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Porsche have produced several iconic models over the years. The Porsche 997, introduced in 2004, continued the legacy of the 911 series with its sleek design and impressive driving dynamics.

However, like any complex machinery, the 997 is not immune to issues, one of the most notable being bore scoring. Bore scoring can affect the engine’s performance and longevity if not addressed promptly.

What is Bore Scoring?

Bore scoring refers to the vertical scratches on the cylinder walls of an engine. Whilst this issue is seen in many manufacturers cars, in the case of the Porsche 997 this primarily affects the 3.6-litre and 3.8-litre variants found in models using the M96 and M97 engine.  Porsche say that it impacts around 10% of these cars, however other sources report a higher percentage.

These engines have Lokasil cylinder liners which are located in less rigidly crankcase than other early water cooled engines from Porsche. Alongside this, due to the design of the lubrication and cooling systems, the right side cylinders run slightly hotter than the left, most notably the sixth.  This then leads to an ovaling of the liner due to increase friction on one side. This then leads to a slap of the piston against the liner which in some more extreme cases can even be heard particularly when the engine is cold.

Additional contributory factors include short journeys, excessive revs for longer periods especially when the engine is not warmed through and even adhering to the Porsche recommended oil change period of two years.

What Bore Scoring indicators should you look out for?

  • An increase in the car’s oil consumption.
  • At the exhaust pipe, one being more black and sooty than the other.
  • A ticking noise which increases with the revs on the engine, especially when cold.
  • A change in the way the car idles. If it has become rougher over time or a reduction in performance overall.

If you suspect, or even just want to check the condition of the cylinders in your 997, or 996 then we can take a look at the following for you.

  • We can scope the bores and see exactly what is going on in there.
  • We can look at your oil for colour (black is bad).
  • We can look at the contents of your oil, checking for any aluminium debris in the filter.

What are the solutions for Bore Scoring?

In severe cases of bore scoring, where the damage is extensive, a complete engine rebuild may be necessary. This involves disassembling the engine, honing or re-sleeving the cylinders, and replacing damaged components.  Also, by installing higher-quality or upgraded piston rings we can help reduce friction between the piston and cylinder walls, mitigating the risk of further scoring.

Porsche 997 bore scoring is a prevalent issue that owners should be aware of to ensure the longevity and performance of their vehicles. By understanding the causes, symptoms, and available solutions, owners can take proactive measures to address bore scoring before it escalates into more significant problems. Regular maintenance, proper lubrication, and attentive driving habits are key to mitigating the risk of bore scoring and enjoying the exhilarating driving experience that the 997 offers.

The key is to keep your car properly maintained and keep the revs down until the engine has fully warmed up, which is common sense advice for any car.  Oh yes, and don’t heed the advice initially issued by Porsche for these cars, instead change the oil annually – it could save you a lot of money and heartache in the long run.

Arrange your Porsche bore scoping inspection now with Cheshire’s leading independent Porsche specialist.

Contact us.