Compression test photos – 2021-08

02 Oct 2021 Compression test photos – 2021-08

Some pictures of my compression test results from the condition inspection in August 2021. Mike Busch says that compression alone is not really that helpful, since the same cylinder can test with low compression one day and high the next, depending on many factors. However, it’s required as part of my OCM process, so I’m doing it.

All my numbers were good, particularly since I did the test with the engine cold. Doing the test is easy, but involves some very serious risk. There are a lot of good links to instructions on how to do the test, but the main thing to recall is that by putting compressed air in the cylinder it can cause the propeller to move suddenly, causing severe injury or death if you are in the wrong place. Make sure you know what you are doing and keep others away from the prop when doing this test. I prefer to do it alone with no “helpers” or “spectators”, in case they inadvertently get into the prop arc.