BREATHER AS 2621044 - Caterpillar

Use the new individual parts for replacement of any former individual parts. If any of the new parts are installed, all 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 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 New Part
133-9306 Valve Guide (Inlet)
197-6995 Valve Guide (Exhaust)
468-8824 Inlet Valve
443-2712 Exhaust Valve 468-8825 Exhaust Valve
197-7006 Seal 316-5980 Valve Stem Seal
209-0962 Washer 316-5981 Washer
194-4901 Outer Spring 316-5976 Outer Spring
194-4902 Inner Spring 316-5977 Inner Spring
197-7062 Rotocoil Assembly (Inlet) 316-5978 Rotocoil Assembly (Inlet)
197-7063 Rotocoil Assembly (Exhaust) 316-5979 Rotocoil Assembly (Exhaust)
2A-4429 Retainer Lock (Inlet)
197-7055 Retainer Lock (Exhaust)
8T-6759 Pipe Plug 8T-6759 Pipe Plug
7N-1902 Dowel 239-0689 Dowel(1)
265-7537 Bridge Assembly (Inlet)
265-7538 Bridge Assembly (Exhaust)
(1) Only required on 3500 MUIThe bridge dowels must be removed and/or a bridge dowel must be modified when a cylinder head that originally had adjustable bridges is rebuilt.Because of the design of the floating bridge, the cylinder head for a 3500 Engine with EUI and for a 3500B Engine does not require any dowels.Because force is placed on the fuel injector by the rack, the cylinder head for a 3500 MUI Engine requires one 239-0689 Dowel to maintain correct orientation of the fuel injector.
Illustration 1 g01023120
(1) 239-0689 Dowel in a cylinder head for a 3500 MUI EngineWhen the cylinder head for a 3500 MUI Engine is rebuilt, only the right dowel is installed. The dimension from the surface of the cylinder head to the top of the dowel must not exceed 30 mm (1.2 inch). Use a 239-0689 Dowel for the correct orientation of the 3500 MUI fuel injector.
Illustration 2 g01097665
Typical example of the slotted pocket in the floating valve bridge
When viewing the bottom of the new valve bridges have a pocket on either end for each tip of the valve stem. One of the pockets is round and the other pocket is slotted. The bridge must be placed on the cylinder head so that the round pocket is toward the outside of the engine. Refer to Illustration 3. This orientation of the valve bridge is more stable. This orientation keeps the bridge in position during the initial valve lash adjustment after an engine rebuild.
Illustration 3 g01097686
Orientation of the valve bridge
(1) Round pocket
(2) Outside of the engineTable 3 lists the effectivity for the new cylinder head groups and assemblies.
Table 3
Effectivity of the New Cylinder Head Groups in 3500 Machine Engines
3500 Engine with EUI
S/N:2PK01621-UP
S/N:4WJ01302-UP
S/N:7YG02212-UP
3500 MUI Engine
S/N:54Z01205-UP
S/N:96Z00938-UP
S/N:99W03548-UP
3500B Engine
S/N:1AW00630-UP
S/N:2CS01062-UP
S/N:2GR04628-UP
S/N:6EF00329-UP
S/N:7TR01351-UP
S/N:8BR00862-UP
S/N:8WM00377-UP