Motor position

The scanning of the original petrol motor done by FormScan in Auckland still blows my mind. It’s extremely accurate, visually impressive, but also fairly easy to work with inside the Rhino 3D software I’m using for modelling.

It was important to get the location of the mounting points right because there just isn’t that much room to work with. The picture below illustrates the situation:


This is the original motor with a regular AC35 motor overlayed. The gearbox input shaft protrudes 1mm past the face, so the output shaft is 1mm back from the gearbox face in this model. However it still doesn’t fit when you look at the side engine mount compared to the end of the motor – and that’s without a mount added, We’re only talking about 7mm or so plus another 5 to 10 for the mount, bolts, etc, but it’s getting into “maybe” territory which usually means not-quite.

So first thought was converting to one of the alternative AC35 motors with internal splines rather than output shaft, but that quickly looked expensive (no case/face conversion, just complete replacement). Next option was input shaft or output shaft modification to create either some space or some overlap…

The motor output shaft has a 7/16″ hole drilled down the centre while the Beat gearbox input shaft is 12mm, so it almost but doesn’t quite fit. That OK because Elektron should be able to drill it out to fit, creating 15mm of additional room. That’s enough to position the motor and mount so it’s within bounds and will fit the Honda engine bay. The 6061 CNC motor plate and mount will be something like this (work in progress.. lots of holes and machining to add):


On a related note, I was trying to figure out how the UK Electro Beat EV managed to fit a Kostov K9 in the same space. Turns out that the Kostov has a 17.5 mm hole in the output shaft already, so drilling out the AC35 maybe isn’t such a hack after all.

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