CAMSHAFT AS 2W7980 - Caterpillar

Illustration 1 g00607099
Cylinder and valve location (four cylinders) (A) Inlet valve (B) Exhaust valve
Illustration 2 g00607038
Cylinder and valve location (six cylinders) (A) Inlet valve (B) Exhaust valve
Put the No. 1 piston to the top center position on the compression stroke. Refer to Testing and Adjusting, "Finding Top Center Position for No. 1 Piston".
Remove the cover for the valve mechanism.
Illustration 3 g00803643
Valve mechanism (A) Clearance (1) Valve seat (2) Valve stem (3) Locknut (4) Adjusting screw
It is not necessary to adjust the valve lash if the clearance is within the tolerance that is listed in Table 1.For four-cylinder engines, measure the valve lash (clearance) between valve seat (1) and valve stem (2) for the inlet valves of cylinders 1 and 2 and the exhaust valves of cylinders 1 and 3.For six-cylinder engines, measure the valve lash (clearance) between valve seat (1) and valve stem (2) for the inlet valves of cylinders 1, 2, and 4 and the exhaust valves of cylinders 1, 3, and 5.
Table 1
Valve Lash Check    
Inlet valves    
0.38 0.08 mm (0.015 0.003 inch)    
Exhaust valves    
0.75 0.08 mm (0.030 0.003 inch)    If the clearance is within the tolerance, proceed to Step 4. Otherwise, adjust the valve lash to the specifications that are listed in Table 2.
Table 2
Valve Lash Setting    
Inlet valve    
0.38 mm (0.015 inch)    
Exhaust valve    
0.75 mm (0.030 inch)    
Loosen locknut (3) and adjusting screw (4) .
Insert the appropriate feeler gauge between valve seat (1) and valve stem (2) .
Tighten the adjusting screw until the valve seat and the valve stem contact the feeler gauge.
Hold the adjusting screw in place and tighten the locknut to a torque of 29 7 N m (21 5 lb ft).
Verify that the setting is correct.
Remove the timing bolt from the flywheel housing. Rotate the crankshaft for 360 degrees.For four-cylinder engines, measure the valve lash (clearance) between valve seat (1) and valve stem (2) for the inlet valves of cylinders 3 and 4 and the exhaust valves of cylinders 2 and 4.For six-cylinder engines, measure the valve lash for the inlet valves of cylinders 3, 5, and 6 and the exhaust valves of cylinders 2, 4, and 6. It is not necessary to adjust the valve lash if the clearance is within the tolerance that is listed in Table 1.If the clearance is within the tolerance, proceed to Step 5. Otherwise, adjust the valve lash to the specifications that are listed in Table 2. Follow the instructions in Step 3.a through 3.e.
Remove the timing bolt from the flywheel.
Install the cover for the valve mechanism.