Valves and piston rings each need to be made from a material that’s strong enough to deal with the demands of a high-performance engine, but they also need to have the right coating to reach their full potential. The correct coating will not only make these parts perform their best, it will increase durability.
We spoke with Engine Pro about its special Nitro Black nitriding process that gives its valves and rings a stronger and smoother finish.
The valves of an engine take an absolute beating inside the cylinder when you crank up the RPM that exponentially expands the stress and heat that contribute to the fatigue of the part. To combat this, Engine Pro’s 21-4N stainless alloy valves are finished with its proprietary liquid nitriding process.
Roger Borer from Engine Pro explains why the Nitro Black nitriding process is so special.
“Deep nitriding increases case depth, strength, and ductility — all of these are important during minor periods of detonation or rising exhaust gas temperatures. Racers also use a wide variety of fuel types, which pairs well to the valve’s corrosion resistance. Friction and wear steal horsepower, Nitro Black surfaces are harder and smoother to reduce friction, hold tolerance, and improve the seal.”
Piston rings are tasked with keeping things sealed up inside the cylinder and if they begin to struggle it will, at a minimum, cost you horsepower. Borer breaks down how Engine Pro’s Nitro Black nitriding makes piston rings work better.
“The top rings start with an ASL 817 stainless steel, known for hardness and elasticity. Gas nitriding increases surface hardness, ductility, strength, and smoothness. The ring face hardness and coefficient of friction are dramatically increased with ceramic coating, applied through vapor deposition. Combined, these attributes handle more heat, improve side sealing, and reduce scuffing, which can make a difference during periods of intermittent detonation or slightly compromised lubrication. The ring pack is finished out with Napier profiled, ductile iron in the second groove to increase durability and improve oil control. The third groove is outfitted with a Flex-Vent, tension-controlled spacer and gas nitrided stainless steel rails.”
As you can see, a lot goes into the nitriding process for valves and rings at Engine Pro. Check out the Engine Pro website right here to learn more about the Nitro Black nitriding process.