Engine Bay

The engine bay now houses a Soliton jr. motor controller and an Advanced Motors and Drives 9″ series wound DC motor, along with the original alternator, power steering pump, and a vacuum pump. Below is a shot of the general arrangement:


Starting from the top:

  • The motor controller is housed in an aluminum sheet metal box
  • The original engine accessory bracket complete with alternator and power steering pump
  • A 9″ series wound DC motor coupled to the original 5 speed manual transmission with the original clutch
  • A welded steel motor bracket bolted to the original engine mount

There is also an OEM VW brake vacuum pump tucked into the side of the engine bay and a PVC vacuum reservoir attached to the bottom of the aluminum box. The vacuum pump uses the original pressure transducer between the vacuum brake servo and vacuum line from the intake along with an attiny and a relay. More on this will come soon.

The aluminum box is intended to keep the motor controller and additional electronics shielded from dust and moisture. It also prevents people from inadvertently trying to touch the high voltage connections on the motor controller. I made box along with a pan lid in the Waterloo student machine shop for a total of about $40 in material.


Currently, a welded frame made of sections of angle iron holds the original belt driven accessories to the electric motor. Though this was a good solution where all the pulleys would be in alignment, it wasn’t very space efficient. New aluminum mounts are being milled in order to hold the alternator and power steering pump directly to the side of the motor.


The motor is interfaced to the transmission bell housing with a 1.5″ thick aluminum plate. There are 2 5/8 dowel pins and 7 M10-ish bolts on the transmission side and 4 – 3/8″ bolts with a 4″ diameter centering bore in the motor side. The only reason for the thickness of the plate was to space the motor out far enough to prevent interference between the transmission input and motor output shafts. In hindsight it probably would have been fine to create a “sandwich” of 3/4″ aluminum to significantly cut down on material cost (I got lucky and Metals Plus in Oshawa had a 15″ square offcut chunk, still ~$300 if I remember correctly)


The business end of the motor has a keyed coupler with an appropriate shoulder and mounting holes for the flywheel. The spacing from the back of the flywheel and front of the adapter plate was roughly 7mm, this distance was critical for the clutch to operate properly. An oilite bushing is also on the end of the coupler in place of a pilot bearing to support the transmission input shaft.


With the front end of the car buttoned on, this is what it looks like:


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