Custom and OEM Valves

Custom Valves to Your Specification

Custom Valves by Summit
Intake and exhaust valves are used for sealing the combustion chamber that controls the gas exchange process in the internal combustion engine. The intake valves are cooled by the incoming gases. In contrast, exhaust valves are subject to extremely high temperatures and harsh chemical corrosion during the exhaust cycle. To compensate for this, Summit uses a wide range of materials and geometries in our design and manufacturing of exhaust valves. A well design valve plays a critical part in engine performance and durability. The proper valves, matched to the proper valve seat can impact flow and compression in the combustion chamber. This immediately translates into lost or gained horsepower.

Several design choices such as valve stem size, material, and backcut are important aspects not only in the design, but the manufacturing tolerances of the finished valve. As far a valve material selection, a few variants of stainless steel (due to its price point durability) are pretty typical when it comes to passenger and light duty racing applications. For maximum performance and very heavy duty applications, custom alloys and titanium is required because of the materials lighter weight and strength.

From a valve seat perspective, keep in mind that titanium is a basically a soft metal. A traditional cast or hard seat easily make a groove into the valve. This is why a nickel or even a bronze seat is recommended.

Keep in mind, the higher quality of EV8 stainless valves are an excellent choice for regular use as well as mid-level racing engines. Titanium accommodates high engine speeds in race engines that don’t need extreme heat tolerances.

More information on our Valve Seat Selection:

Engine valves are now available today in a wide variety of choices. The most popular include: STELLITE - Which is a hard coating applied to valve tips to provide a hard surface specifically to reduce wear. Stellite alloy is a non-magnetic cobalt-chromium alloy that may also contain a tungsten element. It resists embrittlement and annealing at higher temperatures.
SODIUM-FILLED Sodium-filled valves feature stems that are precision-gun-drilled and filled with a specially formulated sodium. This achieves weight reduction (the result of the gun-drilling to create a hollow stem) and better heat dispersion. There is some debate concerning the efficiency of this heat transfer, due to concerns that the heat transfer to the guides increases guide wear. Even with these concerns in mind, it’s interesting to note that the Chevy LS7 engine features sodium-filled exhaust valves (along with titanium intake valves). The hollow space in the head/stem of a sodium-cooled valve is filled to about 60% of its volume with metallic sodium, which melts at about 206 degrees F. The inertia forces that result during valve opening cause the liquid sodium to migrate upwards inside the stem, transferring heat to the valve guide and subsequently to the water jacket.
HOLLOW STEM Hollow-stem stainless steel or titanium valves (no sodium-fill) features gun-drilled stems to create hollow stems, strictly for weight reduction (this reduces valve weight by approximately 10% as compared to a comparable solid-stem valve). Citing Ferrea as an example, their hollow stem valves are gun-drilled and micropolished, and feature friction welded tips, shot-peened and rolled lock grooves, “avionics” chrome plated stems, and feature face hardness up to 42 HRc. This micropolishing reduces the risk of stress risers in the I.D. walls of the stem.
STAINLESS STEEL - These valves are offered in a varying of grades and configurations and are known for high performance which means they are mostly used in heavy duty or racing. Most are made from a one-piece forging, and some configurations offer a stronger stainless steel form with even higher heat resistance.
Valve train design has matured to a fairly high level, and now we can even predict dynamic valve movement with consistent accuracy. We can design valves with a high degree of confidence that what we are simulating will be repeated in real life and on the track. Through the use of the tools in our arsenal we are able to analyze what the Spintron and dyno cannot show. We can visualize the effects of cylinder pressure acting on the valves. The dynamic behavior of the valvetrain is highly dependent on the forces acting on the components. For the worst-case scenario, a NASCAR push-rod engine, the actual exhaust valve opening can be delayed as much as 10-15 crank degrees as a result of the cylinder pressure acting on the valves. The compliance of the push-rod system becomes obvious when you observe this much difference between what you measure on the engine stand vs. what you measure on a firing engine (which requires an expensive high-speed combustion system and application-specific sensors). We can measure the difference in a firing vs. non-firing engine in just a few minutes with confidence that the answer is correct. Broken spring tips are a sign when the valve train is trying to tell you “It’s only a matter of time before I let you down”! Using valve train simulation, we can optimize the design of the valve train components to work better together with your existing cam and spring combination or we can start from scratch with a “clean sheet” design. We design valve train components based on your goals and your needs.