Hyundai Creta: Cylinder Head Assembly / CVVT & Camshaft

Hyundai Creta GS 2014-2024 Service Manual / Engine Mechanical System / Cylinder Head Assembly / CVVT & Camshaft

Components and components location

Components

1. Exhaust camshaft
2. Intake camshaft
3. Exhaust CVVT
4. Intake CVVT

5. Camshaft bearing cap
6. Camshaft front bearing cap
7. O-ring
8. OCV (Oil Control Valve) adapter

Description and operation

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

–	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,

–	the CVVT Oil Temperature Sensor (OTS) which measures the engine oil temperature,

–	and the Cam Phaser which varies the cam phase by using the hydraulic force of the engine oil.

The engine oil getting out of the CVVT oil control valve varies the cam phase in the direction (Intake Advance/Exhaust Retard) or opposite direction (Intake Retard/Exhaust Advance) of the engine rotation by rotating the rotor connected with the camshaft inside the cam phaser.

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.

[CVVT System Mode]

(1) Low Speed / Low Load	(2) Part Load

(3) Low Speed / High Load	(4) High Speed / High Load

Driving Condition	Exhaust Valve		Intake Valve
Driving Condition	Valve Timing	Effect	Valve Timing	Effect
(1) Low Speed /Low Load	Completely Advance	* Valve Under-lap * Improvement of combustion stability	Completely Retard	* Valve Under-lap * Improvement of combustion stability
(2) Part Load	Retard	* Increase of expansion work * Reduction of pumping loss * Reduction of HC	Retard	* Reduction of pumping loss
(3) Low Speed /High Load	Retard	* Increase of expansion work	Advance	* Prevention of intake back flow (Improvement of volumetric efficiency)
(4) High Speed /High Load	Advance	* Reduction of pumping loss	Retard	* Improvement of volumetric efficiency

Repair procedures

Removal

•	Use fender covers to avoid damaging painted surfaces.

•	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 (TDC).

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

2.	Remove the exhaust oil control valve (OCV) adapter (A).

Set No.1 cylinder to top dead center (TDC) on compression piston.

(1)

Turn the crankshaft pulley and align its groove with the timing mark of the timing chain cover.

•	Do not rotate engine counterclockwise.

(2)	Check that the marks of the camshaft timing sprockets are in straight line on the cylinder head surface as shown in the illustration. If not, turn the crankshaft one revolution (360°).

(3)	Put paint marks on the timing chain links (2 places) that meet with the timing marks of the intake, exhaust countinuous variavle valve timing (CVVT) sprockets.

4.	Remove the camshaft bearing caps (A) with the order below.

5.	Remove the service hole bolt (A) of the timing chain cover.

6.	Release the ratchet (A) of the timing chain tensioner by pushing and holding the ratchet upward using a thin rod (B).

Remove the exhaust camshaft first, and then remove the intake camshaft from the timing chain.

•	When disconnecting the timing chain from the camshaft timing sprocket, hold the timing chain.

Tie a timing chain with a string.

•	Be careful not to drop anything inside timing chain cover.

Remove the Intake CVVT assembly (A) and exhaust camshaft sprocket (B).

•	When removing the intake CVVT assembly bolt and exhaust CVVT assembly bolt, prevent the camshaft from rotating by using a wrench at position.

Inspection

Camshaft Assembly

Inspect the cam height.

Using a micrometer, measure the cam height.

Cam height :

Intake : 43.85 mm (1.7264 in)

Exhaust : 42.85 mm (1.6870 in)

If the cam lobe height is less than specified, replace the camshaft.

Inspect the camshaft journal clearance.

(1)	Clean the bearing caps and camshaft journals.

(2)	Place the camshafts on the cylinder head.

(3)	Lay a strip of plastigage across each of the camshaft journal.

(4)

Install the bearing caps and tighten the bolts with specified torque.

Tightening torque :

M6 bolts :

11.8 ~ 13.7 N.m (1.2 ~ 1.4 kgf.m, 8.7 ~ 10.1 lb-ft)

M8 bolts :

18.6 ~ 22.6 N.m (1.9 ~ 2.3 kgf.m, 13.7 ~ 16.6 lb-ft)

•	Do not turn the camshaft.

(5)	Remove the bearing caps.

(6)

Measure the plastigage at its widest point.

Bearing oil clearance :

Standard :

0.027 ~ 0.058 mm (0.0011 ~ 0.0023 in)

Limit : 0.1 mm ( 0.0039 in)

•	If the oil clearance is greater than specified, replace the camshaft.

•	If the oil clearance is still greater than specification after camshaft replacement, replace the bearing caps and cylinder head as a set.

Inspect the camshaft end play.

(1)	Install the camshafts.

(2)

Using a dial indicator, measure the end play while moving the camshaft back and forth.

Camshaft end play :

Standard : 0.1 ~ 0.2 mm (0.0039 ~ 0.0079 in)

•	If the end play is greater than specified, replace the camshaft.

•	If the end play is still greater than specification after camshaft replacment, replace the bearing caps and cylinder head as a set.

(3)	Remove the camshafts.

Continuously variable valve timing (CVVT) Assembly

Inspect the CVVT for smooth rotation.

(1)	Clamp the camshaft using a vise. Be careful not to damage the cam lobes and journals in the vise.

(2)	Check that the CVVT is locked by turning it clockwise or counterclockwise. It must not rotate.

(3)	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.

(4)

Intake CVVT : Apply approx. 150 kPa (1.5 kgf/cm², 21 psi ) of compressed air into the unsealed advance hole to release the lock.

Exhaust CVVT : Apply approx. 150 kPa (1.5 kgf/cm², 21 psi ) of compressed air into the unsealed retard hole to release the lock.

•	Cover the oil paths with a piece of cloth when applying compressed air to prevent oil from spraying.

(5)

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.

DVVT phasing range :

Intake : 25°±1° (from the most retarded position to the most advanced position)

Exhaust : 20°±1° (from the most advanced position to the most retarded position)

(6)	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.

Installation

Install the intake CVVT assembly (A) and exhaust CVVT assembly (B).

Tightening torque :

63.7 ~ 73.5 N.m (6.5 ~ 7.5 kgf.m, 47.0 ~ 54.2 lb-ft)

•	When installing the intake CVVT assembly bolt and exhaust CVVT assembly bolt, prevent the camshaft from rotating by using a wrench at position.

Untie a timing chain with a string.

•	Be careful not to drop anything inside timing chain cover.

3.	Release the ratchet (A) of the timing chain tensioner by pushing and holding the ratchet upward using a thin rod (B).

Install the intake camshaft first, and then install the exhasut camshaft to the timing chain.

(1)	Hold the timing chain, and place the intake camshaft and CVVT module assembly.

(2)	Align the matchmarks on the timing chain and camshaft timing CVVT sprocket.

(3)	Install the exhaust camshaft and CVVT module assembly.

•	The timing marks of each CVVT sprocket should be matched with timing marks (painted link) of timing chain when installing the timing chain.

Install the camshaft bearing caps with the order below.

Tightening torque :

M6 bolts :

11.8 ~ 13.7 N.m (1.2 ~ 1.4 kgf.m, 8.7 ~ 10.1 lb-ft)

M8 bolts :

18.6 ~ 22.6 N.m (1.9 ~ 2.3 kgf.m, 13.7 ~ 16.6 lb-ft)

•	Be careful not to change the position and direction of bearing caps.

6.	Pull out a thin rod from the service hole of the timing chain cover after tensing up the ratchet.

Install the service hole bolt of the timing chain cover.

Tightening torque :

27.5 ~ 30.4 N.m (2.8 ~ 3.1 kgf.m, 20.3 ~ 22.4 lb-ft)

•	The bolt must not be reused once it has been assembled.

8.	Turn the crankshaft two turns in the operating direction(clockwise) and realign crankshaft sprocket and camshaft CVVT sprocket timing marks.

Install the exhaust oil control valve (OCV) adapter (A).

Tightening torque :

9.8 ~ 11.8 N.m (1.0 ~ 1.2 kgf.m, 7.2 ~ 8.7 lb-ft)

10.	Install the cylinder head cover. (Refer to Cylinder Head Assembly - "Cylinder Head Cover")

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