Kia Forte: Cylinder Head Inspection
Cylinder Head
1. |
Inspect for flatness.
Using a precision straight edge and feeler gauge, measure the
contacting surface of the cylinder block and the manifolds for warpage.
Flatness of cylinder head gasket
surface:
Less than 0.05 mm (0.0020 in.) for total area
Less than 0.02 mm (0.0008 in.) for a section of 100 mm
(3.9370 in.) X 100 mm (3.9370 in.)
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Flatness of manifold mounting
surface:
Less than 0.10 mm (0.0039 in.)
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2. |
Inspect for cracks.
Check the combustion chamber, intake ports, exhaust ports and
cylinder block surface for cracks. If cracked, replace the cylinder
head.
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Valve And Valve Spring
1. |
Inspect valve stems and valve guides.
(1) |
Using a caliper gauge, measure the inside diameter of
the valve guide.
Valve guide inner diameter
Intake: 5.500 ~ 5.512 mm (0.21654 ~ 0.21701 in.)
Exhaust: 5.500 ~ 5.512 mm (0.21654 ~ 0.21701 in.)
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(2) |
Using a micrometer, measure the diameter of the valve
stem.
Valve stem outer diameter
Intake: 5.465 ~ 5.480 mm (0.21516 ~ 0.21575 in.)
Exhaust: 5.458 ~ 5.470 mm (0.21488 ~ 0.21535 in.)
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(3) |
Subtract the valve stem diameter measurement from the
valve guide inside diameter measurement.
If the clearance is greater than specification, replace
the valve or the cylinder head.
Valve stem-to-guide
clearance
[Standard]
Intake : 0.020 ~ 0.047 mm (0.00079 ~ 0.00185 in.)
Exhaust : 0.030 ~ 0.054 mm (0.00118 ~ 0.00213
in.)
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2. |
Inspect the valves.
(1) |
Check the valve is ground to the correct valve face angle.
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(2) |
Check that the surface of the valve for wear.
If the valve face is worn, replace the valve.
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(3) |
Check the valve head margin thickness.
If the margin thickness is less than specification, replace
the valve.
Margin
[Standard]
Intake: 1.30 mm (0.0512 in.)
Exhaust: 1.26 mm (0.0496 in.)
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(4) |
Check the valve length.
Valve length
[Standard]
Intake: 102.22 mm (4.0244 in.)
Exhaust: 104.04 mm (4.0961 in.)
[Limit]
Intake: 101.97 mm (4.0146 in.)
Exhaust: 103.79 mm (4.0862 in.)
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(5) |
Check the surface of the valve stem tip for wear.
If the valve stem tip is worn, replace the valve.
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3. |
Inspect the valve seats and the valve guides.
(1) |
Check the valve seat for evidence of overheating and improper
contact with the valve face.
If the valve seat is worn, replace the cylinder head.
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(2) |
Check the valve guide for wear.If the valve guide is worn,
replace the cylinder head.
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4. |
Inspect the valve springs.
(1) |
Using a steel square, measure the out-of-square of valve
spring.
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(2) |
Using a vernier calipers, measure the free length of valve
spring.
If the free length is not as specified, replace the valve
spring.
Valve spring
[Standard]
Free height: 45.93 mm (1.8083 in.)
Out-of-square : Less than 1.5°
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Hydraulic Lash Adjuster (HLA)
With the HLA filled with engine oil, hold A and press B by hand.
If B moves, replace the HLA.
Problem
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Possible cause
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Action
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1. Temporary noise when starting a cold engine
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Normal
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This noise will disappear after the oil in the engine reaches
the normal pressure.
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2. Continuous noise when the engine is started after parking
more than 48 hours
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Oil leakage of the high pressure chamber on the HLA, allowing
air to get in
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Noise will disappear within 15 minutes when engine runs at 2000-3000
rpm.
If it doesn’t disappear, refer to step 7 below.
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3. Continuous noise when the engine is first started after rebuilding
cylinder head
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Insufficient oil in cylinder head oil gallery
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4. Continuous noise when the engine is started after excessively
cranking the engine by the starter motor or band
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Oil leakage of the high-pressure chamber in the HLA, allowing
air to get in
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Insufficient oil in the HLA
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5. Continuous noise when the engine is running after changing
the HLA
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Do not run engine at a speed higher than 3000 rpm, as
this may damage the HLA.
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6. Continuous noise during idle after high engine speed
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Engine oil level too high or too low
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Drain or add oil as necessary.
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Excessive amount of air in the oil at high engine speed
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Check oil supply system.
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Deteriorated oil
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Check oil quality.
If deteriorated, replace with specified type.
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7. Noise continues for more than 15 minutes
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Low oil pressure
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Check oil pressure and oil supply system of each part of engine.
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Faulty HLA
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Remove the cylinder head cover and press HLA down by hand.
If it moves, replace the HLA.
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Identify, valves and valve springs as they are removed so that
each item can be reinstalled in its original position.
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Thoroughly clean all parts to be assembled.
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