Tamiya QD resto-mod

[Nikko85]

I do love a Tamiya QD, and I do love a bargain. I recently picked up this QD spare parts pile for a really good price on eBay (£16 I think). Whilst the tyres were junk and the wheels were wrong the whole thing looked like it might be in OK condition. You might have also spotted a QD buggy rear axle too, which will come in handy for another build...

As I tend to convert these to modern power (regular servo, brushless etc.) having a parts car is actually fine. My thought was that if there was something critical missing, at worst it would just be spares for my two runners. I find given the recent prices of Tamiya QDs online (I just saw a QD Blackfoot go for more than a regular one) it's far better for me to buy junkers like this, especially as I've got a body lined up, as buying a working car to mend just doesn't make financial sense anymore.

Opening it up it was dirty, and some metal will need a cleaning, but overall it's quite nice (apart from the bits that aren't) with a complete, non broken clean chassis, steering parts and gearbox, hurrah.

The plan for this thread is to make a reference and guide for anyone who might be interested, so I'm going to go slowly, and take lots of photos. 

I'm going to start with the power unit.

Here is the gearbox. Spiders webs? Check. Mystery grease? Check. Bird mess? Maybe General yuck? Check. 

 

But the screws weren't rusted, so I could open it up. It's almost pristine under there, amazing! Can we just take a second to look at how well made this is; thick 0.6 Mod gears going into 0.8 Mod, metal motor plate (for sturdiness and heat transfer) and two selectable gears with a full differential. I've owned a few of these and even with a 7800 KV giving me 50K rpm they still feel stable and are relatively quiet. 

The gearbox takes 5x11 bearings, which will come later, but for now I want to focus on the motor. The standard 280 motor sits on the two nubs which come out of the motor plate. These are the standard size for 280 motors and are 14 mm apart.

The Ezrun 2030 motor I want to use has a screw spacing option of 14 mm. As the motor is smaller than stock we shall need to screw it into place. When you flip the motor plate you can see the nubs are pressed from the original plate.

This is great, as it gives really fool proof drilling guide, simply use a 2.5 mm drill bit, place into the recess and drill out, leaving you with two perfectly placed holes. This will be my first job this evening. There is space under the motor mount for screw heads, so there is no issue with these fouling the spur gear. 

The stock motor is a rather weedy 280 motor. I suppose Tamiya just never ever wanted this to break, but the gearbox can take such a faster motor than this, it's odd it's just so over engineered. A QD black motor was released as a hop-up, but from what I see this was only available for the buggies and tour car QDs.

The pinion a 0.6 mod 10 tooth with a 2mm bore. 99% of all toy grade cars I've seen use 8T pinions, so spares might be harder to find. The pinion is not very long. The QD buggies have a spur gear that slides along the pinion, engaging either high or low gears, but here the gear selector is a little further down the line. This might be what makes these gearboxes so stable, as I've often found a long pinion starts to produce oscillations. 

I will pull the pinion and drill out the gearbox this evening. I will also see if these could take a 380 or 390 motor, I've no plan for this myself, but it might be interesting to see and give people more options! 

To be continued when the toddler is fast asleep.

 

 

 

[Mouc-RC]

Great. Great thread
QD's, especially Monsters for me, are amongst the best Tamiyas, in that sense that they're super fun AND super reliable. Got a few of them, with my Bro:

- Midnight Pumpkin QD (46004)
- ClodBuster QD (46012)
- BlackFoot QD (46016)
- Super Sabre QD (46002)
- 2x Avante 2001 QD (46010)

Sir Nikko85, please let us know if you're OK that us, other owners of venerable QD's, do post some pictures/videos in your thread

 

[Nikko85]

8 hours ago, Mouc-RC said:

Great. Great thread
QD's, especially Monsters for me, are amongst the best Tamiyas, in that sense that they're super fun AND super reliable. Got a few of them, with my Bro:

- Midnight Pumpkin QD (46004)
- ClodBuster QD (46012)
- BlackFoot QD (46016)
- Super Sabre QD (46002)
- 2x Avante 2001 QD (46010)

Sir Nikko85, please let us know if you're OK that us, other owners of venerable QD's, do post some pictures/videos in your thread

 

That would be great. I think for now I'd like to keep it on the resto mod as to keep it concise, but once done yes, I want other examples!  I do want to keep this to the monster truck chassis as there are a few buggy threads and the 'brushless QD thunderdragon thread' covers a lot on those! 

[Nikko85]

I had meant to do more this week but my two year old got sick, so haven't really done much of anything for a week. He is better for now, so back to tiny toy cars!

Using the pre pressed holes I drilled out the motor screws. I ended up drilling out to around 2.8 mm, rather than the 2.5 mm I needed for the screws, as when drilled out originally there was a bit of noise from an imperfect mesh. Allowing a tiny amount of wiggle room allowed me to get it spot on, for a much quieter gearbox. Pinion is around 10.8mm proud of the motor plate.

Not shown here but the screws each got a 2.5mm washer then really screwed in tight. The EZrun 2030 18T is the motor of choice for me. Plenty of speed but not too crazy either.

After that the gearbox  gets 4 x MR115 bearings.

This means the axles are now nicely sealed and should run smoother.

Gears get a clean and some grease. The gear selector can get a little stiff in these, so the hexagon shaft was greased and the selector manually moved up and down the shaft till it felt smooth.

All plugged in and running quiet. 

The original 7mm spines were missing but the Tamiya splined 12mm hex works perfectly on these axles. 

This will mean new wheels, but that was the plan anyhow.

Next up soldering. I usually hate soldering usually but this seemed to go ok. My plan is to use the original AA battery connections so I soldered red and black wires onto the battery tabs. These will get a tamiya connector which will in turn plug into the ESC. I removed the old electronics.

Next up is steering. Here is the original servo and horn.

Essentially you remove this, cut the servo tabs off a full size servo and shove into the gap.

You can keep the same servo horn and saver. The only mod you may need to do is file a little off the axle cover where it presses against the servo, stopping the whole thing from screwing back in.

Pre surgery 

And afterwards. Note that little raised part is gone

The whole unit is very neat. Being servo on axle it makes for very direct steering, and there is a good steering angle. With the QD buggies I replaced the 2mm wire with 3mm studding and ball connectors but this feels quite solid, so I don't bother.

And that is it for today. Tomorrow I will clean up some parts and try and throw it all together to check it runs.

 

 

 

[Nikko85]

For these builds I use Tamiya GF01/WR02 wheels. This is for two reasons, firstly the QD wheels are often missing, and secondly they give quite a narrow track width. It's fine with stock power, but when you increase the speed adding extra width will really really help with stability. 

The rear is really easy, you either use a Tamiya splined hub (as pictured above) or 3D print a 7-12 mm hex adapter. 

The front takes a little more work. Essentially you add a spacer and then two 5 x 12 bearings. If the spacer is just right the wheel nut that can be fully tightened. The wheel then sits on the bearings. The wheels need to have the centre holes increased to 5 mm, this is best done by using the bearings as a guide then using a 5 mm drill bit.

You need around a 10.38 mm spacer between the bearings and the steering knuckle - this was done with a 3D printer, but I have in the past just used aluminium tube. I also printed a few versions 0.5 and 0.8 mm short, just in case I want to use a metal washer in between the plastics and the bearing.

When done properly the wheels will spin quite freely, and the front track width will almost match the rear (they are slightly narrower, but you have to really look to see). Yes, the wheels rub against the nut, but I've not found this an issue at all, as the wheels weight rests on the bearing, and a tiny amount of grease (or PFTE coated washer) sorts the problem. 

The upside is a wider car with a much better handling, and the ability to use modern tires/wheels.

Here is a photo of the new track width, much better!

 

[Nikko85]

With a brushless motor on the back these things will tend to wheelie, which means you need a wheelie bar. I designed a few on Tinker cad. They attach to the gearbox guard, with zero modifications needed of the chassis,

So, now we are ready to put a body on!

Obviously you've got the classis QD bodies you can use. The Beetle seems to be the most common one, followed by the Pumpkin, Blackfoot, then perhaps the Clod and Jeep, which are pretty rare and usually pretty expensive. As these cars were made in the late 80s lots of the bodies are toast, so there are many more chassis than good bodies, however there are a few options if you know where to look.

The most easily available is the MN models FJ45 - this fits the wheelbase almost perfectly, arguably better than the GF01 FJ45! It's around £23 or so.

The WPL D12 body also fits really nicely!

However this one is going to have something a little different, which I will try and do tomorrow.

[Mouc-RC]

Excellent!

Also the 12mm hexes with splines, thanks for sharing the tip. Never thought of that before, stupid am I

[Nikko85]

7 minutes ago, Mouc-RC said:

Excellent!

Also the 12mm hexes with splines, thanks for sharing the tip. Never thought of that before, stupid am I

They also work with the QD buggies too. I saw it on @wolfdogstinkus QD Thunder Dragon thread, I would have never thought of it otherwise! It's a good piece of knowledge, as I've never seen the QD wheel hubs for sale anywhere.

 

[wolfdogstinkus]

I'm sure I've got a few spare wheel hexes for the quick drive buggies, my trouble was never being able to find a wheel with such a small hex. I thought I'd found some Chinese wheels on eBay but I never bothered buying them as I had the Kyosho tyres by that point.

[wolfdogstinkus]

15 hours ago, Nikko85 said:

They also work with the QD buggies too. I saw it on @wolfdogstinkus QD Thunder Dragon thread, I would have never thought of it otherwise! It's a good piece of knowledge, as I've never seen the QD wheel hubs for sale anywhere.

 

Not mine, but I must have some spare because I did destroy a few gearboxes.

https://www.ebay.co.uk/itm/155563949986?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=22Slubt5Qyq&sssrc=4429486&ssuid=AmMhQ-pWTKq&var=&widget_ver=artemis&media=COPY

[urban warrior]

Hi, I may be late, but If there is some need of QD rims I could help out, since I got several unused sets in white and yellow.

Cheers

Martin 

[wolfdogstinkus]

Thanks @urban warrior   . I'm ok for rear rims now, found a load ages ago.

Not had my quick drive out for ages, (not at all last year) must make an effort this year. 

The 12mm hex thing has got me thinking about touring car wheels, I know it's cheating a little bit but all the other cars in the speed run thread are 1/10 and it would give me some much needed ground clearance. Hmmmmmm. Lol

[Nikko85]

On 4/9/2024 at 12:30 PM, wolfdogstinkus said:

 

Not mine, but I must have some spare because I did destroy a few gearboxes.

https://www.ebay.co.uk/itm/155563949986?mkcid=16&mkevt=1&mkrid=711-127632-2357-0&ssspo=22Slubt5Qyq&sssrc=4429486&ssuid=AmMhQ-pWTKq&var=&widget_ver=artemis&media=COPY

Nice. The monster trucks have a different hex, much closer to the MK1 buggies (thundershot and super sabre) which are just 7mm plain brass hex with splines on the inside. I did however pick some of these up for the QD buggy gearbox that arrived with this job lot!

I have a rather special body planned for this, but in the meantime I thought I would test this, it's an FJ45 painted orange with matching orange wheels. Needs some livery but I might keep as an alternative runner shell. 

Looks pretty cool. The rear tires are the ones from the GF01TR, an interesting piece of Tamiya trivia, these were first released as a hop up for the QD range

I am actually growing towards the orange. Might go for a monster truck livery perhaps! Good thing is that these bodies are cheap and plentiful so although I've never cracked one you feel a little more relaxed than driving with a 1988 QD clod body!

Ps I can always send over a few 3d printed hex converters to anyone in the uk?

[Nikko85]

So time to wrap this up, and then it would be great to see other users QD monster trucks.

For this I decided to use a Taiyo (often released by Tandy and Radioshack) 4x4 done up in bigfoot style. I printed some brackets to hold the body posts, so I could use the holes in the body which are there for alternative shock mounting.

The posts have sellotape around the base as they are 5 mm and I stupidly made them for 5.5 mm. I will reprint on Monday.

And now the body can go on.

Really happy with this! The roll bar is made from 5 mm aluminium tube hand bent.

So what other QD trucks have people got? 😃

[Grumpy pants]

Both of the have turned out really well ⬆️

Lots of skill is being used by you 👏

[Mouc-RC]

Excellent work, outcome is stunning! Will you run them (gently) ?

My Brother+Me fleet looks very sorry for itself in comparison, but we have some projects for these so-fun little trucks:
- A Sand Scorcher replica (first pass done on the red body, but decals are too big, and no paint-job obviously. This body had a short life on a Nikko buggy chassis, but the kids finally didn't care...)
- Kind of pulling-truck maybe with the Pumpkin (this one has "Blitzer wheels" on the front, with removed spikes only to have the ribs)
- The Blackfoot will certainly deserve a new full paint-job, maybe in brown/beige.
- The Clodbuster will also get a custom paint-job, this one is owned by my Brother.

I'm in the "trial & error" process of making some laser-cut front bumpers. Still hesitating on the design, and I want to incorporate some "bending slots", like Ikea steel drawers, to get a nice (and easy to do) bended shape.

Love these little beasts!

Some YouTube vids: Click

[Nikko85]

On 4/14/2024 at 5:13 PM, Mouc-RC said:

Excellent work, outcome is stunning! Will you run them (gently) ?

My Brother+Me fleet looks very sorry for itself in comparison, but we have some projects for these so-fun little trucks:
- A Sand Scorcher replica (first pass done on the red body, but decals are too big, and no paint-job obviously. This body had a short life on a Nikko buggy chassis, but the kids finally didn't care...)
- Kind of pulling-truck maybe with the Pumpkin (this one has "Blitzer wheels" on the front, with removed spikes only to have the ribs)
- The Blackfoot will certainly deserve a new full paint-job, maybe in brown/beige.
- The Clodbuster will also get a custom paint-job, this one is owned by my Brother.

I'm in the "trial & error" process of making some laser-cut front bumpers. Still hesitating on the design, and I want to incorporate some "bending slots", like Ikea steel drawers, to get a nice (and easy to do) bended shape.

Love these little beasts!

Some YouTube vids: Click

Those look great. I am quite jealous of the Clod. Lovely looking car.

I will run this, I just need to find the time! 

[Mouc-RC]

Thanks (not as nice as yours)..

The "Blackfoot QD" main body is the same as the QD Clodbuster's one.

Bumpers, front-grill, exhausts, & air-scoop/blower filters do differ, but that's it :)

 

[Nikko85]

19 hours ago, Mouc-RC said:

Thanks (not as nice as yours)..

The "Blackfoot QD" main body is the same as the QD Clodbuster's one.

Bumpers, front-grill, exhausts, & air-scoop/blower filters do differ, but that's it

 

Yes, I had not noticed they were the same!

I played around with the gearbox, just trying to get it as quiet as my second QD. It's not quite there, so I'll play tomorrow. I'm not sure if it's a grease, mesh, motor or pinion thing, but it seems to squeal more.

I also replaced all the screws with 3 mm stainless screws. For most of the screws you can use 12 mm ones, apart from the battery holder side panels which need 8 mm.

I also tried out some wheelies.

To be honest the wheelie bar is too pushed out, meaning the car doesn't angle back enough, and so the wheelies are quiet short. The original printed design was for the FJ45, where it needed a much longer wheelie bar to protect the bed of the car. I may design a shorter wheelie bar which allows the truck to get much more vertical, which should increase stability.

[ad456]

That looks a wicked little machine dude! 

[Nikko85]

37 minutes ago, ad456 said:

That looks a wicked little machine dude! 

Thanks, it handles like a smaller, lighter, nimbler CW01, without the bump steer.

 

 

[Mouc-RC]

1 hour ago, Nikko85 said:

Thanks, it handles like a smaller, lighter, nimbler CW01, without the bump steer.

Fully agreed!

I'd say I hugely prefer the QD Monsters to the CW-01s... (would be nice to find a smaller LunchBox body to put on a QD chassis, by the way, could be cool next to a QD Pumpkin )

[Nikko85]

1 minute ago, Mouc-RC said:

Fully agreed!

I'd say I hugely prefer the QD Monsters to the CW-01s... (would be nice to find a smaller LunchBox body to put on a QD chassis, by the way, could be cool next to a QD Pumpkin )

The RadioShack have a model that works well, it's an almost perfect 1/14 scaled down LB. I will find the model.

[ad456]

1 hour ago, Nikko85 said:

Thanks, it handles like a smaller, lighter, nimbler CW01, without the bump steer.

 

 

Sounds like a cracking backpack car!

[Mouc-RC]

On 4/18/2024 at 6:55 PM, ad456 said:

Sounds like a cracking backpack car!

Size of the backpack doesn't matter, the final fun factor is almost the same

(yes, I bought a super-nerdy backpack)