The new 911s have bore score too? Will Porsche ever make a decent engine again?

I’m bummed about Porsche 991 Bore Scoring - another 911 engine problem!

00:37 991 Porsches also have bore scoring
00:45 What is Bore Scoring?
01:16 What Happens with Bore Scoring?
01:47 991 Failures are Different
02:19 Main issues - costs, no replacement parts
03:03 History of Porsche cylinder coatings
04:23 Good news - 991.2 is improved!
04:45 My Rant

996 and 997 had bore scoring issues
It looks like the 991.1 also has bore scoring and even worse!

What is bore scoring?
Lack of lubrication or different expansion rates of the piston/cylinder
Scratches the cylinders
Smoking at startup at first
Eventually can be catastrophic

Replacement engines not avail


The 996 and 997.1 used Lokasil. (M96/M97 engines)
Locally infiltrated silicon particles (Lokasil process) forming the wear surface; exposed silicon acts as the bearing material, paired with iron-coated pistons.

997.2 and 991.1 used Alusil. (9A1 engine)
Monolithic hypereutectic Al-Si alloy block, etched to expose silicon particles uniformly across the bore surface (no separate liners)

Both Lokasil and Alusil rely on exposed silicon for lubrication/support, paired with iron-coated piston skirts, making them fundamentally different from plated systems like Nikasil.
Nikasil (nickel-silicon-carbide plating) was used in pre-1998 engines and most dry-sump Mezger variants (e.g., 996/997 Turbo, GT3) but not in the wet-sump Carrera engines discussed here. It is highly resistant to scoring.

991.2 uses a plasma sprayed iron coating (SUMEbore)
Thin iron layer plasma-sprayed directly onto aluminum bores for superior wear resistance. Should not bore score

991.1 may not just be bore scoring
Piston expansion different than bore expansion. Cooling issues in the new block?
Piston seizes inside the cylinder. Catastrophic

“Overall, the 991 engine is considered reliable with proper care”