Tamiya Lunchbox radio control monster truck

Here is my modified Tamiya Lunchbox monster van. The model is fully ballraced and has a few tweaks for improved performance.

This is the recent re-release of the Tamiya Lunchbox which first saw the light of day back around 1987. The new release of the monster van is much the same as the original, but comes with an electronic speed control instead of a 3 step mechanical device. The steering arms are also improved over the 1980s model.

The model was built up as per instructions first of all, with the exception of fitting ballraces to replace the useless plain bushes. Everything screws together easily and most folks should have the van up and running in two or three hours after opening the box.
The shell was painted all black using Tamiya black acylic paint, and almost before this paint was fully dry off I went to test run the 'Box'.

First test runs were successful but the model was too slow for my liking, being powered by the lowly 540 standard motor I expected as much. Luckily I had a few alternative motors to upgrade this Lunchbox with.

Notch hacksawed into gearbox casing to provide clearance for the extra shock. The standard Lunchbox 4mm shaft passes through the Sonic Fighter coil over end.

The top end is of the third coil over damper is fitted to one of the steel U brackets which come with the kit. The bracket is bolted to the chassis by drilling a single hole. Provided you take care to get everything lined up the modification is a piece of cake.

The 540 was unscrewed and a 15 turn Orion Havok put in it's place. This probably provides double the power of the kit motor and tranformed the Lunchbox into the manic wheely machine which I required.

Next job was to improve the turning circle of the little beast. As I had a couple of old Tamiya Sonic Fighter front wishbones (the old Sonic Fighter was great fun despite what many say about it) handy I looked into the possibility of fitting these in place of the Lunchbox items. Some trial fitting revealed it would indeed be possible with just a little trimming being required. Using the Sonic Fighter wishbones gives a wider front track and enables more steering lock to be obtained. The 3mm steering arms also needed replacing with longer pieces of threaded rod.
Anyhow look at the pictures, it's a pretty straightforward mod (if you have the bits!).

The other improvement was at the back end. The Lunchbox has a kind of floating back axle arrangement, two main springs and two weedy hair springs on the front location bar. These weedy springs break easily and are c&*p. I bet most Lunchboxes are driving around with these broken already and the owner doesn't even know it!. An improvement I've come across from other ingenious model car folks is the third damper modification. This is a simple and highly effective way of chucking the hair springs (which are probably broken anyhow) and using a coil over damper unit to do the same job but better.
The Sonic Fighter came to the rescue again by giving up a front shock. This was mounted as per the pictures and has since been exhaustively tested (total success).

Sonic Fighter front wishbones to increase the track and enable greater steering lock.

There it is then a few easy mods to make a fun model monster van even better. The Box now goes like stink and turns on a dime (when the front wheels are on the ground). The model can be skid turned on a sixpence and will wheely at the least provocation.

I've been using my old 1700mah nicads on the model and yes the kit speed controller which so far has not packed up. It gets mighty hot though pushing all them amps through it (using a 15t motor for a controller meant for 29 turn motors!!). I briefly fitted a 13 turn motor to the model but this caused the electronic speed controller to overheat and shut down, it was OK again after a few minutes passed when the controller had cooled off. Even with the 15t Havok I'm really hammering the thing way beyond it's intended use, so far so good. A 29 turn motor is for my purposes useless anyway so it's death or glory for the poor kit speedo.

You want a bottom line? OK here it is. Go buy a Tamiya Lunchbox and scrape it's rear end down the road.