Inside the cylinders of an engine is an unforgiving place full of heat and pressure every time the rotating assembly turns over and fuel and air ignite. The unsung hero of the combustion process is the piston ring — it helps to keep gases in the correct location while making sure the piston gets enough oil between it and the cylinder wall. Selecting the correct piston ring, especially for an LS-based engine, is critical to maintaining proper engine function.
When the LS engine was introduced it was the first to use a performance-based ring package from the factory where narrow rings were implemented. This lightweight and narrow grove configuration has been carried over to all the various high-performance pistons that can be used in an LS engine. Going with this particular style of ring package has some distinct advantages for a modern engine.
Ron McKey from Engine Pro has been helping people put the best rings possible on various pistons for many years. He explains exactly why these different ring packages are used with LS-based and other high-performance engines.
“The trend towards less axial thickness on the O.E. has carried over to performance and continues to evolve with applications using extremely narrow compression rings of 1.2 mm or less. Rings with less mass and less axial thickness require different materials and different designs to function correctly. Just a few years ago this was cutting edge performance stuff that required custom pistons and rings, but today it’s O.E. in your Chevy pickup truck.”
Piston rings aren’t something that you select on a whim; they have to be of good quality for the application you’re going to use them on and match the pistons going into the engine. LS engines are able to use the OEM-style rings when they’re used in an all-motor application, but when you bring a power-adder into the picture the correct rings become vital. The more power and pressure you add to the combustion process, the more critical it becomes to have a ring that can contain everything going on inside the cylinder.
To combat the harsh conditions piston rings can face when you add boost or nitrous to an LS engine, Engine Pro has designed rings that maximize oil control to prevent oil getting past the rings and causing damaging detonation.
“Engine Pro LS performance ring sets all use a napier hook designed second ring that does a better job of ‘scraping’ oil from the cylinder wall. Our second ring is made of martensitic ductile cast iron that resists fracturing during abnormal combustion events — no more broken second rings. The martensitic ductile cast, because of its properties, is also compatible with all bore surfaces, both cast iron and aluminum blocks with sleeves.
We also use a three-piece oil control ring that does a good job of conforming to the cylinder wall and works well in a narrow application. Finally, we make our top ring out of stainless steel. Because of all the additional heat, in a boosted or nitrous application if you want to maintain ring tension on the top ring it has to be steel. Because the mass of the rings is getting smaller and the temperatures the ring is subject to are going up, we go one step further by nitriding our top ring which makes it even stronger without making it more brittle,” McKey explains.
To learn more about piston rings and see what will work best for your LS engine check out the Engine Pro website right here.