Forged pistons and PVD-coated rings: Forged three-ring aluminum-alloy slipper pistons provide superior strength. The oil control ring on each piston is electro-plated with a chrome-nitride coating applied in a vacuum chamber using a Physical Vapor Deposition (PVD) system. The chrome nitride PVD coating is harder and smoother than conventional chrome plating, reducing friction while improving cylinder sealing. The upper piston ring also features an L-shaped cross section, with combustion pressure pushing the ring tighter against the cylinder wall to further reduce blowby and increase the force actually pushing the piston down.