WEEK 6: Engine repairs and mounted in MR2, designing stator mount, CNC rotor

After rolling the steel rotor I CNC'd last week, I stuck a bunch of the magnets in place, but have found that the internal diameter is several mm too small, so the magnets are rubbing right against the stator. I think this has happened due to the MDF swelling up from the coolant I was adding, which messed up the rebate (1mm cut into the steel), but also the fact that the large steel sheet was slightly warped. So, from this testing I have done, I think I will cut a slightly large steel for the rotor diameter for be just right, even if it is just a little over, it is better than the rotor rubbing on the stators and wrecking havoc. I am excited to get underway with this as it will be one of the hardest parts of my project, so if it works out I will be so happy. I also have my 2 backup plans which is to use an old DC forklift motor which isn't as efficient but much easier to work on, or buying a proper electric car BLDC motor which will be very costly but the most efficient and powerful for my car!


Over the last week, I was pretty busy with getting the engine out and getting it ready for the other guy's MR2.

A summary of what I did:

A good clean and degrease of the engine, I removed my transmission and bolted his transmission on, I switched the water pump and cambelt before reassembly the covers, I then got the starter motor back in and rolled the engine under ready for mounting in his MR2.

It rained the next few days so I covered the engine before I was to get it after Friday.
So, on Friday I managed to get the car on the hoist and lowered it down onto one of its engine mounts which I loosely bolted it onto. This weekend I also was doing my 100 hour famine so I could not do too much after Sunday as I did not have the energy to (till Wednesday). But on Saturday I managed to get the second main engine mount on, which meant the engine was now held in well.
I then hooked up every single hose and electrical line, and swapping some connectors over as the wiring harness was slightly different.

After many hours of getting it all ready I tried to start it where the starter immediately turned on and started cranking the engine well, but it did not start! I had tried over 10 times after swapping other small electrical/mechanical components, but it was not going to start. After performing a spark test, there is no spark in the plugs, which meant there must be an issue with the electrical system somewhere. Over the next week I plan to get his car completely reassembled and on its wheels, and go from there to figure out how to get the engine running, as it was running perfectly fine before I took it out of my car.

Another thing I worked on is the stator mount (for the SmartDrive motors), as the 3 stators I am planning to use have to be very rigid in place to avoid the rotor from rubbing on them.

After talking to one of my Mechatronics stakeholders, Jared Cochrane, he agreed with the idea of using thick 12mm/14mm threaded rod through the 4 original stator mounting holes, with nuts on each side to clamp the stators in place. This also allows me to make fine adjustments to the stator positions to achieve good efficiency and then I can possibly weld them in place or loctite the nuts so they don't come loose as the motor will be spinning very FAST and will be susceptible to vibrations and harmonic frequencies. Another idea was to CNC mill flange plates for each motor out of a thick 10mm steel we have. I think this will greatly increase the rigidity and reduce flexing in the threaded rod, which is important as the electric motor has to be reliable.
Anyway, I will begin designing the mount next week to determine the rotor size so I can get to building it for real, fingers crossed it will work out!