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Compression Test
Disconnect ignition system, having disconnected the high tension of the ignition system of the ignition distributor cap, and grounding it on the block. Connect the device for compression measurement to the spark plug hole of the cylinder N1. Pressure gauge compression | Meter hose is connected to the adapter, and the adapter is screwed into the spark plug hole. |
Fully open the throttle and spin the crankshaft of the engine starter. After one or two turns of the compression pressure should increase to a peak and then stabilize. Record result. Spend similar check with other cylinders and write down the received indications. Pressure in all cylinders should be identical. The difference is more than 2 bar between any two cylinders means malfunction. In the serviceable engine pressure should accrue quickly. A small pressure of the first step gradually raising at the subsequent steps, specifies that piston rings are worn out. A small pressure of the first measure, which does not accrue at the subsequent steps, specifies in leak in valves or on the punched lining of a head. Deposits on the lower parts of the valve can also cause a low compression. If the inspection you have any doubts, contact the experienced professionals. If pressure, in what or the cylinder too low, spend the following check to establish the cause. Pour a teaspoon of engine oil into the cylinder through the spark plug hole and recheck pressure. If after adding the oil pressure increased by compression, this means that the worn piston or cylinder. If the pressure is not increased, means, the reason in the worn out or scorched valves or in the punched lining of a head of cylinders. Low pressure in two next cylinders practically always means that between them the head lining is punched. If one of the pressure cylinders is about 20% lower than in the rest of the engine and poor idling, this means that the cause is possibly worn camshaft lobe. If the pressure is too large, then most likely, the walls of the combustion chambers are covered with deposits of coal. Once validated, screw in spark plugs on places and connect ignition system.
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