Doosan DX60R Shop Manual page 304

4-Valve Cylinder Heads
The 4-valve cylinder head operates two valves with a single
rocker arm by employing a valve bridge (1, Figure 160)
between the two valves (2, Figure 160). Clearance (4, Figure
160) between the valve bridge and valves must be set before
adjusting the clearance (5, Figure 160) between the rocker arm
(3, Figure 160) and valve bridge.
1. Remove the valve cover. See "Removal of Valve Cover" on
page -109
NOTE: If adjusting each cylinder individually, the
cylinder to be adjusted first does not have to be
the No. 1 cylinder. Select and adjust the cylinder
where the piston is nearest to the top dead
center after turning, and make adjustment for
other cylinders in the order of firing by turning
the crankshaft 180° each time.
2. Rotate the crankshaft clockwise as seen from the coolant
pump end, to bring No. 1 piston to TDC on the
compression stroke while watching the rocker arm motion
and the timing grid on the flywheel. (Position where both
the intake and exhaust valves are closed.)
3. Make sure there is clearance (5, Figure 160) between the
valve bridge (1, Figure 160) and the rocker arm (3, Figure
160).
Do not loosen or tighten the valve adjusting screw lock nut
without holding the valve bridge. Always hold the valve
bridge using a wrench to prevent bending of the valve
stems.
4. Loosen the valve bridge adjusting screw lock nut (1,
Figure 161) while holding the bridge (3, Figure 161) with a
wrench (2, Figure 161).
Engine
Page 124
IMPORTANT
Figure 160
Figure 161
SP001693