We remove the engine camshafts when repairing the cylinder head, for replacement as a result of wear, as well as when replacing the rocker arms, valve stem oil seals and hydraulic supports of the valve rocker arms.
We place the vehicle on a lift or an inspection pit.
We remove the timing drive belt (article — Checking and replacing the timing belt of the vehicle).
Using an 8 mm socket, we undo the two bolts securing to the left end face of the cylinder head the bracket of the engine cooling system hoses.
We remove the intake resonator (article — Removal and installation of the engine intake resonator).
Using an 8 mm socket, we undo the nine bolts securing the oil separator to the cylinder head cover.
We remove the oil separator.
We remove the oil separator gasket.
Using an 8 mm socket, we undo the bolts securing the cylinder head cover.
Using a flat-blade screwdriver, we prise at the ribs on the cylinder head cover.
We withdraw the camshaft plugs.
We withdraw from the cylinder head bearings the intake valve shaft.
We also withdraw the exhaust valve shaft.
To assess the condition of the hydraulic support of the valve rocker arm:
We remove the rocker arm.
We withdraw the hydraulic compensator from the cylinder head seat.
The checking and washing of the hydraulic supports is examined below.
When assembling the timing mechanism, the camshaft oil seals must be replaced.
To do this, the camshaft pulleys must be removed.
We place an 18 mm ring spanner on the nut securing the camshaft toothed pulley and insert a powerful screwdriver through the opening in the pulley.
Resting on the pulley hub with the blade of the screwdriver, with the shank of the screwdriver we press on the spanner and turn it anticlockwise.
The pulley with the camshaft must not turn, and the nut securing the pulley will be undone.
Having undone the nut, we remove the pulley from the camshaft nose.
We remove the oil seal.
We also remove the pulley and remove the oil seal from the intake valve shaft of the K4M engine.
On the F4R engine, the intake valve camshaft pulley is combined with the phase regulator.
To remove the phase regulator, using a Torx T-50 key, we undo the screw securing the mechanism plug.
We remove the plug.
The connection is sealed by a rubber ring.
Using an 18 mm socket, we undo the bolt securing the phase regulator.
The shaft can be locked against turning with a screwdriver inserted through the opening in the pulley, as described when removing the exhaust valve shaft pulley.
Resting on the pulley hub with the blade of the screwdriver, with the shank of the screwdriver we press on the tommy bar and turn it anticlockwise.
Having undone the bolt, we remove the phase regulator.
Before installation, we wipe the mating surfaces of the head and the head cover.
We apply to the mating surface of the cylinder head a special sealant Loctite 518, until the surface becomes reddish.
We install the cylinder head cover and tighten the bolts securing it to the torque in the sequence indicated in the table.
We apply to the working lips of the new oil seals a thin layer of engine oil and fit them onto the camshaft noses.
Using a socket of a suitable size, we press the oil seals into the cylinder head seats.
We check the timing phases using special tools (article — removal of the timing belt).
Before installing the pulleys on the camshafts, it is necessary to degrease the openings and mating surfaces of the pulleys and shafts.
We screw in the nuts (on the F4R engine — the nut and the bolt) securing the pulleys, but do not tighten them.
We fit onto the pulleys and tension the timing drive belt (article — replacement of the timing belt).
Having slightly tightened the nuts (on the F4R engine — the nut and the bolt) securing the camshaft pulleys, we turn the crankshaft (having removed the shaft locking tool) clockwise two turns and check the correct setting of the timing phases.
We tighten the nuts (on the F4R engine — the nut and the bolt) securing the camshaft pulleys.
Order of tightening the bolts securing the cylinder head cover:
- first stage — tighten bolts 22, 23, 20, 13 to a torque of 8 Nm;
- second stage — tighten bolts 1 to 12, 14 to 19, 21 to 24 to a torque of 12 Nm;
- third stage — slacken bolts 22, 23, 20, 13;
- fourth stage — tighten bolts 22, 23, 20, 13 to a torque of 12 Nm.
Tightening torques of the other parts:
- nut securing the camshaft toothed pulley: first stage — 30 Nm; second stage — 86±6°;
- bolt securing the phase regulator — 100 Nm;
- screw securing the phase regulator plug — 25 Nm.
Before installing the oil separator, we clean its channels of deposits.
We clean the mating surfaces of the old gasket and fit a new gasket.
The sequence of tightening the bolts securing the oil separator is shown in the figure.
We tighten the bolts securing the oil separator to a torque of 13—15 Nm.
We carry out the further assembly in the reverse order.
Checking and washing the valve hydraulic compensators
The hydraulic compensators of the clearances in the valve drive mechanism serve to compensate for the thermal expansions of the drive elements.
The operation of the hydraulic compensator is based on the principle of incompressibility of engine oil, which constantly fills during engine operation the internal cavity of the hydraulic compensator and moves its plunger when a clearance appears in the valve drive, ensuring constant contact of the roller of the valve drive pressure rocker arm with the camshaft cam without clearance.
Thanks to this, the need for valve adjustment during maintenance is eliminated.
The hydraulic compensators are non-detachable compact devices inserted into the cylinder head seats.
Knocking of the valves of a running engine can be caused by:
- the entry of air into the above-plunger cavities of the hydraulic compensators with a too low or too high oil level in the crankcase, as well as during prolonged parking of the vehicle on a slope;
- contamination of the precision surfaces of the hydraulic compensators of the clearances in the valve drive mechanism with sludge from low-quality engine oil (or during its untimely replacement, as well as in the event of damage to the oil filter);
- wear of the hydraulic compensators.
If pumping or washing fails to restore the working capacity of the hydraulic compensators, replace them, since their construction is non-detachable.
First make sure that the extraneous noise during engine operation is caused by a fault specifically of the hydraulic compensators:
— start the engine.
In the event of a fault of the hydraulic compensators, the extraneous noise in the area of the cylinder head cover appears immediately after starting the engine and changes in accordance with the change in the rotational speed of the engine crankshaft.
If the noise does not appear immediately after starting the engine or does not change when the rotational speed of the crankshaft changes, the fault is not caused by a malfunction of the hydraulic compensators.
Moreover, if the noise does not change when the rotational speed of the crankshaft changes, the cause of the extraneous noise is probably not in the engine;
— during engine operation at idle, make sure that the noise level does not change when the load changes (for example, when switching the selector of the automatic gearbox from position N to position D, when disengaging the clutch of a vehicle with a manual gearbox or when switching on the electrical consumers and the air conditioner).
If the noise level changes, the cause may be the collision of parts due to wear of the connecting rod and main bearings of the crankshaft, and not a fault of the hydraulic compensators;
— warm up the engine to operating temperature.
If the noise has decreased or disappeared, it is possible that the knocking of the hydraulic compensators is caused by oil contamination.
In this case, it is necessary to wash the hydraulic compensators:
— if the noise has not disappeared, it is probable that air has entered the hydraulic compensators, and it must be removed.
With a too low oil level in the crankcase, the oil pump draws in air together with the oil; with a too high oil level in the crankcase, the oil is agitated and foamed by the crankshaft counterweights.
During prolonged parking of the vehicle on a slope, the oil flows out of the cavities of the hydraulic compensators and the oil channels, and the supply of oil to the hydraulic compensators after starting the engine requires some time, during which the cavity of the hydraulic compensator has time to fill with air.
In all these cases, when oil with air enters the above-plunger cavity of the hydraulic compensator, the air inside the cavity when the valve opens will be compressed and the hydraulic compensator will be insufficiently compressed, which will lead to the appearance of a characteristic knocking of the operation of the valve mechanism with increased clearances.
To remove air from the hydraulic compensators, perform the following:
check the oil level in the engine crankcase and, if necessary, bring it to the norm;
- start the engine and warm it up at idle for 1—3 min;
- increase the rotational speed of the crankshaft to 3000 min⁻¹, then sharply reduce it to the idle speed and let the engine run at idle;
- repeat the cycle and check whether the noise of the valve drive mechanism has disappeared.
If the hydraulic compensators are in good order, the noise disappears after 10—30 cycles;
- after the noise has disappeared, repeat to remove air five more times;
- let the engine run at idle for 1—3 min and make sure that the noise of the valve drive mechanism has disappeared.
If the noise of the valve drive mechanism has not disappeared after removing the air and warming up the engine to operating temperature, identify the faulty hydraulic compensators as follows.
Stop the engine and immediately after stopping set the piston of the 1st cylinder to the TDC position of the compression stroke, remove the cylinder head cover.
Remove the camshafts.
To check the working capacity of the engine hydraulic compensators, press on the arm of the rocker arm resting on the hydraulic compensator.
If the rocker arm can be moved practically without effort, the hydraulic compensator is faulty.
Check in a similar way the condition of the hydraulic compensators of the other cylinders (cylinder firing order 1—3—4—2).
After identifying the faulty hydraulic compensators, you must first try to wash them as follows.
Remove the valve rocker arms.
Withdraw the faulty hydraulic compensator from the cylinder head seat.
Prepare three identical containers with a capacity of approximately 2 l for washing the hydraulic compensators.
The dimensions of each container must be sufficient for the hydraulic compensator, lowered to the bottom of the container in a vertical position, to be completely immersed in the liquid.
Fill the containers with clean diesel fuel.
Place the hydraulic compensator in the first container and clean its outer surface.
Having immersed the hydraulic compensator half-way into the first container, plunger downwards, with a light pressure of a wire through the opening, push back the valve ball and, holding the ball pushed back, move the plunger of the hydraulic compensator 5—10 times until the movement of the plunger becomes completely free.
If it is not possible to achieve easy movement of the plunger, replace the hydraulic compensator.
Withdraw the hydraulic compensator from the container and, having pushed back the valve ball, move the plunger until the diesel fuel has completely flowed out of the hydraulic compensator.
Place the hydraulic compensator in the second container and repeat operation 5.
Withdraw the hydraulic compensator from the container and drain the diesel fuel from it, as described in operation 6.
Place the hydraulic compensator on the bottom of the third container vertically, plunger upwards, and push back with a wire the ball of its valve.
Holding the valve ball pushed back, move the plunger downwards and then slowly move it upwards, so that the above-plunger cavity of the hydraulic compensator is filled with diesel fuel.
Withdraw the hydraulic compensator from the container, holding it plunger upwards, press with a slight effort on the plunger and make sure that it has remained motionless.
At the same time check the overall height of the hydraulic compensator, comparing it with a new hydraulic compensator.
If during the check it was possible to move the plunger of the hydraulic compensator, repeat operations 9 and 10 until the cavity of the hydraulic compensator is completely filled with diesel fuel.
If even after this the hydraulic compensator does not reach the working state or its overall height is less than the height of a new hydraulic compensator, replace it.
Until the assembly of the valve drive mechanism, store the filled hydraulic compensators only in a vertical position with the plungers upwards.
Avoid the entry of dirt into the hydraulic compensators.
Install the hydraulic compensators on the engine as quickly as possible after filling, in order to exclude a possible loss of diesel fuel.
Install the hydraulic compensators and all removed parts in the order reverse to removal.
Start the engine and let it run 1—3 min at idle. If necessary, remove air from the hydraulic compensators, as described above.
