... and Treatment for Dedicated CNG/LPG Engines:Engine pistons,valves,valve seats,valve guides,ignition systems,high voltage ... engine configuration2Valves & valve seatsSpecial material and special treatment to valves & valve seats for a longer life.Important for NGV ... models include Isuzu 4JA1, 4JB1 and some Chinese gas engines)Engine pistons, valves, valve seats, ignition systems, high voltage cables, ...