The Griffon was the first Rolls-Royce production aero engine to use a hollow crankshaft as the means of lubricating the main and big end bearings, providing a more even distribution of oil to each bearing.[7] In another change from convention, one high efficiency B.T.H-manufactured dual magneto was mounted on top of the propeller reduction casing;[9] earlier Rolls-Royce designs using twin magnetos mounted at the rear of the engine.[10]