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Motor to Transmission assembly

Mounting the FB1-4001A 9″ motor to the transmission required a custom adapter made specifically for the MR2. I ordered mine from KTA services and they were great; very responsive. First thing to do is to strap the motor to a workbench, to prevent scratching up the motor, I used an old towel around the motor. Here are a few shots, the 3rd picture has the adapter plate on top of the motor.

The plate is bolted to the motor using the supplied bolts, and the key is inserted into the slot on the motor shaft. Note this motor has 2 shafts, the larger one is the one for the motor, I might be able to use the 2nd auxiliary shaft for the air conditioning system.

The hub is then slid over the shaft and key and finger tightened down such that the hub can still slide on the shaft with some force. This is because we will need to adjust where the hub is on the shaft once the flywheel is in place.

Next the flywheel is temporarily bolted to the hub using the original screws. Note, I had the ring gear removed from the flywheel and the flywheel lightened and balanced with the new pressure plate that I purchased. The ring gear is not needed on an electric system and just adds extra weight to degrade performance. I used Ashland Grinding and Balancing in Hayward. Mike, who owns the shop does really good work; he stays busy doing work on high performance cars like the Ferrari for his customers. My flywheel lost about 5 lbs from 15 to 10.

To properly fit the adaptor to the transmission, the distance from the surface of the transmission side of the flywheel must be 1.617+/- 0.005 inches from the surface of the adapter plate facing the transmission. This took a little while to get perfect, but I finally got it done! Next, we need to remove the flywheel from the assembly without moving anything and disturbing this distance. After successfully removing the flywheel, tightened the small bolts to secure the hub to the shaft.

Now bolt the flywheel back to the hub with a torque wrench to specifications based on the bolt size, then bolt the new pressure plate to the flywheel with the new clutch disc sandwiched in the middle. Note the alignment tool used to center the clutch disc along the shaft of the motor. Note also to use a cross pattern when tightening the bolts so that we don’t create an off-center fit.

Time to hoist the transmission to the motor!!

The transmission was aligned to the engine using 2 10mm steel dowel pins, I tried to remove them from the engine but was not successful but I did find replacements at McMasterCarr. I love that place! You can find the almost any thing you want there. The first 2 shots below are marked with the location of the alignment holes on the adapter plate and the transmission. The alignment holes on the adapter place was too tight, so I had to sand down one side of the dowel pin a bit and used a lubricant to help drive the pin into the adapter plate. Make sure you drive this pin straight!! Also, make sure that you protect the motor from metal shavings by wrapping a plastic bag over the motor.

Since the engine has been replaced by the adapter plate and motor, I had to source the bolts and nuts of the right dimensions necessary to mate the motor to the adapter plate from the local Kragens auto parts store. I used grade 8 (class 10.9) bolts where possible. Also, the rust on the mounting brackets were bothering me, so I cleaned them up and spray painted them with a nice coat of Rustoleum, shiny!!!!

After struggling for a bit to mate the transmission to the adapter, I finally got it together! The trick to was to remove the passenger side differential connector to the wheel shaft. When this was removed, transmission fluid leaks out, so be ready with a bucket!

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Posted in Adaptor Plate, DriveTrain, Motor, MR2EV, Transmission

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