Overall setup

The stated goal of the project is to do all of the switch-over work without cutting into the chassis, without welding to any of the original parts, and to re-use existing mounting holes etc. It makes the whole idea “cleaner”, plus it it all turns into a disaster I can revert back to the original power-train and pretend none of this ever happened. That’s a great premise, and it also makes a lot of things more involved.

Part 1 is the chassis, suspension and brakes, and it’s the most straight-forward part of all of it . Mechanical parts for this car (and others like it) are still being made and easy to get, even in really nice quality, so rebuilding things was not-complex. Sure, it takes a bit of creativity to re-create some of the old production methods like the press-in bushings in the rear suspension, but all in all, this went really well.

Part 2 is the motors and gearbox. This is where things get complex because of the setup I’ve chosen and the physical constraints of the car itself. Putting 2 motors together into a Siamese-twin configuration is not simple in and of itself, and by the time you take that stack and add a gear-box, the whole thing is pretty long. I got it in, but only just.

Part 3 is the controllers and battery-frame part II. This frame replaces the core-support that held the original radiators. It also holds the front fenders in place, and it supports the two motor controllers. It’s an exercise in space management, not super-complicated, but a lot of trial and error went into getting it all to fit.

Part 4 is routing of all of the power cables and hoses. This has taken a ton of time with all of the brackets and clamps that needed to get figured out. It’s where I found out how tight everything is and how managing space is actually seriously intricate. But, I think it’s looking good.

All in all, this part of the project is now really taking shape and it should be on the downhill. There’s space for everything, all of the major components are either in place or in production (like the radiators), and all of the big questions have been answered/solved. It’s been quite the project, but it’s looking pretty darn professional (to me)

Chassis, suspension and brakes

The first step was to return everything to the bare OEM components and to rebuild the frame, the brakes / suspension / steering part of the car. After all, the car is going on 65 years old, and the original wear & tear parts are well-worn by now. Everything on the underside was equally surface-rusted, dusty and dirty, but it did all look in decent shape.

After everything had been disassembled every single piece-part proved to be in great condition. There is no structural rust anywhere, nothing has ever been in a collision & re-straightened, it was all in dirty-mint condition. So, everything got shipped off and powder-coated at HighPoint in Leander TX, and then re-assembled will full sets of new wear parts from Kanter Auto. Neither of them are necessarily the cheapest, but both of them do amazing work, thorough, fair-priced, just all-round kudos (no sponsorships, just my honest opinion).

Looking at the weight-before vs. weight-after, it looks like I can rebuild the front part of the car and come in close to original weight. The original V8, radiator setup, transmission, exhausts etc are almost all solid steel parts, and 1,250 pounds (500 kg) is entirely reasonable. What I’m putting in is not light-weight. The motors w controllers and wiring is probably 500 lbs, and the battery is another 1,250 lbs. Let’s round it all up to 2,000 lbs coming back in. 500 lbs of that battery now sits under the trunk / way in the back, and the original setup had maybe100 for a full tank of gas. So, I have upped the grade of the new coil springs to “stiff” to deal with the overall increase, plus I have installed rear shocks with coil-over springs for an extra boost to deal with the rear battery. It should work, and if it doesn’t then I can switch to airbag suspension (that was an option for the original car) and pump it all up a little further.

As for the brakes, I have left the rear end original, but have upgraded the front to disc brakes. The original version’s brake performance was never great, it worked but in an emergency it was decidedly meh, and with an extra 1,000 lbs of weight I wanted to be as safe as I can make this project. The bolt-on conversion kit fit great and should do the job just fine.

Motor(s) and gear-box

For reasons explained in the pre-work section of this web-site, I ended up with a drive-train design that has 2 Siemens Azure motors in tandem. To make that work in the original setup they have to connect into the original drive-shaft, and that means I had to Siamese-twin the motors. That is actually really complex, because these motors were never designed/built to accommodate that.

The short version of the story is that I found a coupler that mated to the spline on the output-shaft of the Siemens motor, and I figured out how to cut that same spline into the back-side of the shaft on motor #2. I don’t recommend anyone try this at home, it was very not fun, but I got it there. I also made a mating adapter plate so I could bolt the motors together, and it is the exact thickness needed to “hide” the spline adapter. The combination looks like

Then I added the (bolt-on) TorqueBox gear-reduction unit, and the whole power-plant looks like

To make this happen, the motors are supported in the middle where they join up and at the gearbox end (and they’re in with anti-vibration mounts etc). There is no support at the front of the car / at the back-end of the secondary motor. Theoretically this is all fine, and at the same time it does make me nervous. If the motors get out of line with the drive-shaft, it could start to try and make the motors “fling around”, and that would be the end of that chapter. I don’t see how they could / why they would, but the doubt lingers. In the mean time, for now, it is all in place and looking solid.

That motor/gearbox setup, just by its lonesome, is a little over 46.5″ (1.20 meters) long. Because, on a project like this, you’re working with Other People’s Parts, you’re also stuck with Other People’s Dimensions, and fitting a powerplant this long was actually really tight, even on a car that’s the size of an aircraft carrier. Cutting the driveshaft etc would go against the no-hacksaw premise, so it has to fit between the first U-joint in the driveshaft and the steering bits in the front of the car. I got it to all fit by literally 0.4″ (1.1 centimeter) which is really an achievement considering everything I had to stack together.

The bracket/frame installed overtop of the motor is for the front battery box. It also holds the hydraulic pump for the power steering (large black one, top left) and the vacuum pump for the power brakes (small grey one, bottom right. By the time all of the power cables and coolant hoses get routed through this space it will be seriously crowded, but it’s looking sharp right now.

Controllers and battery-frame part II

Once this was in, the next part was to build the 2nd support frame for the front battery box and to figure out where the two Azure motor-controllers are going to land.

Based on what’s going to be re-used vs. where I need to modify things, I decided to re-make the filler plates that make up the front of the fender-wells as well as the core-support frame that held the radiator in place in the original car.

The large white styro-foam brick is a dimensional stand-in for 1 battery-cell (the actual part weighs 40 lbs so this made things a lot faster and no risk of electrocution). They sit on the frame over the electric motor, and need a second frame in the front to sit on. The white poster-board mockups are the replacements for the fender-well pieces and the core-support. All in all it took a dozen attempts to get it “right”, but I got it there. The only problem left is that the controllers are a LOT larger than the space left between the battery box and the fender. Per the ruler there’s maybe 11 inches, and the controller is 22 inches long.

That’s a real issue, and I’ve decided to bend a piece of the fender “out of the way” so the controller can sit partially inside the fender. It also means that the controller has to slide in and out of its position (I don’t want to ever have to remove nicely-painted fenders if I don’t have to) and it’s secured at the battery box end. That all comes out like

Water-cooling

The motors, the controllers and the Tesla batteries all have water-cooling capabilities/needs. I’m not sure how much cooling the batteries need, it should be minimal, but the Siemens parts both for sure need a functioning cooling setup. I have set everything up as 2 separate cooling flows. Each flow has a pump, then a controller, then a motor, then either the front or the rear battery pack, and back to the pump via a small radiator.

My radiator sizing math goes something like this. The original engine made 350 bhp, and 40% of that was heat/waste. The thing really was not super-efficient. That’s 150 bhp in waste energy (at peak power), and it had a radiator of app. 25″x35″ to get rid of that. In the electric version, I have around 250 bhp of power, and my efficiency is 96% on the controllers, 98% on the motors, and 99% on the batteries. That’s 5-or-so percent of waste-power, so <15 bhp, or about 1/10th of the original. I’m jumping to my conclusion that I should need 1/10th of the radiator size to accommodate 1/10th of the energy, so something 25″x4″ = 100 sq.in. should be sufficient. So, I’ve designed a dual-core radiator with two cores at 20″ x 3″ each, comes to 120 sq.in. It bolts onto the bottom rectangle of the front carrier-frame, it has fans and flow & temp sensors included, and the setup looks like

Routing of power-cables and hoses

There are a lot of cables and hoses to make this car run. There’s the wiring setup between the battery packs, then getting that power through the central switchbox and out to the controllers, then back to the motors. There’s also the hoses for the power-steering and for the two cooling circuits. And somehow, all of these cables and hoses come together at and/or need to pass through the front support frame. The controllers sit in front of the frame, the batteries and motors are behind the frame. The radiator and pumps are in front of the frame, and have to connect to the same batteries and motors. It is one crowded setup.

For the connections from the engine-bay (motors & controllers) to the trunk (controls, charger & second battery pack) I am following the path of the original exhausts

I have routed the 4-0 power cables on the passenger side of the chassis, and the coolant hoses for the rear battery pack are on the driver’s side. With the power-steering gearbox where it is, the unwieldy power cables were easier to install on that side. There’s also one extra hole in the chassis on this side so I was able to make a much nicer suspension-bracket for the power-cables right where they need to make some serious bends & turns.

The cooling setup is really 3D (as in, convoluted), so I’m using a diagram to document the 2 cooling loops / circuits. The primary motor is the one that connects to the drive-shaft. Its coolant-circuit connects the driver-side motor controller, the front battery pack(s), the lower half of the radiator and the driver-side sensors & water-pump. The secondary motor is the one that connects into the other motor. Its coolant circuit connects the passenger-side motor-controller, the rear battery pack, the upper half of the radiator and the passenger-side sensors & water-pump. The two radiator fans blow on both radiators at the same time so those are considered 1 big fan for the sake of the control-logic etc. If I ever have to start heating the batteries I’ll consider turning them into separate units, but I think the effect would be negligible and the effort would be major.