andrewjt19

Hello everyone,
I can provide more information if needed, but I'm submitting myself to the advice and information of the Porsche community. I have a 957 CTT with cylinder scoring in cylinders 5 and 8. I would like to try and hone the cylinders and replace the rings with larger ones. I have a few questions:

1. What are the stock cylinder sleeves/liners made out of? I understand they are coated with Alusil.
2. What are the specs of the ring gap on all three rings?
3. A place to purchase rings, cylinder sleeves and pistons to insert them myself.

I'm not a mechanic, but I have family and friends who are and would be assisting. I'm aware of LN Engineering's Nickie's, 928 Motorsports solution and basically rebuild options with larger cylinders and pistons. Please help and thank you.

andrewjt19

J'sWorld

The block is solid Alusil. It is not honed or sleeved or plated. It is bored and finished with a multi step etching/lapping process. Sunnen makes the paste and felts to do this. But your block is scored so that wouldn't apply.
Pistons and rings are available in original size only. Specs are not available because Porsche didn't publish them. It's a secret....seriously. I hate to tell you that the options you have are the ones you already know about.
I'm just going to give it to you straight. Your screwed. New engine time. When you put your head in your hands have an extra cold one on me. I recommend 1554 by New Belgium brewery.

Petza914

Information out there seems to suggest that a honing process was introduced sometime during the 2008 manufacturing year for 2009 and newer vehicles, which is why the recent bore scoring survey has none or maybe 1 2009 or newer failure, though that info doesn't help Andrew here in this situation with a 2008. Andrew, what is the engine designation on the label that's under the rear floor in the cargo area of your Cayenne. If you haven't posted onto this thread, please do so and add your info to the survey - https://rennlist.com/forums/cayenne-955-957-2003-2010/1101332-new-bore-scoring-survey-955-958-2003-2010-a.html#post15362219

Looks like honed engines started around those with the engine designation 9PAAN1 or maybe 1 or 2 prior versions.

andrewjt19

Thank you for the replies. I'm not sure which engine series mine is. I'll take a photo of it and post it. I'm pretty much set on the fact that I can't hone it anyways since everything I've learned suggest that the cylinders (sleeves or otherwise) are aluminum/alloy plated with Alusil. That would preclude me from honing. I think the only option is rebuild professionally or replace the motor. I'm leaning towards a rebuild since a replacement could potentially have the same issue down the road. Thanks gents.

user 83838290

Welcome to the club of scored 08s. I scored mine twice in 3 months.

What J said.

andrewjt19

This is ridiculous. I love Porsches but it's stuff like this that makes it very frustrating to be a Porsche owner. I have a 2004 Honda CR-V with 255k and is still running and a beautiful CTT broken down with a factory mishap never acknowledged, just pushed out onto the consumers. What did you do with your two incidences of scoring?

user 83838290

No worries, I also scored an 06 CTTS :-)
Had a rebuild done, warranty and all. First one lasted a couple of hundred kms, second is good for a couple of thousands as of now.
The CTTS is still sitting broken down.

andrewjt19

Wow. I'm sure it's long after the fact, but I wish there was some way to hold Porsche accountable. Well, best of luck on your rebuild and hopefully I'll have a happy ending with mine as well.

Vivid7

Bore scoring is not as common as this place makes it seem to be. if you read this forum as a potential buyer or a newer owner, you would think that your Cayenne could blow up at any second. not the case. People come to this forum mostly because they have an issue and the worst of the worst gets posted. Same with other car forums I’ve been a member on. in 08 porsche sold about 12,000 cayennes in the US alone. The survey has 145 responses with almost 90% of the vehicles having no issues at all. if the survey had 1000 responses I think you would see maybe 3-5% with issues. Change the oil often. I do 4-5k miles in every vehicle I own.

oil change service history would be great to know with owners having these issues. some owners will never know their vehicles history unfortunately. you would be surprised how many people on the road go 20k miles with out changing their oil. My buddy owns a shop and sees it all the time.

andrewjt19

There's no don't that people neglect their vehicle's maintenance. I personally change my oil around 3500-5000 and use only high quality synthetic oil. But the fact that entire businesses are sustained by one manufacturer's mishaps is more than just coincidental or lack of maintenance. Surely they do not help preserve a vehicles performance or sustainability, but it's not the sole reason, in my opinion. I just wish I would have researched this model before I purchased it. Any knowledge of this would offered more awareness than the ignorance I had. I agree though with you.

Vivid7

What is your current mileage and what was the mileage when you bought it?

oldskewel

Sorry to hear about the loss. Some of the things you're mentioning here are wrong (no plating, no sleeves.). J's post #3 is brief, but the first two paragraphs are exactly correct. If you're thinking something else (I know, you can find all kinds of stuff out there on this topic, many of us have read through all of it), refer back to that post #3 and see if what you're hearing or reading fits.

If you keep reading, you may find a few cases where the engine was rebuilt. Most likely not cost effective for most cars due to the high cost of rebuild and low value of the car.

My '04 S had cylinder scoring back at around 50k miles, and Porsche + the dealer covered a little more than half the cost of replacing it with a crate engine from Porsche. That was back in '09, and the price was great (about $5500 back then), but it would be DEEP into 5 digits at this point. No longer a real option from Porsche.

That survey:
https://rennlist.com/forums/cayenne-...03-2010-a.html
will have some more background info and individual case details. It would be helpful to add your details to it. It's tough to figure out how widespread a problem this really is, and that survey is trying to quantify it and maybe find some trends for the engines that fail.

andrewjt19

So unfortunately this was not my best vehicle purchase and I wish I would have researched this model beforehand. We needed another vehicle and it was ok my price range at the time with 107k on the clock. I have under a 108k because I didn't drive it after suspecting the tapping noise was scoring.

andrewjt19

So I have completed this survey already. Unfortunately, I don't know when this happened because I probably purchased the vehicle with the scoring already. As far as the sleeves and such, how come LN Engineering and 928 Motorsports say they resleeve the existing block? I'm not arguing just trying to figure it out. I've reached the conclusion though that it's have to be rebuilt professionally unfortunately.