Isuzu KB P190. Manual - part 663

Engine Mechanical – V6 

Page 6A1–173 

 

1 

Grind the valve seats (2) to the correct angle 
specification, refer to 5 

Specifications. 

2 

Using the correct angle specification, grind and 
relieve the valve seats (1) to correctly position the 
valve seating surface (2) to the valve. 

3 

Using the correct angle specification, grind and 
undercut the valve seats (3) to narrow the valve seat 
widths to the specifications, refer to 5  Specifications.

4 

If the original valve is being used, grind the valve to 
the specifications, refer to 5  Specifications. 
Measure the valve margin again after grinding, refer 
to Valve Margin Measurement Procedure in this 
Section. Replace the valve if the margin is out of 
specification. New valves do not require grinding. 

5 

When grinding the valves and seats, grind off as little 
material as possible. Cutting valve seat results in 
lowering the valve spring pressure. 

6 

Install the valve in the cylinder head. 

Figure 6A1 – 296 

CAUTION

 

If using refaced valves, lap the valves into the 
seats with a fine grinding compound. The 
refacing and reseating operations should 
leave the refinished surfaces smooth and true 
so that minimal lapping is required. Excessive 
lapping will groove the valve face and prevent 
a good seat when hot. 

N O T E  

•  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 Procedure in this Section. 

8 

If the valve stem height is acceptable, test the seats for concentricity, refer to Valve-to-Seat Concentricity 
Measurement Procedure in this Section. 

Engine Mechanical – V6 

Page 6A1–174 

 

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 specification is exceeded, a 
new valve should be installed and the valve stem 
height re-measured. 

Figure 6A1 – 297 

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. 

Assemble 

1 

Install the cylinder head coolant threaded plugs (1) 
and tighten to the correct torque specification.  

 

 

 

 

Cylinder head threaded plug ..............................31.0 Nm 

 

Figure 6A1 – 298 

Engine Mechanical – V6 

Page 6A1–175 

 

2 

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

Figure 6A1 – 299 

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 seals 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 seal 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 – 300 

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 – 301 

Engine Mechanical – V6 

Page 6A1–176 

 

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 – 302 

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 – 303 

10 

With the spring compressed, install the valve collets 
into Tool No. EN 46117. 

 

 

 

 

Figure 6A1 – 304