Valve Clearance Adjustment - Isuzu 4BG1 Instruction Manual

Fig. 35
70
(2) Valve Clearance Adjustment
The valve clearance must be adjusted every
1200
operating
hours, or whenever the valve rocker is abnormally noisy, or in an
engine malfunction though the fuel system is properly working.
Valve clearance : 0.40 mm (0.0157 in) (When the engine is cold.)
Adjustment Procedure
1) In order to bring No. 1 or No. 4 cylinder to the top
dead
center
in the compression stroke, align the notched line on the crank
pulley with the TDC mark on the timing gear case cover.
2) Do the adjustment on the circle marked valves in the below
tabel where No. 1 cylinder is in the top dead center in the
compression stroke.
After the above steps, do the adjustment on the double circle
marked valves where No. 4 cylinder is on the top dead center in
the compression stroke.
I
Cylinder No.
I
1
I 2 I 3 I 4 I
I
Valve arrangement
I I Ml IEll IElI Id
I
When No. 1 cylinder is at TDC
in the compression stroke
I lo/ I I
I
When No. 4 cylinder is at TDC
in the compression stroke
I I 144
I: Inlet E: Exhaust
Fig. 36
3) After the adjustment started from either piston top dead center,
turn the crankshaft 360' to align the notched line with the TDC
mark to do the adjustment again on the remaining valve.