What is Cylinder Pressure?
1 Answers
Cylinder pressure refers to the magnitude of compression force in the cylinder when the piston reaches the top dead center at the end of the compression stroke. Insufficient cylinder pressure indicates reduced cylinder sealing, which will lead to decreased engine power and difficulty in starting. If individual cylinders have insufficient pressure, it will cause unstable engine operation. For gasoline engines, the cylinder pressure typically ranges from 8 to 11 bar, while for diesel engines, it ranges from 12 to 16 bar. Specific values should be referenced according to the manual. Methods for checking gasoline engine cylinder pressure: 1. The engine temperature should be between 80 to 90 degrees, and the battery discharge level should not be less than 50%. 2. Remove all spark plugs and fully open the carburetor's throttle and choke valves. 3. Press the rubber tip of the cylinder pressure gauge firmly into the spark plug hole of the cylinder to be tested and hold it firmly. 4. Use the starter to rotate the crankshaft for 3 to 5 seconds at a speed of 150 to 180 rpm, and record the pressure indicated by the gauge. Repeat the measurement twice, and check the remaining cylinders in sequence. 5. If the cylinder pressure is below the specified value, add 20 to 30 grams of fresh engine oil to the top of the piston and recheck the pressure. If the pressure rises significantly, it indicates severe wear of the piston rings and cylinder. If the pressure remains the same as before, it suggests air leakage from the valves or cylinder gasket, and further inspection is required.
