
Share on other sites

it's probably too late for bearings. the shafts will be too worn to hold them true. replace the shafts or place very thin clear tapeee around the old sharts where you see the wear. then use i razor to trim the excess and true them up. if the tape was too thick just shave off half so the tap covers the shaft like C, or (, instead of O

 :)

see? it will move the gear 0.15mm at the worst, but as long as it sits parallel to the other gears and it's riding clean and tight on the bearing, the shifted spacing doesn't hurt.  in fact, it can help. just place the tape so you're moving the gear closer to it's neighbor. you'll take away some slop.

now the pinion. of course you already know that kyosho and tamiya use different modules then american 'metric' gears, right? so try using kyosho branded pinions when you can. but they don't need to be specific to the 'rocky'. if you only find steel pinions in american 32p use them instead though.  the plastic will morph to match if you let it run without load to break it in. slow. no heat. just flip her upside down and go half throttle for a battery or 2. easier to plug a jury-rigged  4 cell pack of dying household batteries directly into the motor.

2nd, that chart they put in the manual recommends very punchy gearing for competitive racing on japan's typically tight, complicated courses. it's very low gearing ratio for just casual driving.

[side note my 87 turbo ultima came geared so low i went from 16t to 22t and barely noticed lower acceleration. maybe 5 car lengths to reach top speed in high traction surfaces. no stress on the electronics though. if anything i relieved stress because when it was geared that low i was constantly on the throttle. with the higher gear i spent more time coasting through turns. anyway...]

gear her up!

not for speed, but to increase the contact points on your gears. bigger gears, more teeth contacting eachother, less burden on each tooth. 

i don't know what you meant about your mesh being hard to adjust [from the chassis flex?] i don't remember how rocky & turbo rocky mounted the motor.

once you got a big f---in pinion in, adjust the mesh so the spur barely has wiggle room without the pinion moving. it should only wiggle half a degree.

Share this post


Link to post
Share on other sites
45 minutes ago, BardsDirge said:

it's probably too late for bearings. the shafts will be too worn to hold them true. replace the shafts or place very thin clear tapeee around the old sharts where you see the wear. then use i razor to trim the excess and true them up. if the tape was too thick just shave off half so the tap covers the shaft like C, or (, instead of O

 :)

see? it will move the gear 0.15mm at the worst, but as long as it sits parallel to the other gears and it's riding clean and tight on the bearing, the shifted spacing doesn't hurt.  in fact, it can help. just place the tape so you're moving the gear closer to it's neighbor. you'll take away some slop.

now the pinion. of course you already know that kyosho and tamiya use different modules then american 'metric' gears, right? so try using kyosho branded pinions when you can. but they don't need to be specific to the 'rocky'. if you only find steel pinions in american 32p use them instead though.  the plastic will morph to match if you let it run without load to break it in. slow. no heat. just flip her upside down and go half throttle for a battery or 2. easier to plug a jury-rigged  4 cell pack of dying household batteries directly into the motor.

2nd, that chart they put in the manual recommends very punchy gearing for competitive racing on japan's typically tight, complicated courses. it's very low gearing ratio for just casual driving.

[side note my 87 turbo ultima came geared so low i went from 16t to 22t and barely noticed lower acceleration. maybe 5 car lengths to reach top speed in high traction surfaces. no stress on the electronics though. if anything i relieved stress because when it was geared that low i was constantly on the throttle. with the higher gear i spent more time coasting through turns. anyway...]

gear her up!

not for speed, but to increase the contact points on your gears. bigger gears, more teeth contacting eachother, less burden on each tooth. 

i don't know what you meant about your mesh being hard to adjust [from the chassis flex?] i don't remember how rocky & turbo rocky mounted the motor.

once you got a big f---in pinion in, adjust the mesh so the spur barely has wiggle room without the pinion moving. it should only wiggle half a degree.

Great advices! I wish I had so much experience.

It is very weird, the shafts are perfect, no worn, no marks, but when inserted into the bushings, it's tight, it's like the bushings became smaller ( sorry for my english ). I am not an expert at all, but I suppose the shafts should rotate inside the bushings right?  As they don't roll at all, it's the gears that roll and that's why I added some shock oil to make it run smoother. 

I'll gear her up ! 

And regards difficulty for adjusting Mesh, it's not a Rocky ( I wish it was ) it's a Shadow 4WD an entry level model very inspired by the Tamiya Boomerang ( same defects ) The gearbox walls are made of a quite soft black plastic, it's so soft or badly designed,  that when you put a bit of strength, you can see how it bends. 

In any case thanks a lot for sharing your knowledge, I really appreciate it. 

 

 

Share this post


Link to post
Share on other sites
2 minutes ago, esmuz said:

it's a Shadow 4WD

oh i'm very sorry i mistook you for another user. you're the shaft driven chassis with 4 shocks.

exact same advice though :)

 

Quote

Great advices! I wish I had so much experience.

i spent my teen years racing guys in there 50's with unlimited budgets. i had to learn all the tricks to keep my old cars running.

 

Quote

 I suppose the shafts should rotate inside the bushings right?  As they don't roll at all, it's the gears that roll and that's why I added some shock oil to make it run smoother. 

something is terrible wrong. you got it used, right? somebody used the wrong shafts or the wrong bushings. the gear should not move around the bushings at all. this is the key to all your problems. 

do you have calipers to measure everything? let's see were things went wrong.

you're right, it is time to let her retire. not in this condition though.

Share this post


Link to post
Share on other sites
On 12/5/2020 at 6:47 PM, BardsDirge said:

now the pinion. of course you already know that kyosho and tamiya use different modules then american 'metric' gears, right? so try using kyosho branded pinions when you can. but they don't need to be specific to the 'rocky'. if you only find steel pinions in american 32p use them instead though.  the plastic will morph to match if you let it run without load to break it in. slow. no heat. just flip her upside down and go half throttle for a battery or 2. easier to plug a jury-rigged  4 cell pack of dying household batteries directly into the motor.

:blink:

The gears on the Shadow are 32dp. Kyosho used .6 module gears on the Mid, equivalent-era Ultimas and some early Lazers (they switched to 48dp at some point in the production run, for some reason), but pre-Mid Optimas, Aero Streaks, Shadows and various other earlier or simpler models used 32dp gears.

And please, don't tell people "the plastic will morph to match if you let it run without load". Because if the gears are of different pitches, it really, really won't. It will just ruin your gears.

The wear in the picture seems to be even all the way round the pinion, which suggests it has been set up with too much slop between the pinion and the spur and they weren't meshing correctly. @esmuz, you may need to now replace the spur and the pinion to get a good mesh between the two, as once a gear is worn like that it won't come back again. If you are using a Le Mans 05, you might also want to increase the pinion size to a 16t (OT-52) or a 17t (OT-53) or an equivalent 32dp pinion from another manufacturer. I am not certain what part number the spur is (looks like no 26 from the SB-6 diff parts bag, but you'd know better than me) but they seem available, too. Although you might have to order an original parts bag from the USA to get one.

Good luck with it!

Share this post


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

The wear in the picture seems to be even all the way round the pinion, which suggests it has been set up with too much slop between the pinion and the spur and they weren't meshing correctly. @esmuz, you may need to now replace the spur and the pinion to get a good mesh between the two, as once a gear is worn like that it won't come back again. If you are using a Le Mans 05, you might also want to increase the pinion size to a 16t (OT-52) or a 17t (OT-53) or an equivalent 32dp pinion from another manufacturer. I am not certain what part number the spur is (looks like no 26 from the SB-6 diff parts bag, but you'd know better than me) but they seem available, too. Although you might have to order an original parts bag from the USA to get one.

Good luck with it!

Thanks for the info, yes I agree as the Mesh adjusting system is so shabby in this model, it makes all sense that the pinion had some slope when I was trying to get it tight.. Probably when the spur started to degrade I had to force it even more. 

I already got the new spur as part of a gears bag, so I'll get a 32dp steel 16T pinion ( I have a 17T pinion from my Tamiya DT-03 and it is too big to pass through the pinion hole in the gearbox, so I hope a 16T wil do or I'll have to make the hole bigger ) also the ball bearings. 

This will be the last chance for this old lady, I spent too much time and money on it and as said although it's a pretty car it will always be a mediocre design with a terrible steering system. But hey it was my first car! 

Thank you guys.

 

  • Like 1

Share this post


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

I already got the new spur as part of a gears bag, so I'll get a 32dp steel 16T pinion ( I have a 17T pinion from my Tamiya DT-03 and it is too big to pass through the pinion hole in the gearbox, so I hope a 16T wil do or I'll have to make the hole bigger ) also the ball bearings.

I just looked it up and the pinion on a DT-03 is not compatible with your Shadow anyway. The gear pitch on the Shadow is 32dp (metric), while the DT-03 uses .8 module (which is an imperial measurement). People have posted in other threads here before that the two systems are almost equivalent (.8 module apparently works out at roughly 31.75dp). But if you use them together for any length of time, the gears will inevitably chew each other up as they are fractionally different sizes and therefore one gear will always be trying to push teeth into gaps that are just too small for them. Stick to proper 32dp pinions (there are plenty of them available on eBay) and you should be OK. And make sure you keep the two pitches separate, or you could mess up the gears in both cars.

I feel for you with the problem of the hole in the gearbox case being too small to get the pinion through. I have a Raider that uses 32dp gears and it has exactly the same issue. It is hugely frustrating and very poor design to have to take the gearbox apart to swap pinions.

Share this post


Link to post
Share on other sites
7 hours ago, Yalson said:

I just looked it up and the pinion on a DT-03 is not compatible with your Shadow anyway. The gear pitch on the Shadow is 32dp (metric), while the DT-03 uses .8 module (which is an imperial measurement). People have posted in other threads here before that the two systems are almost equivalent (.8 module apparently works out at roughly 31.75dp). But if you use them together for any length of time, the gears will inevitably chew each other up as they are fractionally different sizes and therefore one gear will always be trying to push teeth into gaps that are just too small for them. Stick to proper 32dp pinions (there are plenty of them available on eBay) and you should be OK. And make sure you keep the two pitches separate, or you could mess up the gears in both cars.

I feel for you with the problem of the hole in the gearbox case being too small to get the pinion through. I have a Raider that uses 32dp gears and it has exactly the same issue. It is hugely frustrating and very poor design to have to take the gearbox apart to swap pinions.

Oh, yes I knew the pitch was different, I just mentioned it because it's a 17T and it doesn't fit.. So I was afraid a 16T didn't fit either.. I'll check the size before I buy it. Thanks for all the info. I hope I can make it. 

I was also considering using a couple of 0.5 mm aluminium  1X1 cm plates around the Mesh adjusting bolt hole , so it doesn't get deformed by the small washer.. in other words, a super washer before the washer :)

Thank you guys for so much inputs. 

  • Like 1

Share this post


Link to post
Share on other sites
On 12/7/2020 at 3:53 PM, Yalson said:

 

And please, don't tell people "the plastic will morph to match if you let it run without load". Because if the gears are of different pitches, it really, really won't. It will just ruin your gears.

@esmuz

not the pitch from 32 to 48! no no...
 i meant that i used american 32p in my japanese 32p cars. it's the module or whatever it's properly called. 04 to 06...? something like that.
all my tamiyas and my ultima ran empirical 32p instead of  metric 32p. the taper of each tooth changed slightly but i had no problems.

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

×
×
  • Create New...