Saturday, July 5, 2008

Motor Mounting Design

The past couple of days have been spent getting the motor into its exact final position so I can design the mount. First step was to attach the motor to the tranny (using an adapter from Electro Automotive) - this is just a temporary attachment, since I don't have the clutch / flywheel / hub mounted yet. The center of gravity is just under the transmission bell housing, which makes a convenient place to put a transmission jack (out of the way of the rear mounting holes):

With the motor in place and the Jeep resting on its wheels, the interference I was worried about earlier is very obvious. The corner of the motor mounting "foot" just touches the steering / suspension system:

Here's another view from below. This, obviously, will not do. When the car is moving, this will be rubbing and grinding and banging against the motor, damaging or destroying both the motor and the suspension:

So, when the going gets tough, the tough get their angle grinder out. I marked the corner that I wanted to remove:

I then attacked it with a cutoff wheel on my angle grinder. This is an aluminum foot, so it cut like butter and did not get very warm at all (the corner that was removed, on the other hand, was hot as all getout - less thermal mass):

Finally, before designing the motor mount, I needed to make sure that the electric motor is mounted very close to where the gas motor went. I put threaded rods through the gas motor's mounting points and measured where that lined up against the bell housing mounting points:

I then hoisted the motor until it matched that offset. It's not 100% critical to be exactly aligned, but the closer to aligned, the better it will be for the U-joints and CV joints of the drive shafts.

I was originally just using the motor mounting points as convenient reference points for placing the motor. However, looking at it, it really is an ideal place to hang the motor from (since that is where the gas motor hung from). I've outlined the two motor mounting points with their integral rubber bushings in red here:

After taking lots and lots of measurements, here is what I designed. You can find a PDF file of all of it here.

Next step: prototyping the motor mount with cardboard and then cutting and welding the actual mount!

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