Connecting Rod Bearing: Service and Repair

Fig. 32 Crank Web Numbers & Main Bearing Cap Bore Letters Locations:

Fig. 33 Standard Size Main Bearing Selection Chart:

Fig. 34 0.25 Mm Undersize Main Bearing Selection Chart:

Select new standard size main bearings as follows:
1. Crank webs of No. 2 and No. 3 cylinders have 5 stamped numbers on them, Fig. 32. These numbers represent journal diameters at bearing caps 1, 2, 3, 4 and 5 respectively. These numbers, 1, 2 and 3, represent the following diameters: number 1, 2.0470-2.0472 inch; number 2, 2.0468-2.0470 inch and number 3, 2.0465-2.0468 inch.
2. Mating surface of cylinder block has 5 letters stamped on it, Fig. 32. These letters represent main bearing cap bore diameters at bearing caps 1, 2, 3, 4 and 5 respectively. These letters, A, B and C, represent the following diameters: A, 2.2047-2.2050 inch; B, 2.2050-2.2052 inch and C, 2.2052-2.2054 inch.
3. There are 5 standard bearing thicknesses, distinguished by paint marks as follows: green, 0.0786-0.0787 inch; black, 0.0787-0.0788 inch; colorless, 0.0788-0.0789 inch; yellow, 0.0789-0.0790 inch and blue, 0.0790-0.0791 inch.
4. Using numbers stamped on No. 2 and No. 3 crank webs and letters stamped on mating surface of cylinder block, determine new bearing to be installed using chart in Fig. 33.

Main bearings also come in 0.25 mm undersize, available in five thicknesses distinguished by paint marks as follows: green and red, 0.0835-0.0836 inch; black and red, 0.0836-0.0837 inch; red, 0.0837-0.0838 inch; yellow and red, 0.0838-0.0839 inch and blue and red, 0.0939-0.0840 inch.
When necessary to install undersize bearings, regrind journal to 2.0367-2.0373 inch diameter, measure reground journal diameter in two perpendicular directions, then using journal diameter measured and letters stamped on cylinder block, select the proper bearing using the chart in Fig. 34.
Two kinds of rod bearings are available, standard and a .0098 inch undersize bearing, To distinguish them, the undersize bearing has the stamped number ``US025'' on its backside.