Isuzu KB P190. Manual — part 749

Engine Mechanical – V6

Page 6A1–219

Page 6A1–219

Disassemble

1

Using an appropriately sized deep socket (1) and a
plastic hammer (2), lightly tap on the valve spring
retainer to loosen the valve collets.

CAUTION

Ensure valve heads will not contact anything
during this step in order to avoid bending or
damage.

Figure 6A1 – 369

CAUTION

Do not compress the valve springs less than
24.0 mm. Contact between the valve spring
retainer and the valve stem oil seal can
cause potential valve stem oil seal damage.

Compressed valve springs (1) have high
tension against the valve spring
compressor (2). Valve springs that are not
correctly compressed by, or are released
from the valve spring compressor can be
ejected from the valve spring compressor
with intense force. Use care when
compressing or releasing the valve spring
with the valve spring compressor and when
removing or installing the valve stem keys.
Failing to use care may cause personal
injury.

2

Compress the valve spring (1) using valve spring
compressor Tool No. J-8062 (2) and adaptor Tool No.
EN-46119.

Figure 6A1 – 370

Engine Mechanical – V6

Page 6A1–220

Page 6A1–220

3

Remove the valve collets using Tool EN-46117 (1).

4

Remove the valve spring compressor (2) and the
adapter (3).

Figure 6A1 – 371

5

Remove the valve spring retainer (1).

6

Remove the valve spring (2).

Figure 6A1 – 372

7

Remove the valves (1).

Figure 6A1 – 373

Engine Mechanical – V6

Page 6A1–221

Page 6A1–221

CAUTION

Never reuse a valve stem oil seal.

8

Remove the valve stem oil seal using Tool No.
EN-46116 and discard.

9

Repeat these procedures for the remaining valves.

Figure 6A1 – 374

10

Remove the cylinder head oil gallery expansion
plugs (1).

Figure 6A1 – 375

11

Remove the cylinder head coolant threaded plugs (1).

Figure 6A1 – 376

Engine Mechanical – V6

Page 6A1–222

Page 6A1–222

Clean

CAUTION

Due to the aluminium alloy construction of
the cylinder head, wire brushes and steel
scrapers must not be used during the
cleaning process, as damage to sealing
surfaces may occur. Use a wood or plastic
scraper as an alternative.

1

Remove any old thread sealant, gasket material or sealant using commercially available plastic or wooden scraper.

2

Clean all cylinder head surfaces with non-corrosive solvent.

Safety glasses must be worn when using
compressed air.

3

Blow out all the oil galleries using compressed air.

4

Remove any carbon deposits from the combustion chambers.

5

Clean any debris or build-up from the lifter pockets.

Inspect

Visual Inspection

1

Inspect the cylinder head (1) camshaft bearing
surfaces for the following conditions:
•

excessive scoring or pitting,

•

discoloration from overheating, and

•

deformation from excessive wear.

2

If any of the above conditions exist on the camshaft
bearing surfaces, replace the cylinder head. Do not
machine the camshaft bearing journals.

Figure 6A1 – 377

3

Inspect the cylinder head for the following:
•

Cracks, damage or pitting in the combustion chambers.

•

Debris in the oil galleries. continue to clean the galleries until all debris is removed.

•

Coolant leaks or damage to the deck face sealing surface. if coolant leaks are present, measure the surface
warpage as described under Cylinder Head Measurement within this Section.

•

Burrs or any defects that would degrade the sealing of a new secondary camshaft chain tensioner gasket.

•

Damage to any gasket surfaces.

•

Damage to any threaded bolt holes.

•

Burnt or eroded areas in the combustion chamber.

•

Cracks in the exhaust ports and combustion chambers.

•

External cracks in the water passages.

•

Restrictions in the intake or exhaust passages.

•

Restrictions in the cooling system passages.

•

Rusted, damaged or leaking core plugs.

4

If the cylinder head is cracked or damaged, it must be replaced. No welding or patching of the cylinder head is
recommended.