The comfort of operation depends on the correct operation of the gas distribution mechanism of the car. One of the key roles in this process is assigned to the intake and exhaust valves. They must fit snugly against their seats on the cylinder head in order to create adequate pressure in the combustion chamber.
Necessary
- - a set of flat probes;
- - kerosene;
- - a special template or a wide locksmith's ruler;
- - lapping paste;
- - a device for grinding valves.
Instructions
Step 1
Check the tightness of the mating of the valve and its seat on the cylinder head (cylinder head). To do this, remove it. Clean the cylinder head and bearing housing from carbon and dirt and carbon deposits, wash it from oil deposits, remove deposits from the walls of the combustion chambers with a metal brush.
Step 2
Inspect carefully the cylinder head and bearing housing. They must be intact, without cracks. Inspect the working surfaces of the camshaft bearings, bearing housings and the walls of the bore holes of the hydraulic pushers, scuffing and traces of metal coating are not allowed. The valve seats and guides must fit snugly in the cylinder head body. Their displacement during timing is not permissible. Seats and valves must be free from burn marks and cracks.
Step 3
Check the flatness of the cylinder head with a special gauge. If it is not, then you can check it with a wide locksmith ruler. To do this, attach it with an edge diagonally to the lower mating plane of the block head. Make sure there is no gap between it and the edge of the ruler. It can be observed both along the edges and in the middle of the plane. Measure the gap on both diagonals with flat feelers. The maximum allowable value is 0.1 mm. If the size is larger than the permissible, then the mating plane should be milled or replaced.
Step 4
Check the cylinder head for leaks. To do this, close the coolant supply window to the thermostat on its end surface. Turn the head over and fill its inner cooling jacket with kerosene with kerosene.
Step 5
Make sure there is no kerosene leaking from the cylinder head. If it is found, and also when there are shells on the mating surface, then you can either repair the block head using cold welding, or replace it.
Step 6
Check the tightness of the cylinder head valves. To do this, lay it on a horizontal surface with the mating plane facing up. Fill the combustion chambers of the cylinder head with kerosene and wait a few minutes. A drop in level will mean that one or both valves are leaking.
Step 7
Eliminate valve leaks by lapping them to the seat, if there are no cracks or mechanical damage on it and the valve disc. To do this, remove the valve stem seal. Pull the valve out of the guide sleeve. Apply a lapping paste to its working part, usually "Diamond" is used. Install the valve in the cylinder head and fasten the lapping device to its stem.
Step 8
Press the valve against the seat and swing it from side to side. After about 10-15 movements, turn it 90 ° and continue the process. Lapping until a uniform surface is formed on the valve seat and disc. Remove any residual lapping paste from both elements. Reinstall the valve in reverse order. Replace valve stem seals.
