Okay, I am new to my field as an operating engineer and just have a question concerning insolubles. I say that because I am not an expert when it comes to lube oil but just know to change it when it tests bad based on some basic tests that I do and when the lab sends results back. I know one of our parameters for changing oil is when the insolubles gets to a .8 to 1%, which I always thought was funny because Mobil allows you to go to 2%. This is 30W engine oil I am talking about in a medium speed diesel engine driving a generator so constant load. We use two glacier spin filters to keep the insolubles down but we keep getting to this point after about a 1000 hours of oil life on our older engines as they are about 5000 hours shy of a overhaul including the rings. We'll we have recently tried to run a filter cart when the engines are offline to remove these insolubles, I question the approach but trying to back it up with some data. They were using 10 and 3 micron filters and finally we have some 1 micron filters but I am trying to find more data behind insoluble/soot information. I have found out that most insolubles seem to be less than 3 microns in size and the majority of them at .75 but can't prove this theory. I know when I read about it online the only time it comes to size is testing for particle counts and its confusing because it talks about dispersed and other terms which I do not think apply to insolubles just floating around an engine.
I guess what I am looking for is something I do not know if I can find an answer for that is how big is an insoluble? Are they all sub micron size then as time goes on they actually join each other and "grow" to become larger particles? Then I am worried about running 1 micron filters on them to be a waste of time, because if you are only taking the top of the curve off with using a 1 micron filters isnt everything else just going to build up underneath it still?
Thank you!
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