ZRP Std Intake Valves Black Nitride for BMW 1.8L M42

BMW 1.8L M42 – ZRP Standard Black Nitride Intake Valves (Set of 8)

ZRP Standard Black Nitride Intake Valves are engineered for the BMW 1.8L M42B18 engine. Designed for high-revving naturally aspirated builds as well as performance-enhanced applications, these valves provide excellent durability, dimensional stability, and long-term reliability under demanding operating conditions.

Manufactured from one-piece forged high-grade stainless steel (EV8 / 21-4N), each valve undergoes a specialized black nitriding process. This advanced surface hardening treatment diffuses nitrogen into the outer layer of the valve, significantly increasing wear resistance and fatigue strength while reducing friction between the valve stem and guide thanks to the smoother, hardened surface.

Unlike localized chrome coatings, the entire valve — including both stem and head — receives the black nitrided treatment. This ensures uniform surface protection, improved resistance to abrasion and valve seat recession, and extended service life in high-RPM applications.

Each valve is precision forged, CNC-machined, polished, and tip hardened to meet strict dimensional tolerances. This guarantees accurate valve seating, stable high-RPM operation, and consistent sealing performance in both naturally aspirated and turbocharged engine configurations.

Technical Features

• Base Material: High-grade stainless steel (EV8 / 21-4N)

• Surface Hardness: Nitrided layer up to approx. 800 HV

• Manufacturing Process: Precision forged, CNC-machined, polished, and tip hardened

• Treatment Coverage: Full black nitriding of stem and valve head

• Dimensional Accuracy: Tight tolerances for concentricity, straightness, and sealing surface finish

Advantages

• Reduced stem-to-guide friction for lower wear

• Improved high-RPM stability

• Longer service life compared to untreated stainless-steel valves

• Reliable sealing in naturally aspirated and turbocharged engines

• Suitable for high-performance street, track, and endurance applications

Additional Information

• Set Quantity: 8 valves

• Material: Black Nitride

• Valve Size: 33.00 mm / 5.97 mm / 106.10 mm

• Application: BMW 1.8L M42

• Engine Code: M42B18