Isuzu L Series - Engine Servicing Procedures

III. Engine Servicing Procedures
U L-Series Diesel 21
Valve Adjustment
Bring the engine up on number one compression stroke. Verify the position by checking for
clearance in-between the valve stem tip and the rocker arm. NOTE: Valves can be adjusted
beginning with #1 or #3 (3L) or #4 (4L). This adjustment can only be made with a cold
engine.
3L Engines
Cylinder Number 1 2 3
Valve Arrangement I E I E I E
Valve Numbers
4 4 4
------------ ------------
4
4L Engines
Cylinder Number 1 2 3 4
Valve Arrangement I E I E I E I E
Valve Numbers
4 4 4
--------- ---------
4
--------- ---------
Loosen the adjuster jam nut; insert a 0.40 mm (0.016”) feeler gauge in-between the rocker tips
and the valve stems to adjust the valves. NOTE: Proper adjustment is obtained when there is a
slight drag against the feeler gauge. Jam nut torque is 5.8-8.7 lbs. ft (0.8-1.2 kg m)
Rotate the crankshaft 360° (so that the opposing piston is now on its exhaust stroke) and
adjust the remaining valves.
3L Engines
Cylinder Number 1 2 3
Valve Arrangement I E I E I E
Valve Numbers ------------ ------------ ------------
4 4
------------
4L Engines
Cylinder Number 1 2 3 4
Valve Arrangement I E I E I E I E
Valve Numbers --------- --------- ---------
4 4
---------
4 4