- Caterpillar Products Machine Engines
- All 3500 Series
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.
| Cylinder Head Group | Former Basic Cylinder Head Group | New Basic Cylinder Head Group |
| 3500 Engine with EUI | ||
| 7E-8758 Cylinder Head Gp | 239-0691 Cylinder Head Gp | 335-6219 Cylinder Head Gp |
| 3500 MUI Engine | ||
| 4W-0095 Cylinder Head Gp | 172-0835 Cylinder Head Gp | 335-6218 Cylinder Head Gp |
| 3500B Engine | ||
| 101-0830 Cylinder Head Gp | 201-4257 Cylinder Head Gp | 335-6220 Cylinder Head Gp |
| 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 MUI |
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) | |
When 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
| |
| 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 engine | |
Table 3 lists the effectivity for the new cylinder head groups and assemblies.
| 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 |