Cylinder Head Assembly - 2.0L - Optima: Overview Kia Optima III рестайлинг

Description

Continuous Variable Valve Timing (CVVT) system advances or retards the valve timing of the intake and exhaust valve in accordance with the ECM control signal which is calculated by the engine speed and load. By controlling CVVT, the valve over-lap or under-lap occurs, which makes better fuel economy and reduces exhaust gases (NOx, HC) and improves engine performance through reduction of pumping loss, internal EGR effect, improvement of combustion stability, improvement of volumetric efficiency, and increase of expansion work.

This system consist of

1. the CVVT Oil Control Valve (OCV) which supplies the engine oil to the cam phaser or runs out the engine oil from the cam phaser in accordance with the ECM PWM (Pulse With Modulation) control signal.
2. the CVVT Oil Temperature Sensor (OTS) which measures the engine oil temperature.
3. and the Cam Phaser which varies the cam phase by using the hydraulic force of the engine oil.

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Operation Principle

The CVVT has the mechanism rotating the rotor vane with hydraulic force generated by the engine oil supplied to the advance or retard chamber in accordance with the CVVT oil control valve control.

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DRIVING CONDITION & VALVE TIMING EFFECT TABLE

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1. Remove the cylinder head cover. Refer to TIMING SYSTEM .
2. Set No. 1 cylinder to TDC/compression. Turn the crankshaft pulley and align its groove with the timing mark "T" of the lower timing chain cover. Check that the TDC marks (A) of the CVVT sprockets are in straight line on the cylinder head surface as shown in the illustration. If not, turn the crankshaft one revolution (360°).
3. Remove the service hole bolt (A) of the timing chain cover.
4. Release the ratchet of the timing chain tensioner by pulling the link down using a thin rod.
5. Remove the high pressure fuel pump bracket (A).
6. Remove the camshaft. Remove the front camshaft bearing cap (A) with the upper bearing (B). Remove the camshaft bearing cap (A) in the sequence shown in the illustration. Remove the exhaust CVVT assembly & camshaft (A). Remove the intake CVVT assembly & camshaft (A).
7. Disconnect the intake CVVT assembly (A) and exhaust CVVT assembly (B) from camshaft (C). NOTE: When removing the CVVT assembly bolt, prevent the camshaft from rotating by using a wrench at position D shown in illustration.

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1. Inspect the CVVT for smooth rotation. Clamp the camshaft using a vise. Be careful not to damage the cam lobes and journals in the vise. Check that the CVVT is locked by turning it clockwise or counterclockwise. It must not rotate. Intake CVVT : Seal one of the two advance holes in the camshaft journal with tape. Exhaust CVVT : Seal one of the two retard holes in the camshaft journal with tape. Intake Exhaust Intake CVVT : Apply approx. 150 kPa (1.5 kgf/cm, 21 psi) of compressed air into the unsealed advance hole to release the lock. Exhaust CVVT : Apply approx. 150 kPa (1.5 kgf/cm, 21 psi) of compressed air into the unsealed retard hole to release the lock. CAUTION: Cover the oil paths with a piece of cloth when applying compressed air to prevent oil from spraying. Intake CVVT : With compressed air applied, rotate the CVVT into the advance direction (counterclockwise) within its phasing range and check that the CVVT turns smoothly. Exhaust CVVT : With compressed air applied, rotate the CVVT into the retard direction (clockwise) and check that the CVVT turns smoothly. CVVT phasing range Intake : 22.5°±1° (from the most retarded position to the most advanced position) Exhaust : 20°±1° (from the most advanced position to the most retarded position) Intake CVVT : Rotate the CVVT into the most retarded position (clockwise) and then check that the CVVT is locked. Exhaust CVVT : Rotate the CVVT into the most advanced position (counterclockwise) and then check that the CVVT is locked.

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1. Inspect the cam lobes. Using a micrometer, measure the cam lobe height. If the cam lobe height is less than standard, replace the camshaft. Cam height (Standard value) Intake : 44.10 ~ 44.30 mm (1.7362 ~ 1.7440 in.) Exhaust : 44.90 ~ 45.10 mm (1.7677 ~ 1.7756 in.)
2. Inspect the camshaft journal clearance. Clean the bearing caps and camshaft journals. Place the camshafts on the cylinder head. Lay a strip of plastigage across each of the camshaft journal. Install the bearing caps. CAUTION: Do not turn the camshaft. Remove the bearing caps. Measure the plastigage at its widest point. Bearing oil clearance (Standard value) Intake : No. 1 : 0.022 ~ 0.057 mm (0.00087 ~ 0.00224 in.) No. 2, 3, 4, 5 : 0.045 ~ 0.082 mm (0.00177 ~ 0.00323 in.) Exhaust: No. 1 : 0 ~ 0.032 mm (0 ~ 0.00126 in.) No. 2, 3, 4, 5 : 0.045 ~ 0.082 mm (0.00177 ~ 0.00323 in.) (Limit) Intake: No. 1 : 0.090 mm (0.00354 in.) No. 2, 3, 4, 5 : 0.120 mm (0.00472 in.) Exhaust : No. 1 : 0.090 mm (0.00354 in.) No. 2, 3, 4, 5 : 0.120 mm (0.00472 in.) If the oil clearance is greater than maximum, replace the camshaft. If necessary, replace cylinder head. Completely remove the plastigage. Remove the camshafts.
3. Inspect the camshaft end play. Install the camshafts. Using a dial indicator, measure the end play while moving the camshaft back and forth. Camshaft end play (Standard value) : 0.04 ~ 0.16 mm (0.0016 ~ 0.0063 in.) (Limit) : 0.20 mm (0.0078 in.) If the end play is greater than maximum, replace the camshaft. If necessary, replace cylinder head. Remove the camshafts.

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1. Check the cylinder head bore mark. Cylinder Head Bore Identification Mark Cylinder Head Specifications CYLINDER HEAD SPECIFICATIONS Class Mark Exhaust No. 1 Inside Diameter Of Cylinder Head Bore a A 40.000 ~ 40.008 mm (1.57480 ~ 1.5751 in.) b B 40.008 ~ 40.016 mm (1.57511 ~ 1.57543 in.) c C 40.016 ~ 40.021 mm (1.57543 ~ 1.57563 in.)
2. Select class of camshaft bearing same as class of cylinder head as shown on the table below.

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Exhaust Camshaft Bearing Specifications

EXHAUST CAMSHAFT BEARING SPECIFICATIONS

Oil clearance : 0 ~ 0.032 mm (0 ~ 0.00126 in.)

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1. Install the intake CVVT assembly (A), exhaust CVVT assembly (B) and camshaft (C). Tightening torque: 53.9 ~ 63.7 N.m (5.5 ~ 6.5 kgf.m, 39.7 ~ 47.0 lb-ft) NOTE: When installing the CVVT assembly bolt, fix the camshaft by wrench at position D.
2. Install the camshafts. NOTE: Apply a light coat of engine oil on camshaft journals. Install the exhaust camshaft lower bearing (A). Install the intake CVVT assembly & camshaft (A). Install the exhaust CVVT assembly & camshaft (A). Install the timing chain. Check that the mark (A) of the CVVT sprockets are in straight line on the cylinder head surface as shown in the illustration. Install the exhaust camshaft upper bearing (A) to the front bearing cap.
3. Install camshaft bearing caps (A) in their proper locations. Tightening order: Group A --> Group B --> Group C. Tightening torque: Step 1 M6 : 5.9 N.m (0.6 kgf.m, 4.3 lb-ft) M8 : 14.7 N.m (1.5 kgf.m, 10.8 lb-ft) Step 2 M6 : 10.8 ~ 12.7 N.m (1.1 ~ 1.3 kgf.m, 8.0 ~ 9.4 lb-ft) M8 : 27.5 ~ 31.4 N.m (2.8 ~ 3.2 kgf.m, 20.3 ~ 23.1 lb-ft)
4. Install the high pressure fuel pump (A). Tightening torque : 18.6 ~ 23.5 N.m (1.9 ~ 2.4 kgf.m, 13.7 ~ 17.4 lb-ft)
5. Install the ratchet of the timing chain tensioner by pushing the link up using a thin rod.
6. Install the service hole bolt of the timing chain cover. Tightening torque: 11.7 ~ 14.7 N.m (1.2 ~ 1.5 kgf.m, 8.6 ~ 10.8 lb-ft) CAUTION: The bolt must not be reused once it has been assembled.
7. Install the cylinder head cover. Refer to cylinder head cover under INSTALLATION .

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Exhaust Camshaft Bearing Identification Mark

Refer to EXHAUST CAMSHAFT BEARING IDENTIFICATION MARK .