3406 Industrial, Marine, Truck and Vehicular Engines ( 90U1-2158, 91U1-484, 92U1-5943, 70V1-3144)
Starting with Serial Numbers 90U2159, 91U485, 92U5944 and 70V3145, drilled oil passages are used to permit oil to flow to the rocker arm mechanism. In the earlier engines, the oil flowed around two cylinder head bolts to get to the rocker arm mechanism (see Service Magazine, October 25, 1976, "New Design Prevents Oil Leakage Into Cooling System," Page 5).
Two remanufactured short blocks, which have the later lubrication system for the rocker arm mechanism, are available for repairs of the earlier 3406 Engines. The remanufactured short blocks are available for use in both the precombustion engines and the direct injection engines.
The OR0715 Remanufactured Short Block (precombustion) and the OR0716 Remanufactured Short Block (direct injection) are service replacements for the blocks in engines with Serial Numbers 90U1-2158, 91U1-484, 92U1-5943 and 70V1-3144. Because the remanufactured short blocks have the later lubrication system, additional parts are necessary for installation of the blocks. The necessary parts are shown in the chart which follows.
NOTE: If a 7N1203 Block Group was installed during an earlier repair, it is not necessary to use the additional parts when a OR0715 or OR0716 Remanufactured Short Block is installed. The additional parts will have been installed with the 7N1203 Block Group.
More information about Caterpillar's Remanufactured 3406 Engine Program is available in Technical Partsgram, Form SEBD2062. COSA dealers must check the COSA Remanufactured Products Guidebook only.