Hi All,

Does the 997.1 Turbo Mezger engine use a Timing Chain?

The reason I ask is because I am contemplating buying a 2007 997 Turbo that has 750 Range 4 ignitions (the last that happened 482 operating hours ago) and 11 Range 5 ignitions (which happened 634 operating hours ago). From what I understand 11 ignitions in a Range may not even be "real" (from an article on 911Virgins).

I plan on having the car compression/leak tested which would reveal any damage to valve seating, etc.

However, I am still concerned that their could be Timing Chain stretch that might be a future problem - and there is no way to check this. But then I read one thread somewhere where the poster indicated that the 997 Turbo did not use a timing chain, just gears. I cannot confirm or contradict this in any other searches I did.

So does anyone know? If there is no Timing Chain, then I suppose I needn't worry about Timing Chain stretch due to the over rev events.

If the compression/leak test checks out, what other latent damage could have been caused that is not yet revealed in 438 hours of operation?

I talked to two Porsche shops, one of which was a Porsche dealer, and both advised to walk away from the car (which is stock with 45k miles - and as far as I know was always stock, except for a short shifter). I thought that the 482/634 hours of operating time after the overrev events would have put them at ease, but apparently not. I even emailed 911 Virgins and they responded that they would probably just keep looking for another car.

Any thoughts welcome,
Alan

 

yes they use a timing chain

 

Yes that engine has timing chains. I have never heard of chains going bad on these engines. They are double row thick chains would take some real abuse to stretch them.

If the car has a tune on it, it will move the rev limiter giving false over-rev reports. If a leak down and compression check look good I would buy the car.

Dont look at the report to much, It an ok tool to see how the car was driven but alot of good cars are passed on because of it. When there is nothing really wrong with them.

 

The range 5s are probably real, but the hours since both the range 5 and range 4 show that nothing is going to happen. Just another example of a Turbo with over revs that a. didn't explode and b. is, by virtue of the real world evidence right in front of us (hundreds of hours without problems), literally indistinguishable from Turbos with zero over revs.

 

 

I would like to hear from someone that got an over rev report that was "bad" but got the car anyway and then had a problem with it. Bad cylinder/spun bearing etc.

You rarely if ever hear of people have an issue with these cars unless they are built or people are touching them that shouldn't

Its a great tool for Porsche to not warranty something

 

Thanks for the replies!

My new worry is the dreaded P0021 camshaft sleeve issue. I have been reading a fair amount about that - does anyone have reason to believe that over revving the car can lead to that particular failure? From what I have read it appears to be luck or bad luck - not related to how the car was driven or even how many miles it has.

But I am worried that sellers can clear the CEL and that the light might not come back on during a PPI or a test drive and the new buyer would get stuck with the problem. I have no evidence that this is the case with the car I am looking at, but just general paranoia. I am looking at two cars where the current owners have owned the cars just 22 months and 17 months. The former claims they are selling because they need the cash for a business venture, the latter because he is progressing through a bucket list of cars and while having enjoyed the Turbo, is now looking to move to the next bucket list car.

Thanks,
Alan

 

 

Agree, people with clean DMEs (and low miles, for that matter) can get hit by the camshaft thing. The other Achilles Heel is the coolant pipes, which is usually more mileage/age based but is likewise unrelated to overrevs. It's also way more common and should really just be done preemptively at some point during your ownership.

Besides those two things, dramatic engine problems on cars that aren't highly modified (700hp+) are extremely rare on the Turbos. It's not like the NA 911s with bore scoring and D-block piston wall failures and IMS bearings and so on. The basis of the Mezger is from a Le Mans car, after all.

 

If the vehicle has the camshaft issue you can clear the light but it comes back quick so it would be hard to hide.

When buy one of these cars just go into it thinking you are going to be doing the cam sleeve pinning and coolant pipe repair because most likely you are going to do one or both.

There are plenty of guys out there that say 'Oh I dont have any issues with my coolant pipes" and they dont but at some point they will leak or blow out. So you just have to figure your going to do this repair. I had mine welded just because I take the car out alot and sometime I am not close to home I would rather not end up on a tow truck but thats just me

 

My 2cents - clearly Porsche has faith in the DME and its results (to a point) given that they won't CPO a car with events above a certain range & frequency and they will use the data for warranty claims purpose as well. That said there is/are every chance for spurious readings from the sensors (very low readings in any range are potentially mis-reads given its number of ignitions and at ~7k rpms the events are 1/100 of a second apart and the frequency response of the ECU and sensors is decent for a car but pretty rudimentary versus more critical industrial applications).
As stated a tune on these cars usually raises the rev limit and ends up in a decent number of range 4 (I've seen that on both my TTs).
A few range 5s are not likely to turn the car into an UXB especially if recorded many hours ago...

Perhaps more importantly - every manual car has the ability to over-rev due to incorrect downshifting. That's the cause of ranges 5 and 6 in about 99% of cases (and the reason why the DME report is less relevant on a TIP)
For some reason only 911 owners obsess over this.
I raced R53 and R56 Minis for 5 years in Asia - all manual cars and in the heat of the moment and being an amateur I know I mis-shifted 5-2 on a few occasions. if a DME-like readout were possible I'm sure I'd see range 5s and plenty of 6's on those engines, and you know what? Engines were fine.
If a Mezger 6 can last 24 hours in an endurance race at 10/10ths it can survive a few milliseconds above its normal operating threshold.

I think the reason Porsche uses the DME data is more about financial liability than actually true concern about the car's longevity and strength....

now don't start me on the "all coolant pipes fail" discussion....

 

I had a coolant line give out. Replace all, around $600, plus labor for drop motor. They WILL give out as the are a type of plastic.