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 seal ant 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 fr om 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 cl ean the galleries until all debris is removed.
• Coolant leaks or damage to the deck face sealing surfac e. if coolant leaks are present, measure the surface
warpage as described under Cylinder Head M easurement within this Section.
• Burrs or any defects that would degrade the sealing of a new secondar y 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 r eplaced. No welding or patching of the cylinder head is
recommended.
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ISUZU KB P190 2007
Engine Mechanical – V6 Page 6A1–224
Page 6A1–224
Valve Guide Measurement
1 Measure the valve stem (1) to-guide (2) clearance.
Excessive valve stem-to-guide clearance may cause
excessive oil consumption and may also cause a
valve to break. Insufficient clearance will result in
noisy and sticky functioning of the valve and will
disturb the engine assembly smoothness.
2 Clamp a dial indicator to the cylinder head at the camshaft cover rail.
3 Locate the dial indicator so the movement of the valve
stem from side to side, crossways to the cylinder
head, will cause a direct mo vement of the indicator
stem. The dial indicator stem must contact the side of
the valve stem just above the valve guide.
4 Drop the valve head about 0.064 mm off the valve seat.
5 Use light pressure when moving the valve stem from side to side to obtain a clearance reading, refer to
5 Specifications .
• If the clearance for the valve is greater than
specified and a new st andard diameter valve
stem will not bring the clearance within
specifications, the valv e guide may be oversized
by 0.075 mm using the valve guide reamer, Tool
No. J 42096 or by 0.375 mm using the valve
guide reamer, Tool No. EN-46120. Two sizes of
oversized valve stems are available for service.
• Valve guide wear at the bottom 10 mm of the
valve guide is not significant enough to affect
normal operation.
• If over sizing the guide does not bring the
clearance within specif ications, replace the
cylinder head.
Figure 6A1 – 379
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ISUZU KB P190 2007
Engine Mechanical – V6 Page 6A1–225
Page 6A1–225
Valve Spring Inspection and Measurement
Inspection Procedure
1 Clean the valve springs in solvent.
Safety glasses must be worn when using
compressed air
2 Dry the valve springs with compressed air.
3 Inspect the valve springs for broken coils or coil ends.
Measurement Procedure
1 Use a commercially available valve spring tester to measure the valve spring tension, refer to
5 Specifications .
CAUTION
Do not use shims to increase spring load.
The use of shims can cause the valve spring
to bottom out before the camshaft lobe is at
peak lift.
2 If low valve spring load is found, replace the valve springs.
Figure 6A1 – 380
Valve and Seat Grinding
Valve Cleaning Procedure
CAUTION
Do not use a wire brush on any part of the
valve stem. The valve stem is chrome plated
to provide enhanced wear characteristics.
Wire brushing the stem could remove the
chrome plating.
1 Use soft bristle brush to clean any carbon build-up from the valve head.
2 Thoroughly clean the valve with solvent and wipe dry.
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ISUZU KB P190 2007
Engine Mechanical – V6 Page 6A1–229
Page 6A1–229
NOTE
• Clean any remaining lapping compound from
the valve and seat with solvent and
compressed air prior to final assembly.
• If fitting new valves, do not lap the valves
under any condition.
7 After obtaining the correct valve seat width in the cylinder head, measure the valve stem height, refer to Valve
Stem Height Measurement Pr ocedure in this Section.
8 If the valve stem height is acceptabl e, test the seats for concentricity, refer to Valve-to-Seat Concentricity
Measurement Procedure in this Section.
Valve Stem Height Measurement Procedure
CAUTION
To determine the valve stem height
measurement, measure from the valve
spring seat to the valve spring retainer.
1 Install the valve into the valve guide.
2 Ensure the valve is seated to the valve seat.
3 Install the valve stem oil seal.
4 Install the valve spring retainer and valve stem keys.
5 Measure the distance (1 ) between the cylinder head
to the bottom of the valve spring retainer, refer to
5 Specifications .
6 If the maximum height spec ification is exceeded, a
new valve should be installed and the valve stem
height re-measured.
Figure 6A1 – 387
CAUTION
Do not grind the valve stem tip. The tip of the
valve is hardened and grinding the tip will
eliminate the hardened surface causing
premature wear and possible engine damage.
CAUTION
Do not use shims to adjust valve stem height.
The use of shims will cause the valve spring
to bottom out before the camshaft lobe is at
peak lift and engine damage could result.
7 If the valve stem height still exceeds the maximum height specification, the cylinder head must be replaced.
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ISUZU KB P190 2007
Engine Mechanical – V6 Page 6A1–230
Page 6A1–230
Assemble
1 Install the cylinder head coolant threaded plugs (1)
and tighten to the correct torque specification.
Cylinder head thre aded plug .............................. 31.0 Nm
Figure 6A1 – 388
2 Install the cylinder head oil gallery expansion plugs (1).
Figure 6A1 – 389
CAUTION
• Never reuse a valve stem oil seal. Always
use new seals when assembling the
cylinder head.
• Force should only be applied to the valve
spring contact area of the new valve stem
oil seal during installation.
3 Fit the valve stem oil seal s onto the guides using Tool
No. EN-46116 (1).
4 Push and twist the valve stem oil seal into position on the valve guide until the s eal positively locks on the
guide using Tool No. EN-46116.
5 Lubricate the valve stem and valve guide ID with clean engine oil.
Figure 6A1 – 390
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ISUZU KB P190 2007
Engine Mechanical – V6 Page 6A1–231
Page 6A1–231
CAUTION
The valve stem oil seal must not come loose
from the valve guide when the valve (1) is
installed.
6 Insert the valve into the valve guide until it bottoms on
the valve seat.
Figure 6A1 – 391
7 Position the valve spring (2) on the spring seat (1).
8 Place the valve spring retainer onto the valve spring.
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.
Figure 6A1 – 392
9 Compress the valve spring using valve spring compressor Tool No. J-8062 and adaptor Tool No.
EN-46119.
CAUTION
Ensure correct directional placement of
valve collets (1) in Tool No. EN-46117 (2).
The valve collets must be installed with the
tapered end towards the valve stem seal.
Figure 6A1 – 393
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ISUZU KB P190 2007
Engine Mechanical – V6 Page 6A1–233
Page 6A1–233
Reinstall
Right-hand Side (Bank 1) Cylinder Head
The reinstallation procedure for the right-hand side cylinder head assembly is the reverse of the removal procedure,
noting the following:
1 Ensure all fasteners are tightened to the correct torque specification.
2 Using crankshaft rotation Tool No. EN-46111 (1), align the crankshaft sprocket timing mark (2) with the
indexing mark (3) on the oil pump housing.
Figure 6A1 – 396
3 Ensure the deck face is clean and the cylinder head locating pins are securely mounted in the cylinder
block deck face.
4 Install a new right-hand cylinder head gasket (1) using the deck face locating pins for retention.
Figure 6A1 – 397
5 Align the cylinder head with the locating pins.
6 Place the cylinder head in position on the deck face.
NOTE
Do not allow oil on the cylinder head bolt
bosses.
CAUTION
Do not reuse the old M11 cylinder head bolts
(1 to 8 inclusive).
7 Install new M11 cylinder head bolts (1) eight places and tighten in the sequence shown and to the correct
torque specification.
Figure 6A1 – 398
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ISUZU KB P190 2007