D346, D348 & D349 VEHICULAR ENGINES Caterpillar

(11)Engine Valve Lash

1. With the engine stopped and cold.

2. To prevent dirt from getting into the valve mechanism, clean the base of the valve covers.

3. Remove the valve covers.

4. Remove the timing hole cover from the flywheel housing.

5. Remove the pinion bolts (A), the pinion (B), and the spacer (C).

6. Install the pinion without the spacer.

7. Rotate the flywheel in the direction of normal rotation.

8. Align the "TC-1" timing mark on the flywheel, with timing pointer on the flywheel housing.

Valve Locations:

When on compression stroke both inlet and exhaust valve rockers can be easily moved with finger pressure.

When on exhaust stroke only the inlet valve rockers can be moved freely with finger pressure.

9. Check the No. 1 cylinder rockers for movement. Determine if the piston is on COMPRESSION or EXHAUST STROKE and adjust the valves indicated in the chart.

10. Rotate the flywheel one revolution in the direction of normal rotation and align the flywheel "TC-1" timing mark.

11. Inspect the movement of the rockers for cylinder No. 2.

12. Adjust the remaining valves as specified in the table.

Adjusting Valve Lash:

When adjusting valve lash, engine must be stopped and cold.

1. Turn the adjusting screw clockwise to zero lash position for each of the valves listed.

2. Turn each adjusting screw counterclockwise, the exact number of clicks shown in the chart.

3. After adjusting all of the inlet and exhaust valves, remove the pinion from the flywheel housing.

4. Install the pinion and spacer in the flywheel housing. Tighten the bolts.

Valve Rotation

1. Before installing the valve covers, start the engine.

2. Move the governor control to the low idle position.

3. Watch the serrations on each valve retainer. Each valve retainer should turn slightly each time the valve closes.

If a valve fails to rotate, contact your Caterpillar dealer. If all valves rotate, proceed as follows:

4. Stop the engine.

5. Inspect the valve cover gaskets. Install new gaskets if necessary.

6. Install the valve covers.

7. Install the flywheel housing timing cover.