In my case, They only varied by 10psi or about 5%, which is pretty good. The test conditions are relatively similar across the cylinders, though, so you should look at the difference. The raw numbers will change depending on how long you crank the engine, how good your gauge seals, how accurate your gauge is, etc.
More important than the absolute compression numbers, though, is the variance between cylinders. On an old 90’s miata engine, anything north of 160psi is acceptable across all cylinders. In the case of my miata, I was looking for 128psi minimum, 182 standard, 28 psi max variance.
Mr20de engine compression reading manual#
The field manual for your engine should say what the specifications are for a compression test. The compression tests results were 180 190 190 180 psi for the four cylinders.