Mitsubishi S4Q, User Manual

Page: 36 / 174

36 / 174 Service Manual Mitsubishi SQ-Series diesel engines
Version 08/2004
ENGLISH
CYLINDER HEADS AND VALVE
MECHANISM
ENGINE MAIN PARTS
7.4 Valve Clearance Adjustment
1. Find the top dead center on the compression
stroke for No.1 piston as outlined below:
1) Using the turning handle (30691
–
21800), turn
the nut on the crankshaft pulley in the
engineís forward rotating direction (clockwise
when viewed from the front of the engine).
2) Stop turning when the stamped “0” line on the
periphery of the crankshaft pulley aligns with
the pointer on the turning gear case.
3) Try to move up and down the inlet and
exhaust valve rocker arms of the No.1 cylinder
to make sure they are not being pushed up by
the pushrods. The No.1 piston is at the top
dead center on the compression stroke when
the rocker arms are not being pushed up by
the pushrods. If the rocker arms are being
pushed up, turn the crankshaft one turn.
2. Insert a 0.25 mm [0.0098 in.] feeler gage into
between the rocker arm and valve cap.
Unit: mm [in.]
3. Loosen the lock nut for the adjusting screw and
turn the adjusting screw in either direction until the
feeler gage is slightly gripped between the rocker
arm and valve cap.
4. After adjusting, tighten the lock nut and recheck
the clearance.
Figure 45 Finding top dead center on compression
stroke for No. 1 piston — 1
Figure 46 Finding top dead center on compression
stroke for No. 1 piston — 2
Figure 47 Adjusting valve clearance
Adjusting screw
0.25 mm [0
.0
098
in
.]
Lock nut
Item Assembly Standard
Valve
clearance (cold
setting)
Inlet
valves 0.13 to 0.60
[0.0051 to 0.0236]
Exhaust
valves 1.27 to 1.35
[0.0500 to 0.0531]