How a car works

All partsBMW M4 CSLS58 enginePistons › 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.

MaterialNitrided steel top ring, cast iron second, 3-piece oil ring
SpecEnd gap 0.30 / 0.45 / 0.25 mm
Piston rings highlighted on the car

Appears at

Piston 1Piston 2Piston 3Piston 4Piston 5Piston 6

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