Engine Pro Has The Right Valves For Your Engine

Selecting the correct valves for an engine build can have a profound impact on its performance, longevity, and durability. To make an informed choice, it’s important to evaluate key factors such as valve material, weight, and finish, as each affects how the valve will handle the unique demands of your given application. Drawing expert insight from Alan Stevenson at Engine Pro, we’ve assembled a detailed look at how these elements come together to help optimize your engine build, whether it’s for the street or the track, naturally aspirated or high-stress power adder applications.

The material you select for the valves in your engine is critical. If you try to save a few dollars, you could end up with an expensive machine shop bill later when there’s a failure.

Material Choice Is Not Immaterial

One of the primary considerations in valve selection is material, as it determines a valve’s ability to withstand heat and pressure. For high-stress, high-temperature applications, materials like Inconel are valuable due to their exceptional heat resistance. Engine Pro’s Nitro Black Inconel-alloy diesel and big block Chevy exhaust valves are bi-metallic, meaning they combine HNV-3 alloy stems for compatibility with valve guides and Inconel heads for heat resilience. This combination offers both durability and thermal stability, which are vital in turbocharged or diesel engines. Inconel’s high nickel content and its austenitic structure (a crystal lattice arrangement in the metal) enable it to endure extreme heat and pressure conditions, preventing distortion and maintaining integrity.

For engines that don’t face the same extreme conditions, stainless steel valves, like Engine Pro’s 21-4N variety, offer a great balance of strength and affordability. These one-piece stainless steel valves are forged with a four-percent nickel content, making them very durable for high-RPM and mildly boosted engines. Some max effort racing builds choose to send stainless steel valves out for DLC coating. For builds that are budget-sensitive but still performance-driven, a lower-cost 21-2N stainless steel version, containing two percent nickel, offers reliable performance for street or mild racing engines where extensive high-RPM durability isn’t a primary need.

valves, engine pro, titanium valves, inconel valves

High-end valves are a requirement for some engine builds. The combination might require a lightweight valve that’s meant for elevated rpm levels. The engine might need valves that are made to deal with the heat and pressure that come from a power-adder.

 

Valve Weight, RPM, and Engine Response

Valve weight plays a crucial role in engine efficiency and RPM potential. By reducing valve weight, builders can reduce the stress placed on valvetrain components, allowing the engine to achieve higher RPM and do so more smoothly. Lighter valves reduce strain on springs, rocker arms, and retainers, which translates to increased durability and responsiveness.

Titanium valves, with their low mass and high strength, provide these benefits in high-RPM race engines, where the reduced mass contributes to quick and efficient engine response.

The weight of the valves plays a big role in their performance.

Finishes and Coatings

The right valve finishes play an important role in an engine’s performance, durability, and heat dissipation. Treatments like chroming, nitriding, and DLC coatings provide enhanced wear resistance, friction reduction, and thermal management. Chrome-plated stems, for example, reduce friction and extend the life of both the valve and the guides by minimizing wear. This finish is especially beneficial for engines with high mileage or those exposed to extreme environments, as it maintains smooth movement and consistent operation over time.

Nitriding, a process used in Engine Pro’s Nitro Black valves, strengthens the surface of the valve, providing a wear-resistant exterior. This treatment is ideal for engines that experience high temperatures, such as boosted or nitro-burning builds, as it improves durability by reinforcing the valve’s surface against friction and heat-induced wear. Nitriding not only increases the surface hardness of the valve but also allows it to better handle rapid changes in pressure without compromising its structural integrity. Independent tests have proven that the Nitriding process used by Engine Pro creates a 21% smoother finish than traditional chrome, reducing guide wear and carbon build up.

Valve coatings are another important area you need to keep in mind.

“The valve is more than just its raw materials,” Stevenson says. “Chroming valve stems and inserting a hard wafer tip ensure longer life for the valve and prevent wear and friction. Beyond chrome, there is nitriding, which is a multi-step metal treatment process that makes for a smoother, stronger surface. This is what makes the Engine Pro Nitro Black valves so special.”

DLC coatings, often applied to valve facings, deliver unique benefits in race applications where engines endure high RPM and extreme temperatures. DLC offers a high-wear resistance that’s particularly valuable in turbocharged or nitrous oxide engines, where valves face harsher conditions than naturally aspirated builds. These coatings increase valve life by adding a durable, wear-resistant layer that helps effectively manage heat, allowing the engine to perform consistently under the most punishing of conditions.

Matching Valve Selection to Specific Applications

Selecting valves goes beyond material, weight, and finish; understanding the specific demands of your application is key. Turbocharged, supercharged, or nitrous-assisted engines, for example, generate higher exhaust temperatures and pressure levels, which can distort or damage valves made from lesser materials. For these applications, Inconel valves are often the top choice for their superior heat resistance, ensuring durability even under harsh conditions. DLC-coated facings add another layer of protection by improving wear resistance and longevity, making them ideal for applications that require both endurance and heat management. Even though DLC has many benefits, it is up to the builder to decide if the time and cost involved in out-sourcing this coating is worthwhile.

There’s more than just size when it comes to valve selection.

One of the most critical measures of a quality valve is concentricity. If the stem is not concentric to the head of the valve, it won’t seal correctly no matter how good the valve job is. In addition, every time the valve slams shut, poor concentricity induces side-loading of the stem which increases friction and wear on the guide. In independent testing, Engine Pro valves have consistently shown to have the best concentricity of any valve on the market.

The valve length is crucial to ensure proper operation. Matching the length to your engine’s cylinder head design, rocker arm geometry, and spring height helps prevent issues like misalignment, which can lead to poor sealing, and decreased performance.  Different valve head radii influence flow characteristics, and for performance engines, this choice can result in noticeable power gains. Selecting an appropriate valve radius helps fine-tune airflow for specific needs, making it a valuable adjustment in engines like those dedicated to racing.

Mistakes in valve selection often arise from material mismatches or neglecting to consider high-performance coatings. Choosing incompatible valve and seat materials can lead to poor sealing, excessive wear, or, ultimately, engine failure. Opting for cheaper materials may save on cost initially, but the risk of premature wear, poor performance, and potential engine damage can make this a costly choice in the long run. High-quality valves, properly matched to the application and equipped with advanced finishes like nitriding or DLC coating offers significant benefits for durability and performance, making them worth the investment.

Different applications are going to require different types of valves. An engine that's using a power-adder will need to be able to deal with more heat than the valves for a N/A engine. You'll also want to look at the different coating options to see if they will work with your specific engine. The weight of the valves is another thing to consider and you should consult with your engine builder on how heavy the valves should be for your application.

“You want to consider the engine’s operating conditions, such as temperature, cylinder pressure, and fuel type, to avoid selecting valves that aren’t appropriate for your specific application,” Stevenson adds.

The correct valve selection is vital to unlocking an engine’s full potential. Engine Pro’s offerings — from Inconel valves designed for high-heat, boosted builds to lightweight competition valves and advanced finishes like Casidium coatings — provide builders with the tools to maximize engine reliability and performance. By understanding each valve’s properties and then matching them to your engine’s specific needs, you can ensure that your build will deliver peak performance and longevity, whether it’s built for the street or all-out racing competition. With the right valves, your engine will be well-prepared to handle the demands of high performance, delivering consistent results and reliability no matter the operating environment.

Article Sources

About the author

Andrew Wolf

Andrew has been involved in motorsports from a very young age. Over the years, he has photographed several major auto racing events, sports, news journalism, portraiture, and everything in between. After working with the Power Automedia staff for some time on a freelance basis, Andrew joined the team in 2010.
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