e8879fe5 Check of a compression

In case of reduction of engine capacity which is not defect of ignition or fuel system check of a compression can define a condition of the engine. If check is carried out regularly, it is possible to define defect which will be shown in the nearest future.

The engine has to be heated-up up to the working temperature, the level of oil has to meet standard, the accumulator has to be completely charged. Also the help of the assistant will be required.

1. On engines with system of injection of fuel remove the fuse of the fuel pump from a box with fuses. Now start the engine and let's it work to a stop.
2. Disconnect system of ignition, separating the multioutput socket from the ignition coil. Unscrew all spark plugs.
3. Screw in a tip of a kompressometr in a cylinder No. 1 spark plug opening.
4. The assistant has to press against the stop a pedal of an accelerator and turn the engine a starter within several seconds, at the same time it is necessary to watch indications of a kompressometr. Pressure will grow quickly enough in the serviceable engine. The low pressure on the first piston stroke accompanied with gradually increasing pressure on the subsequent courses indicates worn-out piston rings. Low pressure on the first course which does not increase further indicates leaky valves or the punched laying of a head of the block of cylinders. Deposits on a reverse side of plates of valves can promote low pressure also. Make record of the most high pressure, then repeat the procedure for the remained cylinders.
5. Because of a variety of kompressometr and speed of rotation of a bent shaft of the engine data often differ in a starter when checking a compression. For this reason the actual pressure of compression are not specified. However the most important factor is that pressure have to be identical in all cylinders.
6. Add to cylinders insignificant amount of engine oil (about 20 cm3) through openings for a spark plug and repeat test.
7. If there is an increase in pressure after oil is added, it means that piston rings are worn-out. If pressure does not increase, available leak in valves or laying of a head of the block of cylinders. Leakage of valves can be caused by the burned saddles or plates of valves or the bent valves.
8. If two adjacent cylinders have equally low pressure, it is the most probable that laying of a head of the block of cylinders burned through between them. Emergence of cooling liquid in combustion chambers or on the probe for measurement of level of engine oil confirms this defect.
9. If pressure in one cylinder is about 20 percent lower, than in another, and the engine has slightly rough mode of idling, the worn-out cam on distributive to a shaft can be the cause of it.
10. After check establish spark plugs and repeatedly connect high-voltage wires and the coil of ignition. Install the fuse of the fuel pump in a box with fuses.