HITACHI ISUZU 4HK1 Engine Cylinder Head Assembly Disassembly Guide

Here is a step-by-step guide on how to disassembly cylinder head assembly for Hitachi excavator with 4HK1 stage-v engine.

 

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Procedures:

1 Engine Hanger Bracket Removal

1)Remove the front engine hanger bracket from the cylinder head assembly.

2)Remove the rear engine hanger from the rear engine hanger bracket.

 

2 Inlet Cover Removal

1)Remove the outer inlet cover from the inlet cover.

2)Remove the inlet cover from the cylinder head assembly.

Caution:Do not forget to remove the bolts indicated by the arrow in the diagram.

 

3 Exhaust Manifold Removal

1)Remove the exhaust manifold from the cylinder head assembly.

 

4Thermostat Removal

1)Remove the water outlet pipe from the cylinder head assembly.

2)Remove the thermostat from the cylinder head assembly.

3)Remove the gasket from the thermostat.

 

5 Overheat Switch Removal

1)Remove the overheat switch from the cylinder head assembly.

 

6 Engine Coolant Temperature Sensor Removal

1)Remove the engine coolant temperature sensor from the cylinder head assembly.

 

7 CMP Sensor Removal

1)Remove the CMP sensor from the cylinder head assembly.

Caution: Do not subject the sensor to impact.

 

8 Idle Gear C Removal

1)Press the idle gear C cover using the driver.

Note:Lightly tap the outer perimeter of the cover using a screwdriver and tilt the cover.

2)Remove the idle gear C cover from the cylinder head assembly using the pliers.

3)Remove the idle gear C from the cylinder head assembly.

 

9 Valve Spring Removal

1)Press the valve spring using the special tool.

2)Remove the split collar from the spring seat.

3)Remove the special tool from the cylinder head assembly.

4)Remove the valve spring seat from the valve spring.

5)Remove the valve spring from the cylinder head assembly.

Note:Store the removed valve springs according to the cylinders

 

10 Inlet Valve Removal

1)Remove the inlet valve from the cylinder head assembly.

Note:Organize the removed valve according to the cylinders.

 

11 Exhaust Valve Removal

1)Remove the exhaust valve from the cylinder head assembly.

Note:Organize the removed valve according to the cylinders.

 

12 Valve Stem Oil Seal Removal

1)Remove the valve stem oil seal from the valve guide using the pliers.

Caution: Do not reuse the valve stem oil seal.

2)Remove the valve spring seat from the cylinder head assembly.

 

13 Valve Guide Removal

1)Remove the valve guide from the cylinder head assembly using the special tool.

Note:Tap the valve guides out from the bottom surface of the cylinder head.

 

14 Valve Seat Insert Removal

1)Heat the valve seat insert with the gas burner.

heating temperature： 700.0 to 800.0 ℃ { 1292 to 1472 °F }

2 section(s) Inner surface of the insert

Note: Cool the valve seat insert naturally after heating.

specified time:5 min Natural cooling

2)Remove the valve seat insert from the cylinder head assembly using the driver.

Caution: Do not damage the cylinder head.

 

15 Injector Sleeve Removal

1)Remove the injector sleeve from the cylinder head assembly using the special tool.

Note:Tap the injector sleeve out from the bottom surface of the cylinder head.

Caution: Do not reuse the injector sleeve.

Caution: Do not damage the cylinder head lower surface.

 

16 Bridge Guide Removal

1)Install the nut to the bridge guide.

Note: Electrically weld the nut to the top of the bridge guide.

2)Remove the bridge guide from the cylinder head assembly using the sliding hammer.

 

17 Oil Seal Removal

1)Remove the oil seal from the cylinder head assembly.

Note:Attach a rod from the inner surface of the cylinder head, and tap it to remove it to the outer side.

More repair cases for ISUZU engine,please refer to:ISUZU Engine Trouble Repair