This is a great example of how NOT to do this test. Keeping any part of your body in the prop arc with more than 20 psi or so in the cylinder is asking for trouble. There is simply no reason to do that. If you have the prop at TDC, it isn’t going to move under 80 psi. If you don’t, it may well move and you don’t want to be in the way.
The tester has a calibrated orfice between the 2 gauges. When not connected to the spark plug adapter the hose end is sealed allowing a comparison of the gauges.pressures.They should be close to the same. A small difference will not affect you deciding whether the cylinder tested is acceptable. It was not my intention to show the theory of how the tester is designed. I could make video showing the difference in reading using a tester designed for large cylinders compared to small. Most of the time you don't even have to look at the gauges to tell a cylinder is no good, air whistling out the exhaust little effort to hold the prop from rotating.
Yes you are absolutely right if you want to be that picky. In the aviation world we have been using the term compression test and diffential testing interchangeably. I guarantee you its not that we uneducated or don't know the difference.
I must informed this Gentleman ' that what he is doing Is Not Compression Test,,, What this Gentleman is doing is a Differencial Cylinder test ...I have a conversation with A Continental Engeener ..he also was wrong Educated
A&P mechanics know exactly what it is. We call it a compression test just to tweak people like you who think they know everything. BTW your spellcheck ain't working.
@@KerryWho As a quality Auditor, I don't think, there is a special group of people who are allowed to risk their lives because they are skilled, safety is safety, anyway, maybe that's how you do things over there 😉
Surely, I have avoided imminent death for the past 40 years. Also, there is not a single causality in the hundreds of people that I have instructed. Please post your own video on how you think it should be done.
