Rod Bearing Selection: Notes

Each rod falls into one of four tolerance ranges, from 0 to 0.024 mm (0.0009 in.), in 0.006 mm (0.0002 in.) increments, depending on the size of its big end bore. It's then stamped with a number or bar (1,2,3, or 4/I, II, III, or MM) indicating the range. You may find any combination of 1,2,3, or 4/I, II, III, or III I in any engine.