lobstaboy wrote:Without gurgling the level shown on the dipstick can vary, for example depending on how long it has been since the engine was last run (oil taking several days to drain etc).
Agreed, however as long as there is sufficient shown on the dipstick for the flight there is no need to gurgle another couple of hundred ml in to the tank, because that is all you are doing. You have already determined you are not topping it up. Just leave it in the engine.
lobstaboy wrote:What I'm talking about is a sudden change in oil consumption - indicating the onset of a problem.
Careful monitoring over time of the oil consumption is a simple diagnostic of the health of the engine. So is the colour of the oil.
Again agreed, however careful monitoring of the oil over time
does not necessitate gurgling every day. EG I last flew on Friday, all was well with the oil pressure, level and there were no signs of leaks. If I was to fly today I would check the oil level and if I was off for a bimble and verified the oil in the tank at half way between min and max I would not gurgle. I ask yet
again, what benefit would gurgling in this scenario give? On the other hand if I was heading south for a beer with your good self and found the oil level in the tank to be just above minimum I would gurgle before topping up, thus ensuring I did not overfill. That would be the purpose of gurgling.
lobstaboy wrote:Gurgling as recommended at the start of each flying day and checking the level and colour of the oil is straightforward.
Gurgling is and should be straightforward, however it is not necessary everyday. Consider the OP, did the engine need oil? Did the pilot follow routine and needlessly gurgle resulting in the incident? What we do know for fact
is that if he hadn't gurgled the incident would not
have happened. Next person to gurgle is not likely to have left a 'mag' on. It's all very well folks saying they have x hundred hours and still have all their fingers, but that ain't much consolation to someone who has an avoidable incident.
lobstaboy wrote:The honing marks on the bore are there to trap sufficient oil for lubrication and it stays there for a long time - the oil control ring scrapes excess oil from the high spots, leaving the oil in the honing marks. A few turns by hand are not going to remove the oil sitting in the honing marks, so the lubrication during start up will be fine.
I say again, the risk is not ordinarily high, however not gurgling avoids all risk of leaving the cylinders dry. Particularly after a long lay off, such as with coronavirus. How many members of must gurgle fraternity went out to their Rotax's and immediately gurgled after the engine had been sitting for 3/4/5/6… months.
It may be easier to put any talk of risk of 'scraping' oil off the cylinders aside and just consider the purpose of gurgling? Why do something that is not necessary and provides no tangible benefit?