This post was contributed by UVic EcoCAR 2 team lead John Walsh
In the stock 2013 Malibu Eco platform there is a belted alternator starter (BAS) motor that is connected to the 2.4L LUK engine at the crankshaft. In the University of Victoria (UVic) team’s vehicle, we upgraded the BAS motor to a TM4 80kW electric motor and the LUK engine to a 2.4L LE9 E85 Ecotec engine. We also replaced the pulley/belt parts to allow the TM4 motor to be connected to the crankshaft of the LE9 engine. We were relying on the stock system attachment to be strong enough to transmit the new higher shaft power from the TM4 motor. But as we found out in mid-December, it was not…
The torque component (woodruff key) was not able to handle the load and it catastrophically failed. During the failure, bits of sheared key material left a path of destruction on the crankshaft (see below). Upon further inspection, it was noted that the key was shared with the LE9 timing sprocket. We needed a better, stronger key, and we needed this fixed as quickly as possible.
We decided, since the key was linked to the LE9 timing sprocket, that we would cut a new key slot in the crankshaft and design the key to handle the rated TM4 motor power. Fixing the problem in a timely manner required a speedy design to identify the new key requirements, and coordination with our local sponsor and GM dealership.
We pulled the LE9 engine and sent it to our local GM dealership (Wheaton Chevrolet Buick Cadillac GMC) to be dismantled. We also sent along our LUK engine. The stock engine was worth its weight in gold as the crankshaft is the same as the one needed for the LE9 engine. The stock engine crankshaft was pulled and sent to our local team sponsor PED (Prototype Equipment Design) and a new key slot was machined. The crankshaft was turned around in an astounding 1 ½ days. The GM dealership then rebuilt the LE9 engine with the modified crankshaft (see below).
Finally, we reassembled the engine on the subframe with all the associated components/suspension and raised it back it into the engine bay (with our new TM4 motor). The total turnaround time was 3 weeks and occurred over the holidays. The total turnaround took about three weeks and the team is excited to get back to work on the vehicle.