BRAKE GP 1V2156 - Caterpillar

3406 (90U) 3406B (6TB, 4FD, 1RK) 3408 (67U) 3408B (6NB, 9TD, 6RJ) 3412 (7DB, 9XF, 3NK, 38S) Industrial Engines 3406 (91U) 3406B (4TB) 3408 (1LG, 8RG, 99U) 3412 (3JK, 60M) Marine Engines 3406 (75Z) 3406B (2WB, 3SF, 4RG, 4JK) 3408 (2BG, 78Z) Generator Set EnginesDescription of Change: A material change in the new connecting rod bearing provides improved fatigue resistance. This eliminates the need for a mid-life bearing roll-in.Adaptable To: The new 9Y9497 Connecting Rod Bearing is a direct replacement for the former 1W7524 Connecting Rod Bearing. The former bearing is canceled. The new bearing is in effect as shown in the chart. The new bearing is adaptable to first production of all the above engines. Engines that are built, repaired, or overhauled with the new 9Y9497 Connecting Rod Bearings, DO NOT require a mid-life connecting rod bearing roll-in if the following conditions are NOT encountered: * Extended operation at high load factors.* Extended operation at high rpm (2100 rpm and above).* Excessive lead or aluminum in oil samples.* Reuse of Crankshaft with marginal profile or surface texture.* Engine overheating.* Oil dilution by fuel or coolant.* Rapid cold engine starts.* Dry starts after an engine has set for 30 or more days without prelubing.* Extended oil drain intervals causing excessive lube oil sooting.* Plugged oil filters.* Incorrect oil viscosity (too light during hot weather, or too heavy during cold weather). If these or similar conditions cause marginal lubrication to an engine, Caterpillar recommends the bearings be inspected and/or replaced.