Isuzu KB P190. Manual - part 220

ENGINE MECHANICAL   6A – 75 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

2.  Measure the piston diameter. 

 

 

Piston Measuring Point 

mm (in)

4JA1T(L) 

4JA1TC 

78 (3.07) 

4JH1TC 70 

(2.76) 

 

 

Piston Grade (Service Part) 

mm (in)

AX 

92.949 - 92.964 

(3.6549 - 3.6600) 

4JA1T(L) 

4JA1TC 

CX 

92.965 - 92.980 

(3.6600 - 3.6606) 

AX 

95.359 - 95.374 

(3.7542 - 3.7548) 

4JH1TC 

CX 

95.375 - 95.390 

(3.7548 - 3.7555) 

 

 

Cylinder Liner and Piston Clearance 

mm (in)

4JA1T(L) 

4JA1TC 

0.041-0.071 (0.0016-0.0027) 

4JH1TC 0.047-0.065 

(0.0019-0.0026) 

 

NOTE: 

Cylinder liner kit clearances are preset. However, the 
cylinder liner installation procedure may result in 
slight decreases in cylinder liner clearances. Always 
measure the cylinder liner clearance after installation 
to be sure that it is correct. 

 

 

 

 

 

TAPPET AND PUSH ROD 

Visually inspect the tappet contact surfaces for pitting, 
cracking, and other abnormal conditions. The tappet must be 
replaced if any of these conditions are present. 

Refer to the illustration at the left. 

1. Normal 

contact 

2. Cracking 

3. Pitting 

4.  Irregular contact Uneven contact 

5.  Irregular contact One-sided contact 

 

NOTE: 

The tappet surfaces are spherical. Do not attempt to 
grind them with an oil stone or similar tool in an effort 
to repair the tappet. If the tappet is damaged, it must 
be replaced. 

 

 

 

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6A – 76  ENGINE MECHANICAL 

  

Tappet Outside Diameter 

Measure the tappet outside diameter with a micrometer. 

If the measured value is less than the specified limit, the tappet 
must be replaced. 

 

 

Tappet Outside Diameter mm 

(in)

Standard Limit 

12.97 - 12.99 

(0.510 - 0.511) 

12.95 (0.510) 

 

 

 

 

 

 

 

 

Tappet and Cylinder Body Clearance

 mm 

(in)

Standard Limit 

0.01 - 0.046

 

(0.0004 - 0.0018)

 

0.10 (0.004)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Push Rod Curvature 

1.  Lay the push rod on a surface plate. 

2.  Roll the push rod along the surface plate and measure the 

push rod curvature with a thickness gauge. 

If the measured value exceeds the specified limit, the push 
rod must be replaced. 

 

 

Pushrod Curvature 

mm (in)

Limit 

0.3 (0.012) 

 

3.  Visually inspect both ends of the push rod for excessive 

wear and damage. The push rod must be replaced if these 
conditions are discovered during inspection. 

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ENGINE MECHANICAL   6A – 77 

 

 

 

 

 

CAMSHAFT 

Visually inspect the journals, the cams, the oil pump drive gear, 
and the camshaft bearings for excessive wear and damage. 
The camshaft and the camshaft bearings must be replaced if 
these conditions are discovered during inspection. 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Camshaft Journal Diameter 

Use a micrometer to measure each camshaft journal diameter 
in two directions (1 and 2). If the measured value is less than 
the specified limit, the camshaft must be replaced. 

 

 

Camshaft Journal Diameter mm 

(in)

Standard Limit 

49.945 - 49.975 

(1.9663 - 1.9675) 

49.60 (1.953) 

 

 

 

  

 

 

 

 

 

 

 

 

 

 

 

 

 

Cam Height 

Measure the cam height (H) with a micrometer. If the 
measured value is less than the specified limit, the camshaft 
must be replaced. 

 

 

Cam Height  (H) 

mm (in)

Standard Limit 

42.016 (1.6542) 

41.65 (1.640) 

 

 

 

  

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Camshaft Run-Out 

1.  Mount the camshaft on V-blocks. 

2.  Measure the run-out with a dial indicator. 

If the measured value exceeds the specified limit, the 
camshaft must be replaced. 

 

 

Camshaft Run-Out  

mm (in)

Standard Limit 

0.02 (0.0008) 

0.10 (0.004) 

 

 

 

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6A – 78  ENGINE MECHANICAL 

 

Camshaft and Camshaft Bearing Clearance 

Use an inside dial indicator to measure the camshaft bearing 
inside diameter. 

 

 

Crankshaft Bearing Inside Diameter mm 

(in)

Standard Limit 

50.00 - 50.03 

(1.968 - 1.970) 

50.08 (1.972) 

If the clearance between the camshaft bearing inside diameter 
and the journal exceeds the specified limit, the camshaft 
bearing must be replaced. 

 

 

Camshaft Bearing Clearance 

mm (in)

Standard Limit 

0.055 (0.0022) 

0.12 (0.005) 

 

 

 

 

 

 

 

 

 

 

 

 

 

Camshaft Bearing Replacement 

Camshaft Bearing Removal 
1.  Remove the cylinder body plug plate. 

2.  Use the bearing replacer to remove the camshaft bearing.

Bearing Replacer: 5-8840-2038-0 

 

 

 

 

 

 

 

 

 

 

 

Camshaft Bearing Installation 
1.  Align the bearing oil holes with the cylinder body oil holes.

2.  Use the replacer to install the camshaft bearing. 

Bearing Replacer: 5-8840-2038-0 

 

 

 

 

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