Usage:
D11N Track-Type Tractors;
776B Off-Highway Tractors;
777B, 777C, 785, 785B, 789, 789B, 793, 793B Off-Highway Trucks;
994 Wheel Loaders;
5130, 5230 Excavators
- SUPPLEMENT: 10/14/96
Service Magazine; August 26, 1996; Page 4; "New Lifters Improve Roller-To-Camshaft Contact And New Bridges Provide Commonality With 3508B Engines"
Under the "Adaptable To: " section, the second sentence of the second paragraph should read " The new 129-4181 Bridge Assembly replaces the former 8N-7292 Bride Assembly. "
At the end of the article, make note of the following information:
The new lifter assemblies in the valve mechanism groups also improve roller-to-camshaft contact for Remanufactured 3500 Engines of Caterpillar built machines. The following chart identifies the effectivity of the engine serial numbers for these machines.
NOTE: Remanufactured engines will not switch to the new new bridge. These engines will reuse the old bridge.
--------------- END SUPPLEMENT ---------------
Description of Change: Improvements have been made to the lifter assemblies and bridge assemblies of the valve mechanism groups in the 3500 Engines of the above machines.
Lifter Assembly
The new lifter assemblies in the valve mechanism groups improve roller-to-camshaft contact. As the result, premature pitting on the camshaft is eliminated. The location of the lifter is shown in Illustration 1.
Illustration 1. Typical Valve Mechanism Group: (1) Bridge Assembly. (2) Lifter Assembly.
Illustration 2. Former 4P-1827 Lifter Assembly: (3) Previous slot location. (4) Flat spot caused by slot.
The body of the lifters was improved through the elimination of flat spot on the upper locating arm. This was accomplished by moving the slot further down the locating arm. The roller was improved by the elimination of the sharp edge between the rolling surface and the corner radius. Refer to Illustration 3.
Illustration 3. New 132-9439 Lifter Assembly: (5) Elimination of the flat spot on the upper locating arm. (6) Elimination of the sharp edge between the rolling surface and the corner radius.
Bridge Assembly
The new bridge assemblies, which occur in 3500 Engines, provide commonality with the bridge assemblies in 3500 "B" series Engines. The location of the new bridge is shown in Illustration 1.
Adaptable To: Improvements to the lifter assemblies and bridge assemblies have been made within 4W-1035 and 7E-5314 Valve Mechanism Groups.
New 132-9439 Lifter Assembly replace former 4P-1827 Lifter Assembly. New 8N-7292 Bridge Assembly replace former 129-4181 Bridge Assembly. These engine improvements to lifters and bridges on specific vehicle applications are effective with the serial numbers listed in the following chart.
