Usage:
D346, D348, D349 Engines
Description of Change: The oil pump groups used on D348 Engines have been improved. Reports indicate that some oil pump failures occurred because the bearings in the pump end cover had moved out of their bores. The oil pump groups have been changed to prevent the bearings from moving out their bores. See Illustrations 1 and 2. A tapped hole has been added between the bearing bores in the pump end cover. A spacer, washer and bolt are installed in this tapped hole. These additions and changes will prevent the bearing from moving out of the end cover.
Illustration 1. Location of new components on 8N1928 and 8N5853 Engine Oil Pump Groups cover assemblies.
Illustration 2. Location of new components on 8N1928 and 8N5853 Engine Oil Pump Groups cover assemblies.
Adaptable As: The improved 8N1928 Engine Oil Pump Group is in effect with D348 Vehicular Engine 98S3172. The improved 8N5853 Engine Oil Pump is in effect with D348 Vehicular Engine 98S3206. The additions to the pump groups are shown in the chart.
A tapped hole has been added to the 1N3817 Cover Assembly used on 8N1928 Engine Oil Pump Group and the 1N3771 Cover Assembly used on 8N5853 Engine Oil Pump Group.
The changed covers and new components are adaptable to all earlier 8N5853 and 8N1928 Engine Oil Pump Groups. The new bolt, spacer, washer and changed 1N3817 Cover Assembly can also be used on the 2N3834, 6N5723, 1W2456 Engine Oil Pump Group used on earlier D346, D348 and D349 Engines.
The cover assemblies used in the engine oil pump groups on earlier D346, D348 and D349 Engines can be drilled and tapped for the installation of the bolt, spacer and washer as shown in Illustrations 3 and 4. The tapped hole is located at the midpoint of the center line between the bearing bores.
Illustration 3. Location of tapped hole.
Illustration 4. Location and dimensions for tapped hole.