Kol's Madcap Astute Mongrel

[Frankster 2033]

Just seeing this thread now.  Great write up and build.   Just getting start on my journey 😁

[GeeWings 2830]

On 1/23/2022 at 10:40 PM, Kol__ said:

 

Thanks guys, I picked up the original, vintage TTC in a rather expensive purchase of a Madcap it was fitted to. I have now disassembled that car, started to use the TTC on this car and the chassis is destined for my future build of a mint shelfer Madcap, as its the cleanest chassis I've been able to acquire to date.

Since considering the option of fitting a 2018 Super Astute TTC and then looking at acquiring the parts to build one, it is apparent that it is now near on impossible due to the discontinued parts by Tamiya and the rarity of what's out there now globally amongst both shops and private sellers. So it happened that a nearly complete, unused one popped up on eBay this week (anyone on this forum perhaps?), I struck a deal for it and some other rare Astute parts and now am fitting that to the car instead.

The modern slipper clutch on the TTC is much better in my opinion, sure it doesn't have the nostalgia, but I have that in the original TTC that will now probably go in a shelfer or become a stand-alone piece on the shelf. What it does have is a better design and construction, with much more adjustability.

Fitted the aluminium gear support brace that came with the vintage TTC (these are about £40 delivered to the UK from the US if purchased separately) and this should ensure even more reliable running.

The 2018 TTC purchase didn't come with a polycarbonate gearbox cover, so I picked on up from Revive RC. Very good quality, not quite as detailed as the original vintage cover, but very good and very tough as well.

I pushed the gearbox plate into the cover...

...and cut it out with a sharp blade...

Using the vintage cover as a guide I then marked and cut out the hole for the slipper clutch adjustment nut with a scalpel. I considered drilling this, but it proved a little tricky to find the dead centre of the circular top section where the hole sits. Cutting it out was a bit of a ball ache as the polycarbonate is really quite thick on this repro piece - I consider that a good thing though of course as it should prove very durable I hope.

Beyond the photo above (which shows the rough cut done with the blade) I sanded the hole to shape, periodically testing the fit of the little plastic dust cap that fits in there for running. I was able to shape and centre the hole in the case and then ended up running a 10mm drill through it. Result was a nice snug fit, but it took a bit of time and careful consideration.

Existing Madcap/Astute ball diff gearbox with standard 70T spur before removal. Note the carbon gearbox plate, which is a nice touch on this one.

Cocked up on the pinion for the 2018 TTC though! The vintage TTC is able to take between an 18T- 23T pinion.

As I was originally planning to fit the vintage TTC until I found its shortcomings, I had bought a 19T pinion for the gearbox switch. It wasn't until I fitted the 2018 TTC and offered up with motor and 19T pinion that I realised it wasn't going to work with the 2018 standard 82T spur gear. The 2018 manual states it will take a between a 23T-27T pinion gear, so 19T is well beyond that spectrum.

With the motor rotated right forward it hits the casing...

...and the 19T pinion can't mesh with the spur gear...

Paying a but closer attention or doing a little more research on my part could have flagged this up sooner, but hey ho. There is a lack of steel 0.5 module pinions out there. Although below the 23T limit stated in the manual, I have managed to pick up a 22T one and considering the 19T is almost able meet with the spur gear, going up 3 teeth I hope will enlarge the diameter of the pinion enough to mesh well with the standard spur gear.

@Fruitfly01, do you know where I can source other 3 spur gears for the 2018 TTC that you mentioned in a previous post buddy?

So for now, here she is fitted, with no pinion for the moment of course...

 

 

 

I know people have said this already but this build is like a work of art. So good!

[Frankster 2033]

On 11/14/2021 at 8:49 PM, Kol__ said:

 

@Kol__ is this a PS63 light gun metal colour?  I have used this “Mercedes’” paint on a road car myself and it looks great 

[Kol__ 3377]

20 hours ago, Frankster said:

@Kol__ is this a PS63 light gun metal colour?  I have used this “Mercedes’” paint on a road car myself and it looks great 

Looks like it could be mate. I picked it up the shell second hand, so not sure of the paint code. It's a nice grey though. Suits the Madcap, but I felt it needed more colour and so went with the yellow as an accent colour.

[Kol__ 3377]

22 hours ago, GeeWings said:

I know people have said this already but this build is like a work of art. So good!

That's very kind of you mate. It's certainly still my favourite RC in my collection. I really need to get an update on this thread, a few changes to the buggy since the last post🙂

[Kol__ 3377]

Finally I get around to updating this build thread!

Having swapped out the front and rear shock towers to carbon fibre versions of the Super Astute ones, the old shocks (I think maybe they were Team Associated or something similar) originally fitted to the buggy were leaving me with a crazy high stance. So I sourced some Astute shocks and powder coated the springs gloss black.

I have also swapped out the Madcap rear arms for Super Astute ones. I picked up a used set of original 1991 ones with hubs attached and the eclip pinned arms etc. 

Madcap on left and Super Astute on the right...

Upon fitting the arms, the old brittle plastic of the hubs led to a split at the ball stud. A crack which was already there I assume as it happened almost instantly.

 

I had a new set of Super Astute hubs and tapped them with a 3mm tap, to reduce the stress on the plastic when cutting the thread with the screw itself and hopefully prevent an future splits as shown above.

Standard 5mm ball stud fitted to the camber arm mount point on the rear hub below...

Rather than go with those screw in 5mm ball studs, I went with a screw right through the joint and into one of the hollow screw on type ball heads. Had to use a few washers to get the screw the right length, but I believe will spread the load through the length of the plastic rather than just the front portion.

Cross brace bar that comes as part of the Super Astute arms...

So yes, she's even more Super Astute now, but let's face it, it's better for it (running wise at the very least)

[Kol__ 3377]

I had mentioned ages ago on this thread about wanting to create a gasket to better seal the edge of the polycarbonate gearbox cover, to protect from dust and dirt ingress. Sourcing a thin material with good compression characteristics proved tricky and I kind of gave up on the idea for a while. Recently, I finally sourced something that I thought could work (in white which is not great, as will get grubby quite quickly I'm sure). This is a silicone sponge material 1.6mm thick, called BF1000, adhesive backed.

I traced the outline of the gearbox plate and cut out the shape.

Making a mess...

This stuff is not easy to cut and more aerated than I thought, with lots of air holes.

Polycarbonate gearbox cover 6mm mounting screws and the all important spacer.

Fitted cover, the gasket compresses well and looks to give a good seal from the elements, well dry elements at least.

[Kol__ 3377]

The main thing stopping me getting this buggy running was the problems with the relationship between the vintage Reedy Fury motor (which I believe is 12T, but that is not confirmed) and the ESC. Having fitted a Hobbywing 1060 previously, unfortunately this did not prove to be able to run the motor much better than the TBLE-04S. The HB was able to run it for longer, but was going into limp mode after a few minutes.

So I carried out the capacitor mod, in the hope that this would solve the issue. My soldering skills are not the best, but they do the job...

Done.

Little trick I figured out to get the pins out of the Tamiya connector easily (took them off to slide on the heat shrink). I used shock mounting sleeves, an unflanged one followed by a flanged one (which fit perfectly over the pin inside the connector), pushed them in and the pins pop out of the connector with minimal effort.

[Kol__ 3377]

Final photos of the build, a few more posted here than on the RC Gallery thread...

 

[Kol__ 3377]

Unfortunately the capacitor mod for the Hobbywing 1060 didn't solve the running issues for my motor/ECS combination. Put the feelers out on the forum for what options might be available ESC wise for me to be able to run this motor. Thanks to the chaps who responded and in particular @alvinlwh. I went ahead and ordered the Mtroniks Tio X. It's an ESC with no motor limit, is NiMH and Lipo ready and has built in Li-Po cut off protection. I may never know how many turns this old Reedy Fury motor actually is, or if it's been tuned up for racing or what, but with this ESC it shouldn't matter too much now. A short blast around our tiny garden this evening and... she lives!!! I'll finally be able to get this buggy out for a run again tomorrow!

Let's hope the motor lasts. It's old and I don't know it's history. I assume that as the buggy was last used in the 90's for racing, that the motor won't like a 30min blast around the local park. So initially I reckon I'll do some 5-10min runs on NiMH and monitor the temp of the motor and ESC as best as I can. Wish me luck!

[alvinlwh 5895]

2 minutes ago, Kol__ said:

A short blast around our tiny garden this evening and... she lives!!! I'll finally be able to get this buggy out for a run again tomorrow

Glad to have helped resurrecting your car. Looks good BTW. 

[Frankster 2033]

Great update!   I am looking forward to taking mine apart and learning from your build.   Still on vacation and miss tinkering on my RC cars

[Frankster 2033]

@Kol__ does the paint come off the springs after a few compressions?   What type of paint did you use?

[Kol__ 3377]

11 minutes ago, Frankster said:

@Kol__ does the paint come off the springs after a few compressions?   What type of paint did you use?

I think if you just painted the springs the finish would not be very durable. I took the springs to my local powder coater, as that finish is hard as nails. Time will tell if the finish wears and although powder coating is generally a thicker application than paint there is no rubbing on the shock bodies that I can detect. I got them to do red on my DT-02 springs and blue on my DF-03 springs and they're all good too. The only colours they don't think they can do on such small springs is neon. The neon colours require a white base coat, then the colour and then a clear coat. So 3 coats as opposed to one  as normal, which I think would cause clearance issues and rub on the shock bodies.

Enjoy the remainder of your hols mate, let's hope that metal motor mount is there waiting for you when you get back!

[naturbo2000 1272]

@Kol__ what are the front lower suspension wishbones? They're definitely not Madcap, and I'm not convinced they're Super Astute.

Did I miss the update when you swapped them in, or have they always been that way?

[naturbo2000 1272]

<double post>

[Kol__ 3377]

24 minutes ago, naturbo2000 said:

@Kol__ what are the front lower suspension wishbones? They're definitely not Madcap, and I'm not convinced they're Super Astute.

Did I miss the update when you swapped them in, or have they always been that way?

Have never been able to find out what the are mate, it just came with them...all the way from the 90's They seem tough and durable, and they are a decent width for the Astute chassis. I simply shimmed them a bit some time back, documented in the thread some pages back I believe.

One last mod I'm considering is an aftermarket Astute undertray, just to protect the chassis really. Much like what you did mate, I'd have to pick up an astute shell as well and look at filling in the gaps at the rear sides of the Madcap shell somehow

[kontemax 1725]

Your Madcap is beautiful but without the top brace you will break the bulkhead.

Max

 

[naturbo2000 1272]

15 hours ago, kontemax said:

Your Madcap is beautiful but you without the top brace you will break the bulkhead.

Max

Brutal but true. I used to break the bulkheads back in the day, even with the brace.

You can either use the Madcap brace with chassis standoff posts, or adapt the Super Astute brace to fit. The latter needs shaving some of the bulkhead down and a 2-3mm spacer. My Madtute has the latter.

[Kol__ 3377]

Thanks guys, I do have both the Madcap and Super Astute build head braces, so could fit one.

I'm only really driving this buggy on the flatter off road areas with humps rather than jumps, as I have other cars for more vigorous bashing and I am cautious not to smash this one up. This one is more about having fast race type buggy to blast about. Although I had thought about taking it to the local AstroTurf track for a vintage night maybe. Where's the most weakness come from with the bulkhead, landing jumps or head on collisions?

[naturbo2000 1272]

I never jumped mine more than a 4 inch shallow ramp, so I'll have to vote for collisions. Kerbs and trees are sufficient  

[Kol__ 3377]

Ah I see, so better off fitting one of the braces then! The Madcap one would be the most economical for me, as I have used spares. The bulk head currently fitted is the Madcap one I believe. I'll need to look at how easily it fits with the Super Astute steering arms underneath it. I'll need some stand off posts you say, any idea what size?

[kontemax 1725]

13 hours ago, Kol__ said:

Thanks guys, I do have both the Madcap and Super Astute build head braces, so could fit one.

I'm only really driving this buggy on the flatter off road areas with humps rather than jumps, as I have other cars for more vigorous bashing and I am cautious not to smash this one up. This one is more about having fast race type buggy to blast about. Although I had thought about taking it to the local AstroTurf track for a vintage night maybe. Where's the most weakness come from with the bulkhead, landing jumps or head on collisions?

If you collide with one front wheel the bulkhead will break immediately.
If you mount the top Madcap brace you will save it. To mount that brace without the bathtub chassis you need two alloy columns.
Check my showroom, there's a metallic blue Madcap, check the pictures.

Max

[Frankster 2033]

On 8/15/2022 at 1:48 PM, naturbo2000 said:

Brutal but true. I used to break the bulkheads back in the day, even with the brace.

You can either use the Madcap brace with chassis standoff posts, or adapt the Super Astute brace to fit. The latter needs shaving some of the bulkhead down and a 2-3mm spacer. My Madtute has the latter.

What does this brace look like?  I am new to this chassis

[Kol__ 3377]

Ok, thanks guys, I'll look into this before anymore major running 👍

43 minutes ago, Frankster said:

What does this brace look like?  I am new to this chassis

Don't worry mate, it's standard on the Madcap. If you look at your car, it's the large flat panel piece that bolts down over the steering assembly