1981/07/15 Caterpillar

All Caterpillar Engines

An earlier article told about the start of a gradual change to the use of millimeters instead of inches for size identification marks on engine main and connecting rod bearings. This metric conversion is now complete, and all size identification marks on engine bearings are now shown in millimeters. The chart shows a comparison of millimeter to inch dimensions for different sizes of bearings. These dimensions are shown on all oversize (larger than standard size) and/or undersize (smaller than standard size) bearings, with the letters OS (for oversize) or US (for undersize) or both. Some, but not all, bearings have the letters mm after the dimension to show that the size is given in millimeters.