Isuzu KB P190. 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) 

 
 

 

 

 

 

 

 

 

 

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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 

 

 
 
 

 

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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) 

 
 

 
 
 
 

 

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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. 

 

 
 

 

 

 

 

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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 

 

 

 

 

 
 

 

 

 

 

 

 

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•  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. 

 

 

 

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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. 

 

 

 

 
 

 

 

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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 

 

 

 

 

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