GASKET 7W2478 - Caterpillar

Illustration 1 g00884755
Non-water cooled valve seat insert
Table 2
Specifications Of Water Cooled Valve Seat Inserts    
Part Number     Valve Seat Angle (degrees)     Oversized Dimension (mm)     Usage     Installed Concentricity (TIR)     Replaced Part    
183-5079     30.75     1.00     Exhaust     0.08 mm     160-5771    
183-5080     30.75     0.50     Exhaust     0.80 mm     160-5771    
183-5081     45     1.00     Exhaust     0.08 mm     173-8386    
183-5082     45     0.50     Exhaust     0.80 mm     173-8386    
Illustration 2 g00884756
Water cooled valve seat insertOversized machining of the bore for the valve seat insert in the cylinder head is required. Since the valve guides act as pilots for the tool that machines the bores,Caterpillar recommends installing new valve guides in the head before machining the bore for the insert. The bores for the valve seat inserts need to be machined to the dimensions that are listed in Table 3 and Table 4.
Table 3
Machining Specifications For Non-Water Cooled Inserts    
Part Number     Dimension A (mm)     TIR A (mm)    
183-5075     98.00 0.025     0.04    
183-5076     97.50 0.025     0.04    
183-5077     98.00 0.025     0.04    
183-5078     97.50 0.025     0.04    
203-9566     97.50 0.025     0.04    
203-9568     98.00 0.025     0.04    Note: TIR A is the total indicator reading of the bore (A) for the insert, which is measured off the valve guides.
Illustration 3 g00884757
Table 4
Machining Specifications For Water Cooled Inserts    
Part Number     Dimension B (mm)     TIR B (mm)     Dimension C (mm)     TIR C (mm)    
183-5079     94.50 0.025     0.03     109.50 0.025     0.04    
183-5080     94.00 0.025     0.03     109.00 0.025     0.04    
183-5081     94.50 0.025     0.03     109.50 0.025     0.04    
183-5082     94.00 0.025     0.03     109.00 0.025     0.04    Note: TIR B is the total indicator reading of the bore (B) for the insert. To measure TIR B, first measure TIR C and record TIR C. Then measure TIR B and record TIR B without moving the valve guide pilot. The difference of TIR C to TIR B at any given location must be less than 0.03 mm (0.0012 inch).Note: TIR C is the total indicator reading of bore (C) for the insert, which is measured off the valve guide.
Illustration 4 g00884759
The valve seat inserts have premachined valve seat faces. If the inserts are installed correctly, and if the bore in the cylinder head has been machined properly, the inserts do not require grinding, machining, or lapping after installation.The interface between the valve and the valve seat insert must always be checked after a cylinder head has been rebuilt. The