Remark. To compensate for the thermal expansion of the valve stem, a gap is required between the camshaft cam and the valve tappet). For intake valves, the clearance should be 0.15-0.25 mm, and for exhaust valves — 0.30-0.40 mm. The gap is set by selecting the thickness of the adjustment washers. The washers are installed in a niche located on top of the pushers. To make it easier to remove the washers, grooves are made on the upper edges of the pushers. The size of the washer is marked on its non-working surface.
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Advice: It is more convenient to divide the work into two stages. First measure the gaps and calculate the thickness of the new washers, and then purchase and install new washers.
To complete the work you will need:
- set of flat feeler gauges;
- tweezers;
- micrometer (with a measurement range of 0-25 mm);
- device for adjusting gaps.
Warning! Checking and adjusting clearances is only performed on a cold engine (at a temperature of about +20°C).
Sequence of execution
1. Prepare the car for work ("Preparing the car for maintenance and repair").
2. Remove the cylinder head cover ("Cylinder Head Cover Gasket - Replacement").
3. Remove the front timing belt cover ("Timing Belt - Checking Condition").
4. Using a medical syringe or rubber bulb, remove any remaining oil around the valve tappets.
5. Install the valve adjustment device onto the cylinder head studs and secure it with the nuts that secured the cylinder head cover.
Recommendation. There are several ways to adjust the gaps. They differ in the order of measuring valve clearances. In any case, the clearances are checked only with the valves closed (their tappets are not pressed by the camshaft cams). If it is difficult to determine the position of the valves, follow the method below.
6. Rotating the crankshaft clockwise, we set the piston of the first cylinder to the TDC position of the compression stroke.
Note: The crankshaft can be rotated using a 17 mm open-end wrench on the crankshaft pulley mounting bolt or a large slotted screwdriver on the flywheel teeth. To do this, remove the lower cover of the clutch housing ("Gearbox - removal and installation").
7. Turn the shaft from the TDC position to an angle of 40-50° (for 3 teeth of camshaft pulley), using feeler gauges of appropriate thicknesses, we determine the clearances in the drive of valves 1 and 3 (when counting in order from the camshaft pulley).
Note: The nominal thickness feeler gauge should be slightly pinched in the gap between the camshaft cam and the tappet adjusting washer.
8. If the gap is not within the norm, turn the pusher with the groove towards you. We use the device to push the valve in, holding the pusher from rotating with a screwdriver inserted into the groove. We use the device's locking device to stop the pusher in the lower position.
9. Use tweezers to remove the adjusting washer.
10. Using the markings on the washer, we determine its thickness. If the inscription has been erased, use a micrometer to measure the thickness of the washer.
11. Calculate the clearance of the new adjusting washer using the formula:
- a) for inlet valves: Z = Y + X - 0.2 mm;
- b) for exhaust valves: Z = Y + X - 0.3 mm;
where Z is the calculated thickness of the new adjusting washer, Y is the thickness of the removed washer; X — gap determined by feeler gauge.
12. Select a new washer whose thickness is close to the calculated one (±0.05 mm).
13. Install a new washer into the pusher (marking down).
14. Press the pusher with the device and remove the retainer.
15. Following the sequence indicated in the table. 8.1.3, we check and adjust the clearances in the drive of other valves.
| The angle of rotation of the crankshaft from the TDC position of the compression stroke of the first cylinder, deg. | Cam | |||
| outlet | inlet | |||
| 40-50 | 1 | 3 | ||
| 220-30 | 5 | 2 | ||
| 400-410 | 8 | 6 | ||
| 580-590 | 4 | 7 | ||
16. After removing the valve adjustment tool, install the removed parts in the reverse order of disassembly.