TIRE GP (SEM) 5203141 - Caterpillar

3400 Series EnginesReference: Engine News, December 15, 1982, Page 3. In the article, "New Piston Group Has A Thicker Top Ring," you were told about the availability of new piston body assemblies which use a thicker top ring.These new pistons have a wide taper in the pin boss area. They were designed to be used with wide taper connecting rods. Engine damage can result if these pistons and connecting rods are not used together, correctly.
These new pistons can be used with the earlier connecting rods with the narrow taper in 3406 and 3412 Engines if all the pistons are the same design.
These pistons cannot be used on 3408 Engines with the narrow taper connecting rods because they will cause engine vibration. They cannot be used on any 3400 Series Engines with connecting rods which are the straight design.