PIN AS 8Y7024 - Caterpillar

3306 Engines, Arrangements 3N8100 (250 HP) And 8N1506 (225 HP) For Steiger TractorsDescription of Change: Later 3306 Engines, Arrangements 3N8100 and 8N1506 for Steiger Tractors, use a piston group with keystone-type piston rings instead of rectangular-type piston rings. This change was put in effect with engine Serial Number 66D18441 for arrangement 3N8100, and 66D35454 for arrangement 8N1506. Engine tests and field reports show that the keystone-type piston rings have better resistance to ring sticking (rings are held tight in the grooves) and piston scuffing (scratches) where engine load factors and exhaust temperatures are high. Since the piston groups with keystone-type rings are directly adaptable to earlier engines, the recommendation is to make this improvement during engine reconditioning, especially for engines used in heavy load applications and/or where there is an indication of ring sticking or piston scuffing. The piston groups with keystone-type rings will give longer service life in these applications.Adaptable As: The 9N1303 Piston Group (with keystone-type piston rings) is a direct replacement for the 4N9258 Piston Group (with rectangular-type piston rings) in these applications. Install six new piston groups for conversion of earlier engines.