![Wink ;)](./images/smilies/icon_e_wink.gif)
As mentioned, the noise "should" be obvious, but there is always a first time for not recognising a noise for what it is!
I am not disputing the oil into the combustion chamber of a horizontal cylinder should still do the things we expect it to do, like seal the ring to cylinder bore gaps that would cause loss of compression, but for the life of me I can't see it creeping up and over a 2 inch piston on just a single or double movement of the piston.
A broken ring ought to be making a distinctive noise, but it is very likely to be obscured by all the other noises created by the engine.
What it all boils down to, is that the cylinder head and barrel will have to come off to find out why there is low compression on that cylinder, and I understand Gary's frustration with it and the amount of time already spent on it for it to now require even more effort.
John
I am feeling the same way about the front nearside drive shaft oil leak I still have!