There have been many cases, especially recently of 957 failures. It's a very complex issue, however I do believe it is a design problem. The clearances and the pin offsets are less than ideal, and the extremely rich cold start programming on DFI cars are major contributors. (I'm paraphrasing info from memory, credit to Jake Raby)

The Cayenne Engines are NOT Nikasil (Mine will be after rebuild, with a custom set of pistons to correct the design shortcomings)

If you want some fun tech reading, there is an excellent overview of our engines in this document. (Attached)

It does seem to be a bit of a lottery on these things... Mine was stored in a heated garage it's entire life, oil changes every 5k miles, etc. etc. 110k on the clock now. Hopefully your number doesn't come up!

 

This had always been my impression as well, but after speaking with Flat 6 Innovations, and LN engineering, they are much more common than we think. Even when I called my local dealer for shortblock pricing, they were not surprised. I spoke with the guys at Flat 6 in January, and they told me they had already logged 5 or 6 just that month. He was surprised I was able to get 110k miles out of mine...

 

Weird, I wonder why EVO puts that in their buyers guide then "Turbos and later S models have a Nikasil coating which gives no trouble."

http://www.evo.co.uk/porsche/cayenne...ng-checkpoints

What comes to Flat 6 and LN, these guys kinda live off these problems. Selling 400 dollar online courses with sensational headlines like " the truth about cylinder scoring".

I'm not saying that its not happening, but these guys are actually benefiting from it, so I would maintain a level if criticalness.

Also, here is a direct quote from Jake Ruby from Flat 6 Innovations on the 996 forums back in 2014 on cylinder scoring: "But it does not happen to the Cayenne Turbo, as they have Nikisil cylinders.. Just like it doesn't happen to the 906/997TT as they have the same." Now say what?!

https://rennlist.com/forums/996-foru...l#post11120982

Or in another thread: "The TT engine issues with scoring are very isolated in comparison to the S engines. I've only had 4-5 experiences with TT engines and this issue. The cold wasn't the only contributing factor in a couple of them. "

https://rennlist.com/forums/porsche-...l#post11157262

 

That's very interesting that they quote that. But I can assure you, since I've seen mine with my own eyes, they are not Nikasil

While I can understand your skepticism regarding LN and Flat 6, they would have no reason to lie about the number of failures they have seen. There are only a small number of shops in the US (3 that I'm aware of) capable of repairing the Cayenne block, and they too are backed up with repairs.

I'm doing my rebuild myself, and I will post a thread once things get rolling. I'm still awaiting the block and pistons from the machine shop.

It really stinks we are seeing failures like this, it's very discouraging that Porsche has not made any changes (that I'm aware of) to the engines in light of these problems. I was considering a Porsche short block, but I'm afraid the same issue will just reappear down the road.

I've owned well over a dozen Porsches, and currently have 5. I was sniffing around at a Panamera Turbo S, but after this, I'm thinking negative.

 

You've seen through the BS.
Also look at forums such as pelican, renntech, 6speedonline, cayenneforums etc. and you'll see there is no shortage of trashed turbo engines. Considering turbos are far more rare than NA, I'd go as far as saying it's far more likely to happen to a turbo.

 

I added two quotes By Jake Ruby to my post, he also seems to talk about nikasil. Could it be that the 955 TT is nikasil and 957 isn't?

 

There is a definitive difference in my research on the number of failures on the 4.5 and 4.8 turbo. The 4.5 seems to have almost no failures. The 4.8's have been appearing more and more often.

No idea why Jake states the Cayenne is Nikasil in that post. It's not...

 

This could be a possibility. I've never seen inside a 4.5 personally. I would doubt it, but you never know!

 

Actually, I just read through the tech document above, and both the 4.5 and 4.8 engines describe the exact same manufacturing process.

"The crankcase in the Porsche Cayenne is a two-piece
“closed deck” design, made of a light-weight alloy
(AlSi17Cu4Mg). In closed deck construction, the sealing
surface of the crankcase to the cylinder head is largely
closed, only the bores and passages for oil and coolant
are present. This design will strengthen the entire
structure. The result is less cylinder distortion and benefits
in oil consumption.
The alloy for the crankcase housing is a so-called hypereutectic
alloy, in which silicon crystals are formed. To create
a wear-resistant surface on the cylinder walls, these silicon
crystals are uncovered by multiple special honing
procedures. To minimize thermal changes in bearing
clearance and thus reduce mechanical noise, the lower
section of the crankcase is furnished with cast-in cast iron
bearing blocks. Another advantage is that when the engine
is at operating temperature, oil flow at the main bearings
does not increase substantially as a result of the constant
bearing clearance (approximately the same coefficient of
thermal expansion between steel/crankshaft and cast
iron/bearing block)."

 

Any way you slice it, it SUCKS to be dealing with it!

Ours is maintained impeccably, and it's primarily my wife's grocery getter. We live way out in the boonies, so I never sees short trips, always inside, and the only time it ever sees WOT is when I drive it , which is rare.

 

On post 25, in the second thread you posted jake says they are Alusil, LOL!

These threads can get very, very confusing.

 

I bet. It's my worst nightmare. Some cylinder scoring, leaking dampers, and a bit of failed PDCC pump - and you could just as well have bought a new Cayenne.

Hah, what's he smoking

 

There is something like 150,000 Cayennes floating around in just the US. That doesn't even include the Panamera. If there is an abundance of scored cylinders on the Turbos (of any generation), I must be blind because I'm not seeing them. LN and Flat 6 are in the business of rebuilding blown motors, so their opinion on "what a problem is" is going to be a bit skewed. Even if you factor in 5 in one month at either of those shops, that's .003% of the entire fleet.

The CS has a known issue, and there is obviously plenty of posts about it. The CTT - I must be smoking something because it's something I never worry about. It's rare I see a post about a scored cylinder on a CTT. More often then not, it's the same few people telling the story in a new thread.

When the TTRS came out with the 5-cyl motor, one of the new owners ripped WOT from a stoplight onto an interstate before the motor was totally warm. It was just enough time in a high-load, high heat situation that the pistons expanded faster than the bores, and he shredded the motor. He had to fight with Audi about it as they couldn't figure out how the motor blew like that (he obviously lied about his driving habits). I can't remember the outcome.

The Cayenne is not an enthusiast car. It's often driven by people who couldn't explain what that extra temp gauge means, or why it's important to wait for the motor and oil to reach operating temp before driving it hard. It's a status car, and as such, there won't be a shortage of boneheads that drive them.

Rennlist forums are pretty good about sniffing out genuine issues you should be concerned with. CS scoring is obviously one of them, but I haven't seen any indication from this forum that there is a problem with the TT motors. Or even the 4.8 NA motor.

 

Yo RT930 there is thing called the edit button and can help avoid making like 5 posts in rapid succession. Easier to parse your comments as one post IMO.

This thread is great though. I hope it drives down the price of 957's with all the fear mongering. Let the run away meme begin! I'll gladly buy a 957 TT with complete peace of mind. If all you see is sick engines (like Jake) that is going to create a reality distortion field. The bottom line is CTT's are seeing a failure rate that is no higher than the statistical norm for any high performance engine.

 

I have to respectfully disagree with you on most points. Given the umber of failures of 957's vs owners on this site, I'd say there is a fairly high number. I also think there are as many 957T failure threads on here as there are 4.5S threads. The dealers are seeing the same issues, it's not just LN and flat 6.

I 100% agree the Cayenne is not an enthusiast car. Mine is the wife's family truckster, but she takes very good care of it and knows what she's doing. I do consider myself an enthusiast, and the Cayenne is a nice wifey's ride to compliment the other 5,453 HP in the barn.

I don't think the failures are an Epidemic, but they certainly are discouraging. The noises the OP's car is making are classic cylinder scoring sounds. I truly hope that's not his issue, but there really is no other explanation for the clunk that is consistent with RPM.

There are even a few 958 Engine failure threads on here as well. Even searching youtube for cayenne turbo engine noise returns several cylinder scoring issues.

The way my 957 has been treated and maintained, there is absolutely no explanation for a failure of his magnitude short of a design flaw. Granted, it's a 500 HP engine, and I can't be too upset about 110k miles of service, but it's not the Porsche quality I used to know.


That's no fun though! And besides, how else am I going to drive up my post count after 14 years here

I do think the failure rates are higher than most high performance engines, but without meaningful data I certainly can't back that up.


To the OP: I truly hope you have no issue, but you want to make sure you have it properly diagnosed. If you catch it now it can be a 10-15k fix. Wait til it blows up, and you might as well throw it in the trash.

Not fear mongering or trying to get into a pizzing match.

Just my .02