Valve spring parameters for determining their elasticity.
Outer spring:
free height | 45.2 mm |
height under load 26.0+1.7 kgf | 33.7 mm |
height under load 46.2+2.4 kgf | 24.7 mm |
Inner spring:
free height | 34.1 mm |
height under load 9.0+0.8 kgf | 29.7 mm |
height under load 27.5+1.5 kgf | 20.7 mm. |
a – inlet valve seat
b – exhaust valve seat
I - new saddle
II – saddle after repair
Clearance between valve and guide bushing, mm:
nominal clearance for intake valves | 0,022-0,055 |
nominal clearance for exhaust valves | 0,029-0,062 |
maximum permissible clearance for intake and exhaust valves | 0,3 |
If the clearance is less than the maximum allowable, try replacing the valve. If the clearance is greater than the maximum allowable, replace the guide bushing.
1. Wash the cylinder head parts in gasoline, wipe and dry them.
2. Clean the combustion chambers from carbon deposits. Inspect the head. If there are cracks or traces of burnout in the combustion chambers, replace the head.
3. Check the flatness of the surface adjacent to the cylinder block. To do this, place a metal ruler with its edge on the surface of the head in the center along, and then diagonally and measure the gap between the plane of the head and the ruler with a feeler gauge. Replace the head if the gap exceeds 0.1 mm.
4. Clean the carbon deposits from the valves. This can be done with a suitable metal tool.
5. Inspect the valves. Replace valves with the following defects: deep scratches and grooves on the working chamfer, cracks, valve stem deformation, valve plate warping, burn marks. Shallow scratches and grooves on the working chamfer can be removed by grinding the valves.
6. Damage to the valve working chamfer that cannot be removed by grinding can be ground on a special machine. When grinding, it is necessary to maintain the dimensions indicated in the figure. The different dimensions for the VAZ-21083 engine are given in brackets (see notes).
7. Check the condition of the valve springs. Replace warped, broken or cracked springs. Check the elasticity of the springs. To do this, measure the height of the springs in a free state and then under two different loads. If the spring does not meet the required parameters, replace it (see notes).
9. More significant valve seat defects are eliminated by grinding. When grinding, maintain the dimensions shown in the figure (see note 1). First, grind the chamfer at an angle of 20°, then the chamfer at an angle of 45°. After grinding, grind the valves, then thoroughly clean and blow out the cylinder head with compressed air so that no abrasive particles remain in the channels and combustion chambers. The different dimensions for the VAZ-21083 engine are given in brackets.
10. Check the clearance between the guide bushings and the valves (see note 2). The clearance is calculated as the difference between the diameter of the hole in the bushing and the diameter of the valve stem.
8. Check the condition of the valve seats. There should be no signs of wear, cavities or corrosion on the working chamfers of the seats. Minor damage (minor scratches, marks, etc.) can be removed by grinding the valves.
11. Inspect the valve lifters. If there are nicks, scratches or other damage on the working surface of the lifter, replace the lifters.
12. Inspect the adjusting washers. Their working surfaces should not have any nicks, dents, scratches, traces of stepped or uneven wear, or metal rubbing. If such defects are present, the washers should be replaced. Concentric traces of running-in with the camshaft cams are allowed on the washers.
13. Note the length of the cylinder head mounting bolts, as they stretch when tightened repeatedly. If the bolts are longer than 135.5 mm, replace the bolts.
14. To check the tightness of the head, plug the hole in the cooling jacket pipe at the rear end of the head, turn the head upside down with the combustion chambers facing up and pour kerosene into the cooling jacket channels. If kerosene leaks appear, then the head is not tight and must be replaced.
Information taken from the website VAZbook