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991.1 Bore Scoring

 
Old 04-19-2019, 03:25 PM
  #16  
Southbranch
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So, what caused the scoring? Piston slap? Leaky injector/preignition-related overheating?
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Old 04-19-2019, 03:58 PM
  #17  
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Originally Posted by Southbranch View Post
So, what caused the scoring? Piston slap? Leaky injector/preignition-related overheating?
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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Old 04-19-2019, 04:02 PM
  #18  
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Three primary things (IMO) contribute to bore-scoring:
  1. Cold oil (people screaming the motor before the oil temps are 180 degrees or higher)
  2. Use of Mobil 1 vs. a Good oil like Motul
  3. Cold climates in conjunction to the above
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Old 04-19-2019, 10:53 PM
  #19  
Tampa991
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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.
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Old 04-19-2019, 11:23 PM
  #20  
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Originally Posted by Airbag997 View Post
Three primary things (IMO) contribute to bore-scoring:
  1. Cold oil (people screaming the motor before the oil temps are 180 degrees or higher)
  2. Use of Mobil 1 vs. a Good oil like Motul
  3. Cold climates in conjunction to the above
can you elaborate?

Originally Posted by Tampa991 View Post
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.
and is there anything within our control or preventable in the regard? lol
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Old 04-19-2019, 11:43 PM
  #21  
Airbag997
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Originally Posted by sampelligrino View Post
can you elaborate?



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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Old 04-19-2019, 11:52 PM
  #22  
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Originally Posted by titan7 View Post
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.
Don't believe the hype. PM me if you want a dose of reality w.r.t. Honda/Toyota. All makes have one-off issues, I think. Porsche is as good or better than most is my conclusion. I replaced my MDX with (egads!) a Cayenne which will likely blow a transfer case. I sleep okay at night :-)

cheers!
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Old 04-20-2019, 12:03 AM
  #23  
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Originally Posted by Airbag997 View Post
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.
hmmm I just had my oil changed with what I believe is mobil 0W-40 last week, but this has me interested to find an independent mechanic to swap in the Motul. Will research more on it, thx
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Old 04-20-2019, 10:44 AM
  #24  
Tampa991
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Originally Posted by sampelligrino View Post
hmmm I just had my oil changed with what I believe is mobil 0W-40 last week, but this has me interested to find an independent mechanic to swap in the Motul. Will research more on it, thx
Just change it yourself, it takes about 30 minutes.
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Old 04-20-2019, 12:17 PM
  #25  
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Originally Posted by Tampa991 View Post
Just change it yourself, it takes about 30 minutes.
would love to. unfortunately rent in LA where my car is in an underground parking garage and I think I own a screwdriver and drill, that's it
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Old 04-20-2019, 02:20 PM
  #26  
Tampa991
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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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Old 04-20-2019, 02:45 PM
  #27  
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Originally Posted by Tampa991 View Post
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.
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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Old 04-20-2019, 02:47 PM
  #28  
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Lol you got me with that one lol
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Old 04-20-2019, 02:52 PM
  #29  
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Originally Posted by Tampa991 View Post
Lol you got me with that one lol
lmao
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Old 04-20-2019, 03:26 PM
  #30  
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Isn’t start up where most wear can happen? Isn’t 0-40 better for that? I am running 0-40 mobile 1. Soooo, Motul is a better option? What weight should I run?
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