Kia Picanto: Cylinder Head Assembly / Cylinder Head

Kia Picanto JA 2017-2024 Service & Repair Manual / Engine Mechanical System / Cylinder Head Assembly / Cylinder Head

Repair procedures

Removal

•	Use fender covers to avoid damaging painted surfaces.

•	To avoid damaging the cylinder head, wait until the engine coolant temperature drops below normal temperature (20°C [68°F]) before removing it.

•	When handling a metal gasket, be careful not to fold the gasket or damage the contacting surface of the gasket.

•	To avoid damage, unplug the wiring connectors carefully while holding the connector portion.

•	Mark all wiring and hoses to avoid misconnection.

•	Turn the crankshaft pulley so that the No. 1 piston is at top dead center.

1.	Remove the engine room under cover. (Refer to Engine and Transaxle Assembly - "Engine Room Under Cover")

2.	Drain the coolant. (Refer to Cooling System - Coolant")

3.	Remove the intake manifold. (Refer to Intake and Exhaust System - "Intake Manifold")

4.	Remove the turbo manifold module. (Refer to Intake and Exhaust System - "Turbo Manifold Module")

5.	Remove the water temperature control assembly. (Refer to Cooling System - "Water Temperature Control Assembly")

6.	Remove the vacuum pump. (Refer to Cylinder Head Assembly - "Vacuum Pump")

7.	Remove the cylinder head cover. (Refer to Cylinder Head Assembly - "Cylinder Head Cover")

8.	Remove the delivery pipe. (Refer to Engine Control / Fuel System - "Delivery Pipe")

9.	Remove the timing chain. (Refer to Timing System - “Timing Chain”)

10.	Remove the camshaft. (Refer to Cylinder Head Assembly - "Camshaft" )

11.	Remove the intake and exhaust oil control valve (OCV). (Refer to Engine Control / Fuel System - "CVVT Oil Control Valve (OCV)")

12.	Remove the camshaft position sensor (CMPS). (Refer to Engine Control / Fuel System - "Camshaft Position Sensor (CMPS)")

13.

Remove the cylinder head.

(1)

Using triple square wrench, uniformly loosen and remove the 8 cylinder head bolts, in several passes, in the sequence shown. Remove the 8 cylinder head bolts and plate washers.

Head warpage or cracking could result from removing bolts in an incorrect order.

(2)

Lift the cylinder head (A) from the dowels on the cylinder block and place the cylinder head on wooden blocks on a bench.

Be careful not to damage the contacting surfaces of the cylinder head and cylinder block.

(3)	Remove the cylinder head gasket (B).

Disassembly

Identify MLA (Mechanical Lash Adjuster), valves, valve springs as they are removed so that each item can be reinstalled in its original position.

1.	Remove the mechanical lash adjusters (MLA) (A).

Remove the valves.

(1)	Using the SST (09222-3K000, 09222-3K100), press the valve spring and remove retainer lock.

(2)	Remove the spring retainer.

(3)	Remove the valve spring.

(4)	Remove the valve.

(5)

Using the SST (09222-29000), remove the valve stem seal.

Do not reuse old valve stem seals.

Inspection

Cylinder Head

Inspect for flatness.

Using a precision straight edge and feeler gauge, measure the surface contacting cylinder block and inspect the manifolds for warpage.

If the flatness is greater than maximum, replace the cylinder head.

Flatness of cylinder head gasket surface

Standard : Less than 0.05 mm (0.0020 in)

Less than 0.02 mm (0.0008 in) / 100x100

Flatness of manifold gasket surface

Standard : Less than 0.1 mm (0.0039 in)

2.	Inspect for cracks. Check the combustion chamber, intake ports, exhaust ports and cylinder block surface for cracks. If cracked, replace the cylinder head.

Valve And Valve Spring

Inspect valve stems and valve guides.

(1)

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

Valve guide I.D.

Intake / Exhaust :

5.500 - 5.512 mm (0.2165 - 0.2170 in)

(2)

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

Valve stem O.D.

Intake : 5.465 - 5.480 mm ( 0.2151 - 0.2157 in)

Exhaust : 5.448 - 5.460 mm (0.2144 - 0.2149 in)

(3)

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

Valve stem-to-guide clearance

Intake : 0.020 - 0.047 mm (0.00078 - 0.00185 in)

Exhaust :0.040 - 0.064 mm (0.00157 - 0.00251 in)

Inspect valves.

(1)

Check that the valve is ground to the correct valve face angle.

Valve face angle :

Intake/Exhaust : 45.25° - 45.75°

(2)	Check the surface of the valve for wear. If the valve face is worn, replace the valve.

(3)

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

Margin

Intake : 1.5 mm (0.0590 in)

Exhaust : 1.75 mm (0.0688 in)

(4)

Check the valve length.

Length

Intake : 92.85 mm (3.6555 in)

Exhaust : 93.37 mm (3.6759 in)

(5)	Check the surface of the valve stem tip for wear. If the valve stem tip is worn, replace the valve.

Inspect valve seats.

(1)	Check the valve seat for evidence of overheating and improper contact with the valve face. If the valve seat is worn, replace cylinder head.

(2)	Before reconditioning the seat, check the valve guide for wear. If the valve guide is worn, replace cylinder head.

(3)

Recondition the valve seat with a valve seat grinder or cutter. The valve seat contact width should be within specifications and centered on the valve face.

Valve seat contact width :

Intake : 0.85 - 1.15 mm ( 0.0334 - 0.0452 in)

Exhaust : 1.35 - 1.65 mm (0.0531 - 0.0649 in)

Valve seat angle :

Intake / Exhaust : 44.75° - 45.10°

Inspect valve springs.

(1)	Using a steel square, measure the out-of-square of the valve spring.

(2)

Using vernier calipers, measure the free length of the valve spring.

Valve spring

Free height : 47.9 mm (1.8858 in)

Out of square : 1.5° (MAX)

MLA (Mechanical Lash Adjuster)

Inspect the MLA.

Using a micrometer, measure the MLA outside diameter.

MLA outer diameter

Intake/Exhaust :

27.964 - 27.980 mm (1.1010 - 1.1016 in)

Using a caliper gauge, measure MLA tappet bore inner diameter of cylinder head.

Tappet bore inner diameter

Intake/Exhaust :

28.000 - 28.025 mm (1.1024 - 1.1033 in)

Subtract MLA outside diameter measurement from tappet bore inside diameter measurement.

MLA to tappet bore clearance

[Limit]

Intake/Exhaust :

0.020 - 0.061 mm (0.0008 - 0.0024 in)

Reassembly

•	Thoroughly clean all parts to be assembled.

•	Before installing the parts, apply fresh engine oil to all sliding and rotating surfaces.

Install the valves.

(1)

Using the SST (09222-1S100), push in a new valve stem seal.

•	Do not reuse old valve stem seals.

•	Incorrect installation of the seal could result in oil leakage past the valve guides.

(2)

Install the valve, valve spring and spring retainer.

Place the valve springs so that the cone shape side faces the retainer above it.

(3)	Using the SST (09222 - 3K000, 09222-3K100), compress the spring and install the retainer locks. After installing the valves, ensure that the retainer locks are correctly in place before releasing the valve spring compressor.

(4)	Lightly tap the end of each valve stem two or three times with the wooden handle of a hammer to ensure proper seating of the valve and retainer lock.

Install the mechanical lash adjuster (A).

MLA can be reinstalled in its original position.

However, the valve lash clearances must be rechecked and adjusted accordingly before the cylinder head is installed onto the cylinder block.

Installation

•	Thoroughly clean all parts to be assembled.

•	Always use a new cylinder head and manifold gasket.

•	Always use new cylinder head bolts. Cylinder head bolts are torque-to-yield bolts designed to be permanently elongated beyond the state of elasticity when torqued, so if the bolts are removed and reused, it may cause the bolts to break or fail to maintain clamping force.

•	The cylinder head gasket is a metal gasket. Be careful not to bend it.

•	Rotate the crankshaft, and set the No.1 piston at TDC.

Install the cylinder head gasket.

(1)	The sealant locations on cylinder head gasket, cylinder block and timing chain lower case must be free of engine oil and etc.

(2)

Before installing the cylinder head gasket, apply sealant on the upper surface of the cylinder block and reassemble the gasket within five minutes.

Bead width : 2.0 - 3.0 mm (0.08 - 0.12 in.)

(3)

Install the cylinder head gasket (A) on the cylinder block.

Install in the correct direction.

(4)

After installing the cylinder head gasket on the cylinder block, apply sealant on the upper surface of the cylinder head gasket and reassemble in five minutes.

Bead width : 2.0 - 3.0 mm (0.08 - 0.12 in.)

Sealant : TB1217H or LOCTITE 5900H

(5)	Remove the extruded sealant after assembling the cylinder head assembly.

Install the cylinder head assembly.

(1)	Carefully place the cylinder head (A) so as not to damage the gasket.

(2)

Tighten the cylinder head bolts and plate washers, in several passes, in the sequence shown.

Tightening torque :

12.7 - 16.7 N·m (1.3 - 1.7 kgf·m, 9.4 - 12.3 lb·ft) + 90 - 95° + 120 - 125°

Always use new cylinder head bolts. Cylinder head bolts are torque-to-yield bolts designed to be permanently elongated beyond the state of elasticity when torqued, so if the bolts are removed and reused, it may cause the bolts to break or fail to maintain clamping force.

3.	IInstall the remaining parts in the reverse order of removal.

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