Bore scoring question
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Bore scoring question
Hey all, hope you're well! I've just recently picked up my first Porsche - a 3.4L 9871.1 S - and the thing I'm most worried about is bore scoring. This may be a stupid question, but would bore scoring cause the check engine light to come on? Or is it something that you really just find out the hard way if it's not checked up on regularly?
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Hey all, hope you're well! I've just recently picked up my first Porsche - a 3.4L 9871.1 S - and the thing I'm most worried about is bore scoring. This may be a stupid question, but would bore scoring cause the check engine light to come on? Or is it something that you really just find out the hard way if it's not checked up on regularly?
If you don't have scoring, then make a plan to run better oil and change at shorter intervals - 5,000 or every 6 months. A low temp thermostat will help a little. Get a spin on oil filter. That will give you FULL filtration all the time unlike the OEM canister that has a bypass valve. Let the engine warm up before driving it hard. Don't let the engine idle to warm up. Drive it regularly!
If you want to know more about Bore Scoring, please watch Jake Raby's video series on the subject:
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From: Phoenix
Model Year
Hey all, hope you're well! I've just recently picked up my first Porsche - a 3.4L 9871.1 S - and the thing I'm most worried about is bore scoring. This may be a stupid question, but would bore scoring cause the check engine light to come on? Or is it something that you really just find out the hard way if it's not checked up on regularly?
If you really want to be sure, drop the oil pan and from underneath do a borescope check with video. If you have it there’s not much you can do other than do the nitrate cylinder sleeve option from Jake Ruby. In fact he has a series of eight videos that I highly recommend you watching up on YouTube. One key though, if you have it, the sooner you fix it, the less likely there will be any affects to the rest of the engine. Jake’s process will leave you with a 4 liter motor.
Last edited by vanlieremead; Aug 4, 2022 at 10:47 AM.
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You didn’t mention the model year. I have a 2005S 3.4 just like you and with that year and I think with all the rest of the Ss, the Pistons were cast. This left them much less likely to bore score. In fact with the reading I’ve done, there is no evidence of scoring with cast pistons on that engine.
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Actually, it's the other way around. All non-S model M9X base engines (e.g. 2.7L), came from the factory with cast pistons and have shown to be less prone to cylinder bore scoring as noted by Charles Navarro, Jake Raby, Tony Callas, Barry Hart, and others that have spent years working with these engines. S model engines within the Boxster/Cayman lineup have forged pistons like the M96/M97 Carreras and more susceptible to cylinder bore scoring. Sorry... that the facts.
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The '05 model year was the devil and I'm afraid he gave you the double whammy. That is, you got the most problematic bearing - the 6204 and the 3.4L suffers from bore scoring. Sorry.
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https://flat6innovations.com/cylinder-bore-scoring/
Cylinder Bore Scoring is the #1 leading cause of misdiagnosed engine failures for the following vehicles:
*1999-2004 Porsche 996 (all models except GT3 and Turbo, less prominent with 99-01 years, but still occurs)
*2005-2008 Porsche 997.1 Carrera and Carrera S (Turbo and GT3 models excluded)
*2006-2008 Porsche 987.1 Cayman S (Base model remains unaffected)
*2007-2008 Porsche 987.1 Boxster S (Base model remains unaffected)
*1999-2004 Porsche 996 (all models except GT3 and Turbo, less prominent with 99-01 years, but still occurs)
*2005-2008 Porsche 997.1 Carrera and Carrera S (Turbo and GT3 models excluded)
*2006-2008 Porsche 987.1 Cayman S (Base model remains unaffected)
*2007-2008 Porsche 987.1 Boxster S (Base model remains unaffected)
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In 2007 the Boxster received the M97.21 Cayman (3.4) engine. At this time bore scoring began to impact the Boxster. Boxster S models prior to 2007 (3.2 engine) are not impacted by bore scoring.
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From: Zuffenhausen, Georgia
I guess I'm scratching my head cause vanlieremead said his '05 Boxster S has the 3.4L.
Last edited by ZuffenZeus; Aug 4, 2022 at 02:43 PM.
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I guess I'm scratching my head cause vanlieremead said his '05 Boxster S has the 3.4L.
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From: Phoenix
So what you're saying is the M96.26 engine found in the '05 Boxster S has not been shown to be susceptible to cylinder bore scoring and, there is no 3.4L for any S model Boxster in 2005?
I guess I'm scratching my head cause vanlieremead said his '05 Boxster S has the 3.4L.
I guess I'm scratching my head cause vanlieremead said his '05 Boxster S has the 3.4L.
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From: Zuffenhausen, Georgia
Well anyway, I'm sure you're resting a little easier knowing your car is not susceptible to this horrible bore scoring problem.
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From: Phoenix
Resting Yes
