Electrical Work

Today I spent a good deal of time locating places for some of the electrical components and installing them in the area I call the electrics bay. First I mounted one of the fuse boxes. This one will be reserved for items that will be switched on only when the ignition is on. I have a second fuse box for items that will be powered all the time, but I haven't installed it yet.

Next, I found a location for the main contactor. That is a really big relay that turns the car on and off. It has an input for a 12 volt positive line and ground. When power is applied to that, it closes a contact that lets the full 160 plus volts through to the controller. That way, a small switch (the ignition) can control a very big load. Mounting it was a breeze, but I haven't run the high voltage lines to it yet.

There is plenty of space in the electrics bay, but it's mostly volume rather than surface area. I need surface area to mount the various components, so I built another small tray to hold them and it will sit below the controller's tray. Here's the tray and the components I'll mount to it.


Traveling clock wise around the tray from upper left, we have...
1. The off delay timer. It will turn the electric power steering pump on when it receives a signal from the positional switch Len sent me. I'll set it so that once the pump comes on, it will stay on for a minimum of 1 minute. This way, I avoid "short cycling" the motor and burning it out.
2. The heavy duty relay that will deliver up to 85 amps to the power steering pump.
3. A self resetting breaker to protect the power steering pump from drawing too much current.
4. A 30 amp relay that will be wired to deliver power to the fuse box. When the ignition comes on, it will trigger the coil in that relay to turn on power to all the devices wired to it (i.e. the motor blower, the vacuum pump, the ceramic heater, the water pump to cool the Zilla, the pedestrian horn and a few other odds and ends).
5. And last, the relay to provide power to the ceramic heating element. With no engine to provide hot water to heat the inside of the car, I'll be using something similar to the guts of a modern space heater. They draw a lot of current, but fortunately, I live in Arizona so I won't be needing it very often :)

I also sealed the drain plug for the transmission and filled it up with fluid again. Lets hope this time we see no drips.

Last, I gave the car a new model name. When it was new, it was the 2.3 version of the Z3, which I thought was odd because the motor was a 2.5 liter motor, same as the 2.5 model. Anyway, on the back of the car, opposite the Z3 badge was a smaller 2.3 badge. It has been replaced.


Seemed appropriate.

Odds & Ends Part VII

No big projects today because I mangled my hand last night while trying to drain the transmission: more on why later. I had a craftsman ratchet wrench fail while I was putting all my might into it, and my hand was crushed/sliced open against that beautiful, accursed aluminum plate I made a few weeks back. I had thought the drain plug just gave way quickly, but that wasn't the case. The ratchet system on the wrench failed. You can imagine my surprise. So, what did I do today? Where to start...

1. Using a solid breaker bar I managed to break loose that drain plug with no further harm to my hands. Since I put the transmission back in and filled it with fluid, there's been a slow persistent leak coming from the bottom plug. Every few days, there would be a couple new drops of fluid on the floor. I kept looking at it, willing it to stop, but that didn't seem to work. The plug originally had some sort of blue sealant painted on it before it was inserted. I got some thread sealant to use, and soon, I'll be able to get the plug in and the tranny full of fluid again.

2. I ran all the coolant lines from the Zilla, the pump and the radiator. The Zilla controller will be handling up to 1000 amps and nearly 160 volts DC, so it will get hot without adequate cooling. A constant flow of coolant will keep it safe.

3. Using some JB Weld, I affixed some bolts to a side panel inside the electrical compartment. Those bolts will hold a big 12 volt distribution block. In the electrical compartment I found the original positive battery cable that supplied some of the car's power. I'll be tying that down to this distribution block for easy access to power. From that I can draw all the 12 volt power I'll need for the car's subsystems. Most of lines off of that will run to relays that are triggered only when the car is running. That cable originates in the back of the car where the original battery was, right near where the DC to DC converters are. Clever huh?

4. I also did a bit of repair work on the front bumper's lower spoiler. Someone had hit a parking structure at one point, and cracked the plastic. I was able to use a bit of the insanely strong plastic from the gas tank as a brace, and epoxied it in place from inside the bumper. The bumper has the original line now even if there is still visible damage. Perhaps some day, I'll replace it, but for now, I have more important things to work on.

Odds & Ends Part III

Today and yesterday I did a number of small things that are of no particular interest make for riveting reading.

1. Torqued down most of the bolts mounting the drive shaft to the transmission. That was fun. Working alone under a car with almost no room trying to torque down bolts to 74 ft/lbs. I recommend it to anyone in search of a hernia. I still have to torque down the nuts that mount the drive shaft to the differential. Unfortunately, the space is too tight. I can get a socket on the nut, but not when my torque wrench is attached to it! Makes it a bit challenging. Fear not, I have a clever plan...

2. Fitted some of the cars cross bracing back in place. After all, we all love a firm chassis.

3. Worked out some spacing details, locating where exactly to put the battery trays. Still need to work out how to affix them to the chassis and brace them properly. It's astounding how well each of them is fitting at this point. They're exactly where I need them to be with just enough clearance to make it all work.

4. Took some measurements and made cardboard templates to help cut some aluminium sheets. I'd like to create a floor under the engine compartment to help keep dirty air and water out of the space, and to improve aerodynamics under the car. Plus, given the right bracing, some of the equipment can be bolted to the plate.

5. I got the remaining battery trays back. Thanks for welding them up Tim (no relation), they turned out just great! I ground down some of the welds, took a wire brush to them remove all the rust and gave them a good coat of primer.

That's about it for now. I'll be doing more paint work on the trays tomorrow. I need to sort out how to mount them in the chassis. I could use a second brain or two for that. Especially one with experience in this sort of thing.

Good News Everyone!

After carefully measuring and re-measuring the positions of the transmission, drive shaft, motor and their relative position's to each other and the chassis, I've come to the conclusion that everything is lined up nearly perfect. I had been concerned that because the motor was resting on the sub fame, once I put the motor/transmission assembly in place, that it was tilting the whole assembly up. It turns out that while it's resting on the sub frame, the assembly is angled down ever so slightly. I will need to determine how much it needs to come up from the sub frame and then construct the front motor mount to create and maintain that space. Good news indeed!

Also, Futurama has been picked up by Comedy Central for 26 new episodes! Not really relevant to the EV, but cool anyway.

Hoisting the Motor

I put the motor in this afternoon/evening. It all went pretty well. Here's a shot of the assembly hanging over the engine bay. By the time I finished, I was pretty tired, and it was too dark to get a good shot of the motor in place. I'll shoot that tomorrow.

At this point it looks like I may have a problem I was hoping to avoid. The motor extends far enough forward, and is big enough in circumference that it is resting on the sub frame. Actually it's resting on the power steering rack that's bolted to the sub frame. It looks like the transmission may be pitched up slightly. I connected the gear shift arm to the transmission, but there is another bar called the "selector link rod" that I'm having difficulty with. I can't quite tell if it's because the transmission is pushed too far back into the chassis, or because it's tilted up as I suspect.

I had forseen this potential problem when I started the project, but the best measurements I could make at the time showed that I was going to be either ok, or as much as 1/2" short of the space I needed. The worse case scenario is that I have to remove the front sub frame and put spacers between it and the chassis. Id certainly rather not do that, but I may have no option. I'll try to figure it out tomorrow.

The Transmission is on the Motor

Check it out!



Not a big post, but an important step non-the-less.

Transmission Arrives

Well, the transmission arrived today, as I'd hoped it would. It was in good condition with one minor exception, a guide plate that's bolted to it used for two hoses was bent. A couple careful whacks with a rubber mallet and it's good as new.

In the mean time, I needed to torque down the flywheel and attach the clutch and pressure plate. Realizing I needed to lock the flywheel in place, I started looking around for some way to do it. I ended up using a leftover piece of channel iron, a long bolt and a C clamp to hold the bolt down.

I realize this means I'm dangerously close to achieving the status of "redneck", but BMW wanted crazy money for the "official" tool. Anyway, here's a good picture of the whole assembly.



Next, I have to get some replacement hardware to bolt the tranny up to the motor assembly.

Brown Disappoints

Early last week the transmission arrived at the shop that I've hired to build the adaptor plate and mounting hub. In spite of the fact that we used the paper from 10 hectares of forest packing it into that box so that it was immobile, UPS managed to inflict a bit of bad. You can see one of the eyelets along the bell housing was broken off. The machinist at the shop said that it would not effect the adaptor plate, so that was good news. I looked at the photo closely and began to think "I don't remember an eyelet in that location." I looked at the service manual and sure enough, I found that it was the location of a locating pin used simply to help you hold the tranny to the motor in the right place as you bolt it on. Sweet! Absolutely no impact. Big sigh of relief.

Packing the transmission

My daughter Emily was kind enough to help me wad up a forest's worth of newsprint and cram it in the box I used to send the transmission off. Why send it off, you ask? Well I couldn't find a local shop with experience making the adaptor plate and taperlock hub to mount the motor to the transmission. In six to eight weeks, it should come back ready to mount to the car.