The long awaited adapter and hub arrived today and for the most part it seems good except for a couple of issues which I will go into more later. I started by nailing a couple pieces of wood to my workbench to cradle the motor. The last thing I wanted was a 180lb chunk of metal to roll of the workbench on to my toes!
The adapter plate
The adapter is made of 3 pieces of aluminum plate that apparently have been water-jet cut. They are attached to the motor with 4 bolts that were included along with 8 flat washers (presumably to keep the bolt from shanking out) and 4 split washers. I normally don’t see plate this thick water-jetted because of the kerf from the jet fanning out. It is okay as long as you account for it by giving plenty of clearance to adjacent parts. I am not crazy about it for the mounting bolts but this plate is so thick it shouldn’t be a factor. 
The first really issue is the hole in the plates for the hub is just barely oversized and the tolerance of the plate means it’s not quite centered on the shaft. Because there was so small of a gap designed between the hub and plate, this just bearly causes an interference. There is no play in the bolts mounting the plates to the hub so the hole in the plates must be opened up or the hub turned down (I think the best answer is both).
This really could have been avoided by making center hole ID (Inside Diameter) much bigger. All of that aluminum inside the 4 motor mounting holes is not doing any good. It doesn’t carry any load and is just dead weight that should have been just put into the recycle bin for the machine shop to get a few bucks back.
One last note on those split washers. In this application they are useless because you have to use the flat washers underneath them. Split washers only *work* when they make contact between the base part and the fastener. I will be using Loctite to keep these in place.
The hub
The design of the hub is… interesting. It looks like part of a cast shaft coupling that screwed into the actual hub by 3 M10? socket head cap screws. These screws alone would not be sufficient to carry the repeated +200ft-lbs torque of the 9” motor but since the coupling appears to be wedged in (kind of like a taper lock) when you clamp it up it should be strong enough. The hub is also larger in OD (Outside Diameter) then it needs to be which like the ID of the adapter is un-necessary weight and leads to the interference above but also causes a interference with the flywheel. The flywheel has a recess that would normally go around the end of the crankshaft. The hub is considerably larger OD then the original crank so it does not fit inside.
I am going to email Electric Car Company and we’ll see what they say. I am sure they will fix the issues but it's a matter of how long it will take. I have a feeling I may be borrowing some lathe time soon to turn down the hub OD and opening up the plate IDs myself just to make it happen faster.
One other issue is I don’t have bolts for the flywheel. :-( This is 100% my fault because I should have resused the ones from the engine. But I left the old clutch and flywheel on for the guy who bought the engine as he was converting from auto to manual. Oops.
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