October 19, 2011 — HSR Sebring

After Roebling Road, an event where we experienced exceptional reliability, the HSR Sebring event on October 14 -16 proved rough on our Datsun 510.

Thursday’s three practice runs were uneventful.  Knowing Sebring is so hard on equipment, our plan had been to inspect our brake rotors after our last practice.   An existing stress cracks had opened enough to warrant installation of new rotors prior to our next run the following day.

During Qualifying on Saturday, a vibration was experienced and we cut our run short to investigate.   A discrepancy in the steering was discovered and corrected.  Our plan was to run the 1-Hour Enduro, but we decided to run a shorter race that preceded it as a further testing session and found the vibration was still present.  The culprit was traced to a problem in the drivetrain.  This was rectified with no time to spare before the Enduro.

Unbeknownst to us, our real problem laid just ahead.  During the Enduro pace lap, our driver reported that the vibration was gone and everything was normal.  Later, coming down the back straight at close to maximum rpm in top gear and just before the braking zone, two loud bangs were heard in rapid succession.  Our crankshaft had broken, ending our weekend.

We had planned to run one more event with this engine before the end of this year.  Then, install a new engine that’s already being built and freshen up the existing one for a spare.  The flaw that resulted in the catastrophic engine failure could have been detected if only it would have lasted for one more event.  I guess that’s why they say “that’s racing”.

Our research on the history of our Datsun prior to Moya Motorsports does not tell us much about its engine’s service history, but we do know the short block was built in 2006.

The failure will put us out for the rest of this year.  In consolation, the fact that the failure was unpredictable and not caused by anything we did, or failed to do, is encouraging.

Broken Crank -- Catastrophic Engine Failure

Broken Crank -- Catastrophic Engine Failure


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