To disassemble, repair and assemble the cylinder head on a car, you will need: the same tools as when replacing the cylinder head gasket (see "Replacing the cylinder head gasket"), when replacing oil scraper caps (see "Replacing valve stem seals"), as well as keys "13", "21".
1. Remove the cylinder head (see "Replacing the cylinder head gasket").
2. Unscrew the five nuts securing the intake module to the intake pipe, and remove the module together with the throttle assembly from the intake pipe studs.
3. Unscrew the two nuts securing the front heat-insulating shield and the transport eye, remove the shield and the eye.
4. Unscrew the two nuts of the rear fastening of the intake pipe and catalytic converter (the rear heat shield is attached with the same nuts) and remove the rear heat shield. Remove the washers installed under the shield.
5. Unscrew the two nuts of the front fastening of the intake pipe and catalytic converter and remove the washers installed underneath them.
6. Unscrew the three upper nuts securing the intake pipe and catalytic converter...
7. ...the two lower nuts, remove the washers installed under the nuts.
8. Disconnect the intake pipe and catalytic converter from the cylinder head.
9. Remove the intake pipe and catalytic converter sealing gasket from the cylinder head studs.
10. Remove the coolant temperature gauge sensor from the cylinder head...
11. ...and the sensor of the emergency oil pressure drop warning lamp.
12. To replace the cylinder head cover mounting stud if its thread is damaged, loosen the stud and unscrew it from the cylinder head.
13. Unscrew the two thermostat mounting nuts, remove the washers installed under the nuts...
14. Remove the thermostat and the cardboard sealing gasket installed under its socket. Replace a gasket that is severely compressed or torn during cylinder head assembly.
15. Unscrew the two nuts, unscrew the bolt securing the rear cover of the cylinder head and remove the rear cover.
16. Install the cylinder head with the bearing housings facing up, placing wooden spacers underneath it to avoid damaging the valves.
17. Evenly unscrew the four nuts securing the front 1 and six nuts securing the rear 2 camshaft bearing housings and remove the washers. Then remove both housings.
18. If the key does not fit tightly in the camshaft groove, remove it so as not to lose it.
19. Remove the camshaft from the cylinder head.
20. Remove the oil seal from the camshaft.
21. Remove the valve tappets together with the adjusting washers 1.
22. Clean the combustion chambers from carbon deposits. Inspect the cylinder head. If there are cracks or signs of burnout in the combustion chambers, replace the head. Remove burrs and nicks from the cylinder head surface.
23. Check the flatness of the surface adjacent to the cylinder block. To do this, place the ruler with its edge on the surface of the head, first in the middle along, and then diagonally, and measure the gap between the plane of the head and the ruler with a feeler gauge. Replace the cylinder head if the gap exceeds 0.1 mm.
24. Check the condition of the bearing surfaces under the camshaft journals on the cylinder head and bearing housings. If at least one of them shows signs of wear, scoring or deep scratches, replace the cylinder head and bearing housings.
25. Flush the oil channels. To do this, plug the vertical oil channel on the combustion chamber side (the channel is located between the 3rd and 4th cylinders)...
26. ...pour gasoline into the oil channels in all camshaft bearings and leave for 15-20 minutes. Pour out the gasoline, remove the plug and finally flush the oil channels with gasoline using a bulb syringe.
27. To check the tightness of the valves, pour kerosene into the intake and exhaust channels of the cylinder head. If kerosene does not leak from the channels into the combustion chambers within 3 minutes, the valves are sealed. Otherwise, rub (see "Lapping valves") or replace the valves.
28. Place a suitable support, such as a bearing, under the valve being removed.
29. Install the valve spring compressor and use it to compress the valve springs. Remove two crackers with a screwdriver or tweezers.
30. Remove the upper spring plate, outer and inner valve springs. Similarly, remove the crackers, plates and springs of the remaining valves.
31. Mark the valves with cylinder numbers, for example by punching.
32. Push the valves from below and remove them from the cylinder head.
33. Remove the oil seals using a tool or pliers (see "Replacing valve stem seals").
34. Remove the lower valve spring plates.
35. Clean carbon deposits from the valves with a suitable tool (for example, with a metal brush). Then carefully inspect the valves.
36. Replace valves with the following defects: deep grooves and scratches on the working chamfer 1, cracks, deformation of the stem 3, warping of the plate 2, traces of burnout. Shallow marks and scratches on the working chamfer can be removed by grinding the valves (see "Lapping valves").
37. Check the condition of the valve seats. There should be no signs of wear, cavities, corrosion, etc. on the working chamfers of the valve seats. The valve seats can be replaced in a specialized auto repair shop. Minor damage (minor scratches, marks, etc.) can be removed by grinding the valves (see "Lapping valves").
38. Inspect the valve lifters. If there are burrs, scratches or other defects on the working surface of 1 tappet, replace the valve tappets. Measure the outside diameters of the valve lifters (see "Replacing valve lifters"), replace worn valve lifters. The working surfaces of the adjusting washers 2 must not have any burrs, nicks, scratches, traces of stepped or uneven wear, or metal rubbing. Washers with such defects must be replaced. Concentric traces of running-in with the camshaft cams are allowed on the washers.
Clearances between valve and guide bushing, mm:
- nominal for intake valves - 0.022-0.055
- nominal for exhaust valves - 0.029-0.062
- maximum permissible for intake and exhaust valves - 0.300
Figure 4.5. Dimensions of valves and their guide bushings
39. Check the clearances between the guide bushings and the valves. The clearance is calculated as the difference between the diameters of the hole in the sleeve and the valve stem (figure 4.5). It is recommended that the clearance check be performed in a specialized auto repair shop, since a special tool (a bore gauge) is needed to measure the diameter of the valve guide bushings.
40. If the gap size does not reach the maximum permissible value, you can try to eliminate it by replacing the valve. If this fails or the clearance exceeds the maximum allowable value, replace the valve guide bushing. To do this, press out the defective valve bushing from the combustion chamber side using a special mandrel.
41. After lubricating the valve guide bushing with engine oil, insert it into a special mandrel and press it in from the camshaft side until the retaining ring rests against the cylinder head. Ream the bore in the bushing using a reamer to 8.022-8.040 mm for intake valves and to 8.029-8.047 mm for exhaust valves.
42. If you are installing an old valve, remove any burrs from the grooves under the crackers. After this, it is necessary to grind the valve to the seat (see "Lapping valves").
43. Install the valves into the cylinder head in accordance with the previously indicated markings, having first lubricated the rods with engine oil.
44. Install the lower valve spring retainers.
45. Install the oil seals (see "Replacing valve stem seals").
Article based on information from the website www.Ladaman.ru
46. Install the camshaft and bearing housings (see "Replacing valve stem seals").
47. Install all parts and assemblies removed during disassembly onto the cylinder head.
48. After installing the cylinder head on the engine, check the valve clearances and adjust them if necessary (see "Adjusting valve clearances").