DRIVE GP-FINAL 1947086 - Caterpillar

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 installation guides can then be removed and the remainder of the spacers, washers and nuts installed.
When assembling the manifold sections, make sure the male end of the manifold end sections is clean, dry, and free of grease or oil. Apply a thin uniform coat of 2P-2333 Manifold Sealer to the male end sections. Apply a thin coat of engine oil to the female end of the manifold section. After installing the assembled exhaust manifold group on the engine, allow the manifold sealer to cure thoroughly (overnight if possible) before starting the engine.
If a previous end or center section is damaged beyond repair, the new manifold sections are interchangeable. When replacing a previous manifold section make sure to use the equivalent new parts as indicated in the illustrations.
A new nut tightening sequence and lower torque are required with the new exhaust manifolds. Tighten the exhaust manifold retaining nuts in the sequence shown in Illustration 2. Tighten the nuts to a torque of 38 5 N m (28 4 lb ft).
Illustration 2. Tightening sequence for exhaust manifold retaining nuts.