GASKET-SI ACCESS 4N2630 - Caterpillar

Engines:
3606 (S/N: 8RB1-UP)
3608 (S/N: 6MC1-UP)
3612 (S/N: 9RC1-UP; 9FR1-UP; 2NZ1-UP)
3616 (S/N: 1PD1-UP; 1FN1-UP)
3618 (S/N: 2MW1-UP)
Description of Change: New basic cylinder head groups are used on these distillate fuel 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 engines that are listed in Table 1. The new cylinder heads are adaptable to all earlier 3600 Engines that are used in distillate fuel applications.
Table 1
Effectivity of the New Cylinder Heads    
Engine Model     Effective Serial Numbers    
3606     S/N:8RB773-UP
   
3608     S/N:6MC616-UP
   
3612     S/N:9RC319-UP
S/N:9FR21-UP
S/N:2NZ176-UP
   
3616     S/N:1PD364-UP
S/N:1FN150-UP
   
3618     S/N:2MW86-UP
   The part numbers for the new basic cylinder head groups and the former basic cylinder head groups are listed in Table 2. The basic cylinder head groups are components of the respective cylinder head groups that are listed in Table 2.Note: The cylinder head groups are not available for parts service. The cylinder heads are serviced at the "basic cylinder head group" level.
Table 2
Cylinder Head Groups    
Application     Cylinder Head Group Pt. No. (1)     New Basic Cylinder Head Group Pt. No.     Former Basic Cylinder Head Group Pt. No.    
Standard (Constant Load)     1W-0021     175-6340     7E-9012    
Standard (Cyclic Load)     4P-2335     175-6341     4P-2334    
Injector Tip Cooling (2)     107-0275     175-6336     107-0274    
3618     138-7908     180-5344 (3)     138-7907 (3)    
Fast Ferry     164-7886     176-3600     164-7885    
( 1 ) These part numbers are not serviced. The cylinder heads are serviced at the "basic cylinder head group" level.
( 2 ) These cylinder heads are used in light crude applications.
( 3 ) The new 180-5344 Basic Cylinder Head Group has 20 degree inlet valves. The former 138-7907 Basic Cylinder Head Group has 30 degree inlet valves.The components that are listed in Table 3 can be used to rebuild the new cylinder heads. The premachined valve seat inserts MUST be used with the precision valve guides.Note: The valve seat counterbores in the former cylinder heads were not machined to the same tolerance as the new cylinder heads. When the former cylinder heads are rebuilt, continue to use the former valve seat inserts.
Table 3
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 (2)     Exhaust Valve Seat Inserts (2)    
175-6340     7C-2422     9Y-6232     175-6344     175-6339