See Figures 1 and 2
Valve adjustment is required on the diesel engine every 36,000 miles.
- The engine must be cold for this adjustment. Mark the crankshaft pulley into three equal 120° sections, starting at TDC or 0 mark.
- Remove the valve cover.
- Disconnect the fuel line from the injector on cylinder #1. Be very careful not to kink the line.
- Using a socket and a breaker bar on the crankshaft bolt, turn the engine in the same direction as it normally runs until the 0 mark on the crankshaft damper rear face is aligned with the pointer on the bottom of the timing gear case. As you are turning, keep an eye on the fuel line that was disconnected. Fuel will squirt out of the line a few degrees before you reach the 0 mark. If it doesn't squirt out, you've got the wrong cylinder at TDC. Turn the engine another 360° (one revolution) and you will have #1 at TDC.
- The cylinders are numbered from front to rear. Refer to the illustration for valve identification.
- The lash is measured between the rocker arm and the end of the valve. To check the lash, insert a 0.012" feeler gauge between the rocker arm and the valve as illustrated. Adjust the proper clearance by loosening the locknut on the rocker arm and turning the adjusting screw. After the adjustment is made, tighten the locknut and recheck the clearance to be sure it did not change as the locknut was being tightened.
- After both valves for the No. 1 cylinder are adjusted, turn the engine so that the pulley turns 120° in the normal direction of rotation (clockwise). The distributor rotor will turn 60° since it turns at half engine speed.
- Check that the rocker arms are free and adjust the valves for the next cylinder in the firing order, 5. The firing order is 1-5-3-6-2-4.
- Turn the engine 120° to adjust each of the remaining cylinders in the firing order. When you are done the crankshaft will have made two complete revolutions (720°).
- Replace the rocker cover with a new gasket. Attach the fuel line to the injector. Start the engine and check for leaks.