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Stainless Steel Black Nitride Exhaust Valves

 
Stainless Steel Black Nitride Exhaust Valves
Engine
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      Supertech valve details – stem, head and tip close-ups

      Stainless Steel Black Nitride Exhaust Valves

      Supertech Stainless Steel Black Nitride (BN) Exhaust Valves combine the strength of EV8/21-4N stainless with a low-friction, wear-resistant surface. The result is reliable sealing, smoother operation, and long service life for street performance, track days, and moderate boost applications.

      • EV8 stainless base with BN surface for durability
      • Hardened tips, controlled stems, and swirl-polished heads
      • OE and oversize options (by application)

      Key Benefits

      Why Choose Stainless + BN

      • EV8 stainless base material for hot hardness and durability.
      • Black Nitride surface helps reduce friction and scuffing.
      • Improved wear and corrosion resistance for daily use and track days.
      • Controlled stem finish and hardened tips to extend guide and follower life.
      • Offered in OE diameter and oversize options where supported.

      Materials and Surface Finish

      Stainless EV8 (21-4N)

      High strength at temperature with consistent seat-face accuracy and stem concentricity.

      • Excellent fatigue resistance for long service life.
      • Stable performance in street and track-day duty.

      Black Nitride (BN) Finish

      A hard, low-friction surface treatment that promotes smoother motion and wear resistance.

      • Helps reduce guide and seat wear.
      • Dark appearance for quick identification.

      Surface Details

      • Swirl-polished heads for smoother boundary layer.
      • Controlled stem finish for consistent clearances.
      • Hardened tips for follower and lash component life.

      Engineering Options

      Geometry

      • Flat, dished, and tulip head shapes by application.
      • Undercut or straight stems as validated.

      Sizes

      • OE diameter for stock ports and chambers.
      • Oversize options for ported heads where supported.

      Compatibility

      • Match with Supertech springs and retainers for your cam profile.
      • Works with performance guides and seat materials.

      Use Cases

      Street and NA

      Stainless + BN offers excellent durability and smooth operation for daily-driven and naturally aspirated builds.

      Moderate Boost

      Suitable for moderate turbo and supercharged applications. For sustained high EGT or endurance racing, consider Inconel exhaust valves.

      Installation Notes

      • Measure guide ID and set stem-to-guide clearance by material.
      • Cut seats to proper angles and contact width; verify concentricity.
      • Check installed height, seat pressure, coil bind, and retainer-to-seal clearance.
      • Verify piston-to-valve clearance at intended lift and timing.
      • Follow appropriate break-in and inspection intervals for your application.

      FAQ

      How does Black Nitride compare to Inconel?

      BN is a surface treatment that improves wear and reduces friction on stainless valves. Inconel is a high-temperature alloy. For the highest EGT and endurance racing, Inconel is recommended.

      Does BN change valve dimensions?

      BN is a thin surface layer. Always verify stem-to-guide clearance during assembly to ensure proper fit.

      Can I re-coat or refinish BN valves?

      Consult your machine shop and Supertech support for guidance. Do not remove material that affects stem finish or seat geometry.

      Do I need upgraded springs?

      Use springs matched to your cam profile and valve mass. Proper seat and open pressures control valve motion at RPM.