Rev Ranges and Scored Cylinder Walls

[NA55]

I have just recieved a rev range report from my local opc and it has the following details, was hoping domeone could help me deipher what it means:

Range, Number of Ignitions at overspeed, Operating hours counter reading upon engine:
Range 1, 27480, 2361.100h
Range 2, 3882, 2358.300h
Range 3, 364, 2251.800h
Range 4, 102, 1657.600h
Range 5, 1, 420.700h
Range 6, 0, 0.000h

They have also stated that cylinder 6 has scoring on cylinder walls.

I was hoping someone could help me with the following:
- advise me as to whether the rev range 4 and five reading are correct and the car has in fact ben over revved (have no idea how to read these)?

- If the car was over revved, how can I work out when it was done. I want to try and ascertain whether it was prior to me purchasing the car or a recent event?

- what are my options in solving the problem with the scored cylinder walls?

[996GT2]

What are the total operating hours?

[NA55]

Not a clue what total operating hours are as only details I have so far are in the original post... Will reach out to OPC to get this. Any ideas on what rev values mean and options for repairing a scored cylinder?

[996GT2]

NA55 said:

Any ideas on what rev values mean and options for repairing a scored cylinder?

Over-revs are logged in the DME whenever the engine spins at beyond the rev limiter. Range 1 is generally logged when bouncing off the rev limiter, so is range 2, range 3, 4, 5 and 6 will usually have been caused by a missed gear shift causing a mechanical over-rev.

Looking at the numbers this car has had at least 3 trips into range 3-5 which is where Porsche generally start to use the data to blame any engine damage on the owner. If the last range 1 event was relatively recent then the last range 3 event was less than 200 engine hours ago, which means that Porsche will most likely use this as part of the reason why the engine has scoring.


If the car is out of warranty I'd take it to somewhere like Hartech and get it rebuilt for less than OPC money, if the OPC will offer some goodwill and works out the same then that might be an option as they'll warranty it going forward.

Hope that's of some use.

Edited by 996GT2 on Thursday 7th August 18:07

[NA55]

thanks for the advice, appreciate the help.

I have been told by the OPC that my 'total operating hours' are 2392 and the car has approx. 530000 miles on the clock. Takibng this into consideration can anyone roughly tell me when the over revs in range 3, 4 and 5 occured?

Also is the range 5 reading correct as having only one misfire in that range seems to be a little strange.

[996GT2]

NA55 said:

thanks for the advice, appreciate the help.

I have been told by the OPC that my 'total operating hours' are 2392 and the car has approx. 530000 miles on the clock. Takibng this into consideration can anyone roughly tell me when the over revs in range 3, 4 and 5 occured?

Also is the range 5 reading correct as having only one misfire in that range seems to be a little strange.

You just need to subtract the hours of each event from the current hours, you can then work out the mileage by taking your car's average which appears quite low at 53000/2392 = 22mph

Range 1, 27480, 2361.100h (2392 - 2361) 31 hours ago (31 x 22 = 682 miles ago)
Range 2, 3882, 2358.300h (2392 - 2358) 34 hours ago (34 x 22 = 748 miles ago)
Range 3, 364, 2251.800h (2392 - 2251) 141 hours ago (141 x 22 = 3120 miles ago)
Range 4, 102, 1657.600h (2392 - 1657) 735 hours ago (735 x 22 = 16,170 miles ago)
Range 5, 1, 420.700h (2392 - 420) 1972 hours ago (1972 x 22 = 43,384 miles ago)
Range 6, 0, 0.000h


1 ignition in a rev range does seem unusual but I guess it's not impossible that the over-rev would be right at the top of range 4 and the software logged a single cylinder ignition at that rpm, could be a rounding up type issue in the code - I don't write DME software so happy to be corrected!



I think that's all correct, this is based on my understanding of the over-rev data - I've had to use over-rev data to prove that an OPC tech drove my car with a serious lack of care!

[MrTickle]

I have a 1 reading in 4, 5 and 6 - so yes a reading of 1 can be an error and probably safe to ignore.

Your reading is 4 is the more relevant, but of course it might have absolutely no bearing on the bore scoring anyway!