Isuzu KB P190. Service manual — part 361
6A-84 ENGINE MECHANICAL (4JK1/4JJ1)
Manifold Fitting Face Warpage
mm (in)
Standard
0.05 (0.002) or less
Limit 0.20
(0.008)
Maximum Grinding Allowance
0.40 (0.016)
RTW56ASH017501
Exhaust Manifold Warpage
Use a straight edge and a feeler gauge to measure the
manifold cylinder head fitting face warpage.
If the measured values exceed the specified limit, the
manifold must be replaced.
Exhasut Manifold Warpage
mm (in)
Standard
0.05 (0.002) or less
Limit 0.20
(0.008)
027RY00002
Valve Stem Cap
Make the necessary part replacements.
If excessive wear or damage is discovered during
inspection.
Valve Stem Outside Diameter
Measure the valve stem diameter at three points.
If the measured value is less than the specified limit, the
valve and the valve guide must be replaced as a set.
Valve Stem Outside Diameter
mm (in)
Intake Valve
Exhaust Valve
Standard
6.955 – 6.970
(0.2738 – 0.2744)
6.939 – 6.949
(0.2732 – 0.2736)
Limit
6.935
(0.2730)
6.920
(0.2724)
011LX027
Valve Stem and Valve Guide Clearance
1. Measure the valve stem outside diameter.
Refer to the item “Valve Stem Outside Diameter”.
2. Use a caliper calibrator or a telescoping gauge to
measure the valve guide inside diameter.
If the measured values exceed the specified limit,
the valve and the valve guide must be replaced as
a set.
Valve Stem Clearance
mm (in)
Intake Valve
Exhaust Valve
Standard
0.039 – 0.071
(0.0015 – 0.0028)
0.064 – 0.096
(0.0025 – 0.0038)
Limit
0.200
(0.008)
0.250
(0.0098)
ENGINE MECHANICAL (4JK1/4JJ1) 6A-85
011RY00023
Valve Thickness
Measure the valve thickness.
If the measured value is less than the specified limit, the
valve and the valve guide must be replaced as a set.
Intake and Exhasut Valve Thickness
mm (in)
Standard 1.32
(0.052)
Limit 1.1
(0.043)
014RY00020
Valve Depression
1. Install the valve (1) to the cylinder head (2).
2. Use a depth gauge or a straight edge with steel
rule to measure the valve depression from the
cylinder head lower surface.
If the measured value exceeds the specified limit,
the valve seat insert must be replaced.
Valve Depression
mm (in)
Standard 1.8
(0.07)
Limit 2.5
(0.098)
014RY00021
Valve Contact Width
1. Check the valve contact faces for roughness and
unevenness. Make smooth the valve contact
surfaces.
2. Measure the valve contact width.
If the measured value exceeds the specified limit,
the valve seat insert must be replaced.
Valve Contact Width
mm (in)
Intake Exhaust
Standard
1.7 (0.067)
2.0 (0.079)
Limit
2.2 (0.087)
2.5 (0.098)
6A-86 ENGINE MECHANICAL (4JK1/4JJ1)
014RY00027
Repair of the seat surface
• Remove carbon from the surface of the valve
insert seat.
• Use a seat cutter to minimize the scratch and
other roughness (15/45/75 degree-blade), thereby
returning the contact width to the standard value.
LNW21BSH018201
Note:
Remove only scratches and roughness, and do not cut
the surface too much.
Use the free adjustment valve cutter pilot.
Do not let the valve cutter pilot waver inside the valve
guide.
Valve Seat Angle
Degree
45
LNW21BSH056101
• Attach compound in the valve insert seat.
• Insert the valve into the valve guide.
• Attach compound on the valve seat surface, rotate
the valve and hit it lightly to grind it, and confirm
that it has even contact all round.
Note:
Remove compound completely after grinding.
LNW21BSH031801
ENGINE MECHANICAL (4JK1/4JJ1) 6A-87
Remove the valve seat insert
• Arc-weld the entire inner diameter of the valve seat
insert.
• Cool the valve seat insert for two to three minutes.
Contraction due to cooling makes it easier to
remove the valve seat insert.
• Remove the valve seat insert, using a screw
driver . Be sure not to harm the cylinder head.
LNW21BSH056001
Legend
1. Arc-Weld
2. Valve Seat Insert
3. Screw
Driver
Install the valve seat insert
• Carefully place a washer (the outer diameter is
smaller than the valve seat insert) on the valve
seat insert.
• Use the press to apply pressure gradually on the
washer, thereby pushing the valve seat insert.
Note:
Do not apply too much pressure with the press. Attach
compound on the valve seat surface, rotate the valve
and hit it lightly to grind it, and confirm that it has even
contact all round.
LNW21BSH018601
Legend
1. Attach
Compound
2. Valve
Seat
3. Press
Reassembly
1. Install the oil seal.
• Install on the surface of the injection pipe insert.
• Hammer it in so that the seal does not incline.
Note:
Be sure not to harm the lip.
Special tool
Injection pipe oil seal installer: 5-8840-2820-0
RTW56ASH008801
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