cello

Thx for the detailed reply. I agree with you re why the over-revs require consideration even if older in time/miles, etc. We also agree on post usage sampling for analysis..

I guess what I was looking for was any info imparted re bottom end issues. That is, i agree that upper end (head/valve) issues can be sussed out relatively easily by DME. But what of lower end issues like bearing wear, connecting rod stress, etc.

If I am getting it, the Tech is saying that so long as the oil filter is not showing signs of likely grenading; then if enough time or miles pass with 'normal' (non-abusive) usage, the warranty will not be affected: So long as the service dept is known to PCNA and is important to them, i would think... A good reason then to develop a real relationship with a trusted tech/service adviser that could go to bat for you....

zanwar

overrev zones are like Pokemon, you're supposed to collect them all.

Macster

If the mains/rod bearings suffer from overrevs you'll know it by the noise the engine makes. The engine will have knocking sounds from the increased clearances and the lack of sufficient oil pressure. Hot oil pressure at idle and at some other (higher) rpm will be lower than 'normal'.

An oil analysis might find elevated levels of bearing metal in the oil or an inspection of the oil filter might find some scary bits of metal but if the oil/filter was just changed before you examined the car... Unless the engine was nearly at death's door the oil analysis and filter inspection is nearly worthless.

(An exception to some extent is after your test ride/drive if you still like the car, if you think you can buy the car, when you have the car PPI'd at that time the oil filter (at least) is examined again. If the engine is truely at death's door, what is in the filter will be the signs of pending doom.)

The effects of stress of the higher revs to other parts of the engine are harder to gage or determine.

For instance I know of an owner of a Boxster who tracked his car regularly and the car/engine accumulated some very big miles, way over 100K miles. Then a rod bolt let go. I do not think he missed (ever) a gear (did the money shift) but I'm sure he took the engine to redline often. He gave the car the servicing his usage required too.

The engine is only as good as its weakest part and in this case it was this one rod bolt.

All you can do, all the test ride/drive and your checkout of the vehicle, no matter how involved this is, all it can do is give you a good idea of the car's condition at the time you did the checkout of the car.

The next time you start the engine...

But in most cases, the overwhelming majority of cases there is no drama other than the engine just starts, runs and does this over and over and over again.

Sincerely,

Macster.

San Rensho

If the over-rev was a while ago and the car runs ok, then there was probably no engine damage, but the over-rev history tells me the PO was driving at the red line all the time and downshifting at the hairy edge. Not good for the life of the engine or the synchros in the tranny. In other words, the car has been abused, look for another.

Sharkys

1.5 yrs ago, I bought a '05 c2s with 40K miles from a private party with the following DME:

Current hrs: 1435

R1 978 1285.2
R2 74 1174.9
R3 3 1174.9
R4 1 316.6
R5 1 316.6
R6 0 -

Is it possible to find one with 0s in all ranges? What is the range of acceptable values? To some, the scan is almost 'virginal', but to others the scan means stay away. The reputable Porsche Indy wasn't overly concerned with the scan so I bought it. The cumulative hrs are now roughly 1791 with 52K miles and there are no issues. I did however, hit the rev limiter a handful of times. I'll get a DME scan the next oil change to see at what range the # of ignitions increment. I would expect R1s only since the last time I 'money shifted' was in a 1600cc VW bug (many years ago) and blue all the way threw 2nd only to get stuck in 3rd. But, I never lifted the clutch so it doesn't count And yes, you can drive a bug home in 3rd gear only - but I digress.

sandwedge

I had the DME unit replaced on my -06 C4S and all data was reset including R1 through R6. The service manager told me this would happen so I asked for before and after readouts. Sure enough, straight zeros throughout the range after the swap. My before readings weren't bad. Some 1's and 2's but it begs the question: How many cars are out there with a nasty history that's been cleaned up with a DME replacement? Could be a fair amount since this was a campaign item. Not an all out recall but one of those things they would do if you brought the car in for something else.

Riccardog

Well, quite a few detailed responses, which is nice.

I have driven the car in question for ~30 miles on two separate occasions and have taken it through the rev range, let it fully warm up until the fans come on, observed very very closely the exhaust for any smoke and listened to the engine up close from every angle, both at idle and when driving. No engine check light came on and all the other observations were fine.

Also, of all the 997s I have driven (6 total) it is by far the best driving one, the gearshift is particularly smooth and there are absolutely no strange noises.

Its being sold by one of the most well respected UK Porsche mechanics which has been running his shop for over 20 years now. He is foremost a mechanic (still gets his hands dirty every day) and then a car sales guy (in fact, he was replacing a wheel bearing on a 944 while I was viewing and driving the 997). He knows that if the engine is damaged I am coming back straight to him and he will have to repair it for free, so ultimately this is what gives me piece of mind.

Also, while I can see why some risk adverse people would be wary of cars with rev ranges recorded, I think its important to actually calculate the time which these represent. Approx 0.1 sec over nearly 1400 hours of driving really can't be considered by ayone as 'thrashing the car'.

No HTwo O

Get this in writting.