CLAMP-INJECTOR 2244991 - Caterpillar

3408B (28V) Truck EnginesReference: Truck Engine News, January 1991, Page 2, "Update Information For Exhaust Manifolds". Description of Change: New exhaust manifold end sections and center sections and longer spacers are used in the exhaust manifold groups on the engines in these machines. In conjunction with this change, longer exhaust manifold mounting studs are used in the cylinder heads on these engines. The new exhaust manifold sections incorporate the following improvements: * A 10.5 mm (.41 in) diameter slotted hole 15.0 mm (.59 in) wide alternating from the top to bottom at each mounting flange. This provides increased mounting stud clearance with manifold thermal expansion. It also provides for improved horizontal alignment of the manifold slip joints.* A 15.0 mm (.59 in) diameter hole at each flange (adjacent to the slotted holes) for increased mounting stud clearance. Only one slotted hole at each flange is needed for alignment of the slip joint.The longer exhaust manifold mounting studs and spacers provide increased durability and are more resistant to bending fatigue.
Adaptable To: The illustrations identify the new and former exhaust manifold sections. The former 4S-6137 Stud has been replaced by the new 100.0 mm (3.94 in) long 106-1792 Stud. The former 2S-3770 Spacer has been replaced by the new 53.0 mm (2.09 in) long 108-3612 Spacer. The chart identifies the effectivity of the new components. Since one new manifold section replaces two former sections, some components are not direct repalcements. Using the illustration as an example: If a 9Y-1229 Manifold (1) needs to be replaced, then a 107-8106 Manifold (4) needs to be used. This would require the elimination of one of the 9Y-1230 Manifolds (2). If a 9Y-1230 Manifold (2) needs to be replaced, then a 107-8106 Manifold (4) or 107-8112 Manifold (5) needs to be used. This would require the elimination of either a 9Y-1229 Manifold (1) or 9Y-1231 Manifold.
Illustration 1. (Both Left And Right Sides) (A) Former Exhaust Manifold Components For 3408B (28V) Truck Engine. 8N-0990 or 9Y-1229 Manifold (1). 8N-0989 or 9Y1230 Manifold (2). 8N-0991 or 9Y-1231 Manifold (3). (B) Current Exhaust Manifold Components For 3408B (28V) Truck Engine. 107-8106 Manifold (4). 107-8112 Manifold (5). Put 5P-3931 Anti-Seize Compound on the studs. New 2N-2766 Lock Nuts should always be used. Do NOT use an impact wrench to run the nuts down; the threads could become galled. This can result in false torque readings when the nuts are tightened.A 9U-7224 Manifold Installation Guide is available to align the manifold studs in the center of the slotted and oversize holes during installation of the exhaust manifold group. Since each flange has slotted and oversize holes, a 9U-7224 Installation Guide is required for each manifold section. The installation guide is slid over a stud and into the upper 15.0 mm (.59 in) oversize holes in each manifold section. The spacers, washers and nuts can then be installed on the other studs and pre-torqued to 14 N m (10 lb ft) to hold the manifold group in place. The