The short answer: bore scoring is wear on the cylinder walls of some M96 and M97 flat-six engines. It shows as oil use, a ticking noise and a sooty tailpipe, and it's found with a borescope.
Which Porsches suffer from bore scoring?
Mostly larger M96/M97 engines: 997.1 Carrera S (3.8), 987.1 Boxster S and Cayman S, and some 996s. Mezger and 9A1 engines are far less affected.
How do I check for it?
A borescope inspection through the spark plug holes. It's the single best test before buying.
What does it cost to fix?
Usually an engine rebuild with new liners - often £10,000 to £20,000 at a specialist.
More: pre-purchase inspection · IMS bearing · 911 generations guide.
Quick answers
What is Porsche bore scoring?
Wear on the cylinder walls of some M96 and M97 engines, causing oil use, ticking and sooty tailpipes.
How much does it cost to fix bore scoring?
Usually an engine rebuild, often £10,000 to £20,000 at a specialist.
