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Hi Bodydoc. Thanks for the input. I bought the videos and book already. I'm waiting to get everything back and ready to assemble before I watch them so it's fresh in my mind.
are wondering, the car is a 2005 Porsche 911 Carrera 3.6 with only 53k miles on the odometer. And it was rapping like 50 cent when I bought her (you could call it a tick, but it was a pretty loud tick) I was hoping it was a broken exhaust manifold, but no such luck. At least we caught it before it blew up.
Pete
Thank you Pete for sharing your rebuild story. I'm looking forward to seeing the progress. And, don't feel bad about Tiptronic. They are very capable cars and actually make better sense for daily drivers that commute in stop-and-go traffic.
Frankly, it's not surprising that this car only has 53,000 and suffering from bore scoring. Many believe low mileage Porsche cars in general are the gold standard, but not M96/M97 based Carreras. They seem to live longer if driven daily and driven hard. But it seem the low mileage examples are the most susceptible to cylinder bore scoring and IMS bearing failure based on data that LN keeps record of. Unless this engine was replaced under warranty, the original engine would have the small single row bearing and so I'd definitely encourage you to put the LN Engineering IMS Solution in the car so that you don't have to worry about it again. One reason is because (as you have found out) the whole engine has to be dropped to remove the transmission unlike manual cars.
Again, thank you for this thread and keep up the good work!
Thank you Pete for sharing your rebuild story. I'm looking forward to seeing the progress. And, don't feel bad about Tiptronic. They are very capable cars and actually make better sense for daily drivers that commute in stop-and-go traffic.
Frankly, it's not surprising that this car only has 53,000 and suffering from bore scoring. Many believe low mileage Porsche cars in general are the gold standard, but not M96/M97 based Carreras. They seem to live longer if driven daily and driven hard. But it seem the low mileage examples are the most susceptible to cylinder bore scoring and IMS bearing failure based on data that LN keeps record of. Unless this engine was replaced under warranty, the original engine would have the small single row bearing and so I'd definitely encourage you to put the LN Engineering IMS Solution in the car so that you don't have to worry about it again. One reason is because (as you have found out) the whole engine has to be dropped to remove the transmission unlike manual cars.
Again, thank you for this thread and keep up the good work!
I've long believed that bore scoring starts on the M96/97 with the piston skirt coating flaking off, it's presence is critical to prevent aluminum to aluminum galling. Jake Raby has recently dubbed this condition Stage 0 bore scoring, i.e. once the coating is gone it's just a matter of time until it scores.
I think this might answer why low mileage engines can score. The piston skirt coating is a soft, sprayed-on material (as opposed to hard electroplated on earlier and later engines) that was used from around 2002 to 2008. I suspect the coating gets hard and brittle as a function of time, not miles. In other words, it ages and deteriorates whether or not you are driving the car.
To the OP - Please don't try and reuse the pistons you removed and think long and hard about about how you are going to resleeve the block. There's disagreement about why bank 4-6 goes first but most agree that the piston skirt coating is a real problem and the root cause. Those pistons have to be replaced, you don't want to do this again a year from now. Personally I'd send the block to LNE for Nickies (around $6k with pistons) but there have been a few reports of success with steel sleeves (and a few failure reports too).
To the OP - Please don't try and reuse the pistons you removed and think long and hard about about how you are going to resleeve the block. There's disagreement about why bank 4-6 goes first but most agree that the piston skirt coating is a real problem and the root cause. Those pistons have to be replaced, you don't want to do this again a year from now. Personally I'd send the block to LNE for Nickies (around $6k with pistons) but there have been a few reports of success with steel sleeves (and a few failure reports too).
When Porsche moved from ferrostan to ferroprint in later engines, the problem seemed to get worse. (For the record we're talking Carrera M96 engines here, not Mezger) And yes, many theories surrounding why bank#2 scores in most cases. Some say it's because of poor cooling channels that cause cylinders to go out of round, thrust side of the engine, poor lubrication, etc. I think the more plausible theory on the M9X carrera engines is because Porsche chose the same piston pin offset for bank#2 as bank#1, where as in the past, Porsche engines had pistons pin offfset opposite for bank2 vs. bank2.
I commend you for your endeavors! I was fully prepared to start pulling the engine when I just got my new to me 06 C2S with 106k miles four weeks ago. But after a borescope, happy to report that there were no signs of borescoring. Will follow your progress though!
When Porsche moved from ferrostan to ferroprint in later engines, the problem seemed to get worse. (For the record we're talking Carrera M96 engines here, not Mezger) And yes, many theories surrounding why bank#2 scores in most cases. Some say it's because of poor cooling channels that cause cylinders to go out of round, thrust side of the engine, poor lubrication, etc. I think the more plausible theory on the M9X carrera engines is because Porsche chose the same piston pin offset for bank#2 as bank#1, where as in the past, Porsche engines had pistons pin offfset opposite for bank2 vs. bank2.
Yup, the change from ferrostan platings to the ferroprint certainly did not help things. The other big change was how the cylinder bores are finished at the factory. In years past, an etching process was used to expose the silicon particles, but now they use a mechanical activation process. The big difference is that you end up with fractured silicon particles that can't support the Al-Si cylinder system. Once 40% of the exposed silicon particles have fractured, it's game over. I think that would explain whey some engines fail with low mileage.
Also, compared to Porsche engines with Alusil cylinders or blocks in the 70s through the 90s, oils have changed significantly (higher detergency and lower anti-wear additives) and we also didn't have ethanol enriched fuels.
As I've mentioned previously, there isn't one single smoking gun but I believe it's multiple factors that combine to lead to cylinder bore scoring.
About 9 months ago, I bought a used 06 C2 and did my due diligence (yes borescope with pictures, zero evidence) but every now and again I get spooked by videos and threads like this. I think M96/97 owners to a certain extent will get this anxiety as part of their ownership experience for as long as they own their rides, oh well.
Arm yourself with education, budget for a rebuild, and do as much preventative maintenance as you can, but it seems inevitable. The video below is from FCP Euro, but I found it informative along with the dozens of other videos on this subject on YT, the money shot happens around 5:30.
Looking forward to more updates from your rebuild experience. I didn't even know you could take an engine out of our 997's with a quickjack. I too own one, but I always thought the lift height was too low.
I'm still waiting on the block to get back from the machine shop and was hoping to get some opinions on this IMS bearing. I think it is the Porsche non-serviceable one, but figured someone on here would know for sure. Should I replace it? Thanks! I can make out "Germany" and "99602401"
I think the 99602401 is the part number of the cap/flange, not the IMS as an assembly.
What size is the nut on the center bolt that you took off, 13mm or 22mm? If I recall, the 13mm indicates serviceable, vice the 22mm as non-serviceable.
Based on your early posts, I am assuming that this project is more of a repair than a rebuild and you want to be "penny wise" but not "pound foolish". It really comes down to whether or not the existing bearing is still good, your tolerance for the unknown risk of how much longer it will last and whether it can be replaced in situ. If yours is the type that has the seal on the other side, I think the conventional wisdom is to remove the seal to support more oil to the bearing internals.
Well, a lot has happened since I sent the block off to US Chrome at the end of August. A career opportunity was offered to me that I simply couldn’t pass up so I spent all of September clearing out the inventory and finding a buyer for our store. I got the block back the day before I started the new job, so progress has been slow.
we did get the crank carrier into bank one and have the bank one pistons installed. Bank 2 is going on this weekend, unless life gets in the way. My dad has been watching Jake Raby’s video series over and again so I’m starting to rely on him as the Porsche brains of the family.
I’m posting a couple of pictures and hope to update with more soon. Thanks to all for the kind words and messages. I will try to reply to everyone as time permits. Dad after a fun day working on bank one
09-09-2023 | 12:08 PM
