Valve Clearance Adjustment; Adjustment Procedure - Isuzu AU-4LE1T Maintenance Manual

Mark groove
TDC mark
Timing gear
case cover
Crank pulley
IMLE0072
Cylinder No.1 Cylinder No.1 exhaust
intake
IMLE0026
84
(2)

Valve Clearance Adjustment

The valve clearance must be adjusted every 1000 operating hours, or
whenever the tappet 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.)
The model 4LE1 engine has two types of the valve clearance adjusting
method. Confirm the aligning marks (mark grooves) on the outside
diameter of the crank pulley.
Type l method with an aligning mark on the outside diameter of the
crank pulley.

Adjustment Procedure

1) Turn the crankshaft clockwise so that the mark groove on the crank
pulley is aligned with the TDC mark (cast out) on the timing gear case
cover.
2) Remove the cylinder head cover and check that the cylinder No. 1 is at
TDC in the compression stroke or at TDC in the exhaust stroke. When
the intake and exhaust valves are closed, the cylinder is at TDC in the
compression stroke, and when the intake and exhaust valves are open,
it is at TDC in the exhaust stroke.
3) In accordance with the conditions of cylinder No. 1, measure and
adjust, if required the clearance of the valves marked with either
in the table below.
or