2004 ISUZU TF SERIES engine

ENGINE MECHANICAL 6A – 67













Valve Spring Free Height
Use a vernier caliper to measure the valve spring free height.
If the measured value is less than the specified limit, the valve
spring must be replaced.


Spring Free Height mm (in)
Standard Limit
4JA1T (L)
4JA1TC,
4JH1TC Single spring 48.0 (1.89) 47.1 (1.85)
















Valve Spring Squareness
Use a surface plate and a square to measure the valve spring
squareness.
If the measured value exceeds the specified limit, the valve
spring must be replaced.


Spring Squareness mm (in)
Limit
4JA1T (L)
4JA1TC,
4JH1TC Single spring 1.7 (0.070)

















Valve Spring Tension
Use a spring tester to measure the valve spring tension.
If the measured value is less than the specified limit, the valve
spring must be replaced.


Valve Spring Tension N (kg/lb)
Compressed
Height Standard Limit
4JA1T (L)
4JA1TC,
4JH1TCSingle
spring38.9mm
(1.53in) 296.0
(30.2/66.4) 257.7
(26.3/57.9)

011LX024
014RY00025
011LX026

6A – 68 ENGINE MECHANICAL






























ROCKER ARM SHAFT AND ROCKER ARM
Rocker Arm Shaft Run-Out
1. Place the rocker arm shaft on a V-block.
2. Use a dial indicator to measure the rocker arm shaft
central portion run-out.
If the run-out is very slight, correct the rocker arm shaft
run-out with a bench press. The rocker arm must be at cold
condition.
If the measured rocker arm shaft run-out exceeds the
specified limit, the rocker arm shaft must be replaced.


Rocker Arm Shaft Run-Out mm (in)
Limit
0.3 (0.012)
















Rocker Arm Shaft Outside Diameter
Use a micrometer to measure the rocker arm fitting portion
outside diameter.
If the measured value is less than the specified limit, the rocker
arm shaft must be replaced.


Rocker Arm Shaft Outside Diameter mm (in)
Standard Limit
18.98–19.00 (0.747–0.748) 18.90 (0.744)












Rocker Arm Shaft and Rocker Arm Clearance
1. Use either a vernier caliper or a dial indicator to measure
the rocker arm inside diameter.


Rocker Arm Inside Diameter mm (in)
Standard Limit
19.010–19.030
(0.748–0.749) 19.100 (0.752)









2. Measure the rocker arm shaft outside diameter.
If the measured value exceeds the specified limit, replace
either the rocker arm or the rocker arm shaft.


Rocker Arm Shaft and Rocker Arm Clearance mm (in)
Standard Limit
0.01–0.05
(0.0004–0.0020) 0.20 (0.008)
015LX009
014RY00024015LX008

ENGINE MECHANICAL 6A – 69
3. Check that the rocker arm oil port is free of obstructions.
If necessary, use compressed air to clean the rocker arm
oil port.




Rocker Arm Correction
Inspect the rocker arm valve stem contact surfaces for step
wear (1) and scoring (2).
If the contact surfaces have light step wear or scoring, they
may be honed with an oil stone.
If the step wear or scoring is severe, the rocker arm must be
replaced.



CYLINDER BODY
Cylinder Body Upper Face Warpage
1. Remove the cylinder body dowel.
2. Remove the cylinder liner.
Refer to "Cylinder Liner Replacement".
















3. Use a straight edge (1) and a feeler gauge (2) to measure
the four sides and the two diagonals of the cylinder body
upper face.
If the measured values exceeds the limit, the cylinder body
must be replaced.


Cylinder Body Upper Face Warpage mm (in)
Standard Limit
0.05 (0.002) or less 0.20 (0.008)


Cylinder Body Height (H) (Reference) mm (in)
Standard
4JA1T(L), 4JA1TC : 244.945-245.055 (9.6435-9.6478)
4JH1TC : 269.945-270.055 (10.6277-10.6320)
4. Reinstall the cylinder liner.
Refer to "Cylinder Liner Replacement".
5. Reinstall the cylinder body dowel.


014RY00024
012R100001
012RY00009014RY00023

6A – 70 ENGINE MECHANICAL





















Cylinder Liner Bore Measurement
Use a cylinder indicator to measure the cylinder bore at
measuring point (1) in the thrust (2-2) and axial (3-3) directions
of the crankshaft.
Measuring Point (1): 20 mm (0.79 in)
If the measured value exceeds the specified limit, the cylinder
liner must be replaced.


Cylinder Liner Bore mm (in)
Standard Limit
4JA1T(L), 4JA1TC 93.00 (3.6614) 93.08 (3.6646)
4JH1TC 95.40 (3.7559) 95.48 (3.7590)
NOTE:
The inside of the dry type cylinder liner is chrome
plated. It cannot be rebored or honed.
If the inside of the cylinder liner is scored or
scorched, the cylinder liner must be replaced.




















Cylinder Liner Projection Inspection
1. Hold a straight edge along the top edge of the cylinder liner
to be measured.
2. Use a feeler gauge to measure each cylinder liner
projection.


Cylinder Liner Projection mm (in)
Standard
0-0.1 (0-0.004)
The difference in the cylinder liner projection height
between any two adjacent cylinders must not exceed 0.03
mm (0.0012 in).













Cylinder Liner Replacement
Cylinder Liner Removal
1. Insert the cylinder liner remover (1) into the cylinder body
(from the lower side of the cylinder body) until it makes firm
contact with the cylinder liner.
Cylinder Liner Remover : 5-8840-2039-0 (4JA1L/TC)
: 5-8840-2304-0 (4JH1TC)
2. Use a bench press (2) to slowly force the cylinder liner
from the cylinder body.


NOTE:
Take care not to damage the cylinder body upper face
during the cylinder liner removal procedure.
3. Measure the cylinder body upper face warpage.
Refer to "Cylinder Body Upper Face Warpage".
012RY00010
012LX016
012RY00012

ENGINE MECHANICAL 6A – 71











Cylinder Liner Grade Selection
Subtract the average cylinder body bore from the average
cylinder liner outside diameter to obtain the fitting interference.


Fitting Interference mm (in)
Standard
-0.0010*-0.019 (-0.00004*-0.0007)
* A minus (-) value indicates that the cylinder body bore is
smaller than the liner outside diameter.



Cylinder Body Bore Measurement
1. Take measurements at measuring point (1) across
positions 1-1 and 2-2.
Measuring Point (1):
4JA1T(L), 4JA1TC : 13,48,83,118,153 mm
(0.51,1.89,3.27,4.65,6.02 in)
4JH1TC : 18,53,88,123,158 mm (0.71,2.09,3.46,4.84,6.22
in)





Cylinder Liner Grade Selection and Standard
Fitting Interference
Accurately measured fitting interference and proper cylinder
liner grade selection are extremely important.
If the cylinder liner fitting interference is too small, engine
cooling efficiency will be adversely affected.
If the cylinder liner fitting interference is too large, it will be
difficult to insert the cylinder liner into the cylinder body.
012RY00013
012RY00014
012R300001

6A – 72 ENGINE MECHANICAL


012RY00022
A mark was stamped on the upper side of the cylinder block
during production to indicate the correct liner.
The liner grade (i.e.1.2.3.4) is indicated in metal stamp.



Cylinder Liner Grade
4JA1T (L), 4JA1TC mm (in)
Liner
Outside
Grade Cylinder Body
Bore Diameter Liner Outside
Diameter Liner Bore
Grade Service Liner Bore Measurement
AX 93.035-93.050 (3.6628-3.6634) 1 95.001-95.010
(3.7402-3.7405) 95.011-95.020
(3.7406-3.7409)
CX 93.051-93.066 (3.6634-3.6640)
AX 93.035-93.050 (3.6628-3.6634) 2 95.011-95.020
(3.7406-3.7409) 95.021-95.030
(3.7410-3.7413)
CX 93.051-93.066 (3.6634-3.6640)
AX 95.035-93.050 (3.6628-3.6634) 3 95.021-95.030
(3.7410-3.7413) 95.031-95.040
(3.7414-3.7417)
CX 93.051-93.066 (3.6634-3.6640)
AX 93.035-93.050 (3.6628-3.6634) 4 95.031-95.040
(3.7414-3.7417) 95.041-95.050
(3.7418-3.7421)
CX 93.051-93.066 (3.6634-3.6640)
4JH1TC mm (in)
Liner
Outside
Grade Cylinder Body
Bore Diameter Liner Outside
Diameter Liner Bore
Grade Service Liner Bore Measurement
AX 95.435-95.450 (3.7573-3.7579) 1 97.001-97.010
(3.8189-3.8193) 97.011-97.020
(3.8193-3.8197)
CX 95.451-95.466 (3.7579-3.7585)
AX 95.435-95.450 (3.7573-3.7579) 2 97.011-97.020
(3.8193-3.8197) 97.021-97.030
(3.8197-3.8200)
CX 95.451-95.466 (3.7579-3.7585)
AX 95.435-95.450 (3.7573-3.7579) 3 97.021-97.030
(3.8197-3.8200) 97.031-97.040
(3.8200-3.8205)
CX 95.451-95.466 (3.7579-3.7585)
AX 95.435-95.450 (3.7573-3.7579) 4 97.031-97.040
(3.8200-3.8205) 97.041-97.050
(3.8205-3.8209)
CX 95.451-95.466 (3.7579-3.7585)

ENGINE MECHANICAL 6A – 73






Cylinder Liner Installation
1. Cylinder Liner Installation Using The Special Tool
1. Use new kerosene or diesel oil to thoroughly clean the
cylinder liners and bores.
2. Use compressed air to blow-dry the cylinder liner and
bore surfaces.

NOTE:
All foreign material must be carefully removed from
the cylinder liner and the cylinder bore before
installation.

3. Insert the cylinder liner (1) into the cylinder body (2)
from the top of the cylinder body.










4. Set the cylinder liner installer (3) to the top of the
cylinder liner.
Cylinder Liner Installer : 5-8840-2040-0 (4JA1L/TC)
: 5-8840-2313-0 (4JH1TC)
5. (3) is directly beneath the bench press shaft center (4).

NOTE:
Check that the cylinder liner is set perpendicular to
the bench press and that there is no wobble.

6. Use the bench press to apply a seating force of 4,900
N (500 kg/1,100 Ib) to the cylinder liner.
7. Apply a force of 24,500 N (2,500 kg/5,500 Ib) to fully
seat the cylinder liner.
8. After installing the cylinder liner, measure the cylinder
liner projection.
Refer to "Cylinder Liner Projection Inspection".

012RY00017
012RY00018

6A – 74 ENGINE MECHANICAL










Piston Grade Selection
Measure the cylinder liner bore after installing the cylinder liner.
Then select the appropriate piston grade for the installed
cylinder liner.
1. Measure the cylinder liner bore.
Refer to "Cylinder Liner Bore Measurement"


Cylinder Liner Bore (Service Part) Grade mm (in)
Grade Bore measurement
AX 93.035-95.050
(3.6628-3.6634) 4JA1T(L)
4JA1TC
CX 93.051-95.066
(3.6634-3.6640)
AX 95.435-95.450
(3.7573-3.7579)
4JH1TC
CX 95.451-95.466
(3.7579-3.7585)

NOTE:
It is most important that the correct piston grade be
used. Failure to select the correct piston grade will
result in engine failure. Always measure the cylinder
bore and select the correct piston grade.