Oils ain't oils

[Echo]

Aircraft piston engine oil - what does 'Ashless' mean?[?] Should we be running it in our four stroke gyro engines ? Eric[)] ....& dont say 'old loco oil is the best' Murray , or I'll #@?&^%# come up to QLD & staighten out all them bananas...[xx(]

[asra]

Ashless Dispersant (AD) OilAshless Dispersant Oil could be written as Ashless and Dispersant Oil. There are two distinct features to remember about AD oil. Ashless stems from a requirement to clarify that the oil does not leave behind any ashes, or burning embers as it cleans. Decades ago in aviation history, oils that cleaned involved metallic cleaning particles that left embers. Such glow ing metallic embers contributed to pre-ignition. Detergent oils have long since been removed from aviation piston engines. Aviation oils that clean are required to be Ashless. When an oil has Dispersant qualities, the particles created and removed by cleaning are suspended (dispersed) within the oil. Being dispersed, they are collected better by the oil filter. During the initial engine break-in period, RAM believes that AD cleansing is premature. RAM recommends a non dispersant Mineral Oil during the initial twenty-five hour break-in period of an aircraft piston engine, or replacement cylinder.Also check outhttp://www.lycoming.textron.com/support/publications/maintenancePublications/serviceInstructions/SI1014M.pdf