Replacement of the 2.0L engine phase regulator on the Renault Megane II

General structure and operating principle of the phase regulator

To improve the filling of the cylinders with the fuel mixture in all modes, the 2.0 l engines are equipped with a phase regulator of the inlet valve camshaft.

The offset of the closing moment of the inlet valves optimises the filling of the cylinders with the fuel mixture depending on the crankshaft rotational speed. As a result, the torque in the medium load mode and the power at high crankshaft rotational speed are increased.

Operating principle:

At high crankshaft rotational speed, a later closing of the inlet valves ensures the admission of an additional portion of the fuel mixture thanks to the high speed of movement of the mixture.
At low rotational speed, the inertia of the mixture movement is small. Therefore an earlier closing of the exhaust valves is desirable in order to avoid insufficient filling of the cylinders and loss of torque due to the displacement of part of the fresh mixture.
The higher the crankshaft rotational speed, the later the closing of the inlet valves must occur.

Diagram of the operation of the phase regulator — Operating principle of the phase regulator

The phase regulator is either switched off or controlled by the injection system ECU through the electromagnetic valve installed on the cylinder head cover (see Fig. 2). The electromagnetic valve and the high-voltage coil are secured by a single bolt (Fig. 3).

Electromagnetic valve of the phase regulator — Phase regulator control electromagnetic valve

Operating modes of the phase regulator

Control algorithm:

At a crankshaft rotational speed within 1500–4300 rpm the ECU applies voltage to the electromagnetic valve.
When 4300 rpm is exceeded, the supply to the electromagnetic valve is cut off.
At a rotational speed up to 1500 rpm no voltage is applied to the electromagnetic valve. The mechanism is locked by the plunger.

When 4300 rpm is exceeded, the position of the phase regulator mechanism promotes the filling of the cylinders at high crankshaft rotational speed. In this position the locking plunger locks the mechanism.

From the moment the supply is applied to the electromagnetic valve at a crankshaft rotational speed of more than 1500 rpm, under the action of oil pressure the locking plunger withdraws and releases the mechanism.

Valve opening conditions: in the initial position the electromagnetic valve is closed. The valve opens the oil passage for controlling the phase regulator subject to the following conditions:

the crankshaft rotational speed sensor is serviceable;
the camshaft position sensors are serviceable;
the injection system is serviceable;
after the engine has started;
the engine is not running at idle;
the battery voltage is more than 11.4 V;
the coolant temperature is above 30 °C;
the engine is running within 1500–4300 rpm;
the load is more than 87 % (approximately 900 mbar).

Signs of a fault: when the electromagnetic valve is locked in the open position, the engine runs unstably at idle, the pressure in the intake pipe is increased. At the same time a noisier engine operation is noted. The engine may even stall (there have been cases of engine failure).

Replacing the phase regulator

Preparatory work

Precautions: to replace the phase regulator we disconnect the negative battery terminal.

Sequence:

We remove the plastic engine cover.
We remove the throttle body (see the article on removing the throttle).
We remove the right front wheel.
We remove the right wing arch liner.
We remove the lower engine guard.

Unscrewing the reinforcement securing nuts — With a 13 mm spanner we unscrew the reinforcement securing nuts and remove it

Removing the auxiliary drive belt — With a 16 mm ring spanner we turn the auxiliary drive belt tensioner and remove the auxiliary drive belt

Removing the crankshaft pulley: we unscrew the bolt securing the auxiliary drive belt pulley. To unscrew the bolt, we lock the crankshaft against turning. We engage the highest gear in the manual gearbox and an assistant presses the brake pedal.

Unscrewing the crankshaft pulley bolt — We unscrew the pulley securing bolt

Removing the engine mounts

Jacking up the engine — We jack up the engine through a soft spacer

Removing the brace — We unscrew two bolts and remove the brace

We unscrew two bolts securing the right rear power unit mount.

Withdrawing the right rear mount — By manipulating the jack or the lift, we withdraw the right rear power unit mount

We unscrew the bolts securing the right front mount.

Unscrewing the front mount bolts — We unscrew the bolts securing the right front mount

Withdrawing the front mount: by raising and lowering the engine, we withdraw the right front mount, trying not to damage the air conditioning pipe.

Withdrawing the right front mount — We withdraw the right front mount

Removing the timing covers and preparing to set TDC

Removing the upper timing cover — Through the service openings we unscrew and withdraw the upper timing cover

Removing the lower timing cover — We unscrew and remove the lower timing cover

Removing the heat shield cover — We unscrew the two nuts securing the heat shield cover to the cylinder head and withdraw it. (This is done for access from above in order to insert the TDC retainer).

Removing the plugs: we pierce the camshaft service plugs and withdraw them.

Setting TDC

Important! In order not to disturb the valve timing, before removing the timing belt the crankshaft must be set to the TDC position of the first cylinder piston.

To turn the crankshaft we screw in the bolt securing the alternator belt pulley, having fitted a bush or a set of washers.

Unscrewing the plug for the TDC retainer — We unscrew the plug from the service opening intended for fitting the crankshaft TDC retainer

Position of the camshafts at TDC — **Fig. Position of the camshafts in the TDC position:** 1 — camshafts. The slots (1), offset from the axis of the camshafts, must be below the axis and must be arranged almost horizontally with a slight offset.

**Fig. Fitting the TDC retainer of the first cylinder piston of the 2.0 l engine.** Insert the TDC retainer so that it is located between the opening on the balancer and the crankshaft locking slot.

Turn the crankshaft slightly in the direction of working rotation so that the Mot.1054 retainer is located in the crankshaft locking slot.

TDC retainer fitted — **Fig. Fitting the TDC retainer:** 1 — retainer

Fitting the Mot.1496 tool — **Fig. Fitting the valve timing setting tool:** 1 — Mot.1496 tool, 2 — bolt

We insert the Mot.1496 tool into the slots of the camshafts.

Removing the phase regulator and the timing belt

Removing the phase regulator (two people with an assistant):

Locking the phase regulator with a screwdriver — The assistant inserts a powerful flat-blade screwdriver between the splines of the phase regulator and locks it against turning in this way

Unscrewing the cover and the bolt of the phase regulator — Meanwhile we unscrew the phase regulator cover and the phase regulator bolt

Loosening the tensioner roller — **Fig. Loosening and tensioning the timing belt using the tensioner**

We loosen the tensioner roller and remove the roller.

Removing the timing belt — We remove the timing belt

Withdrawing the phase regulator — We withdraw the phase regulator

Refitting

Important! We refit the phase regulator in the reverse sequence. When refitting it must be taken into account that the phase regulator must be tightened last.

Before refitting the phase regulator, the bolt and the end of the inlet camshaft must be degreased. The phase regulator mounting point must be clean and degreased.

Tightening torques of the main assemblies when replacing the phase regulator:

crankshaft pulley securing bolt — 40 N·m and tighten further by 110°;
camshaft toothed pulley securing nuts — 30 N·m and tighten further by 86° ± 6°;
guide roller bolts — 50 N·m;
tensioner roller axle securing nut — 28 N·m.