Table 5.4. Engine valve parameters
Valve parameters | Valve | |
inlet | prom | |
Model engine « N62 B44» | ||
Valve seat seat | 34,5 | 28,6 |
Head plate diameter, mm | 35,0 | 29,0 |
- manufacturing approval | +0,10 | |
Rod diameter, mm | ||
- nominal | 6,00 | |
- approval isp. vp. | -0.025 to -0.040 | |
- approval isp. issue | -0.033 to -0.047 | |
Gap between guide bushing and valve stems, mm* | 0,5 |
* The measurement procedure is shown in Figure 3.7.
Minimum height of the cylindrical part of the valve disc «b» (pic. 5.6) - 0.5 mm.
The state of the valve mechanism is judged by one of the main indicators of engine wear - the amount of compression in its cylinders, which is checked by a special device - a compression gauge installed in the spark plug hole. The rules for its installation and taking measurements are given in the instructions for the device and are described below.
Instrument reading for a new engine - 12-14 bar (kgf/cm2), with minimum valve lift. With extreme wear, this value must be at least - 10.0 bar. The difference in pressure between the cylinders of the same engine must not exceed 1.5 bar. If the difference is more than 1.5 bar or the pressure is less than 10.0 bar, then this indicates increased wear of the piston rings, cylinder mirrors, valves. Such an engine must be removed and repaired.
Valve springs
Valve springs are designed to provide a hermetically sealed valve seat. Each inlet and outlet valve has a single spring with a complex cylindrical-conical shape. The springs are not identical for the intake and exhaust valves, do not mix them up.