991.1 Bore Scoring
04-19-2019, 03:58 PM
#17
Agreed, I'd like to know the root cause and how to avoid. Is the only fix literally a new engine? And is that appropriate under warranty but outside of it is it safe to live with and what precautions does one have to take when they have confirmed scoring?
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PatrickBateman (07-24-2021)
04-19-2019, 04:02 PM
#18
Rennlist Member
Three primary things (IMO) contribute to bore-scoring:
- Cold oil (people screaming the motor before the oil temps are 180 degrees or higher)
- Use of Mobil 1 vs. a Good oil like Motul
- Cold climates in conjunction to the above
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Robocop305 (04-19-2021)
04-19-2019, 10:53 PM
#19
Instructor
Thread Starter
One theory - I believe the main cause of bore scoring is due to DFI where the injector could be compromised and be spraying too much fuel...this causes the lubricated cylinder wall to be washed down and metal to metal wear occurs over time.
04-19-2019, 11:23 PM
#20
and is there anything within our control or preventable in the regard? lol
04-19-2019, 11:43 PM
#21
Rennlist Member
Thinner than other oils of the same grade.
Greater burn-off than other oils of the same grade.
Piston-slap observed/noted with long-term use.
Increased valve noise compared to oils of the same grade.
Greater thinning-out/inability to stay-in-grade during use.
Poor performance on the Timken test (tri-synth)
In my 997.2 with Mobil it use to burn about ~1 quart every 1,000 miles. Then I switched to Motul 8100 5W-40 xcess, didn't burn a drop, ran quieter, and felt smoother. 991 since day 1 Motul 5w-40, doesn't burn a drop, runs like velvet smooth brand new motor.
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04-19-2019, 11:52 PM
#22
Rennlist Member
Wow, it just amazes me, Honda and Toyota can build pretty much bullet proof motors but we have these crazy odd issues with just about every generation of 911. Okay before pounding, yeah I know these are high performance cars, and I am a 911 fanboy, but still, at this point you would figure they could get past these crazy things like PDK bombs, IMS/RMS, bore scoring. Now with that said, my 911 is going nowhere.
cheers!
04-20-2019, 12:03 AM
#23
Thinner than other oils of the same grade.
Greater burn-off than other oils of the same grade.
Piston-slap observed/noted with long-term use.
Increased valve noise compared to oils of the same grade.
Greater thinning-out/inability to stay-in-grade during use.
Poor performance on the Timken test (tri-synth)
In my 997.2 with Mobil it use to burn about ~1 quart every 1,000 miles. Then I switched to Motul 8100 5W-40 xcess, didn't burn a drop, ran quieter, and felt smoother. 991 since day 1 Motul 5w-40, doesn't burn a drop, runs like velvet smooth brand new motor.
Greater burn-off than other oils of the same grade.
Piston-slap observed/noted with long-term use.
Increased valve noise compared to oils of the same grade.
Greater thinning-out/inability to stay-in-grade during use.
Poor performance on the Timken test (tri-synth)
In my 997.2 with Mobil it use to burn about ~1 quart every 1,000 miles. Then I switched to Motul 8100 5W-40 xcess, didn't burn a drop, ran quieter, and felt smoother. 991 since day 1 Motul 5w-40, doesn't burn a drop, runs like velvet smooth brand new motor.
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pkalhan (01-06-2023)
04-20-2019, 10:44 AM
#24
Instructor
Thread Starter
04-20-2019, 02:20 PM
#26
Instructor
Thread Starter
There’s a video of a guy in an apartment building garage working on his 991..changes the oil, pulls off the bumper, changes air filters...tools are cheaper than dealer/Indy labor after you use them twice.
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PatrickBateman (07-24-2021)
04-20-2019, 02:45 PM
#27
there's also a video of a guy stuffing a 4 foot sword down his mouth I don't know what your point is. there will be a time God willing where I can have a garage/space to enjoy taking the time to learn more about the engineering & components of the car, but for now I'll just utilize an indy or dealer
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westcoastj (01-14-2021)
04-20-2019, 02:52 PM
#29
