Aircraft piston engine oil "stuff"

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Years ago, I was an aeroshell 100 user. The Extra 300L sales and maintenance shop said: "Aeroshell 100 gives the best results". However, after pulling one of our engines apart after a prop strike at 93 hours total time, I was horrified. Plenty of corrosion, wear, varnish and some sludge. In fact, the camshaft was ruined by obvious corrosion, as were the connecting rods. 1 year, 93 hours!

I switched to A/S 15W-50 Semi Syn in all our aircraft. That same engine came apart after another 100 hours for the Lycoming crankshaft AD. It was in perfect condition!

I'm getting the same hot oil pressure, better cold startup oil pressure and cleaner looking oil. All good things.

Here is an interesting blurb on aircraft engine oils: Avweb "oils"

Both Shell and Exxon say good things about the multi grades they sell. Shell says the multi grades have the most complete additive package of the oils they sell. Exxon says the multi grade outperforms the mono grades. Phillips calls the multi grades the premium oil of choice.

The article goes on to discuss mono and multi grade corrosion, additives, synthetics, super oil, and more.

However, none of the company engineers interviewed give away any trade secrets. Other than Phillips seems to have fewer additives, if I read it right.

After reading a BITOG post by Ed Kollin from Camguard and the sidebar on the above article, he seems to favor Phillips so he can add his product.

I still favor A/S 15W-50 due to real world results. My Cardinal engine failed prematurely on a diet of Phillips XC, with massive internal corrosion.

Sure, I have limited data points. However, the premium oils seem to be the right direction for my flight department.
 
Wrong venue.
This should be a letter to the editor for "Plane & Pilot" and "Flying".
Yeah, I get both.
Owner/Operators need to be aware of you findings.
I'd certainly want to hear about your experiences if I had a costly engine to take care.
It blows my mind that the single grade Aeroshell did so poorly in service, and the Extra people had no clue that it would.
 
0320 Lycoming here. I use shell 100+ in the summer & aeroshell 15w-50 in the winter. I also preheat with a Tanis heater in the cold & aim to fly at least every 2 weeks. You always hear how not flying can lead to corrosion more that the type of oil used. If my plane may sit for a bit I try to have clean oil in it for that sit.

I'm always looking for more tips, but that's my current regimen.
 
I agree with what Mr. Joe was aluding to. . .the frequency of flight and the environment probably play a bigger role than the type of oil.

That being said, I fly a light twin with Lycoming IO-360-200 engines. It gets flown about 500 hours per year. The plane is 23 years old and I've run several engines to TBO without any oil-related issues. I did have a camshaft go bad early on one, and I was subject to the crankshaft AD on another. The bad camshaft was chalked up to a manufacturing defect and was waranteed.

The engines have always run AeroShell 15-50 except for a year of Exxon Elite (I had no issues with Exxon, except it wasn't stocked locally, so I went back to AeroShell). We run this aircraft in all weather conditions, in very hot summer conditions, very cold winter start-ups (have electric engine heaters on for most, but not all cold starts) and everything in between. It gets flown regularly, with fairly long 3-4 hour sorties being common.

It should be noted that I'm in PA. . .CuJet is in FL (I believe) and his engine is probably kept in a moist, tropical, environment with lots of salt present in the rains, air. A plane in that environment is going to have more internal corrosion than my airplane without a doubt. That combined with flying an average of only 8 hours a month is a recipe for corrosion on the internals. The only thing you can really do about it is fly it more often. . . .
 
I'm in Florida, but I fly North! So, it's not unusual to have starts, without a preheater, at well below freezing. In fact, I'm heading North again soon. Last winter, we had a number of 20 degree F days in TN. Plus one day that was 4 degrees! Engine would not start.
 
If you end up North with out a pre-heat I'd consider paying for a heated hanger the night prior to your departure, if that's an option. I did that myself years back in N MI. It was Jan & I didn't want to chance a no start. Of course us oil guys know it's also easier on the engine.
 
No hangars exist at the private airports I frequent. So a portable preheater may be in order this year.
 
Interesting tidbit about the Extra 300. I am not one tearing down engines much anymore, but while working a stint for several years accomplishing NDI work, it seemed many of the Lycoming parts were what appeared to be copper clad. One would suspect the copper clad was to minimize corrosion concerns. This was often on connecting rods, rocker arms, accessory gears and so forth.

Cams do take a beating not only from use but from what appears to be inferior metals currently used for lifters, and of course corrosion.

As for sludge from engines running straight viscosity oils. Yes and same is true about an often light varnish coat.

Two of my greatest cringe moments are so often hearing a cold engine cranked and fired, then run right to 1500 or more rpm. Then allowed to sit there for 10 seconds or more before being throttled back.

The other is hearing high rpm prop cycle checks...huge manifold pressure swings and mechanical stress on sometimes a not fully warmed up engine. Prop checks done at far less rpm will still verify, governor operation, blade cycling and if needed feathering.

PK
 
Originally Posted By: PMK

Two of my greatest cringe moments are so often hearing a cold engine cranked and fired, then run right to 1500 or more rpm. Then allowed to sit there for 10 seconds or more ...
The other is hearing high rpm prop cycle checks...


Seems crazy, but Lycoming camshafts are above the crankshaft. A high RPM start provides much needed camshaft lubrication. There was a rather large discussion about this. The conclusion of that discussion was simply that RPM's above 1200 were required to get oil to the camshaft.

With all the Lycoming camshaft failures out there, I suspect corrosion as the number 1 culprit, and dry startup as the other.

Here was my worn camshaft:

DSC00149_resize_with_arrow.jpg


Here is the new camshaft, with oiling holes to prevent dry startup problems. (yes, these seem to last much longer)

DSC00426_resize02.jpg
 
Who did the cam mod? Firewall Forward Centrilube?

Yes there are plenty of camshaft and lifter concerns with engines now a days.

Recently in the Duke I installed Carbide faced STC lifters. Even in that Lycoming, which is the TIO541 with the cam below the crankshaft, with older lifters the cams last and lifters don't spall. The newer lifters from Lycoming are junk and if lucky will maybe make 700 hours. The carbide lifters are seeing 3 full TBO overhauls typically.

Odd statement about the high rpm starts. I could be wrong, but this was not really a standard accepted practice 30 years ago. Kind of the same era when spalling lifters was not a major problem either.

Bummer about that cam and the rest of the corrosion.

PK
 
Oh, lest you think Lycoming camshaft problems are new, they have been an issue, especially in infrequently flown personal aircraft, since just before the start of the Civil War! This is certainly nothing new, nor is it surprising, considering the design.

More seriously, the camshaft issue, along with others, were among the reasons Continentals were favored by owners of personal aircraft.
 
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