Similarly a compression of 85 psi or lower is extremely bad. What are good compression numbers for this motor.
Engine Diagnosis Leakdown And Compression Test
Good compression test numbers. Healthy engines should have compression over 100 psi per cylinder with no more than 10 percent variation between the highest and lowest readings. The most desirable situation is that all cylinders give the same or close to the same reading. A compression test can be used to compare the compression of one cylinder to the others. As a general rule of thumb compression pressure around 90psi is the minimum required for combustion to occur in a gasoline engine. Wet compression test diagnosis. Engine compression atmospheric pressure at sea level is approximately 147 psi.
With a compression tester a few hand tools and. Ill do a compression test soon just thought id ask now. 1000 9711 2000 9428 3000 9151 4000 8881 5000 8617 6000 8359 7000 8106 8000 7860. A 91 compression ratio cylinder is compressing the air and fuel mixture to about 132 psi at sea level 9x1471323. That is if the compression test reveals less than 90psi that particular cylinder can be declared dead on the other end of the spectrum 200psi is about the most compression pressure you will see in a non racing gasoline engine. 2006 subaru impreza sti 650 whp e85 67mm turbo too much to list 1994 black mkiv na supra full 1200 hp treatment in slow progress full swap.
As a general rule a compression of 135 psi or better is excellent. While each engine and manufacturer are unique and have different levels of recommended compression psi generally speaking a compression over 100 psi with less than a 10 percent variation between the lowest and highest reading is considered acceptable. The results of a compression test can be quite telling. Furthermore that reading should be above 135 psi. An engines cylinders need a good seal between the piston rings and the cylinder walls and between the valves and their respective seats.
Gallery of Good Compression Test Numbers
