I finally went looking for more info (I made a double shot of coffee this morning, had to do something), here's Phillips' web page for the AW oil
Phillips 66® Victory AW 20W-50 Oil is an ashless dispersant, multi-grade engine oil specially formulated for year-round use in aircraft piston engines. Victory AW 20W-50 is pre-blended with the proper concentration of anti-scuff/anti-wear additive (LW-16702) mandated by Lycoming Service...
phillips66lubricants.com
and here's the blurb from the web page
Phillips 66® Victory AW 20W-50 Oil is an ashless dispersant, multi-grade engine oil specially formulated for year-round use in aircraft piston engines. Victory AW 20W-50 is pre-blended with the proper concentration of anti-scuff/anti-wear additive (LW-16702) mandated by Lycoming Service Bulletins 446E and 471B and Service Instruction 1409C. It provides distinct performance benefits compared with single-grade engine oils, including easier starting and faster oil circulation at low temperatures, reduced warm-up time, and reduced oil consumption in most engines. It maintains its film strength under high loads and at high temperatures to protect against wear and piston scuffing.
The ashless dispersant formulation helps minimize the formation of engine sludge, varnish, piston deposits and combustion chamber deposits, resulting in a much cleaner engine compared with the use of straight (non-dispersant) mineral oils.
They reference Lycoming
SERVICE BULLETIN 446E, and
SERVICE BULLETIN 471B, as well as
SERVICE INSTRUCTION 1409C.
Service Bulletin 446E makes it mandatory for operators of Lycoming O320 H, O360 E, LO360 E, TO36 0 E and LTO360 E series
engines to use an oil additive (Lycoming LW 16702) because "when the engine is first started, for a very brief interval there is insufficient residual oil between the rubbing parts which affects the service life of components"
Service Bulletin 471B says essentially the same thing but it specifically applies to Lycoming TIO-541-and TIGO-541 series engines.
In 471B it makes reference to Service Instruction 1409C, "Original approval of the oil additive was released in 1981 to the field in the form of Service Instruction No. 1409.
We believe that some operators may not realize the importance of the use of this additive."
It also makes the very startling comment, "The additive must be consistently used at each oil change. A period of non-use can initiate distress which will not be cured by later use of the additive. Its use is essential in new, rebuilt and overhauled engines."
What I'm drawing from this is that there are certain Lycoming engines that are really prone to wear at start-up due to some specific areas of the engine not holding a film of oil if oil without the wetting additive is used. But aren't all Lycoming engines, with their overhead cams that are prone to dryness when left to sit for prolonged periods of time, prone to corrosion and wear? So why is this oil additive recommended by Lycoming for only the worst offenders?
My IA recommends the use of CamGuard which I understand is essentially the same as Lycoming LW-16702 (edit: I'm wrong, read the article two posts down). I'm thinking, if Phillips makes oil with the stuff already in there at the correct proportion, and since Cam Guard isn't exactly cheap or easy to work with (the little bottles seem to leave a schmear of goo everywhere you put them, or maybe I'm just messy!), maybe I just keep buying the AW oil instead of the XC?
I have been buying oil from AviationOilOutlet.com and it's a few bucks more for a case of AW over XC but a pint of CamGuard (about one oil change plus refills before the next one) is almost $30 at Aircraft Spruce!
Nobody's paying me for the free advertising but maybe my mistake of buying the AW was destiny and that's what I'll use from now on?
What do you guys (any gals here?) think?
Edit: Even more interesting is the FAA's Special Airworthiness Info. Bulletin related to this,
https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID125536679820220927131908.0001
In the SAIB there are limitations and an AMOC related to using other brands with equivalent additives. I guess the rub in all of this is that if you use an oil with the additive, when it comes time to add oil (in between oil changes), you are going to want to use more of what is already in there. If you don't, then the limitations kick in. This isn't a huge deal for our engines as they aren't subject to the AD, or the service bulletins, but if you want the protection to be 100%, then the limitations should be read as pretty worthwhile recommendations.
mmmm, coffee.
