RM38T0EC _51 Engine / Hybrid System _144958 M20F-FXS, M20G-FXS ENGINE MECHANICAL _0604255 CYLINDER HEAD G

M20F-FXS, M20G-FXS ENGINE MECHANICAL  CYLINDER HEAD  INSPECTION  


PROCEDURE

Hide 11101 1.INSPECT CYLINDER HEAD SUB-ASSEMBLY

a.

Using a precision straightedge and feeler gauge, measure the warpage of the contact surfaces where the cylinder head sub-assembly contacts the cylinder block sub-assembly, intake manifold and exhaust manifold.

A426808C01
3.823,0.271 4.135,0.427 0.313,0.156 10 false *a 3.833,1.813 4.146,1.969 0.313,0.156 10 false *b 3.833,2.698 4.146,2.854 0.313,0.156 10 false *c
*a Bottom Side *b Intake Manifold Side
*c Exhaust Manifold Side - -


Maximum Warpage:
Item Specified Condition
Bottom side 0.05 mm (0.00197 in.)
Intake manifold side 0.10 mm (0.00394 in.)
Exhaust manifold side 0.10 mm (0.00394 in.)


HINT:

If the warpage is more than the maximum, replace the cylinder head sub-assembly.



b.
A400449

Using a dye penetrant, check the intake ports, exhaust ports and cylinder head sub-assembly surface for cracks.

HINT:

If cracks are found, replace the cylinder head sub-assembly.



Hide 2.INSPECT COMPRESSION SPRING

a.

Intake Side:

i.
A400450

Using a vernier caliper, measure the free length of the compression spring.

Standard Free Length:

58.81 mm (2.32 in.)


HINT:

If the free length is not as specified, replace the compression spring.



ii.
A400451C03
1.635,0.208 1.948,0.406 0.313,0.198 10 false *a 0.948,1.302 1.26,1.5 0.313,0.198 10 false *b
*a Deviation
*b 37 mm (1.46 in.)


Using a steel square, measure the deviation of the compression spring.

Maximum Deviation (Reference):

1.0 mm (0.0394 in.)


HINT:

If the deviation is more than the maximum, replace the compression spring.




b.

Exhaust Side:

i.
A400450

Using a vernier caliper, measure the free length of the compression spring.

Standard Free Length:

58.81 mm (2.32 in.)


HINT:

If the free length is not as specified, replace the compression spring.



ii.
A400451C03
1.635,0.208 1.948,0.406 0.313,0.198 10 false *a 0.948,1.302 1.26,1.5 0.313,0.198 10 false *b
*a Deviation
*b 37 mm (1.46 in.)


Using a steel square, measure the deviation of the compression spring.

Maximum Deviation (Reference):

1.0 mm (0.0394 in.)


HINT:

If the deviation is more than the maximum, replace the compression spring.




Hide 13711 3.INSPECT INTAKE VALVE

a.
A400452

Using a micrometer, measure the diameter of the valve stem.

Standard Valve Stem Diameter:

5.470 to 5.485 mm (0.215 to 0.216 in.)


HINT:

If the valve stem diameter is not as specified, check the intake valve guide bush oil clearance.



b.
A400453C01
0.969,1.396 1.281,1.594 0.313,0.198 10 false *a
*a Margin Thickness


Using a vernier caliper, measure the valve head margin thickness.

Standard Margin Thickness:

1.0 mm (0.0394 in.)


Minimum Margin Thickness:

0.5 mm (0.0197 in.)


HINT:

If the margin thickness is less than the minimum, replace the intake valve.



c.
A400454C01
2.479,1.063 2.792,1.26 0.313,0.198 10 false *a
*a Overall Length


Using a vernier caliper, measure the overall length of the intake valve.

Standard Overall Length:

102.45 mm (4.03 in.)


Minimum Overall Length:

101.95 mm (4.01 in.)


HINT:

If the overall length is less than the minimum, replace the intake valve.



Hide 13715 4.INSPECT EXHAUST VALVE

a.
A470347

Using a micrometer, measure the diameter of the valve stem.

Standard Valve Stem Diameter:

5.465 to 5.480 mm (0.215 to 0.216 in.)


HINT:

If the valve stem diameter is not as specified, check the exhaust valve guide bush oil clearance.



b.
A400456C01
0.969,1.594 1.281,1.792 0.313,0.198 10 false *a
*a Margin Thickness


Using a vernier caliper, measure the valve head margin thickness.

Standard Margin Thickness:

1.0 mm (0.0394 in.)


Minimum Margin Thickness:

0.5 mm (0.0197 in.)


HINT:

If the margin thickness is less than the minimum, replace the exhaust valve.



c.
A400457C01
2.385,1.125 2.698,1.323 0.313,0.198 10 false *a
*a Overall Length


Using a vernier caliper, measure the overall length of the exhaust valve.

Standard Overall Length:

106.4 mm (4.19 in.)


Minimum Overall Length:

105.9 mm (4.17 in.)


HINT:

If the overall length is less than the minimum, replace the exhaust valve.



Hide 5.INSPECT VALVE GUIDE BUSH OIL CLEARANCE

a.
A426809

Using a caliper gauge, measure the inside diameter of the valve guide bush.

Standard Valve Guide Bush Inside Diameter:

5.51 to 5.53 mm (0.217 to 0.218 in.)



b.

Subtract the valve stem diameter measurement from the valve guide bush inside diameter measurement.

Standard Oil Clearance:
Item Specified Condition
Intake Side 0.025 to 0.060 mm (0.000984 to 0.00236 in.)
Exhaust Side 0.030 to 0.065 mm (0.00118 to 0.00256 in.)


Maximum Oil Clearance:
Item Specified Condition
Intake Side 0.08 mm (0.00315 in.)
Exhaust Side 0.10 mm (0.00394 in.)


HINT:
·

Oil clearance = Valve guide bush inside - Valve stem diameter

·

If the oil clearance is more than the maximum, replace the valve and valve guide bush.




Hide 6.INSPECT INTAKE VALVE SEAT

a.

Apply a light coat of Prussian blue to the valve face.


b.
A426810C01
1.5,1.531 1.813,1.688 0.313,0.156 10 false *a
*a Width


Lightly press the valve face against the intake valve seat.

NOTICE:

Do not rotate the valve while pressing it.



c.

Check the valve face and intake valve seat by using the following procedure:

i.

If Prussian blue appears 360° around the entire intake valve face, the valve face is concentric.

HINT:

If the valve face is not concentric, replace the intake valve.



ii.

If Prussian blue appears 360° around the entire intake valve seat, the intake valve seat and valve face are concentric.

HINT:

If the valve face is not concentric, replace the cylinder head sub-assembly.



iii.

Measure the width of the contact area of the intake valve seat and valve face.

Standard Width:

1.0 to 1.4 mm (0.0394 to 0.0551 in.)




Hide 7.INSPECT EXHAUST VALVE SEAT

a.

Apply a light coat of Prussian blue to the valve face.


b.
A426811C01
1.406,1.708 1.625,1.917 0.219,0.208 10 true *a
*a Width


Lightly press the valve face against the exhaust valve seat.

NOTICE:

Do not rotate the valve while pressing it.



c.

Check the valve face and exhaust valve seat by using the following procedure:

i.

If Prussian blue appears 360° around the entire exhaust valve face, the valve face is concentric.

HINT:

If the valve face is not concentric, replace the exhaust valve.



ii.

If Prussian blue appears 360° around the entire exhaust valve seat, the exhaust valve seat and valve face are concentric.

HINT:

If the valve face is not concentric, resurface the exhaust valve seat.



iii.

Measure the width of the contact area of the exhaust valve seat and valve face.

Standard Width:

1.2 to 1.6 mm (0.0472 to 0.0630 in.)




Hide 8.INSPECT CAMSHAFT THRUST CLEARANCE

a.

Clean the No. 1 camshaft bearing cap, No. 2 camshaft bearing cap, 2 No. 3 camshaft bearing caps, No. 4 camshaft bearing cap, camshaft housing sub-assembly and camshaft journals.


b.

Place the intake camshaft sub-assembly and exhaust camshaft sub-assembly on the camshaft housing sub-assembly.


c.

Install the camshaft bearing caps.

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d.

Install the camshaft housing sub-assembly.

Click hereEngine / Hybrid System>M20F-FXS, M20G-FXS (ENGINE MECHANICAL)>ENGINE UNIT>REASSEMBLY


e.
A426812

Using a dial indicator, measure the thrust clearance while moving the intake camshaft sub-assembly and exhaust camshaft sub-assembly back and forth.

Standard Thrust Clearance:
Item Specified Condition
Intake camshaft sub-assembly 0.04 to 0.17 mm (0.00157 to 0.00669 in.)
Exhaust camshaft sub-assembly 0.04 to 0.17 mm (0.00157 to 0.00669 in.)


Maximum Thrust Clearance:
Item Specified Condition
Intake camshaft sub-assembly 0.22 mm (0.00866 in.)
Exhaust camshaft sub-assembly 0.22 mm (0.00866 in.)


HINT:

If the thrust clearance is more than the maximum, replace the camshaft housing sub-assembly. If the thrust surface is damaged, replace the camshaft.