BASE GP-3500B 1252744 - Caterpillar

Illustration 1.
Valve Mechanism Cover Group Components. Valve cover (1).9M-1974 Washer (2).133-1247 Seal (3). 0S-1617 Bolt (4). Adaptable To: The new 133-1247 Valve Cover Seal replaces the former 8S-1605 Valve Cover Gasket in the above Caterpillar 3306 Machine Engines. The new valve cover seal is effective with 3306 (6NC3148, 13Z42582) Machine Engine. If a new seal is installed in place of a former gasket, the fifteen 3B-4505 Lockwashers under the heads of the fifteen bolts that fasten the valve cover to the cylinder head must be replaced with fifteen 9M-1974 Washers. When the new 133-1247 Valve Cover Seal is used, tighten the fifteen 0S-1617 Bolts (that fasten the valve cover to the cylinder head) in number sequence (see Illustration 2) to a torque of 16 3 N m (142 27 lb in). When the former 8S-1605 Valve Cover Gasket was used, the fifteen bolts were tightened in number sequence (see Illustration 2) to a torque of 11 3 N m (98 27 lb in).
Illustration 2.
Valve cover bolt tightening sequence.