For a while, the sound of Mark Farver’s MR2 has been a topic of amusement. Not the shhhh sound during acceleration that’s characteristic of its 1000-amp Zilla motor controller, or the sounds of shock absorbers and other parts you don’t normally hear as clearly in a gas-powered car. These are common features of electric vehicles, ones that offer little remaining surprise or novelty.

The sound in question has come from Farver’s abused transmission. The MR2 packs the punch of an 11-inch Kostov motor, and after a while the immense torque developed by this motor had caused the transmission to fail in some interesting ways. Besides broken gears and synchros worn down to nothing, it was the clink-clink-clink of metal parts floating around that made us wonder what sort of part had broken loose internally; with no engine noise the sound was clearly audible from within the car as the motor stopped spinning.

Mark has recently had his transmission rebuilt, and this gave us the opportunity to see what had caused the noise. The clutch springs, which provide some absorption of the torsional shock applied to the drivetrain from the force of acceleration, hard shifts and potholes, had decided they weren’t really happy with their lot in putting up with the Kostov’s treatment, and freed themselves into the bell housing where they bounced around and made their metallic sounds of emancipated happiness.

Farver decided to try reusing the damaged clutch disk by replacing the springs with a weld between the disk and its formerly spring loaded hub. I TIG-welded around the hub on both sides, and then applied some small tack welds by the spring pockets for a little additional strength.

Modified in this way, the car should lose its annoying forward-backward bounce in first and second gear which is due to the high inertia of the motor’s large, heavy armature bouncing against the driveline on the clutch springs. However, without any cushion in the driveline, it will be interesting to see what other aspects of the car’s handling change.

This will be of some interest to me as well, since I will have an entirely solid connection between my motor and the differential, with no transmission between.

Pictures posted here.