This book include elementary study of Piston-Ring lubrication in Hydrodynamics (HL) and Elasto-Hydrodynamic (EHL) domain at low load-low speed operating conditions. Effects of Piston-Ring running face profile, Engine speed and Elliptically distorted bore are investigated. Vogelpohl parameter technique along with Finite Difference Method is used to solve steady state Reynolds equation for Compression ring of a gasoline engine. Performance parameters (Oil Film thickness in HL and EHL, Friction Force, Power Loss and Flow-rate of lubricating oil) are shown graphically and explained.