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3.3.6. Check of the directing valves

At repair work on a head of cylinders with leaky valves it is not enough to process or replace valves and saddles. Besides it is necessary to check wear of the directing valves. Check is especially important for engines with a big run. Worn-out guides do not guarantee the central landing of valves and lead to a big consumption of oil. If wear is too big, guides of valves should be replaced (it is carried out in a workshop).

PERFORMANCE ORDER
1. Remove the valve.
2. Clear a valve guide a cylindrical brush.
3. Enter the valve into a guide from the combustion chamber and measure a side play moving the valve here and there. The side play of the valve should be measured parallel to the corresponding yoke since in this direction the greatest wear is shown.
4. For check apply a steel ruler. Practically there should be no gap. Boundary value: 0,2 mm.
5. If there is a micrometer and нутрометр, it is possible to measure the actual gap between a guide and a core of the valve.
6. If necessary replace a guide (it is carried out in a workshop).

Prevention

Do not establish a guide of the same diameter again at all.



Valve guide
The required value
Border
Admission
0,02 – 0,05 mm
0,10 mm
Release
0,04 – 0,07 mm
0,10 mm