All parts › BMW M4 CSL › S58 engine › Pistons › Piston rings
Piston rings
Part of Pistons · about $60 to replace
What it is
Two compression rings and one oil-control ring.
What it does
Seal combustion gas and scrape oil from the bore.
How it fails
Worn rings show as blow-by and oil consumption.
| Material | Nitrided steel top ring, cast iron second, 3-piece oil ring |
|---|---|
| Spec | End gap 0.30 / 0.45 / 0.25 mm |