TRUNNION 5K4290 - Caterpillar

Engines:
G3606 (S/N: 3XF1-UP)
G3608 (S/N: 4WF1-UP)
G3612 (S/N: 1YG1-UP)
G3616 (S/N: 4CG1-UP)
Description of Change: New basic cylinder head groups are used on these engines. The new cylinder heads include new premachined valve seat inserts and precision valve guides. The premachined inserts provide the following advantages:
improved reliability
simplified field serviceThe new premachined seat inserts provide improved concentricity of the seating surface. The manufacturing process has been improved so that no machining of the valve seats is necessary after installation.Adaptable To: The new cylinder heads are effective with the following engines: G3606 (3XF214-UP), G3608 (4WF141-UP), G3612 (1YG179-UP) and G3616 (4CG152, 153, 155-UP). The new cylinder heads are adaptable to earlier engines that have the listed serial number prefixes.The part numbers for the new basic cylinder head groups and the former basic cylinder head groups are listed in Table 1. The basic cylinder head groups are components of the respective cylinder head groups that are listed in Table 1.Note: The cylinder head groups are not available for parts service. The cylinder heads are serviced at the "basic cylinder head group" level.
Table 1
Components of the Cylinder Head Groups    
Application     Cylinder Head Group Part Number (1)     New Basic Cylinder Head Group Part Number     Reman Pt. No. for New Basic Cylinder Head Group     Former Basic Cylinder Head Group Pt. No.    
Natural Gas (Low Compression)     7C-0400     171-3994     0R-9794     155-4093    
Natural Gas (High Compression)     N/A     171-3995     0R-9752     161-1205    
Landfill Gas     172-2227     171-3996     0R-9753     148-3056    
( 1 ) These part numbers are not serviced. The cylinder heads are serviced at the "basic cylinder head group" level.The components that are listed in Table 2 can be used to rebuild the new cylinder heads. The premachined valve seat inserts MUST be used with the precision valve guides. The part numbers for the valves have not changed from the former cylinder heads.Note: The new cylinder head components are not adaptable to the former cylinder heads.
Table 2
Major Components of the New Basic Cylinder Head Groups    
Basic Cylinder Head Group     Inlet Valves     Exhaust Valves     Valve Guides     Cylinder Head Assembly (1)     Inlet Valve Seat Inserts (1)     Exhaust Valve Seat Inserts (1)    
171-3994     4P-2854     154-2417     175-6344     170-7740     171-3992     171-3993    
171-3995     4P-2854     149-0588     175-6344     170-7740     171-3992     171-3993    
171-3996     4P-2854     9Y-6232     175-6344     170-7741     171-3992     160-5770    
( 1 ) The valve seat inserts are components of the cylinder head assemblies. The inserts are available individually for parts service. The cylinder head assemblies are not available for parts service.Note: Do not perform any machining or any lapping on the valves or seat inserts after installation. Proper seating is established very early in the break-in period.Note: It is VERY IMPORTANT to perform bridge adjustment and valve lash adjustment at the proper interval.