This company has five Interim Tier 4/Stage III B diesel engines that feature full-authority electronic controls, a four-valve cylinder head, a high-pressure fuel system, turbocharging, and an air-to-air aftercooling system. The lineup of engines is fuel-efficient and built with field-proven technologies without sacrificing performance, reliability, durability, or operator convenience. John Deere Power Systems. 800-533-6446.