The International Cessna^® 170 Association

It was suggested I switch to Aeroshell 100 W since there are times when my plane sits for a month without flying . Said the W means there is a bit of synthetic added which will help oil to remain on engine parts. Question is---is Aeroshell W100 the same thing as 100W?

I believe you are talking about the W Plus oils that shell came out with. My supplier told me that it was something that Lycoming wanted for their engines. A friend said he started using it his C145 in his 172 because his AE said he doesnt fly that much and it is a good idea for him. My friend wrote to Dave Visser, who was formerly with Shell and now writes for GA NEWS. He seemed to feel that there was no advantage to using it unless you were flying less than 50 hrs a year. He didnt seen to feel that a month of no flying was a problem.

Larry

the Aeroshell oils are all the "Plus" I think nowadays, which means they have the EP lube in them. That makes them legal to use in the Lyc engines that require the additive at each oil change, without having to add the extra additive. They are supposed to provide a little better anti-scuff at startup etc, which can't be a bad thing.

any other brand of oil that is AD100 or whatever the label is just good old 50 wt oil like always, with whatever gee-whiz stuff their particular brand is famous for. I use AS 15W-50 which has the "Plus" additive in it in my 172, as we have sort of changeable weather up here and we use multi weight oil in all of our company piston airplanes. Since I don't fly it that often either I like the additional (perhaps spiritual only) possible protection of the additive in the oil. Can't hurt, I figure.

In addition to mineral oil (which is made from dinosaurs, not minerals), you can still get regular W100, which is a SAE50 weight oil with ashless dispersant. Then there's the multigrade 15w50, which is a semi-synthetic that also has an anti-wear additive package as well as the Lycoming anti-wear additive. Then there is W100PLUS, which is W100 with the same anti-wear additives in the multigrade.

I switched to multigrade for a while because it was semi-synthetic and had the anti-wear additives. Also I didn't want to have to switch oil grades during the winter. Well, "winter" in Texas isn't really cold enough to warrant using a cold weather oil and I discovered that the W100PLUS has the same anti-wear additives as the multigrade (not just the Lycoming antiwear additive).

I don't think the slippery semi-synthetic multigrade oil keeps a good coating during periods of innactivity so I switched to the W100PLUS, which I feel offers the best combination of protection.

guys, correct me if I'm wrong! In Kelowna the engine shop we visited told us that the Continental engines O-300 series oil pans did not like the PLUS additive. It has something to do with the magnesium material . Am I right? Ron

The next "The 170 News" is expected to have an article which addresses these topics.
Ben Visser is the self-proclaimed "expert" and contributor to GAN whose biography includes employment with Shell.

(Some folks have referred to me as an "expert" too, so you can be fairly certain that's not a compliment. Ben and I have disagreed on certain details of his writings. I feel it's important to recognize that the purpose of his contributions are to generate interest and readership for GAN.... not to establish truths or provide supporting evidence for his statements. Doubtless he does not intend to deliberately provide false information, but unfortunately he succumbs to the same bogey as all authors who purport to be "expert". I would never claim to be "expert" in my own biography.)

An example of his expert writing is his dissertation on lead in fuels, in which he claims that one of the reasons it is added to fuels is to prevent valve wear. ("Recession" is the term commonly referred.) His and my disagreement was over that unsupported claim. Although I was not the target of his article in which he ridiculed another for disagreeing with him, I did respond thru our intermediary Ron Massicot. (Another "expert" - Ha! Defn: Ex- a has-been Defn: Spurt- a drip, under pressure.)

Long story short: I suggested that Ben should not make claims that lead is deliberately included in fuel to prevent valve wear. I am of the opinion that lead was put into fuels for one purpose, and one purpose only: to raise apparent octane. Ben politely called me an idiot (one of his more accurate statements, by the way) and I challenged him to provide proof, any proof whatsoever, that valve wear was a problem and that lead was added to combat that problem. It's been over a year and I am still waiting for his response.

Of course, it's not true. While lead may contribute to less wear in certain valve designs.... hardened valves and seats are the answer to such wear. And that has been proven for twenty years now with the use of such materials in modern engines using totally-unleaded fuels. (By the way, if lead is required to prevent valve "recession" in internal combustion engines.... Then why is it that diesel engines that run on even higher compressions which should contribute to recession, and who have never had lead in their fuels, not suffered from such problems?)

The argument is one of perspective, not substance. But I digress....

The "W" in AeroShell 100W does not indicate anything other than "With" additives, according to Shell's own marketing dept. The anti-wear (phosphorous-based) additive package which Lycoming requires in some of their engines is addressed, not by 100W, but by their AeroShell 100W "Plus" oils. Ordinary, so-called "mineral" (meaning non-additive) oil from Shell is AeroShell 100, without the "W". (or 80, etc., depending upon SAE viscosity)

"W" in multi-grade oils is included because they virtually always are additive oils. Marketing departments have promoted that "W" (as in 15W50) as an indicator of "Winter" use,... but that's just anecdotal info from such marketing departments as a method of promoting their product and now it's become common-use in the marketplace.

Don't let the "W" fool you, tho'. In a straight weight AeroShell-brand.... it merely denotes an "AD" ashless dispersant oil.

Personally, I use 100W in my engine year-round. If I live way up "Nawth" I'd use 80W in the winter, and I'd always use pre-heat below freezing. If I couldn't regularly use pre-heat, I'd use a multi-grade, and that's the ONLY reason I'd use a multi-grade. I believe that straight-weight oils are better for all-round use, and they provide better storage conditons during dis-use by "hanging on" to stationary parts thereby preventing rust and providing lubrication during initial start-up, while multigrades tend to "drain off" due to their lesser viscosity. My opinion, of course.

Ron, I didn't have the benefit of the entire "tour" at Kelowna so I don't know if they made such statements or not, but I'll tell you that "Plus" oils contain phosphorus as extreme-pressure additives and that they "leach" copper out of bearings and other "yellow" metals such as bronze and brass internal parts/bushings. I would not use a "plus" oil or a multi-grade oil in an engine unless it was used VERY regularly...never in one that did as much sitting as mine and yours does. (less than 150 hours/year)

Appreciated the Aircraft Oil Debate, in the 170 Technical Section, of the 170 News.

Other than making sure the oil is hot and hasn't had time to settle, is there anything else I could do like flushing something through the engine to take out any remaining contaminates during an oil change. MM, Diesel, Hoppes #9, Mineral Oil? George I give you all the credit for my inspirations!

You could take a new quart of aviation oil and use it as a "flush" while the drain was still open. That's the only endorsement I will make.