Engine Valve Clearance Adjustment

The valve clearance should be adjusted every 3,000 hours.

1. Remove the rocker arm cover.

2. Remove the round cover (plug) from the timing mark access hole on the front of the bell housing.

Warning
• Risk of Injury
• Loosen all of the injection lines at the injection nozzles to prevent the possibility of the engine firing while it is being rotated.

3. Place the engine at top dead center of the compression stroke for the number one cylinder. See steps a through d.

   1. Rotate the engine in the normal direction of rotation (clockwise viewed from the water pump end) until the 1-4 timing mark on the flywheel lines up with the index mark in the timing mark access hole.

      
      

      Top Dead Center One and Four

      Open

      1.	Index Mark
      2.	Top Dead Center Mark for 1 and 4

   2. Check the rocker arms on the number one cylinder to see if they are loose.

   3. If the rocker arms are loose, the engine is at top dead center of the compression stroke for the number one cylinder.

   4. If the rocker arms are tight, the engine is at top dead center of the exhaust stroke for the number one cylinder. Rotate the engine 360 degrees to place the engine at top dead center of the compression stroke for the number one cylinder.

4. Use a feeler gauge to check the valve clearance on both valves for the number one cylinder, the intake valve for the number two cylinder, and the exhaust valve for the number three cylinder. The valve clearance for both the intake valve and the exhaust valve should be 0.15 to 0.25 mm (0.006 to 0.010 in.).

   1. Check to verify that the valve stem cap is in good condition and is positioned squarely on the top of the valve stem. Replace the valve stem cap if it shows significant wear.

5. Adjust the valves if necessary by loosening the locknut and turning the adjustment screw until the valve clearance is correct.

   
   

   Adjusting the Valve Clearance

   Open

6. Hold the adjustment screw in place and tighten the locknut.

7. Recheck the valve clearance.

8. Rotate the engine one full turn (360 degrees) in the normal direction of rotation (clockwise viewed from the water pump end), and align the 1-4 timing mark on the flywheel with the index mark in the timing mark access hole. This is top dead center of the compression stroke for the number four cylinder.

9. Check and adjust the exhaust valve for the number two cylinder, the intake valve for the number three cylinder, and both valves for the number four cylinder.

10. Replace the rocker arm cover, the cover for the timing mark access hole, and tighten the fuel injection lines when finished.

    Valve Adjustments and Cylinder Configurations
    	Rear Flywheel End						Front Pulley End
    Cylinder Number	1		2		3		4
    Valve arrangement	E	I	E	I	E	I	E	I
    Piston in No. 1 cylinder is at TDC on compression stroke	Open	Open		Open	Open
    Piston in No. 4 cylinder is at TDC on compression stroke			Open			Open	Open	Open