Didn't realise you were present super guppy when we did this work!!!!!!!!!!!
We did the test wrong did we!!!!!!
As I said due to the results I had another engineer repeat the check and we also used another diff comp tester as we didn't believe the results we were getting.
Given that we had a fleet of over 25 piston engined aircraft comp checks were a daily occurrence.
The cylinders were removed and you could move the valves around in the guides like a belly dancers ar*e.
New cylinders fitted and we were back to 76/80 all round.
When carrying out the test on the R22 0-320 the valves were closing very slowly under hand rotation and were failing to seat properly as the were hanging so far down in the guides.
Air was pouring out through the exhaust. We took the exhaust off and were able to watch the valves closing and what was happening. Under full speed there would be enough dynamic energy to slam the valves closed onto their seats.
Exactly the same problem on the 0-200. Air leaking past the valve seat due to the guide being shot. Again not showing under dynamic conditions.