A test program, sponsored by the U.S. Navy, was performed using a high-speed, two-stroke cycle, diesel engine (DDC 6V-53T) to evaluate the impact of specially formulated test fuels using an L-16 full-factorial test matrix. Sixteen test fuels were evaluated with sulfur contents, cetane numbers, viscosities, and trace metals contents exceeding the limits contained in the Navy fuel specification, MIL-F-16884H,Fuel, Naval Distillate (NATO F-76). Surface layer activation (SLA) techniques were used to quantify piston ring and cylinder liner wear rates for each test fuel. The results indicated that sulfur was the primary contributor to piston ring wear. Cylinder liner wear was not significant.