Interesting combination...

[Juggular]

I found this while restoring Blazing Star TA01. 

hmmm.... what could be wrong with this...?  (it took me some time to figure this out)

 

And this looks like 48 pitch, right?   (or is it 06?) 

I was thinking, "Oh, the youth..."  Then I remembered I once wanted all the speed I could get, when I was younger.  Wouldn't it be funny, if I had done this in the 90's in the pursuit of speed, sold it, forgot all about it, and re-bought the very same car?  This could be my doing... and I'd go "oh, the younguns..."  

Anyway... the result of running 23t gear on 20t spacing is below... almost no grease left either... 

Fortunately, judging by wear on tires, bushings, and underside, this vintage looks like it ran less than 10 packs.  

And spur gear's teeth are about to be like shark teeth, but still usable.  

I once thought the meeting of teeth is like feet walking on stairs. 

While trying to understand why gears would turn to dust, I found the video below. 

It seems like the teeth are actually sliding and grinding on each other. 

Bad spacing will worsen it. Swamping in grease won't be good either, though... 

I'll have to get some suitable 48DP pinion.  I'll run maybe 5% larger tires, so maybe 19T?   

 

 

[TurnipJF]

Possibly better to get a 0.6 Module pinion to match the spur. Subtly different to 48 DP from what I gather. 

[Juggular]

6 minutes ago, TurnipJF said:

Possibly better to get a 0.6 Module pinion to match the spur. Subtly different to 48 DP from what I gather. 

I forgot which was metric.  I guess 0.6 is the metric Tamiya uses?  Then I shall go with 0.6 module. Thank you, Turnip! 

[ThunderDragonCy]

Definitely 0.6mod. Get the 50529 gearset to replace the Spur. I think 21t is the largest pinion you can fit there. If that's going to be a runner I would really strongly suggest a metal motor mount before you put it all back together too. Isn't there a speed tuned gearset you can get with a smaller Spur for bigger pinions? Or did I confuse that with something else? 

[Juggular]

46 minutes ago, ThunderDragonCy said:

Definitely 0.6mod. Get the 50529 gearset to replace the Spur. I think 21t is the largest pinion you can fit there. If that's going to be a runner I would really strongly suggest a metal motor mount before you put it all back together too. Isn't there a speed tuned gearset you can get with a smaller Spur for bigger pinions? Or did I confuse that with something else? 

I'm looking into that motor mount.  Initially, just to have something that could cool the motor better. 

But now I'm curious... Does that break often?  

 

[Superluminal]

Yes - the hole position needed for the motor doesnt always match the pinion teeth if the spur was also changed previously. The speed tuned kit has a table that tells you what holes to use.

[ThunderDragonCy]

13 minutes ago, Juggular said:

I'm looking into that motor mount.  Initially, just to have something that could cool the motor better. 

But now I'm curious... Does that break often?  

 

Yes. The blazing star I bought it was broken despite the car being completely mint otherwise. There's a Manta Ray hop up kit from tamiya with metal mount and top force upgraded prop shaft to replace the coat hanger. 

[Honza]

10 hours ago, Juggular said:

I forgot which was metric.  I guess 0.6 is the metric Tamiya uses?  Then I shall go with 0.6 module. Thank you, Turnip! 

If you have issues sourcing 0.6, you can use 42p. Do not use 48p, that's equivalent of 0.53 metric, so it won't work.

[Ray_ve]

9 hours ago, ThunderDragonCy said:

Yes. The blazing star I bought it was broken despite the car being completely mint otherwise. There's a Manta Ray hop up kit from tamiya with metal mount and top force upgraded prop shaft to replace the coat hanger. 

Sounds familiar, my 2nd hand blazing star has the exact same problem.

I just ordered the Tamiya 47373 kit on ebay from our friend Tony.  And I'll get a steel pinion instead of the aluminium one. 

[Re-Bugged]

On the subject of gear spacing so to speak, one tip mentioned in a recent Kyosho Javelin build with slots in the motor mount plate is to take a slip of paper and mash it between the pinion and spur gears before tightening up the screws, something not mentioned in any Tamiya kits I've built. 

[Juggular]

7 hours ago, Re-Bugged said:

On the subject of gear spacing so to speak, one tip mentioned in a recent Kyosho Javelin build with slots in the motor mount plate is to take a slip of paper and mash it between the pinion and spur gears before tightening up the screws, something not mentioned in any Tamiya kits I've built. 

Come to think of it, in recent years, I have not seen the paper-thing.  But I think Tamiya must have had that.  If my memory is not failing (prematurely), I learned that from Tamiya manual back in the 80s.  I wonder why they are not showing that anymore... It's still a good tip.