Oil

N395V · #1 05-22-2006, 06:20 AM

What exactly do aviation oils have in them that automotive oils do not?

Lots of discussion about MoGas what about MoOil

Mike S · #2 05-22-2006, 08:18 AM

I used Castoroil GTX 20-50 in my Franklin for years, could not see any problems, other than slight increase of leakage on the engine and inside the cowling.

I finaly changed back to av oil beacuse my wife is starting to fly, and was nervous about not using av oil.

Mike

pierre smith · #3 05-22-2006, 09:07 AM

Hi Guys/Gals,
I wouldn't be tempted to use automotive oil for the simple reason that your insurance may be void if you do. I have a couple of huge cylindrical air filters on my ag plane (Air Tractor 502) that cost upwards of $80 each. A friend of mine checked his automotive crossover book and ordered me two Wix filters for a substantial savings. I mentioned that to my IA and he said that if I ever crashed and the insurance co. found the Wix filters they could deny payment for the simple reason that the airplane was not certified with those filters.......go figure,

Chickenlips · #4 05-22-2006, 10:00 AM

It seems like I read in Light Plane Maintenance about 20 years ago that there ARE good reasons and differences for use of air cooled aircraft engine oils versus automotive engine oils... the consensus then was that the two were different and formulated for the specific application. Something to do with what they hold in suspension.... lead? cl

BOBM · #5 05-22-2006, 03:13 PM

Mobil bought a bunch of aircraft engines a few years back because their Mobil1 full synthetic couldn't hold the lead in suspension. Result-- blocked oil passages & ruined engines. Also EPA has been messing with auto oil specs in recent years & they have removed the manganese from the oil cause roller tappet engines on the new cars don't need the protection it provides. The classic car folks are recommending use of racing oil which still has this protection. You might call Valvoline at 800-TEAM VAL & talk to the tech rep about current specs. Just tell them it's for a classic car or old tractor. Don't mention airplane.

JimWoo50 · #6 05-22-2006, 05:01 PM

I always thought the main difference between auto oil and aviation oil was the fact that av oil is ashless dispersant oil. Now somebody tell me what that means!

Harvey · #7 05-22-2006, 05:35 PM

I just had this discussion yesterday - Ashless Dispersant aviation oil is designed to minimise the formation of ash deposits in the combustion chamber that can cause pre-ignition. It is also designed to keep the lead deposits in suspension which I understand is where Mobil's full synthetic came undone, as full synthetics seem unable to do this.
I use Aeroshell 15-50 semi-synthetic.

Cheers

Martin in Oz

mlw450802 · #8 05-22-2006, 05:58 PM

Quote:

Originally Posted by pierre smith

Hi Guys/Gals,
I wouldn't be tempted to use automotive oil for the simple reason that your insurance may be void if you do. I have a couple of huge cylindrical air filters on my ag plane (Air Tractor 502) that cost upwards of $80 each. A friend of mine checked his automotive crossover book and ordered me two Wix filters for a substantial savings. I mentioned that to my IA and he said that if I ever crashed and the insurance co. found the Wix filters they could deny payment for the simple reason that the airplane was not certified with those filters.......go figure,

I wonder if that's only true for certificated a/c?
Nothing on these things needs to be certificated and often isn't. The auto powered versions seem to be insureable with nothing aircraft related under the hood.
That being said, I think the reason one should use aircraft oil in our a/c engines is related to the amount of oil that gets past the rings in these things.
A/c oil is supposed to be ashless, resulting in cleaner plugs. Auto engines push so little past the rings that the oils don't need to be formulated as ashless.

Or not

-mike

hevansrv7a · #9 05-22-2006, 08:04 PM

The full story is much too big for this little note. That said, the comment above is correct that they are designed for different uses and don't cross over well. Example: car oil is not ashless and thus can lead to carbon formation which can lead to hot spots which can give you very bad things - see Walter's comments in recent threads on detonation and pre-ignition. For Lycoming, you need the "Lycoming additive". It's less necessary for non-Lycoming. I don't know if that applies to Lyc-clones or not. In many cases, it's not what av-oil has that car oil doesn't, but the reverse. There are things in car oil that are bad for sloppy air-cooled, high cylinder pressure engines. As an aside - don't put av-oil in your car either!

I have not tried it yet, but consider http://www.aslcamguard.com/. Mr. Kollin, the brains behind it, gave an excellent presentation at S-n-F. Does anyone know if he will be at OSH?

h

osxuser · #10 05-23-2006, 11:15 PM

There is no requirement for the lycoming additive in most lycoming engines. Only the O-320H2AD engine, and one version of the O-360. These are required by AD, but a lycoming service bulletin recommends it for all lycs. At the shop I work at, we DON'T use it, an have had ZERO problems with tappet galling. It is my personal opinon that lycoming is simply trying to sell more LW-16702...