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Range 4 overrev

I had my 2006 3.8L 997.1 S at the track and missed a gear resulting in a Range 4 alert for 105 ignitions.

First, Is that enough to spin a crank bearing?

My car has 40K miles. It doesn't smoke and doesn't leak oil.

I'm embarrassed to admit, but the car was very low on oil (4.5 quarts low). My car had a full 40K mile $2500 service performed at the dealer just 600 miles before the failure.

After the 3rd 30min session on the track it was still running great! After it cooled down, I fired up the engine to go get gas. I immediately heard 4 knocks and a rattling noise which to me sounded like the timing chain rattling in the guides. I THEN checked the oil and proceeded to put 3.5 quarts of oil in the car and that brought the digital indicator up to one quart low. So, my was 4.5 quarts low! I flat-bedded it to a nearby Porsche specialist. They pulled the oil filter and found what they said was crank bearing material - lots of it.

Grant it I pulled a knucklehead mistake by not checking my oil. I had been away from the track for a few years and checked tire pressures on and off the track, torqued the wheels, but didn't think about checking the oil... urrrggghhh!

Anyway, the dealer is telling me that being 4.5 quarts low on the track did not cause the failure... they say it was my missed shift. I drive aggressively taking some sweepers at ~100 mph. I don't have baffles in the oil pan. They are telling me that since the oil pressure fault didn't show up on the log, it wasn't low oil that caused the failure (which obviously would be their fault for not putting enough oil in the car during the 40K mile service). I've asked them for oil level and oil temp data from the data logger, but they've not responded.

One other thing... the time recorded for the Range 4 was 1 hour before the bearing failure. That means I ran 2 more 30-min sessions on the track after the Range 4 overrev fault. Seems to me if the Range 4 overrev caused the bearing to fail, it would have failed before and additional hour on the track after the overrev.

So, four questions: 1) can a range 4 overrev for 105 ignitions spin a crank bearing if the car had full oil? 2) What about if the car was low on oil? 3) Can being 4.5 quarts low on oil not cause the failure without losing oil pressure? 4) is it possible that the low oil condition had nothing to do with the failure as the regional Porsche service guy is telling me?

Old 07-07-2020, 09:47 AM
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Over-rev is usually associated with valvetrain damage. Low oil pressure is usually associated with bearing failure. I would go with low oil level causing your failures.

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Old 07-07-2020, 11:26 AM
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Thank you!
That is my thinking as well...
Old 07-07-2020, 01:56 PM
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Old 07-07-2020, 04:03 PM
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I’ll second the low oil being the cause.
M96/M97 motors are prone to oil starvation in hard cornering even with the oil topped up.
104 ignitions at stage 4 is nothing. That’s a fraction of a second. And the warranty isn’t voided until stage 5 or 6.

Also. I’ve seen plenty of race cars spin a bearing from low oil pressure and not have any events recorded on the PIWIS. Only takes a moment under full load and less than adequate oil pressure to do damage.
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Last edited by Tyson Schmidt; 07-07-2020 at 07:03 PM..
Old 07-07-2020, 06:58 PM
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Also agree that low oil was the cause of the failure. A time machine sure would be a handy item in these cases, just go back in time and add oil - wouldn't it be great!

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Old 07-09-2020, 04:28 PM
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crank bearing failure , range 4 overrev; 997.1 s


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