Usage:
D346, D348, D349 Industrial, Marine and Off-Highway Truck Engines;
641B, 650B, 660B, 651B, 657B, 666B and 772 Tractors;
773 Trucks and 992 Loaders
In some variable timing advance assemblies for the above models, the 3B551 Plug is extended beyond the end of the shaft assembly. This has no effect on the operation of the timing advance, but can cause problems during testing on the fuel injection test bench. If the outside end of the plug is not even with or below the surface of the shaft assembly, the drive adapter of the 2P5504 Adapter Group will not fit correctly on the shaft assembly. As a result, the test bench coupling can be damaged.
Location of plug in variable timing drive assembly.
Modification of drive adapter.
If a variable timing drive assembly is found with a 3B551 Plug that is extended beyond the end of the shaft assembly, make a modification to the drive adapter before testing on the fuel injection test bench. Cut a 1.5" (38.1 mm) diameter circle .07" (1.8 mm) deep in the center of the drive adapter.