PIPE 4W0548 - Caterpillar

Caterpillar Products:
3500 Family Generator Sets and Power Modules
3500 Family Pumpers Engine: Commercial
3500 and 3500B Family AllEngine News SEBD9328, December 2003, "New Cylinder Head Groups and Valve Mechanisms". Disregard this article. Corrections have been made to the supplement. The correct information follows.Description of Change: New cylinder head groups and assemblies are available for all 3500 and 3500B Engines. The new head groups and assemblies include a new exhaust valve with a larger stem diameter and an exhaust valve guide with a larger inside diameter. The larger stem diameter reduces stress in the valve stem during severe engine operation. The new groups also include floating valve bridges that eliminate the need for bridge adjustments. The new groups also include the following new components: valve springs, rotators, spring washers and valve stem seals.Adaptable To: Use the new basic cylinder head groups for Top End overhauls and for Major overhauls on all 3500 and 3500B Engines. The new basic cylinder head groups may be used individually in replacement of the former basic cylinder head groups.The former cylinder head groups and the new cylinder head groups are listed in Table 1.
Table 1
Cylinder Head Group     Former Basic Cylinder Head Group     New Basic Cylinder Head Group    
3500 Engine with EUI    
7E-8758 Cylinder Head Gp     172-0837 Cylinder Head Gp     239-0691 Cylinder Head Gp    
3500 MUI Engine (Locomotive)    
203-2170 Cylinder Head Gp     203-2144 Cylinder Head Gp     239-0692 Cylinder Head Gp    
3500 MUI Engine    
4W-0095 Cylinder Head Gp     172-0835 Cylinder Head Gp     239-0690 Cylinder Head Gp    
3500B Engine    
101-0830 Cylinder Head Gp     145-3216 Cylinder Head Gp     201-4257 Cylinder Head Gp    
3500B Engine (Locomotive)    
203-2169 Cylinder Head Gp     203-2168 Cylinder Head Gp     234-8779 Cylinder Head Gp    Use the new individual parts for replacement of any former individual parts. If any of the new parts are installed, all of the former parts on that side of the cylinder head must be replaced with the new parts. For example, if one inlet valve spring is replaced with the corresponding new spring, then all of the springs on both inlet valves, both of the seals, and both of the valve rotators must be replaced with the new part numbers. The former parts and the new parts of the basic cylinder head groups are listed in Table 2.
Table 2
Former Part Number     New Part Number    
133-9306 Valve Guide (Inlet and Exhaust)     133-9306 Valve Guide (Inlet)    
197-6995 Valve Guide (Exhaust)
210-2542 Inlet Valve     210-2542 Inlet Valve    
210-2529 Exhaust Valve     194-4897 Exhaust Valve    
137-6856 Seal     197-7006 Seal    
2W-2662 Spring Seat     209-0962 Washer    
101-1180 Outer Spring     194-4901 Outer Spring    
7N-1904 Outer Spring    
101-1177 Inner Spring     194-4902 Inner Spring    
7N-1903 Inner Spring    
197-6999 Rotocoil Assembly (Inlet and Exhaust)     197-7062 Rotocoil Assembly (Inlet)    
197-7063 Rotocoil Assembly (Exhaust)
2A-4429 Retainer Lock (Inlet and Exhaust)