Compression Test

Before checking compression (compression pressure) pre-check the engine oil level. Make sure that the starter motor and battery are in good working condition.

Let engine and to wait until the coolant temperature reaches 80-95 ?� C.

Stop the engine and disconnect the wire from the spark plug.

Clean the areas next to the spark plugs for what blow compressed air (in the absence of the compressor blow sites automobile or a bicycle pump). This is necessary in order to prevent contaminants from entering the cylinder during the compression pressure check. Remove the spark plugs.

Rotate the crankshaft of the engine to remove foreign objects from the cylinders.

Screw the tip compression tester into the well of the spark plug.

Fully open the throttle.

Include a starter and a cranked shaft of the engine (about four revolutions), following the indications of compression tester. On the serviceable engine pressure should accrue quickly. Low pressure after the first piston stroke and slow increase in the subsequent steps of compression specifies in deterioration of piston rings. If after the first piston stroke pressure low, and in the subsequent steps of compression does not increase, the reason is leak in valves or infringement of tightness of the cylinder head gasket (the cause may be the formation of cracks in the head). Compression decrease can also be caused by deposits of carbon on the reverse sides of the valve plates. Record highest compression setting.

The reference value compression -1200 kPa.

If a compression equally low only in two next cylinders, the most likely reason is the lining burn-out between these cylinders. As acknowledgment may appear in the combustion chamber or the oil pan traces of coolant.

If the compression in one cylinder is lower than the rest, and the engine is unstable idling, the cause may be the wear cam camshaft.

If the compression exceeds the nominal value, it means that the combustion chamber is covered by deposit adjournment. In this case, the cylinder head must be removed, and remove carbon deposits.

Repeat the same operation on the other cylinders, making sure that the difference between the pressure values for each cylinder does not exceed the permissible value.

The maximum allowable difference between the values of compression in the cylinders of the engine is 100 kPa.

If the difference is less than the allowable value, pour into the cylinder through the spark plug hole a little oil, then recheck the compression.

When pouring oil will improve compression possibly worn piston rings and the cylinder wall.

If the compression will remain the same, maybe jammed valve, the valve seat is worn or broken cylinder head gasket.

Replace the spark plug and connect them to the wires.

The tightening torque of the spark plug - 20-30 Nm.