Body bits

I built the body as a series of separate panels which are fastened on to the frame with stainless steel screws and captive nuts. Similar to a motorcycle, these panels are relatively easy to remove to get access to mechanical things, or to repair or reshape them. I have enjoyed the freedom of form that fibreglass construction offers, especially the way that common household objects can be pressed into service as moulds. For example:

• rear-view mirror moulding : 2 litre Sprite bottle and half a tennis ball
• speedometer housing : 2 litre soy oil bottle
• rear “plug” for headlights : beer can
• tail light “pods” : 2 litre antifreeze container
• clearance lights : tomato sauce squeeze bottle
• raised section of “boot lid” : plastic bucket
• air intakes : 10 litre plastic paint bucket

Where possible I have tried to use female moulds for fibreglassing so as to get a smooth finish surface straight off. However, in most cases there had to be so much reshaping afterwards by cutting bits off and glassing them back on that the advantage of doing this was pretty much lost. Most of the body bits were finally moulded directly on the car by arranging the separately made pieces and filling in the gaps with fibreglass. In making a shape for this, I wired a wooden substructure onto the car chassis, glued and/or screwed more wood onto this and then formed the necessary shapes with MDF board, corrugated plastic sheet (garage sale signs) and gib-board plaster. I found that it is not necessary to let the plaster cure fully. It works OK when still a bit damp. For bond release I used mostly packing tape. This is much quicker and cleaner than wax and guaranteed to release easily. For the first “glass-up” I used just one sheet of chopped strand mat, and then added additional layer(s) to the backside later, when I was happy that everything fitted and looked right. Final finishing involved a bit of bog and a lot of sanding. There is much less than one litre of bog in the car, as most of it gets sanded back off. I note that I am talking about body panels with a maximum dimension of less than one metre. This technique would work OK for a single whole-car moulding, but there would need to be extra stiffness built in somehow.

Before going with fibreglass I experimented with beating some aluminium with a view towards making all the bodywork in this material. My thought was to use some beaten and some single curvature sections riveted together like you see on the engine covers of an aeroplane. However I gave up on this pretty quickly. It was too hard. And, I am glad I gave this away as fibreglass panels are so easy to modify and so tough. They are also easy to “recondition” after the inevitable scratches etc. happen.

Painting

My word, those proper car-painting businesses do an excellent job. Needless to say I opted to have a go at this myself. The main reason was that I was completing different parts of the car at different times. I would have liked to have a nice powder coated chassis, but there were obviously going to be a number of changes and lots of attachment points to be welded on as the car grew, so to keep rust at bay and avoid the necessity of having to pull everything apart one more time, I tried to keep everything made of steel painted as I went. For the fibreglass bits I thought, well, it’s a tiny car so for safety reasons a bright colour is important. From then on the philosophy went something like : We are used to seeing a certain fashionable range of colours on cars. These are chosen by people who do market research and are targeted at making their product appeal to a group of statistically generated non-real punters. There is no need to be part of this process. In fact, it is your duty to clearly not be part of it. So, fluorescent red it was for the nose cone, and finally, a similar green for the rear panels. I did all this with spray-cans; first a coat of white, then a few coasts of the colour, then clear polyurethane. I found that it pays to get all the paint from the same manufacturer. I learned this the hard way when I noticed that The Warehouse paint was causing the previous layer to bubble up. All this hasn’t really made a quality paint job… but it looks great at 50 metres and/or 100 km/hr.

Steering : Ackerman humbug

Lets not get too technical about the VW T3 trailing arm front suspension geometry, but with the shortened Toyota steering rack located to achieve negligible bump-steer, the result was negative Ackerman. This means that on full lock, the outside wheel was at a greater turning angle than the inside wheel. Unless you plan a lot of very serious tail-out cornering, this is not right. I was a bit suspicious of how much the theory of Ackerman angles actually is used in cars today so I did a bit of research. On full lock the front wheels of my old Sherpa van were at 30deg and 40deg. That seemed about right. Our BMW was something like 32deg/36deg but the several Japanese cars I checked, even a RWD starlet, were all 30/30 .

So significant Ackerman for light cars seems now to be out of fashion. Still I needed to at least get the Road Rat into positive Ackerman, and this was going to need new steering arms. This was also an opportunity to increase the steering ratio. Nothing feels worse to steer than a sporty car with a slow steering rate. It is also dangerous with a short wheelbase car because when you need opposite lock, you tend to need it real quick. No time for any hand over hand business. I designed the new steering arms so that no cross section on them was less than twice the moment of inertia of the equivalent donor vehicle part. Coupled with the much lighter weight of the new car, this seemed a safe design approach. These were profile cut out of 32mm plate for me, then I drilled, hack sawed, ground and filed then into the final shape. Roy helped put the tapered hole in for the tie-rod end. Toyota, VW, BMC, Honda, Mazda and lots of other cars use the same 14mm thread for tie rods, and VW uses hollow tube tie rods which can easily be cut and treaded to suit the required length. The final outcome was about +2deg of Ackerman at full lock, and 2.25 turns of the steering wheel lock to lock.

Lights

Having the right standard numbers on the various lights seems to be really important to the powers that be. The simplest way to address this is to just buy ADR (Australian Design Regs) compliant bits from your local car parts shop. Not wanting any more hassle than necessary, in the end this is what I did. And it worked out very well. The "Trailer" lights on the back seem rather gauche, but they are actually really good. They are cheap, easy to put on, easy to wire up, easy to replace and they are good and bright. In fact, without reversing lights, in the dark I can see quite clearly enough to reverse down our curved driveway and into the garage with just the light of one blinker or the odd touch on the brake pedal. I think this requirement for lights meeting a certain standard is a good thing.

Brakes

Here I had some trouble. I tried to use all the VW bits in their normal roles. The donor car was a type three VW (Variant) with disks at the front and wider drums at the back than as used for the beetle. I replicated the floor fixing detail for the pedals. The result was very effective brakes, but a spongy feel to the pedal that didn’t give confidence. I replaced at lot of parts and used up about $50 in brake fluid with bleeding, but to little avail. I then took it to a local garage where the proprietor, formally a sports car club scrutineer, bleed it again and advised that he would give it a warrant, and that VW’s are often a bit like that.

Back to basics. The VW has a mechanical advantage on the pedal of about 11:1 . This is much more than the more modern power brake systems which seem to only have about 5:1 on the pedal. This gives a good feel, but will not give much hydraulic pressure without the servo. So I reckoned that the sponge in the VW system was lack of rigidity in the structure between the pedal and the master cylinder. Then I was watching the Bathurst race on TV and the “pedals cam” showed the driver’s feet. The top Holdens and Fords all had bottom hinging pedals, even though the original cars had had top hinging pedals. The way forward was clear. I built a whole new bottom hinging brake pedal box for the car. I made it very rigid and complete with new pedal and a new master cylinder (mail order for USA). I gave it about a 6:1 ratio and bolted it into the car. It works great. Very good feel and can lock the wheels up at 100km/hr without too much effort.

Wiring

I was not so smart with the wiring. Because the steering column is from a Toyota Starlet and has all the switches etc. on it I thought the best way to do the wiring would be to emulate the Toyota system for the whole car. I had the Toyota fuse box etc, and thought all I would have to do would be to lengthen the wires to the engine a bit. Wrong. I did all this on a big sheet of plywood with wires zigzagging all over it and it all turned out to be very tedious. I tried to reverse-engineer the Toyota wiring, to understand why they had done it the way they did. Then reinterpret this for my purposes. I used up about three wiring looms for extra wire, valiantly persevering with maintaining the original colour coding etc. I stuck to it, and made it all work, in all aspects but the headlights. I just failed to see reason in the way Toyota had done the headlights the way they had, and I put in an extra relay and used my own design for the headlights.

I will pass on the lesson I learned from this experience. Do it this way:

1. Buy some rolls of new wire, any colour will do.
2. Design the system you want and understand.
3. Put all your lights, switches, fuses etc. in place on the car.
4. Put in the grommets.
5. Run the wires one at a time. Joint each one up, or at least label it.
6. Wait until the car is almost complete.
7. Tape up the loom in place in the car.

Fuel tank, gauge etc.

The tank is from the original VW with a different filler neck soldered on including a provision to vent air from the other side of the tank back to the filler neck. I also fibreglassed on a catch basin and drain round the filler cap to avoid any mess and reduce danger from problems at the filling pump. The tank had to be panel beaten a bit at one corner to give clearance for the right shock. The sender unit is original VW, but the gauge is Citroen as I thought I needed to use a 12v component here. (the Road Rat is 12v although the donor car was 6v). I now got the gauge reading very accurately with a few resistors strategically added to the system. This did not work out so well in the first attempt as I initially used a very low current variable resistor to affect the calibration, and it burned out. This resulted in a false “half full” reading that caused me to run out of fuel one fine night on the desolate stretch of coast road between Paekakariki and Pukerua Bay. This is the only thing that has gone wrong with the car during the eight months that I have now had it on the road.

I realised a long time afterward that there was no need for all this trouble. I could have used the VW gauge without any recalibration by including a resistor to limit the voltage supplied to it to less than 6v. Could have saved a lot of trouble.