Primary gear thrust washers are made in varying sizes to take up the play.Standard gap size should be between 3-6 thou. This type is for the 1275cc crankshaft only which has a raised step for the primary gear to sit on. Thrust washer 0.116-118”(2.94-2.99mm). The measurement is taken as plus or minus one to the size hence the two thou tolerance on each part number.