Connecting Rod Big End Bore Code Location
- 2. Each rod has a tolerance range from 0 to 0.024 mm (0.0009 in.), and in 0.006 mm (0.0002 in.) increments, depending on the size of its big end bore. It's then stamped with a number (1, 2,3, or 4) indicating the range. You may find any combination of numbers in any engine, (half the number is stamped on the bearing cap, the other half on the rod).
If you cannot read the code because of an accumulation of oil and varnish, do not scrub them with a wire brush or scraper. Clean them only with solvent or detergent.