Mahle Standard Engine Piston w/ Rings for Dodge Cummins 5.9L Turbo L6 Diesel. MAHLE STANDARD ENGINE PISTON w/ RINGS FOR DODGE CUMMINS 5.9L 24V TURBO L6. MAHLE Original Pistons are built to be an exact fit for your application. Each piston features an OE quality construction and OE design. Ni-resist top grooves to control groove wear. Balanced Set of 6 for smooth engine operation. The M124 Piston material (used in these pistons) is a highly evolved “Eutectic” material, which contains approximately 12% silicon for excellent strength and excellent thermal expansion properties. For diesel engines, the Eutectic material is chosen because it bonds better with the ring land or ring groove inserts used to strengthen and better support the piston rings in high performance/ high load diesel applications. The Eutectic material with MAHLE’s ring groove inserts make a better piston than a forged material which does not hold the insert very well. Eutectic (12% silicon) vs. In diesel applications, the Eutectic material is desired over the Hypereutectic material which has approximately 16% silicon. Hypereutectic is a harder material with the increased silicon content from 12% to 16% but tends to be more brittle with a shorter life span in diesel applications. MAHLE uses Eutectic material so they can install high strength ring-land inserts into the piston grooves for longer life. The ring insert is a much harder material than the bare piston material and doesn’t allow the rings to wallow out the ring groove, hence… The inserts can also be made smoother and controlled better than the process of cutting a groove in a raw piston. Engine(s): 5.9L ISB (24-Valve) B-Series Cummins.