1/13/2008

Heavy Lifting

The day finally arrived: time to bolt on the electric motor!

EV America calls this system "clutchless," although the car's original clutch disc is in fact put to use here (see below). In the end, there'll be no need to engage a clutch to shift gears, because the electric motor's high starting torque makes it possible to get going in 4th gear, if you want. So the plan here is to permanently mount the motor to the transmission's input shaft using a coupler, an adapter plate, plus any necessary spacers.

Make sure you've got these tools nearby: drill press and bits, metric and SAE sockets, torque and ratchet wrenches, hex keys, a pneumatic cutting wheel, floor jack, Loctite®, lipstick and some dependable man power.

The electric motor attaches to the old VW transmission via a ½ inch aluminum plate, which arrived as a big square with holes drilled for motor. Earlier, we had this square plate cut down to an appropriately sized circle, so the first step today was to determine where to drill holes to bolt this plate to the transmission. Here's a picture of the plate aligned on the input shaft with the white cylindrical alignment tool loaned from EV America.

Once the plate was aligned, mark the upper mount holes with a sharp drill bit pushed in from behind--aluminum gouges nicely with a few twists of the steel bit--and the lower mount holes with lipstick. (Thanks, Mom!)

With holes drilled in the plate, pull the transmission's throwout bearing and component pieces and plug the holes left by their removal (underneath Dan's right finger; note the surgical gloves--a nice thing to have when digging around in all this ancient grease) and also by the removal of the old electric starter, equally obsolete. A heavy duty bolt works for the former, a sturdy sheet of metal for the latter.

Next come the fireworks: cut off the excess length of the pilot shaft that once guided the engine back onto the transmission when shifting. Cross your fingers and hope the sparks don't start a fire in the oil spill underneath the car.

On to the electric sandwich.

First, mount the motor coupler to the motor's driveshaft. This piece will ultimately lie behind the adapter plate, out of sight inside the transmission, so check that it has clearance your motor-to-adapter-plate mounting bolts before tightening. (The coupler is the can-of-tuna-sized piece of aluminum sticking out to the left here; ultimately, we pulled it out another .125 inch to clear the bolt heads and lock nuts.)

Next in the sandwich: connect any spacer(s) to your adapter plate. (All of these pieces were provided by EV America, based on measurements of the transmission and the input shaft we supplied very early on.) Then slip the plate over the coupler and onto the motor. Warning: Make sure you bolt it down with the side you want the world to see facing the motor!

Now attach the old cluth disc to the motor coupling (the old clutch disc has splines that mate to the original transmission input shaft, so you've got a little recycling at the heart of this new drive system). This is the point where you'll see if, a few steps back, you left enough clearance between this twirling disc and the bolts that hold the motor to the adapter plate.

And finally: the moment of truth. Assuming you've tightened every screw and bolt and layered things in the right order, lift this little baby up into the engine bay. Align the splines of the clutch disc onto the transmission input shaft. Slip bolts through the holes you drilled in the adapter plate. Center it all where you want it, torque it all down, and stand back and marvel!
Hallelujah!

All in all, this took 3-4 hours, as we worked fairly cautiously and made missteps here and there. What great day, though. The first work that was all about putting new things on instead of taking old things off.

1/12/2008

Tracking Packs and Training Schmucks

Dropped in on the Denver Electric Vehicle Council meeting today--held in Boulder, doncha know--and walked away feeling buzzed, like an acolyte who was eavesdropping on the Council of Trent. They knew so much, I knew so little, and yet nobody kicked me out of the room.

This particular meeting concerned the PakTrakr, a battery monitoring system built by Ken Hall & co. up in Windsor, Colorado. The PakTrakr is a single instrument that can do the work of voltmeter, ammeter, and a whole lot more. I'm miles away from putting batteries in the car, and I don't yet know the dark art of monitoring volts and amps, but it's not too early to start thinking about batteries.

For simplicity and economy, in the end I'll probably load the car up with six garden variety, 12-volt, deep cycle batteries, but here are some things worth considering:
  • No battery pack (collection of separate batteries, wired together to supply the juice) will be ever be perfectly balanced, and weaker batteries charge faster, causing over-charging, thus
  • Charging the whole pack without attention to the weaker links will inevitably cause trouble, and
  • Trouble = $$, needless frustration and other "events" (explosions, fires, etc.).
So what's a guy to do? Maybe put the PakTrakr to use, which allows you to monitor the whole pack and each battery individually. We'll see.

1/01/2008

Onward!

With both the holiday season and my faithful assistant's prostatectomy now in the past (as he puts it, "I used to have prostate cancer; now I have neither"), let's make some headway with this project!

Today's work goes like this. After more hours than I care to relate--generally trying to wrestle a 45-year-old chunk of magnesium alloy into submission--the Bug now has has two new, bright red, polyurethane transmission mounts. And don't they look gorgeous?Basically, this was prep work for what comes first in the conversion: installing the electric motor. The new motor and the old engine don't resemble each other in the least, so to mount the electric motor to the transmission you've got to use an adapter plate. And because the old rubber transmission mounts would have kept the adapter plate from fitting flush against the transmission--they'd squished out past the edge of the bell like little love handles--they had to go.

Coming up: aligning that adapter plate on the input shaft to mark and bore it for mounting; assembling a repurposed clutch to the motor with adapter plate and spacer sandwiched between; then bolting it all onto the old gearbox. The date: a week from Sunday.