Restoring 2x Vintage Madcaps

[Muso31 75]

Hi all, approaching the mid life crisis caused me to enter the loft to find my vintage Tamiya Madcaps that have been stored away for 25 years. The cars were originally purchased in the late 80's and I'll be rebuilding these, so I thought I'd share the progress as a lot has changed over the years and I haven't kept up to speed since the late 90's, even so far it's been a bit of a learning curve.

To start with, here's some photos as as I begin the journey, I'll call them the 'Red' and 'Blue' madcaps. In the Red Corner we have:

Red Madcap

20220705_095754.jpg - Shell on photo

The stock motor was previously updated to a Demon Power Bushed 18T motor. The decals were also updated to include Fiat and Ford stickers etc... yes these will be removed (I was a teenager). The hole in the shell was my boyhood attempt to cool the ESC as in the late 90s's I found out that an ESC could be fitted... so I ordered an Mtronics Digi Sport RV M ESC. Which leads me on to the internals:

20220703_163211.jpg - Shell off photo

Nothing much to see here aside from the new ESC and a lot of dust. The ESC is already on eBay as I'll be replacing it with a more modern component. 

The plan for the Red Madcap will be to keep it similar to its current configuration, but clean it up, improve some screw types, and look into a new body/shell. It'll remain on the 18T brushed motor.

On to the Blue corner:

Blue Madcap

20220705_100020.jpg - Shell on photo

Stock Tamiya 540 motor and the stock yellow patch up paint to fill in the original spray paint wear! No idea what I was thinking here but fortunately I've matured over the 25 years and acquired much better craft skills. This Madcap was originally sprayed the same colour as the wing until teenage hormones were unleashed in the form of some yellow paint. There's a few more rogue decals which will be removed of course.

0220703_193430.jpg - Shell off photo

All very basic here, a lot of cleaning to do and a lot of components will be replaced with their more modern day counterparts.

The plan for the Blue Madcap will be to push the boundaries a little more and take some inspiration from the following post: 

 

Having done some research I've decided on a Hobbywing quicrun 1060 ESC for the Red Madcap. And so far for the Blue Madcap I've picked up a Hobbywing Quicrun 10BL60 Sensored ESC, FlySky FS-GR3 receiver, and 3Racing DT-02 Aluminium dampers. I'll be replacing the Futaba S148 steering servo with a Etronix ET2035 for now, and am undecided on the new brushless motor, but it'll most likely be a 17.5T brushless sensored. Next up I'll share some photos of progress so far as I start the project. I'll use a follow up post to keep this a shorter read... 

 

[naturbo2000 570]

Subscribed.

Everyone loves a Madcap. @Kol__ will be along shortly. If you go find his or my build threads, you'll see you can go nicely overboard.

[Muso31 75]

Starting with the Red madcap, the plan is mostly to keep it true to its roots but improve upon some weaknesses in the model such as screws which are easily threaded, and reducing play and so on. The new ESC is in place, and I opted for XT60H connectors after doing plenty of research:

 

The XT60H version doesn't require heat shrink also. The on/off switch that comes with the Hobbywing 1060 really isn't ideal for the madcap, and I really liked the switch being accessible underneath the chassis rather than removing the shell. The switch on the Hobbywing is too short to reach under the chassis and the cables themselves are also short, so I rewired the original madcap switch. It pops out of the housing where its easily accessed for soldering:

I soldered a JST connector to the switch and then crimped one onto the ESC:

This allows the original switch to sit in its rightful home, and addresses the issue with the crazy short Hobbywing switch:

The shocks are being de-greased while I await some new CVA oil seals (Tamiya item 50600), and some 400 Tamiya oil (Tamiya item 53443):

 Next up I'll be replacing a lot of the screws in the vehicle with new stainless steel ones including additional nuts rather than using self tappers which can thread. I'll reduce some of the play in the front suspension arms also...

[Muso31 75]

The front shocks have new seals and new oil as I've removed the 20 year old rubber seals...

 

In addition to this I've begun to remove old screws, especially where self tappers can be replaced, out with the old:

In with the new flanged stainless steel screws:

I've then used Hexagon Serrated Flange Nuts wherever possible, or M3 half nuts with some locktite as below:

 

The goal now is to address the issue where a self tapper into plastic is a point that can ultimately fail. Many people are probably happy to address this with threadlock, but I much prefer a nut. For most screws it's easy enough to undertake a straight swap, but for screws such as Tamiya 9805729 used in the front damper mount there's a bit more of a problem as the shaft is thicker than the screw thread for a reason. If I were to replace the screw with an M3 flanged one it would leave a 1mm space around the initial part of the thread:

 

So to fix this issue I ordered some M3 x 6mm black nylon bearings:

6mm was slightly too long on this occasion so I cut those down to fit, and the 25mm flanged screw can then be used with a flanged nut, rather than relying on a self tapper:

 

The almost complete assembly is in place:

I'll be replacing the tyres, and the observant will spot the suspension shafts (37mm shafts from TAMIYA 54613) which I've not clipped yet as I'm awaiting some shims. Most likely I'll replace the two self tap screws in the lower suspension arms with the 48.5mm shafts from this set. These screws were always a prime example of self tappers threading in the Madcap (and most other cars I'd assume). Replacing all self tap screws may be overkill but there's one particular area of weakness that the teenage me tried to resolve with a bit of improvised threadlock:

These screws were threaded, to resolve this I've used half hex nuts again with 12mm M3 stainless steel button screws, excuse the dirt, I took the photo before cleaning this up:

With a 12mm button screw, and a small nut, there is just enough clearance between the new screws and the drive shaft/propeller joint (when factoring in any play). For me, this is a much more reliable solution that the 10mm self tap screws that are present in all madcaps in this area... it's also more reliable than the paint that was previously slopped in! I've now replaced screws on both sides. I've used this approach to screws right throughout, another example being the rear shock mount:

On to some basic maintenance and I've replaced the steering rod adjusters (Tamiya 50633) with some new ones:

And have replace all ball studs (Tamiya 50590), e.g.

For the blue madcap no doubt I'll be doing something more interesting with the steering connectors and turnbuckles. Apologies if there's nothing new here so far, I'm new to this restoration game and haven't read up a massive amount on it! More updates later for those interested....

[Muso31 75]

Last of the mundane updates before things start to get more interesting with some possible vacuum molding for a shell, CNC'ing an engine plate, and deciding upon the tyre conundrum...

Tamiya 54613 contains some nice suspension pins to replace the screws:

I've used the 37mm shaft and the 48.5mm shaft with Tamiya 53539 spacers:

The magic formula here for an exact fit seems to be the 2mm spacers with the 37mm shaft, and 1x 1.5mm spacer with a 2mm spacer on the 48.5mm shaft. This leaves some nicely fitted suspension pins and no play, I've also oiled the pins with 3 in 1:

So here's where we're up to with the Red madcap:

All that's left is to fit some new blue and yellow 16 AWG cable to the motor (with new bullet connectors), and then comes the more interesting parts of the build - As you can see on the photo I'm experimenting with Schumacher mini spikes with some speed disc decals. One for the next post...

[Kol__ 2491]

Nice work mate, that one looks almost ready for action now, and you can relive your youth!👍😀

[Muso31 75]

5 hours ago, Kol__ said:

Nice work mate, that one looks almost ready for action now, and you can relive your youth!👍😀

Cheers, hoping to make the body/wing over the next couple of weeks but she's already had a test ride which was exciting after all this time. I'll have to replace bearings and the front axles as there's quite a bit of 'wobble' when spinning the freewheels. 

Would you know about gearing at all? The pinions were never changed despite the upgraded 18T motor.

[Kol__ 2491]

Interesting about the shell, look forward to seeing what you come up with 👍

The wheel wobble may well just be due to the need to shim the front wheels, rather than worn out parts. There's always a bit of wobble on the wheels as stock, they can be shimmed with 5mm (internal diameter) shim washers, just need to make sure the outer diameter isn't more than 7mm or they can potentially over heat the bearings. Tamiya sell shim sets, which are a bit pricey, but they can be sourced elsewhere. 

In my limited knowledge, gearing wise you should aim for a final drive ratio (FDR) of between 8.5-10. Check out the last page or so of my Madcap Modified build thread, the chaps on here were happy enough to explain it for me. Knowing the ball diff weaknesses on the Madcap, I'd imagine that if you've come down in turns on the motor, you prob want to come down a few teeth on the pinion to reduce the top speed and therefore the stress on the ball diff.

[Muso31 75]

Ah ok I've got some shims thanks, I assumed the axle was worn. I'll have to do something about the gearing as 18T does seem a bit overpowered for the current setup but I could be wrong.

Regarding the shell, the wing casts are ready for forming...

I'll produce some polycarbonate wings/shells alongside some carbon effect wings just for fun. While polycarbonate sheets can be thin (similar to the original) the ABS carbon effect plastic is a different ballgame in that it is no thinner than 2mm so they'll be pretty solid. Aside from this there will be no difference to the originals. Fortunately I have access to the relevant machinary so I can do something about the distinct lack of parts! I'll get them formed over the next week or two. Hoping to cast the A wing 53055 hop up also as it's hard to come by 

[Kol__ 2491]

On 7/25/2022 at 10:10 AM, Muso31 said:

Regarding the shell, the wing casts are ready for forming...

I'll produce some polycarbonate wings/shells

Sounds cool mate. There are a few companies and peeps who do aftermarket shells. I've always wondered about the process. So you create a mould or cast from the original, how is that done and what is the cast made of? And then do you use some sort of press machine to push a sheet of lexan down over the cast to form it? 

[Muso31 75]

On 7/26/2022 at 10:37 AM, Kol__ said:

Sounds cool mate. There are a few companies and peeps who do aftermarket shells. I've always wondered about the process. So you create a mould or cast from the original, how is that done and what is the cast made of? And then do you use some sort of press machine to push a sheet of lexan down over the cast to form it? 

The answer to this depends on the quality level you're aiming for. I've seen a lot of people use plaster of paris and use their ovens etc to create their own shells and while this may work, I don't think it'd be possible to achieve a 'Tamiya standard' level. Initially I've used a dental grade plaster but these casts will also will have a shelf life and could be prone to absorbing moisture. To avoid moisture blistering the lexan requires a polycarb oven. If I were to produce more wings I'd create a stronger cast (could be one for the future). To create the shell from my cast I've used industry standard forming machines, most likely they're the same used in any RC factory. Fortunately I have access to two of these which enables a reproduction which should be exact. I've added a newly formed wing to the red madcap which was sprayed red and some decals applied:

 

:

And also decided to introduce some carbon reinforced uprights (Tamiya 54154):

I removed the screws to pin these with 25mm HPI racing front outer suspension shafts (101302):

 

Red madcap is now complete and awaiting a new shell which I'll get round to forming next month at some stage: 

On to some fun with Blue madcap, for this I formed a carbon effect wing which is quite thick at approx 1.8mm (there doesnt appear to be a supplier of anything thinner):

And have added the 3racing shocks alongside egress wheels, schumacher mini spikes, carbon reinforced uprights, and some 32mm turnbuckle shafts (Tamiya 54249):

Blue madcap will follow the same approach with suspension shafts and E clips etc. I'll post the completed red madcap early September as I have a busy few weeks coming up!...

 

[Muso31 75]

Before I get to the new shells there's a quick update regarding the gearbox plates. I've milled some aluminium plates to fit to the cars, out with the plastic:

 

And in with some aluminium:

 

I was pondering anodizing these but it actually looks quite nice machine finished...

]

 

Will find some time for the new shells soon...

[Muso31 75]

It's been a good while to get these finished but finally an update. Firstly, with help and feedback from @Kol__ I put my CAD skills further to the test to come up with this contraption:

 

Both cars now have some key plastic parts replaced with a much stronger alternative:

 

With these in place I also finished off Blue madcap with the Hobbywing QuicRun-10BL60-Sensored ESC, FlySky FS-GR3E receiver, and a brushless sensored hobbywing QuicRun 3650 SD G2 17.5T motor (more on the brushless discussion shortly):

 

With that we have the evolution in the restoration of these two cars, red staying a bit more true to it's roots than blue:

As for the promised bodies, they're done! Will post those in the next post as there's a 4mb limit on photos, but back to the brushless conundrum... Obviously the current alloy parts will help, but they're not going to resolve a flawed diff design that appears to be present in the model (thanks again to guru @Kol__). Therefore, soon I'll be embarking upon what could be a complete failed venture, but I will be looking into pushing the CAD skills further with a view to creating a custom diff that will be a significant upgrade. May well post the outcome of that whenever it eventually happens

 

 

 

[Muso31 75]

As for the shells... I settled with a nice metallic PS-16 backed with a black PS-5 for Blue madcap:

 

In forming/reproducing the shells I wanted to produce the highest quality possible, the bar was set very high and I'm pleased with the outcome. I've opted for no decals for this model, for red madcap I completed the shell and sprayed it with PS-1 and PS-5. However, there's a decal issue. I ordered 2x sets of Madcap decals from RC Decals and sadly it appears the bar was set very low with these - I've found the quality to be unusable and completely the wrong size, I'm not sure how anybody could use them. Therefore I'm delayed whilst finding a decent set of decals, but that's the last remaining piece of the jigsaw before Red madcap is also complete. It's been a long but enjoyable ride nice to relive the youth, which is something this hobby brings to the table 

 

[Kol__ 2491]

Top work all round mate. The machined parts are of such a high quality👍🏻😎 I like the machining marks too, and I also think an anodised option could be a winner - black or gold for example could be very popular. Would you have to polish out the machine finishing marks first I guess?

Both Madcaps looks awesome mate! Such nice work on the blue one😎 Perhaps just some subtle white Tamiya logos could set it off nicely? I think I have a set of the TRF stickers, just let me know if you need some👍🏻

[Muso31 75]

39 minutes ago, Kol__ said:

Top work all round mate. The machined parts are of such a high quality👍🏻😎 I like the machining marks too, and I also think an anodised option could be a winner - black or gold for example could be very popular. Would you have to polish out the machine finishing marks first I guess?

Both Madcaps looks awesome mate! Such nice work on the blue one😎 Perhaps just some subtle white Tamiya logos could set it off nicely? I think I have a set of the TRF stickers, just let me know if you need some👍🏻

Any finish could be applied to the parts, I made the assumption that as they're behind a cover and nobody sees them it could mean anodised wouldn't be preferred - if it's a preference though I'll have a look into sorting something out, good shout  

Some white decals could look good, cheers for your help with it all 👍🏻

[Nikko85 2231]

Looks great. Love the sensible hop ups and consideration to making something that will really last.

[Muso31 75]

11 hours ago, Nikko85 said:

Looks great. Love the sensible hop ups and consideration to making something that will really last.

Thanks they'll be running from time to time so it's nice to have a few hop ups. Haven't given them a good run yet, obviously I'll need to think about the gearbox for the brushless motor unless a 17.5T is low enough for the diff to manage. I'm assuming not 

[Kol__ 2491]

Any more tinkerings or running of these badboys mate?😎

[Muso31 75]

8 hours ago, Kol__ said:

Any more tinkerings or running of these badboys mate?😎

Red madcap went to my brother from Santa as it was his originally! I'm still waiting to run mine properly as it has a Brushless in. Once the newly designed diff is in production I'll be taking her for a spin! 

I'll be upgrading the A2 diff cover, popping in the new diff, and then looking into designing a new counter gear and spur that can slip and handle more punishment than the stock option. I also upgraded to the racing A wing Hop Up which is quite nice: 

 

Once the gear box parts are in I think that will be it.... unless alloy C hubs etc are desirable 

[BuggyDad 1299]

This topic alongside @bavee's project thread and @Kol__'s many exploits have got me looking at ebay Madcaps. They do seem to come up.

Very impressed with your aluminium parts and interested to hear what your diff redesign is? 

[Muso31 75]

2 minutes ago, BuggyDad said:

This topic alongside @bavee's project thread and @Kol__'s many exploits have got me looking at ebay Madcaps. They do seem to come up.

Very impressed with your aluminium parts and interested to hear what your diff redesign is? 

Hi @BuggyDad - I've taken the Avante/Super astute planetary gears and housed them in a newly designed Madcap diff...

 

 

It's still in testing before being released to prod, although that wont be too long. Full info is on the thread here -