2001/03/01 Caterpillar

Marine Engine:

3412C (S/N: 3JK1-UP; 60M1-UP)

Description of Change: A new plastic belt guard is available for the 3412C Marine engine. The steel belt guard that is used on the 3412C Marine engine can be replaced with a plastic belt guard which is used on the 3412E Marine engine. The new plastic belt guard will provide better durability and longer life than the steel guard.

Illustration 1	g00780697
(1) 6I-1845 Guard

Illustration 2	g00780699
(1) 144-4581 Guard

Table 1

Belt Guard
Former Belt Guard Part Number	New Belt Guard Part Number
6I-1845	144-4581

Adaptable To: The new 144-4581 Guard can be adapted to engines that were originally equipped with the 6I-1845 Guard. Refer to table 2 for the components that are needed to adapt the new 144-4581 Guard to the 3412C Marine engine.

Table 2

Required Parts List for Mounting the New Belt Guard
Quantity	Part Number	Description
1	7X-3186	Bolt
1	7X-0289	Bolt
2	4L-6459	Bolt
6	5P-1075	Washer
6	8R-8088	Spacer
3	7W-9094	Spacer
2	6V-8801	Nut

To install the 144-4581 Guard onto the 3412C engine, the top two existing mounting holes must be used. Spacers must be added between the new guard and the engine front cover in order to eliminate an interference between the new guard and the alternator bracket. A 8R-8088 Spacer must be used in each of the bolt holes for the mounting ears before installing the new 144-4581 Guard. This is done in order to prevent crushing of the new guard when the mounting bolts are tightened. Refer to figure 3.

Illustration 3	g00780701
(1) Spacer

Installation instructions

1. Mount the 144-4581 Guard with the two top bolts. Follow the instructions below.

   1. Place a 7W-9094 Spacer against the front of the water pump cover for the top left mounting ear of the guard.

   2. Install a 5P-1075 Hard Washer and the 144-4581 Guard with the 8R-8088 Spacer .

   3. Install a 5P-1075 Hard Washer onto the 7X-3186 Bolt and insert the bolt through the belt guard and through the spacer. Tighten the bolt by hand.

   4. Mount the top right ear by placing the 7W-9094 Spacer against the alternator support. Use a 5P-1075 Hard Washer and a 8R-8088 Spacer in order to secure the 144-4581 Guard .

   5. Install the 5P-1075 Hard Washer onto the 7X-0289 Bolt and insert the bolt through the belt guard and through the spacer. Tighten the bolt by hand.

2. Adjust the bottom of the belt guard so that the top of the belt guard has enough clearance for the alternator belt and the pulley.

   Note: Ensure that the belt guard does not rub against any moving parts. The plastic belt guard is very flexible. When the bottom two bolts are not installed the belt guard might come into contact with the belt or the pulley.

3. Mark the location for the holes on the front engine support and drill a clearance hole for the bottom two bolts.

   Note: The guard may need to be removed in order to drill the holes. Ensure that the belt guard clears the alternator belt and the pulley. Use caution not to drill into the oil pan.

4. Insert a 5P-1075 Hard Washer onto a 4L-6459 Bolt. Insert the bolt with the washer through the 8R-8088 Spacer into the guard.

5. Add a 5P-1075 Hard Washer and a 7W-9094 Spacer to the bolt that is protruding through the guard. Insert the bolt into the new hole in the front engine mount.

6. Add a 6V-8801 Nut to the back side of the front engine mount. Perform this same procedure for the second lower mounting hole. Tighten all four mounting bolts at this time to 52 N·m (38 lb ft).

Note: The holes for the bottom two mounting bolts may be drilled and tapped instead of drilling a hole through the engine mount. The 4L-6459 Bolt can be substituted with an 8T-2501 Bolt for a tapped hole.