Adjustment of the WD305 series diesel engine Valve clearance adjustment and distribution timing check

- Jan 16, 2018-

Before adjusting valve clearance, adjust Valve bridge is needed. Valve bridge is used to make a rocker arm controls two valve institutions. Adjusting valve bridge is designed to make two valves work is consistent, and avoid the valve not at the same time open and produce stress. Specific steps are as follows:

A. Loosen adjusting nut of the valve bridge, and the adjusting screw (NO.3 in the following figure) unscrew;

B. The bridge into the valve bridge guide rod (NO.5 in the following figure), fingers gently press contact surface (NO.2 in the following figure) of rocker-arm, make the valve bridge and valve stem (NO.1 in the following figure) contact;

C. Light tightening valve bridge adjusting screw until its contact with the valve stem (NO.4 in the following figure) tip;

D. Tighten the nut on the adjusting screw;

According to this requirement, adjust all adjusting screw of valve bridge. Then we can adjust the valve clearance.


Fig.1 Valve bridge for adjustment and structure

Before adjusting the valve timing, attach a degree plate with 360°marks to the free end of the crankshaft and mount an adjustable pointer onto the timing gear case cover as a reference pointer when the crankshaft is turned.

Remove the cylinder head cover and turn the crankshaft until the timing pointer on the flywheel housing is pointing at the “0” mark on the rim of the flywheel.

Note: There are two punched marks on the timing mark inspection window of the flywheel housing for locating the timing pointer. For correct indication of timing, the timing pointer can not be distorted and its two sides must be located within these two punched marks.

With the crankshaft at this position, adjust the adjustable pointer mounted on the timing gear case cover to point at the “0” mark on the degree plate.

This indicates that the piston of the first and the sixth cylinders of the engine are at their top dead center position. To determine whether the first cylinder is at the beginning of its expansion stroke, remove the injection pump inspection door cover and check whether the plunger spring of the first pump elements is compressed or slightly bar the crankshaft and observe whether the intake and exhaust valves move. If the plunger spring of the first pump elements is compressed or if the intake and exhaust valves remain still when the crankshaft is slightly barred, it means the first cylinder is at the beginning of is expansion stroke.