SEAL-O-RING 1221874 - Caterpillar

3500 Family Of EnginesReference: Specifications and Disassembly And Assembly Modules for Service Manuals for all applications of these engines, and for D11N and 776B Tractors, and for 777B, 785, and 789 Trucks.Description of Change: A slightly wider main bearing cap is now used on the 3500 Family Of Engines. Also, the tightening torque on the cap bolts has been increased by increasing the turn on the bolts from 180° to 210° (3 1/2 flats) after tightening to the torque of 135 15 N m (100 10 lb ft). The new cap has a nominal width of 0.030 mm (.0012") more than the former cap. This means that the fit of the cap in the block will range from no clearance to a slight interference fit. Depending on the block saddle and the former cap tolerances, the former cap can have as much as 0.030 mm (.0012") clearance.
These changes keep the cap tighter in the block.
Adaptable To: The new 9Y6422 Cap can be used as a direct replacement for the former 8N8216 Cap which is canceled. (Line boring still required.) Use the new torque-turn specification on the bolts regardless of which cap is used. The width of the new cap is 340.030 0.015 mm (13.3870 .0012"). You should note both this change and the additional amount to turn the bolts after reaching the initial tightening torque in all the referenced Service Manual modules.