Ticking 957 turbo
03-22-2016, 06:16 PM
#16
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Interesting. While I did research on what Cayenne to buy I run in to the cylinder scoring issue online only with the 955 CS, Turbos and V6's use a different cylinder coating (nikasil instead of lokasil) and are supposedly not affected - and basically 2007 onwards with the 957 the issue is gone.
However after registering on these forums I have now seen 2 or 3 cases of cylinder scoring on the 957, and all Turbos.
I live in a cold climate, my car has been started daily in deep negative degrees for 80k miles now. My car does tick a bit when the engine is cold, but it's not constant, the rythm varies. No noticeable ticking when warm. My car runs very smooth on idle and does not consume any oil between services unless you have been flooring it a lot.
I'm interested in the cause. Why does it happend, how can it be prevented, why does it not happend to everyone? If cold climate was the culprit, this problem would be all over the internet - but it isn't. The only place I have came accross the cylinder scoring and popping cooling hose on the 957 is this very forum.
However after registering on these forums I have now seen 2 or 3 cases of cylinder scoring on the 957, and all Turbos.
I live in a cold climate, my car has been started daily in deep negative degrees for 80k miles now. My car does tick a bit when the engine is cold, but it's not constant, the rythm varies. No noticeable ticking when warm. My car runs very smooth on idle and does not consume any oil between services unless you have been flooring it a lot.
I'm interested in the cause. Why does it happend, how can it be prevented, why does it not happend to everyone? If cold climate was the culprit, this problem would be all over the internet - but it isn't. The only place I have came accross the cylinder scoring and popping cooling hose on the 957 is this very forum.
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!
03-22-2016, 06:19 PM
#17
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A scored cylinder is a result. Just like bald tires are a result. Did you get a bald tire from putting 50K miles on it, or because your alignment was off? It's the same with scored cylinders. You can't just group them all together since the mechanism that leads to scoring is vastly different.
The CS motor on the 955 was built with tolerances too tight. Combine that with a cast piston that expands faster than a forged unit (on the turbos), tighter tolerances, and the lack of an oil squirter on the skirt, and the result is a scored cylinder caused by a large thermal expansion difference. Cold and mileage increase the chances with the CS.
Every motor Porsche has ever made has a very small percentage that suffers from scored cylinders. These are mostly from defects, not a design flaw. That's a really important distinction that often fails to register with people. Most of the 957 Turbos I've seen with scored cylinder (and I only need one hand to to count them), were lower mileage units and under warranty. One was a few k miles out of warranty, but Porsche stepped up to the plate anyway.
Visit any forum on rennlist, and you'll find a very small incidence of scored cylinders. Of all the 4.8TT motors running around out there (957 motor is the same unit in the panamera and 958), and I can think of less than 5 reports of scored cylinders in the Cayenne.
M1 0W40 is a really really thin 40 weight oil. A friend of mine had a loud CTT, and he switched to a thicker oil, and it runs nice and quiet now. Consider almost anything other than M1 (on the approval list or not), and my guess is you'll get a quieter motor.
The CS motor on the 955 was built with tolerances too tight. Combine that with a cast piston that expands faster than a forged unit (on the turbos), tighter tolerances, and the lack of an oil squirter on the skirt, and the result is a scored cylinder caused by a large thermal expansion difference. Cold and mileage increase the chances with the CS.
Every motor Porsche has ever made has a very small percentage that suffers from scored cylinders. These are mostly from defects, not a design flaw. That's a really important distinction that often fails to register with people. Most of the 957 Turbos I've seen with scored cylinder (and I only need one hand to to count them), were lower mileage units and under warranty. One was a few k miles out of warranty, but Porsche stepped up to the plate anyway.
Visit any forum on rennlist, and you'll find a very small incidence of scored cylinders. Of all the 4.8TT motors running around out there (957 motor is the same unit in the panamera and 958), and I can think of less than 5 reports of scored cylinders in the Cayenne.
M1 0W40 is a really really thin 40 weight oil. A friend of mine had a loud CTT, and he switched to a thicker oil, and it runs nice and quiet now. Consider almost anything other than M1 (on the approval list or not), and my guess is you'll get a quieter motor.
03-22-2016, 06:29 PM
#18
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
03-22-2016, 06:44 PM
#19
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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.
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.
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.
03-22-2016, 06:49 PM
#20
Burning Brakes
However after registering on these forums I have now seen 2 or 3 cases of cylinder scoring on the 957, and all Turbos.
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.
03-22-2016, 06:51 PM
#21
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.
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.
03-22-2016, 06:53 PM
#22
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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
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
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...
03-22-2016, 06:54 PM
#23
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03-22-2016, 06:56 PM
#24
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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)."
"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)."
03-22-2016, 06:59 PM
#25
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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.
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.
03-22-2016, 07:07 PM
#27
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.
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.
03-22-2016, 08:53 PM
#28
Three Wheelin'
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.
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.
03-22-2016, 09:53 PM
#29
Rennlist Member
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.
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.
03-22-2016, 10:32 PM
#30
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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.
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.
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.
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.
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 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