Supertech Performance HEVN-1001F Black Nitrided Exhaust Valve Oversize - 0.5mm

The Supertech Performance HEVN-1001F is a Black Nitrided stainless steel exhaust valve designed as a +0.5mm oversize replacement for Honda B-series engines. Built from one-piece forged 23-8N stainless steel, this flat-face valve delivers the high-flow performance, durability, and precision dimensional tolerances demanded by performance engine builders.

The Black Nitride surface treatment goes beyond standard chrome coating — it is applied to the entire valve rather than just the stem, resulting in a harder, smoother finish that reduces friction between the valve stem and guide. Nitride layer hardness reaches a minimum of 800 Vickers (approximately 52 Rc), significantly increasing wear resistance without sacrificing the ductility of the base material.

Key Specifications:

• Head Diameter: 28.50mm (+0.5mm oversize)
• Stem Diameter: 5.45mm
• Overall Length: 102.50mm
• Face Style: Flat (No Dish)
• Material: Stainless Steel 23-8N
• Finish: Black Nitrided
• Groove Type: Single Groove
• Valve Type: Exhaust

Black Nitride vs. Chrome Coating:

• Nitriding is applied to the entire valve; chrome is applied to the stem only
• Smoother surface finish than chrome, reducing stem-to-guide friction
• Nitrided layer is bonded at a microscopic level — will not flake or fracture under impact
• Suitable for naturally aspirated, daily-driven, and moderate forced-induction applications

This valve is sold individually (per valve). Order the quantity equal to the number of exhaust valves required for your engine build. For sustained high exhaust gas temperatures or endurance racing use, Supertech's Inconel exhaust valve series is recommended instead.