Cylinder Head Assembly - 2.4L: Overview Kia Optima III

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.

Scheme 329

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.

Scheme 330

Scheme 331

Note. The Graphs in the illustrations below refer to the conditions in the chart above.

Scheme 332

Scheme 333

Scheme 334

Scheme 335

DRIVING CONDITION & VALVE TIMING EFFECT TABLE

Scheme 336

Scheme 337

Scheme 338

Scheme 339

Scheme 340

Scheme 341

Scheme 342

Scheme 343

Scheme 344

1. Remove the cylinder head cover. Refer to «REMOVAL»(ref-429611-S39351082482011101500000) .
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 mark (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 illustration. Remove the camshafts (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.

Scheme 345

Scheme 346

Scheme 347

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) (Scheme 344)
2. Install the camshafts. Install the exhaust camshaft lower bearing (A). Install the camshafts (A). (Scheme 343)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. (Scheme 337)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, then Group B, then 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).
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)
7. Install the cylinder head cover. Refer to cylinder head cover under «INSTALLATION»(ref-429611-S31712045082011101500000).

Scheme 348

See also:
• INTAKE AND EXHAUST SYSTEM