WEEK 2: Rolling Rotor Housing (too small) and Test Fitting, Lathe Crankshaft Coupling, Rotor End Cap Design for CNC

This week, I finished rolling out my rotor housing with the metal roller at school. I am fairly happy with how it has turned out, but by design, there are 2 sort of flat ends.
I then went to fit 14 of the magnets in, only to find out the rotor was somehow too small. This really frustrated me as I had spent so long on perfecting the design and even left a 4mm oversize in case it ended up too small, but it still at least a 5mm gap.

I have to choose to stick with it now as the rotor cut took me a very long time in the holidays and it would not be worth cutting it out again. I had to think hard about why it ended up too small, and I managed to come up with a theory of how the steel rolls physically.

I had calculated my measurements from the (inner diameter of the rotor * pi), to calculate the length of steel I needed to roll. I thought this would be the same for when I roll the 3mm flat steel, but I have now realised that when you roll the steel, the inner compresses and the outside stretches slightly. This means the actual calculated diameter should have been approximately halfway in the 3mm steel, so effectively 1.5mm + 1.5mm larger diameter than I had calculated. This would make the rotor over 9mm smaller than needed, which would make sense in how my rotor housing turned out.

But I will have to make do with the current state and maybe weld a filler in between the gap to complete the rotor housing.

I also worked on lathing/turning my crankshaft coupling down to fit into the rotor end cap which I am preparing to cut out next week.

I decided on taking all the old teeth off to create a cylindrical coupling of 50mm OD to slot into the rotor end cap and be welded in.

Term 3 WEEK 1: Rotor Housing Cut, Started Rolling, 3mm SmartDrive Flange Mounts cut out

This week on Monday, I finished the rotor cut out on the CNC router after routing the rebate in the steel. I had to make another cut file to go a little bit deeper (0.3 lower) to get the steel out afterwards.

I then cleaned up the strip with getting rid of the burring and excess lubricant, it is looking quite good so far.

After the issues of the metal roller not bending exactly right, I decided to try and level the roller and try to align the rollers as much as possible so it would bend my piece uniformly. This is especially crucial for balance and precision of the rotor housing.

Once I was happy with the bender, I had one of my stakeholders Mr Smith help me with starting to roll it out. We also used a metal square and spirit level balance to get the steel feeding in right before beginning to roll it.

I ran out of time to finish it this week but will continue next week.

I also continued on working on the flange design and getting all the thin 3mm flanges cut out.

I tweaked my design after the first 2 or 3 plywood and steel tests to get a flange mount I was happy with. I then set up the router as usual and after leveling by planing with the 22mm router piece, I then began my cut with the 6mm carbide tip with settings I found to work well: 11 - 15% speed, 0.1mm cuts, 6000RPM, and a dab of lubricant around cut path.

After a few hours of more CNC routing, I managed to get all three flange plates cut out and after cleaning them up a little, they fit really nicely into the SmartDrive stators, with the 4 M16 threaded rods going through.

Term 2 Holidays, transmission repaint, designing, coupling, electric motor CNC

Its been quite an eventful holidays with this project as I tried to hit out as much of it in the first week or so as there is still heaps of work to go!


I finished stripping out all the unnecessary stuff like the radiator, condenser, coolant pipes and tubes, AC compressor and fuel lines.
It is surprisingly spacious with plenty of room for my electric car design.

I also got to cleaning and repainting my transmission which is looking so much better now.

I also got to designing an adapting plate for the electric motor to bolt onto the transmission securely, I would ideally like to cut it out of a thick aluminium plate professionally, although there are other methods of doing this too without an adapting plate, when I get to this part in the build I will go more indepth into it.

I then removed the clutch and flywheel assembly from the old motor (now a parts motor), and then removed the crankshaft which I plan to use its flywheel coupling on the SmartDrive shaft. This involved a bit of brute force to get the thing out!

I had tried cutting down the flywheel coupling piece and lathing it down at school to fit the SmartDrive shaft in. I then plan to put an M6 bolt through the shaft. Although this is quite a small equivalent key of maybe a 40mm squared, which could be 4mm wide and 10mm long. This is plenty to handle the torque loads of my motor in combination with a tight, almost interference fit.

One of the main things I began doing in the holidays was setting up and beginning to CNC my steel rotor housing (magnet rotor). I first planed off the CNC board a couple weeks before, to which I screwed a piece of pine over the top (to reduce swelling if oil/lubricant for cutting spills). 

I layed a plastic sheet underneath all of these to seal off the oil soaking into the wood as much as possible. I managed to get a tolerance of about 0.1mm difference from one end of my 3mm steel stock to the other which I am fairly happy with.

Anyway I began cutting it out on Tuesday in the second week of the holiday, going for a solid 2 or 3 hours cutting out about half of the magnet tracks. I found the first 6mm flat endmill I tried was not designed for steel cutting as it went blunt in the first couple passes (probably about 1000 passes in total so no where near). Luckily, I found a carbide 6mm flat endmill which I chucked in and it cut out so much better at 15% speed. I dabbed a bit of lubricant every so often but it was doing very well without any supervision, which meant I could go on to working on the coupling stuff above.

By the end of the holidays, I managed to get all the magnet tracks rebate cut in, which I aimed to do before the wood began to swell a little and throw off my leveling.

By Monday, Week 1 of Term 3, I got to cutting out the rotor housing and am about halfway through.

It was good that I managed to cut the magnet tracks earlier as now the tolerance was about 0.3 or 0.4mm just from the swelling. The cut out file doesnt matter too much as the depths are not affected therefore it will cut out the same.

WEEK 10: Getting Ready to CNC Rotor, Flange Mounts, Holiday Work

This week, I began finalising my design for cutting out my rotor for the electric motor.
I also figured out my flange mounts design which sit in the centre of each stator and align all the threaded rods and bearings so everything fits nicely together.

I had also placed an order for thermistors and LCD's to temperature monitor my batteries with the Arduino microcontroller.

I will hopefully be able to setup and begin cutting out my final rotor design for the electric motor and start getting my batteries together, and order the remaining parts throughout the holidays to get the project going.
I will also design an adapter plate to make out of aluminium plate or steel to attach my motor to the transmisison, this will have to align the motor shaft to the transmission shaft, and also I have to figure out how to couple my electric motor shaft to the transmission through the clutch/flywheel like I had planned earlier.

WEEK 9: Engine Swap finished ready for WOF and pickup, battery design module cut out, thermistors and LCD's

This week I pretty much finished the entire engine swap and figured out the rest of the wiring to get the car operating as normal.

I wired the power steering back in as well as the cooling fan in the side and then soldered in the ignition jumpers I made earlier in properly.

I then got the car tided up and gave it a good wash so it is now ready for a WOF and pickup maybe next weekend!

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After taking it in for a WOF on Tuesday morning of week 10, it is now ready to drive on the road and roll once again!





I also milled out my battery module design out of plywood and it turned out great, I want to implement a temperature sensor in each one as well.

And I cut out test flanges for the stator motor mounts out of plywood. I plan for these to be made properly out of either thick aluminium or steel.

WEEK 8: Ignition success! Plywood test rotor end cap, Battery Design

On the weekend of week 8, I spent the whole of Saturday (again) trying to figure out the wiring for the igniter. I looked up the wiring diagrams in the online service manuals and watched a couple videos to trace them all back.

I managed to trace all the 5 wires to the igniter and found several things that might be causing the issue. The 3rd pin 12V supply had no pin connector power source, which meant the igniter could not operate at all. The wiring under the fuse box had 3 or 4 wires difference, which need to be copied of the layout of mine, and possibly the ECU signal wires were not going.

After hooking up a couple jumper wires and ground connection to how I thought the wiring should go, I then gave the engine a crank, which after a second or so it backfired which it hadn't done before. This gave me a lot of hope as I figured their couldn't be any ignition without some sort of spark, especially when the engine is cold. I cranked it several more times and kept getting a kick back or bang every so often, which I knew must be close to the problem, the RPM tachometer was also going all over the place and managed to throw itself off, which will need to be calibrated.

Anyway, the next morning, I then had another go at cranking it over with the same occasional backfires. After doing lots of research and having a chat to the guy who I was doing the engine swap for, I kept working at the wiring, which I then managed to trace the signal wires back to the ECU, which was good.

I then tested continuity of all my ground connections which I found that the igniter was now not grounded properly, so I hooked up a ground lead to it, cranked the engine over and bang it fired up to several thousand RPM's as noisy as a plane with no muffler on it.
This was truly amazing hearing all my work going to plan and now I needed to get the rest of the car back together.

On Sunday, I then got the muffler sealed and bolted back in which drastically reduced the noise, and then I took it out for a test drive and it felt great, I adjusted the idle revs down and the engine was running just like how it was in my MR2.

Anyway, on Monday of Week 9 I then did a fresh oil change and also refilled the transmission with oil as it had gone quite low. On Tuesday I gave it a good blast around town and it is running very nicely with all its power and high revs. I will be continuing to get it ready for the owner to pick it up.
The funds from doing the job will help me a lot to support my electric conversion project.\

Also in week 8, I worked on CNC milling a test plywood rotor end cap, which I was very happy with. I used the plastic spline attachment piece to simulate the coupling. After talking to one of my stakeholders Mr Smith, we agreed on using a solid welded coupling to the motor as it will probably be the most reliable and strong.

I also wanted to get the design sorted for my battery pack. I have decided on getting a proper battery management system from Aliexpress which will balance and protect the batteries in many ways to extend their cell life. I want to use the Arduino microcontroller to build a monitoring system with temperature control, which I have trialled and tested all ready with good results (using thermistors).
I will buy these parts over the next few weeks to get onto building the battery pack.

My stakeholder Jared Cochrane also agreed with the idea to split the battery into 27 different modules which will each be wired in series to produce the desired 99.9V nominal volage up to 113.4V fully charged. This will make each module lighter and more portable, safer, and makes the maintenance easier. But will be slightly more complex and will require more production of battery holders. But the benefits of doing the design like this compared to as one big unit is the sizing is more flexible also and the packs could also be expandable later on if needed.