Elements of the gas distribution mechanism of 2.0 liter engines of 2001-2005 of release
A, B - adjustable clearance;
1 - valve;
2 - spring;
3 - crackers;
4 - pusher;
5 - adjusting washer.
Valve clearance is one of the factors that determines how long the intake and exhaust valves will be open.
If the valve clearance is too large, then part of the stroke of the pusher and camshaft will be spent on compensating for excess clearance, i.e. valves are not open long enough. In this case, two effects appear: the parts of the valve drive mechanism will make a knocking sound, the engine will work poorly, because. the intake valve will not open enough, and less mixture will enter the cylinder. Insufficient opening of the exhaust valve will result in excessive exhaust gas pressure in the cylinder, which prevents the required amount of working mixture from entering the cylinder.
If the valve clearance is too small, the intake and exhaust valves do not fit snugly in the cylinder head when they are closed. When the valve sits in the cylinder head, it performs two functions - it closes the combustion chamber so that no gases can escape the cylinder, and it cools itself by absorbing some of the heat from the combustion process by the cylinder head and engine cooling system. Thus, if the valve clearance is too small, the engine will not run well (due to the fact that gases exit the combustion chamber), and the valve will overheat and deform (because it cannot transfer heat until it touches the valve seat in the cylinder head).
Caution: While all valve adjustments must be made with the utmost care, it is best to have more «free» adjustment than more «squeezed», since burnt valves are the result of more «clamped» adjustments.
Valve clearances must be periodically checked / adjusted during the operation of the vehicle, as well as after the repair of the engine associated with the gas distribution mechanism.
If the engine is on a vehicle, remove the air filter. Remove also a cover of a head of the block of cylinders. If you do this carefully, you can not damage the gasket.
Remove the front toothed belt cover.
Adjusting the clearance consists in selecting the adjusting washer of the valve lifter until the required clearance is reached.
Caution: The clearance must be checked and adjusted when the engine is cold (engine coolant temperature is 15-25°C). At the specified temperature, valve clearances should be 0.2 mm for intake valves and 0.28 mm for exhaust valves.
Turn the crankshaft clockwise with a wrench so that the marks on the crankshaft gear are aligned with the protrusion of the rear cover.
In this position, the alignment marks of camshafts A and B, as well as the marked chain links, must match (arrows) should be on top (see fig. on the trail. page).
If not, turn the crankshaft one more turn.
By inserting a feeler gauge between the cam and the shim, check the gaps on the cams (1, 2, 3) camshafts shown in the figure.
The probe should move with a slight pinch.
Rotate the crankshaft 360°and measure the valve clearances on the cams (2, 3, 4), indicated in the figure.
If the measured clearance is within tolerance, there is no need to replace the shims. If the clearance differs from the required, then replace the valve lifter shim.
Rotate the tappet so that its notch faces the center of the cylinder head. This will make it easier to remove the washer.
Using a special mandrel, press the pusher with the valve down.
Insert fixing mandrel (brace) between the edge of the pushrod and the camshaft.
Using a screwdriver with a narrow blade (A) and magnet (IN) remove the adjusting washer from the pusher using the slot in the pusher.
Determine the required thickness of the new washer using the formula:
- N=R+ (M-0.2mm) - for intake valves;
- N=R+ (M-0.28mm) - for exhaust valves,
where R is the thickness of the old washer, N is the thickness of the new washer, M is the measured valve clearance.
Use a micrometer to determine the thickness of the removed washer (see fig. on right).
Spare parts are supplied with washers with a thickness of 3 mm to 4.5 mm in increments of 0.05 mm.
Select a new washer with a thickness closest to the calculated value.
Install a new washer using a suitable tool.
Caution: The surface of the numbered washer must face down.
After removing the tappet retainer, check the valve clearance again.
Turning the crankshaft each time by 180°, check and adjust the clearances of the remaining cams in pairs in the following sequence: 5-2; 8-6; 4-7.
After checking / adjusting the valve clearance, fill the cylinder head baths with oil and reinstall the previously removed elements.