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Seeing how often the topic of bore-scoring comes up on this forum, I am "surprised" we don't see a large number of 997.1 rollers.
Something to consider...
You would think there would be lots of them for sale and a great opportunity for companies like Slakker/Hartech to buy them up and become the Singer of 997's.
It is curious. Every p car shop I talked to basically said all 997’s will eventually have this issue. It sure seems to not have affected the values at all.
Many buyers do not have a deep understanding of this issue -- or even know that it exists in the first place -- and this is reflected in market prices. In smaller markets arbitrage is much more easy. 997.1 is distinctly different than 997.2 -- completely different engines that are different in so many ways so you can't really lump all 997s together.
As I understand, while less common the 997.2 still have ims issues, and still have bore scoring issues.
There is no ims bearing in the 997.2. So no problems.
The cylinder wall coating structure in the 9A1 motor is more stable, as well as finer, so shedding is less likely and in the event of such there is much less apt to be gouging.
The failure in the 997.2 is cold seizure which occurs low in the bore, rather than bore scoring. This is a very rare event that is thought to be due to casting or curing defects. If this occurs failure will be seen early in life.
Are there exceptions to the rule? Of course. But ims failure and bore score are not a worthy concern in the .2 cars.
Bore scoring is still a worthy concern on the 997.2 because it can happen but it is far less common than 997.1.
IMS is not an issue on the 9A1 or Mezger as noted. The "IMS Solution" is a design that is basically borrowed from the Mezger.
Bore score is talked about by some members here and is lately being echoed. I've watched and studied this topic closely for 9 years now and I have yet to see any pictures of a 9A1 motor with bore score (as opposed to cold seizure). Somebody, prove me wrong with actual hard evidence. This would need to include the full cylinder wall, top to bottom, and pictures around the cylinder indicating the thrust side. Analysis is critical before cause can be determined.
Bore score is talked about by some members here and is lately being echoed. I've watched and studied this topic closely for 9 years now and I have yet to see any pictures of a 9A1 motor with bore score (as opposed to cold seizure). Somebody, prove me wrong with actual hard evidence. This would need to include the full cylinder wall, top to bottom, and pictures around the cylinder indicating the thrust side. Analysis is critical before cause can be determined.
I ask bc I think it's characteristic of cylinder seizure (high load, low oil temps) that happens with the block expanding at different rates, wanted to get your take
I ask bc I think it's characteristic of cylinder seizure (high load, low oil temps) that happens with the block expanding at different rates, wanted to get your take
I'm on the hill above the house right now with the pups, a morning routine. My weak network coverage up here won't let me back up beyond post 21 on your link. And soon I've got a friend's car arriving for cats, plugs, and some other stuff. Let me study what you've linked later on today. Thanks in the meantime for the share.
Bore score is talked about by some members here and is lately being echoed. I've watched and studied this topic closely for 9 years now and I have yet to see any pictures of a 9A1 motor with bore score (as opposed to cold seizure). Somebody, prove me wrong with actual hard evidence. This would need to include the full cylinder wall, top to bottom, and pictures around the cylinder indicating the thrust side. Analysis is critical before cause can be determined.
In one of his last posts before he left RL Jake told me that ~90% of the 9A1 failures are due to bore scoring (piston seizure still scores the bores, there is technically supposed to be no metal-to-metal contact only a thin film of oil, and it is still bore scoring just a different mode of failure of it). Charles would tell you that LN gets some in sometimes too but not very often compared to M9x.
Performed sparkplug and coil-pack change for friend, he was present, I started taking photos and showed him live. Said he did not want photos, so these are the only 2 saved. He traded in 991.1 for a new M2.
In retrospect I wish I would have taken more photos regardless of his request. (Photos are crap, yes I know but you can se the scoring on both)
Car ran fine with little oil consumption. (.5qt 3000 miles) Changed oil to DT40 from Mobil 1.
So catastrophic, nope, but its bore-score.
Friend down street with 2012 991.1 (traded for 991.2) showed me photos of his bores (4,5,6), much worse than this. Car ran fine with little oil consumption.
Next 991.1 or 997 I get in for a plug change I will scope properly with photos, simply out of curiosity.
I'm on the hill above the house right now with the pups, a morning routine. My weak network coverage up here won't let me back up beyond post 21 on your link. And soon I've got a friend's car arriving for cats, plugs, and some other stuff. Let me study what you've linked later on today. Thanks in the meantime for the share.
Wayne, I don't see a reason to differentiate between cold seizure scoring (997 2) vs piston rock scoring from the skirt contacting the wall (997.1) because both result in scored cylinder walls and the need for a rebuild so A leads to C and B leads to C and it's C that we're all concerned with.
11-16-2023 | 01:18 PM
