How to Inspect & Adjust Valve Clearance for ISUZU 4JJ1

This instruction show you guide on how to inspect and adjust valve clearance for Isuzu 4JJ1.

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ISUZU Worldwide EPC 2018.03 Snap-on EPC Installation Service

 

Rotate the crankshaft in the forward direction to align the first cylinder piston to the compression top dead center(TDC).
Check the TDC alignment position using a mirror, etc.

Legend
1.Crankshaft pulley
2.Mirror
3.TDC alignment position
2.Adjustment of the valve clearance.
Loosen each adjust screw of the rocker arm.

Legend
1.Screwdriver
2.Ring spanner
3.Valve clearance adjust nut wrench Special Tool Valve clearance adjust nut wrench:
5-8840-2822-0
NOTE: Make sure to adjust while cool.

Insert a 0.15 mm(0.0059 in) thickness gauge between the rocker arm roller and the cam, and tighten the rocker arm adjust screw. When the movement of the thickness gauge becomes stiff, fasten the adjust screw nut of the rocker arm.

Legend
1. Cam: exhaust side
2. Cam: intake side
3. Roller: intake side
4. Roller: exhaust side
· When the first cylinder is at the compression top dead center,a circle is marked in the table; when the fourth cylinder is at the compression top dead center, an X is marked in the table for adjustment of valve clearance.


Compression pressure inspection
· Warm-up the engine.
· Remove the battery negative terminal and remove all glow plugs.
· Disconnect the injector harness connector.(this will prevent fuel injection.)


NOTE: When the harness connector is removed, the ECM determines a malfunction and records the DTC. After the end of measurement, be sure to clear the ECM memory.
(Refer to "Diagnostic Information and Procedures"in Section 1A, Engine Control System.)
· Connect the battery negative terminal.
· Engage the starter to discharge foreign materials from inside the cylinders.
· Install the compression gauge adaptor and the gauge.
NOTE: Before measuring the 4th cylinder, remove the EGR valve assembly, attach the adaptor and gauge and install the valve.(Refer to "EGR System"in Section 1F, Emission Control.)

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