Usage:
3306 Truck Engines
Description of Change: New rod and piston groups with new pistons and rings are used in 3306 Truck Engines. The new piston rings will give better control of engine slobbering, especially during operation under light load or no load conditions.
New keystone type top and intermediate rings are used. In comparison with the former parts, the new top ring is made of different material, and both new rings have design changes to improve ring performance in the engine. The top ring has a different shape, as shown in the illustration. The new intermediate ring has a keystone "twist" design, and is changed to increase the surface area in contact with the cylinder wall. These changes will decrease engine slobbering and increase the service life of the rings.
Adaptable As: The new parts are direct replacements for the former parts, as shown in Chart A. The new parts are in effect with the serial numbers shown in Chart B. Chart C shows the replacement piston ring groups (or kits) which are available for the basic piston groups, and the rings in each group.
Troubleshooting
If engine slobbering becomes a problem, use the procedure that follows to find and correct the probable cause.
1. Inspect turbocharger seals for wear or damage. Install new seals if necessary.
2. Check valve guide clearances. See the " Specifications" section of the Service Manual for the correct clearance specifications.
3. Install a 6N7174 Oil Shield on each rotocoil assembly on the engine valves in the cylinder head.
If these steps do not correct the problem, install the new top and intermediate rings shown in Chart A.
Comparison of top ring designs.