wstar's Journal

wstar

I don't think the failure is really 7AT-related, but I guess the answer to that question is a matter of opinion.

Keep in mind nobody's opened up the engine or even the bellhousing yet, this is all based on an experienced, trustworthy 370Z mechanic's opinion that a main bearing is spun based on the sound, and that the flywheel is damaged by looking through the bellhousing access holes. I 99% trust he's right on both counts.

Given the audio data from the datalogger late Saturday (where the engine was operating fine in terms of revs and performance, but there was a buzzing/grinding noise), I think the flywheel failed first, and then the imbalance/drag from that affected the crank and caused the eventual spun crank bearing within a couple sessions after the flywheel got bad. The flywheel *is* different on the 6MT and the 7AT, obviously (the 7AT has a "drive plate" that the torque convertor bolts to, it's a different part number than the 6MT flywheel). I've seen reports of cracked driveplates on 7AT's elsewhere (e.g. Megan's here: 7AT Owner , look at this ! ). The 7AT itself is supposedly still in good shape right now, but perhaps there's a weakness in the 7AT-specific driveplates under heavy loads at the track.

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