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Terra Scorcher 2020!!

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OK Folks, good news, I have completely stripped and rebuilt my daughters rear gearbox and the noise and vibration issues no longer exist, gearbox runs super smooth and MUCH quieter.

  • I removed and binned all the re-re gears, shafts and UJ's
  • Fitted 1980's vintage gears and vintage (dark bronze coloured) shafts
  • Fitted vintage diff drive cups, dog bones and axle cups
  • All the bearings were checked, found to be dry so were oiled using a penetrating oil
  • Filed a poor bit of moulding off inside gearbox face that was scrubbing on spur
  • Used Hudy graphite grease on everything (my daughter had only used a small amount of the grease Tamiya supply and most of that had flung off so the gears were dry)

Re-assembled and test run and it now purrs :)

NOTE: We also replaced the rear UJ driveshafts with dogbones. The new design of UJ with the re-re, while stronger than then original style UJ, will not operate at anywhere near the same steep angles (I've just bench tested this tonight) and due to the long droop on the rear suspension of this buggy when held off the ground or even on the ground with a light battery, the driveshaft angles are still too steep and create horrendous vibration. The thundershot dogbones are far superior in this respect, they will run very steep angles without complaint and in this case they they have now eliminated all vibrations even under full throttle with the wheels off the ground. I have run dogbones on the rear of all my thundershot based cars for decades behind very high power motors and suffered no worse wear rates than UJ's. The UJ's should only really be used on the front of this buggy design IMHO.

NOTE2: I know I should not have to be doing this to a brand new buggy but it was the cheapest, simplest fix. My daughter was getting very concerned by the noise the gearbox was making and she was concerned she would damage it by continuing to use it. Even though I re-assured her that was not a problem as we had stacks of spares anyway however she still felt the noise and vibration was taking the edge off the enjoyment of running her new buggy. I'm glad it is all now fixed, 30 minutes to do and cost me nothing.

gearbox_rebuild.jpg

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So just to update after contacting Tamiya USA. I did send them a video of my buggy.. after some back and forth about doing this and that, I asked what they can do to fix this issue given that this is technically a "new" kit... now thery are telling me that if I want to send it to them for evaluation, they would gladly check it... I asked if there's any cost to me if I send it to them for evaluation.. they are telling me that they have not encountered any bad batches of this kit... if this is zero out of pocket, I would really consider it... I guess I just have to make sure I install the stock can and remove my 17.5t brushless... 

Do you really think that they will check it and find any design flaw with it? Or will they just claim that every component is up to spec and it is a build issue? I remember watching something on YT... I think it is on the Tamiya Legend video, where he built a ReRe Big Wig and it had the same drive gear problems... 

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Guess we’re pretty much doomed with these T shot family of cars. Can’t see the fire dragon being any better unless they change the moulds.

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It's annoying yes, but the buggy runs fine, just a bit noisy

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51 minutes ago, Avante2001R said:

Guess we’re pretty much doomed with these T shot family of cars. Can’t see the fire dragon being any better unless they change the moulds.

I am extremely lucky to have rationalised my car collection 20 years ago and concentrated on just two chassis types (thundershot and Avante 2001), I then bought thousands of spares for just those two types twenty years ago when parts were cheap and plentiful (Used Terra Scorchers sold on eBay for £25-£40 back in 2002!).  I bought enough parts to build 20 new chassis and bought 10 used thundershots and terra scorchers for more spares. Total cost was about £1000 in 2002 for the equivalent of 30 thundershots.... I'm not joking!

However I can see a time soon when we'll be able to mould or print our own replacement parts at home with relative ease. Maybe within a few years? Plastic technology and 3D printing are developing rapidly. Maybe not good enough for gears just now but we'll get there.

Also you can now get very small CNC lathes and milling machines for home use that will allow a broader number of people to machine shafts, axles etc at home using programs downloaded off the web. I am fortunate to be able to program a CNC machine tool but many can't so I can see a market for either cottage industry in making parts or selling the programs)

I have great optimism that thundershots will still be running in 40 years time :)

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1 hour ago, mud4fun said:

I am extremely lucky to have rationalised my car collection 20 years ago and concentrated on just two chassis types (thundershot and Avante 2001), I then bought thousands of spares for just those two types twenty years ago when parts were cheap and plentiful (Used Terra Scorchers sold on eBay for £25-£40 back in 2002!).  I bought enough parts to build 20 new chassis and bought 10 used thundershots and terra scorchers for more spares. Total cost was about £1000 in 2002 for the equivalent of 30 thundershots.... I'm not joking!

However I can see a time soon when we'll be able to mould or print our own replacement parts at home with relative ease. Maybe within a few years? Plastic technology and 3D printing are developing rapidly. Maybe not good enough for gears just now but we'll get there.

Also you can now get very small CNC lathes and milling machines for home use that will allow a broader number of people to machine shafts, axles etc at home using programs downloaded off the web. I am fortunate to be able to program a CNC machine tool but many can't so I can see a market for either cottage industry in making parts or selling the programs)

I have great optimism that thundershots will still be running in 40 years time :)

I can believe it, I bought a brand new Egress back in 2001 with technigold motor and Adspec radio setup for £140 from a guy in the USA. 

Im not a fan of current 3D printing but as you say I’m sure it will improve to where it’s almost like an injection moulded or machined finish. 

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4 hours ago, taffer said:

It's annoying yes, but the buggy runs fine, just a bit noisy

True... but in terms of quality, fit and finish, this is by no means acceptable especially coming from a company like Tamiya who is considered to have high standards with the product they sell... anyhow, Tamiya USA will cover the shipping cost back to me but I do have to pay the cost to ship it to them... if the shipping cost is reasonable to me then i would probably send it for me to have a closure... if they do something about it then great... if not and they say it is within spec, then ok... i honestly dont expect them to give me a new kit or new parts but at least i made my point to them... thoughts?

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A lot of Tamiya kits have switched from cream coloured gears to black, but not in this case?

I would add to your letter in your package to Tamiya USA why use new style CVD's when at full throttle, at full extension they chatter and vibrate!

I'd chip in a £1 towards your postage cost to help....

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7 hours ago, taffer said:

A lot of Tamiya kits have switched from cream coloured gears to black, but not in this case?

I would add to your letter in your package to Tamiya USA why use new style CVD's when at full throttle, at full extension they chatter and vibrate!

I'd chip in a £1 towards your postage cost to help....

Nah, no need to chip in... it's all good... I'm just hoping that they would really look and evaluate what's going on with it... If future ReRe's will have a similar issues with fit and finish, I don't think people will be satisfied with it... So the least they should do is to actually look into it...

I'm just hoping that they won't give me a hard time for using hinge pins and not following the assembly manual as-is... but that should have nothing to do with the drivetrain issues anyway... 

Do you think I should put the stock silver can instead of the brushless motor though?

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30 minutes ago, taffer said:

Yes with silver can

how about the hinge pins? now I'm getting anxious because they might claim that i deviated from the manual... 

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The gearbox in mine is horribly loud.  i have taken it apart twice to see if everything is in place and it looks good.  I have taken out the rear universals as well in favor of dog bones and that seemed to correct a bit of noise.

Has anyone had any issue with the VQS?  I saw a few posts up it stated someone had an issue with the bigwig too?  

 

 

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7 minutes ago, Sweatpants said:

The gearbox in mine is horribly loud.  i have taken it apart twice to see if everything is in place and it looks good.  I have taken out the rear universals as well in favor of dog bones and that seemed to correct a bit of noise.

Has anyone had any issue with the VQS?  I saw a few posts up it stated someone had an issue with the bigwig too?  

 

 

 If you jump tp 3:50 on the video, it will shows you the concerns he was having with the tight feel of the gearbox... i know @mud4fun came with a brilliant solution but unlike him, I don't have any spares to use and I certainly don't want to shell out more money being that I am not into racing my RCs or a hardcore collector/enthusiast... 

not sure if we should all let Tamiya USA (at least) our concerns and maybe create some buzz for them to take action? highly doubt but... who knows... 

 

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19 minutes ago, MICHAELs TopForce17 said:

i also emailed tamiyausa about the noise issue but they stopped responding to my emails.

Post on social media tag them in. 

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1 hour ago, MICHAELs TopForce17 said:

i also emailed tamiyausa about the noise issue but they stopped responding to my emails.

I guess it depends on which customer rep gets the ticket. Mine was responsive and I may had to follow up once after a week of not hearing back... other than that, the person I'm in contact with are responsive. As a matter of fact, he told me that he will the be one actually checking out the car himself... do you think it would a difference if you make a follow up email and inform them that you know someone with similar problem and that it will be looked upon by another tamiya rep? 
 

so it looks like it would cost me about $20-25 to send it to them... debating if the cost is justifiable and if they even consider doing anything about it... anyhow, i captured a video of my Terra so hopefully we can have a comparison amongst our kits... mine is really scary loud especiallt when throttle and is let go...like allnif a sudden it is getting stuck... 

https://youtu.be/JlRHb1gWclM

 

 

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The video seems to be posted as private and I can't see it.

14 hours ago, burakol said:

how about the hinge pins? now I'm getting anxious because they might claim that i deviated from the manual... 

Put everythink back to manual specs before sending it, no doubt 

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Yes you wouldn't want to send it with hinge pins and get it back with screw pins!

Do they confirm they return it tracked and insured?

What is their procedure if you receive it back damaged?

It sounds like if something goes wrong you will be waiting to sort it out?

@burakol your vid comes up as private

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As for the hinge pins, I'm concerned that by screwing the screw pins it will compromise the integrity of the chassis. They shouldn't even disassemble the suspension parts to check the drivetrain... 

Sorry about the video, here it is again.

If you notice when I let go of the throttle,theres the loud grinding sound... it is not coming from the driveshaft but inside the diff case... 

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Ahhh if you have built it with shafts from the outset I'd stick with your shafts, I wouldn't put the screw pins in.

Maybe put a note in explaining this just in case?

Your rear is at full droop, if you squeeze the arms up slightly I'd expect it to be slightly quieter because a few of us have noticed the new CVD's they have shoe-horned in do catch at full droop!?

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yeah it quiet downed a bit but it is still noticeably loud and concerning. i did email the guy from Tamiya asking to give me a rundown of what he will be doing and if he needs to disassemble the kit up to its internals... i would assume he will, but at the same token, I did mention that I used some hinge pins and c-clips in lieu of the screw pin due to a know weak spot on the A5 part... I would hope he knows what that means given that he works for Tamiya... I would be weary of sending the car if does not know a thing about these cars... 

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i sent another message yesterday and today they responded that i could send my car in for inspection. i dont think its a good idea for me as i am in canada. hopefully my car will quiet down in the spring when i plan to use it. also seeing if they would send me a new set of gears e parts.

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Guys, I can honestly say that my daughter's re-re terra scorcher is running superbly now. It is quiet, smooth and quick.

Even with the 22T (17K rpm, 400g torque) Kyosho truck motor in it which she ran on the last two postal racing rounds it is so quiet compared to when built using kit supplied parts. It also matched my Avante2001 for performance and lap count despite me running a 13T 33k rpm motor and 2S LiPo whereas my daughter was running the 22T on a 7.2v NiMh!!! She could have gone alot quicker but was worried about rolling and trashing her nice shell.

There are literally no other issues with this buggy other than the bevel gear noise and the new design UJ driveshafts which are not suitable for the rear end of a TS when running with shock spacers.

Since fitting dogbones and vintage bevels it is not only quiet but has zero vibration. My daughter is over the moon with it.

For the next postal race round she is reverting back to a Reedy 19T and a 14t pinion so will be back up to 25mph top speed. She doesn't need it any quicker as she has her Egress with a Dyna run super touring motor and 8.4v for really high top speeds.

She has now done about 300 laps (10 x 5min races) with her Terra scorcher since fitting dogbones and the car has zero issues. It is very obvious the issues were a combination of bad moulding on bevels, lack of lubrication of kit supplied bearings and naff driveshafts. She is also now running on a vintage steel motor mount too. That also helped drop noise levels especially after setting pinion correctly, NOT to the kit supplied incorrect offset.

 

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Note: the driveshafts were causing horrific vibration when my daughter lifted off the throttle to enter a corner. As the rear became unloaded and lifted, as the front dived, those driveshafts just couldn't cope with the angles involved and created a horrendous rattling. All that has now gone completely. The original vintage UJ driveshafts did not suffer these issues BUT they were not as strong. There is nothing wrong with the new driveshafts as long as driveline angles are kept smaller, so fitting spacers in shocks, heavier batteries or not using the widest shock spacing collar.

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