The comfort and safety of car operation directly depends on how correctly its gas distribution mechanism works. An important role in this is played by the intake and exhaust valves, which should fit as closely as possible to their seats located on the cylinder head. The valves must be absolutely tight. Only if these conditions are met, the pressure required for normal operation will be created in the combustion chamber.
Necessary
- - a set of flat probes;
- - special template or locksmith wide ruler;
- - lapping paste;
- - a device for grinding valves.
Instructions
Step 1
In order to check the valve lapping, remove the cylinder head (cylinder head), then clean it and the bearing housing, which often accumulates carbon deposits and dirt. Also remove oil deposits and use a metal brush to clean carbon deposits from the walls of the combustion chambers.
Step 2
Inspect the cylinder head and bearing housing for cracks. Also check the camshafts, hydraulic pusher bores and bearing housings for traces of metal coating. Notice how tight the valve guides and valve seats are in the cylinder head. Make sure that there are no traces of their displacement when the gas distribution mechanism is operating. Check the valves and their seats for signs of burnout and cracks.
Step 3
Using a special template, check the flatness of the cylinder head. If no such template is available, use a wide locksmith's ruler and check the bottom seating plane of the head.
Step 4
To check for flatness, place a ruler against the plane of the head. Make sure that there are no gaps between its edge and the plane. Inspect the entire plane, as gaps can be both in its middle and along the edges. The gap should not be more than 0.01 mm. If it is greater than this value, the mating plane of the head will need to be milled or replaced. It is necessary to change the cylinder head together with the bearing housing.
Step 5
Also check the head for leaks. To do this, close the window for supplying coolant to the thermostat from the end surface of the head, then cut a gasket from a piece of rubber and place it under the thermostat branch pipe. After that, turn the cylinder head over and fill all internal cavities for the coolant with kerosene.
Step 6
The valves also need to be checked for tightness. This is not difficult to do. To do this, lay the block head on a flat surface so that its mating plane is on top. Then pour kerosene into the combustion chambers and wait a few minutes. A decrease in the level of kerosene in one of the chambers means that one or both valves are leaking.
Step 7
Check the cylinder head for leaks. If leaks or pits are found on the mating face of the head, it can only be repaired using cold welding. It can be replaced if desired.
