2.1.8. Compression check

Before measurement of a compression check level and a condition of engine oil. Besides, be convinced that the condition of a starter and the storage battery corresponds to norm.

Start the engine and warm up it to temperature of cooling liquid of 80-95 °C.

Muffle the engine. Disconnect candle wires of a high voltage.

Remove spark plugs.

Scroll a cranked shaft of the engine a starter for removal of extraneous particles from cylinders.

Fig. 2.8. Installation компресометра

Establish компрессометр in an opening for a spark plug (fig. 2.8).

Press an accelerator pedal before complete opening of a butterfly valve.

Scroll a cranked shaft of the engine a starter and consider indications компрессометра.

Nominal rate: 1500 kPas.

Minimum admissible value: 1400 kPas.

Repeat measurement for all remained cylinders and be convinced that a compression difference between cylinders less than limiting admissible value.

Limiting admissible value: no more than 100 kPas

If in any cylinder the compression does not correspond to a range of admissible values or the difference of compressions on cylinders exceeds maximum permissible value, fill in a little engine oil in an opening for a spark plug of this cylinder and repeat measurements.

If after oil filling the compression increased, causes of defect are wear or damage of a piston ring and/or a cylinder mirror.

If after oil filling the compression does not increase, the reasons is the burn-out or damage of a saddle of the valve, or leakage of gas (pressure) through laying of a head of cylinders.

Moment of an inhaling of spark plugs: 20–30 N · m.