Oil...again?

[azmuth1]

I've read a lot on this site and columns refered to on this site, on the subject of engine oil. I am convinced on using a straight weight oil. Some reason, my mind has been leaning to Aeroshell...W100 or 100 W plus, W80 or W80 plus. Shell's site states the newer 'plus' prohibits corrosion for engines that sits quite a bit...sounds convincing...but what are your experienses, Plus or not, without getting to the chemistry part of it. Price is about the same.

This is my first plane and I purchased it in Aug, '09. 9291A has a C 142-2 with 50 hrs SMOH using 100W mineral oil (changed twice for service reasons). I've been told by some who should know, and even may know , that the C 142-2 is a "looser" engine by pedigree, though a good engine, and that the heavier weight oil would be desirable. We live in central Illinois and average about 5 hrs a month...so the other 715 hrs it sits and I play hanger rat.

Thanks all for your imput.

Rookie John

[GAHorn]

I cannot imagine what is meant by "looser engine" and would recommend you totally DISregard that comment.

Use AeroShell 100W and you will be reassured you are using the most popular, and most trusted oil in aviation.

[Bruce Fenstermacher]

When I use straight weight oil which is most of the time I use Aeroshell 100W. I don't feel the need for Plus oil flying about 50-60 hours a year with about a 2 weeks in between flights on average. There is no science or long term experience behind my decision. And I don't second guess myself.

[cessna170bdriver]

...I've been told by some who should know, and even may know , that the C 142-2 is a "looser" engine by pedigree, though a good engine, and that the heavier weight oil would be desirable.

Absolutely incorrect. Both engines are overhauled using the SAME overhaul manual and the SAME set of tolerances.

I use Phillips multigrade ONLY because that is what ECI, the manufacturer of my cylinders recommends, cradle to grave, and I've complied with that recommendation. I figure they wouldn't risk a huge amount of warranty work on oil they hadn't tested.

[GAHorn]

I took your comment "without getting into the chemistry of it" to mean you didn't want details about the difference between AeroShell and "Plus" oils. Perhaps it might be helpful to mention the results of the difference, however.

Regular AD AeroShell 100W is an additive/dispersant (in automotive-terms commonly called "detergent") oil. The "100" is the military-grade for SAE 50 wt oil. ("80" is SAE 40 wt, which the engine mfr recommends in freezing ambient temps./winter.)

The "Plus" oils have phosphate additives similar to automotive oils, which provide greater protection against scuffing of internal parts during operations. Those additives are already in the multi-grade oil Shell mfrs, such as their 15W50. (This is also the additive which Lycoming requires in certain models of their engines due to cam/tappet wear/spalling issues.)
So, (opinion follows), if you are operating a subject Lycoming engine and are manually adding the special stuff to your oil because Lycoming requires it...then the "Plus" oils, or the multi-grades, both of which have the "plus" additive incorporated, might be a good choice for you.

If you don't have the need for that additive because you don't operate those particular engines and your engine mfr doesn't require it, then you can avoid the "Plus" additives and not suffer the erosion of your "yellow metals" inside your engine that the additives supposedly injure during periods of inactivity. (TBO Advisor author Kas Thomas wrote extensively about this matter some years ago when Exxon produced their "Plus" oils. His tests demonstrated copper bearing mateiral "leaching" during tests of engines using "Plus" oils. Opponents of Thomas argue that during the ordinary TBO of engines that insufficient damage is incurred from leaching to be a concern, and Thomas responded to the effect that those opposing views were from operators such as airlines/charter/schools with high-useage and frequent, almost bi-annual, overhauls, not from private owners who expect to overhaul their engines only once every 10-20 years or so.)

I subscribe to Thomas' view and therefore use only 100W oils, and since I live in Texas, have only very-rarely used 80W.

[Harold Holiman]

Over the years I most always used single grade oil in my 170, 172, and 180 and never had any major engine problems. In the 70's and early 80's I used Texaco Oil W-100 with an occasional winter change of W-80. I changed to Shell W-100 and W-80 when the Texaco oil either quit being made or became hard to find. I never used additives in the oil, although I would give the planes an occasional taste of MMO in the fuel.

Harold

[azmuth1]

Thank you all for your great information. I will do without the 'plus'...I was leaning that way. George, I didn't mean the chemistry wasn't important...it was just that I had read all the past great information threads on this site and the info was quite a bit to digest. Your further explination in this thread shook the good or important stuff to the front of my thoughts.

It'll be great to meet all of you at AirVenture this year.

Rookie John