What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

auto oil in aircraft engine

6

6 Gun

Well Known Member
ok i know i will get flamed on this but i want some comments on this i purchased a case of 100w and the prices was over $54
so my ?
is anyone out there running a heavy weight auto oil in there Lyco its about 3 times cheaper
i know there is additives that are not in 100w but the base should be close
its not all that long ago that auto fuel had lead also
id like to here from any car oil users
bob
 
I'm no expert, but there are different formulations for different types of engines, i.e. air cooled vs oil cooled, high RPM vs low RPM, internal tolerances etc. How much does a new lyclone cost and how much does it cost to overhaul and compare that to your savings on a few quarts of oil over the life of an engine? Have you ever heard of the old saying "Penny wise and pound foolish"? Just my dos centavos.
 
Last edited:
I know people who have run car oil for years and many hundreds of hours with no problems but I would not do it. Car oil is designed to stay clean and not carry the dirt around. Aviation oil is the opposite. Look into the term "ashless dispersant" for a little more on this.
 
I use what the designer / manufacturer recommends in all my engines. The designer of the engines know more than what I do about keeping the engine running and lubricated correctly.

IF I thought I knew more than the engine designer / manufacturer, I would still be concerned about using a non-Ashless Dispersant oil in my air-cooled, high leaded fuel aircraft engine.
 
Auto oils are pretty much all detergent oils. Aviation oils are AD(ashless dispersant. All that creamy gray lead paste (sludge) is supposed to settle into gobs inside your Lyc. and stay in fairly specific places. If you put detergent oil in an aircraft engine that has substantial time on it, it will break up sludge and move it around. This can actually clog oil passages leading to spun bearings, etc. I haven't seen much on operating a "clean" lyc on detergent oil, maybe not so bad. I know the rotox uses car oil but it's also not a "real" airplane motor.:D
 
Oil

Modern automotive oils assume several important things including unleaded fuel, roller tappets (cam followers,) and the very tight clearances in modern liquid cooled auto engines. The presence of lead in the fuel changes the dispersant needs and the clearances change the viscosity needs. Saving a few bucks in either application is, in my view, foolish. 50 weight ashless dispersant in my Lycoming, 5W30 synthetic in my turbocharged Audi, by the book.

John Clark
RV8 N18U "Sunshine"
KSBA
 
I am not that familiar with the detergent aspects of auto vs aircraft, but I am somewhat familair with issues regarding special addititives intended to help lube different types of bearings. The large "plain" bearings used in the lyco designs (especially at the cam and follower bearings) require different lubrication characteristics than the roller bearings and other types used extensively in modern auto engines.

This is a serious consideration for people running the old VW and Porsche designed engines and the builders of those older engines are very particular about what oils they run. There are some modern oils formulated with the special lube additives for these bearings - Brad Penn is one of them. A prominent builder of these engines (jake raby) has some in depth oil discussion on his site. Google "massive type 4" or "aircooled technology" to find Jake Raby's site.

Having said that, I wouldnt want to be the beta tester for any oil substitution program - what John said.
 
Last edited:
Check out AeroShell.com...

... there is a pdf in "The AeroShell Book" on "Piston Engine Oils". This information gives the why & why not to using the aviation oils in auto applications and vice versa.
 
oil

thats good food for thought guys ive tried to study this for the last few years and iv read aeroshell and spoke with Ben at S-N-F lots of times but i want to get to the meat of the matter with someone that has ran modern oil and what results they have had
on another subject ive looked up data on MS sheets and some of the additives are mostly minerial spirits with a dab of acid that people pay 20 bucks a bottle for
 
Sig600 said:
The post this was quoted from has been deleted
Click to expand...
I think this is the crux of the majority of answers you are going to receive concerning your query. Experimental builders are building "Kitted", meticulously engineered, and mass manufactured experimental airplanes for various reasons and may be interested in some measure of experimentation. However, I would expect most are not willing to experiment on them to the point that their lives would be at high risk just to save money. It seems to me most replies are going to be along these lines and not on first hand experience.
 
Last edited by a moderator:
oil

no im not willing to risk mine or any ones
but im asking ? to learn from others that know more than me
ive learned so far that detergent oil is now called ashless
Detergent" is replaced by "Ashless"
"Non-detergent" is replaced by "mineral"
ashless is to clean inside and to suspend particals so filter takes it out
in my champ i run ashless and it doesnt have a filter and it has not fell out of the sky
ashless oil does not leave gray goo in engine it cleans it out
still looking for answers
do you trust the oil makers anyone out there that knows anyone who works for an oil company that doesnt make aircraft oil chim in
 
Last edited:
Sig600 said:
The post quoted from has been deleted your comment below is spot on
Click to expand...

In my experience, that kind of leading and inflammatory question tends to inhibit open dialogue and debate. The guy is just asking, and from the looks of the rest of the thread is getting good info.

Thanks, Bob K.
 
Last edited by a moderator:
Bob Kuykendall said:
In my experience, that kind of leading and inflammatory question tends to inhibit open dialogue and debate. The guy is just asking, and from the looks of the rest of the thread is getting good info.

Thanks, Bob K.
Click to expand...


Fair enough. I'm of the opinon though that there are somethings you shouldn't be the first to try, or go against the specs of the manufacturer. This question being one of them. Especially when the motivation behind the question was to save some cash. I'm all for the experimental motivation, but I'll personally let others shell out the cash/learning on new ideas before I jump on board. Case in point, I was all amped up at the Innodyn Turbines a few years ago. They had all kinds of potential/promise. For the money I could've been one of the first to have one. How would THAT have worked out? And that's just a fiscal example. Toying with the health of your one and only engine is much more serious in my opinion. Which takes me back to the original question (although less inflamatory)... is the risk worth the reward?
 
Aviation oil has several "packages" that automobile oils do not have. The major one that comes to mind is a "corrosion protection package". The therory is an automobile (water cooled) is going to be used nearly daily using the oil as corrosion protection. With aircooled aircraft engines they are rarely used on a daily basis and require a "corrosion package" in the oil to assist with helping the oil and corrosion protection for long term storage and non use.

After listening to several oil seminars, and aircraft engine seminars at the major airshows and having this question asked dozens of times, there is not any good reason to use auto oil in an aircraft engine.

JMHO.
 
Sig600 said:
. . . Which takes me back to the original question (although less inflamatory)... is the risk worth the reward?
Click to expand...
Of course that is a question that will be asked. But it will be up to the guy asking the question to answer for himself. Your Risk/Reward analysis might have a totally different result than his may have. He has to base his decision on his level of comfort to the risk. I did not get the feeling he was wanting to base it upon our level of comfort.

I get the feeling this person is asking for experience(s) NOT OPINIONS. Why should he care what my (or your) feelings are about experimenting in this manner? He is willing to push the envelope in order to find an answer. Do we want to really stymie his pursuits of experimentation because he is not following what we view as the path he should be taking in his experimental process?
 
Risk/reward

Sig600 said:
Which takes me back to the original question (although less inflamatory)... is the risk worth the reward?
Click to expand...

Difficult to answer because, unlike some of the statements made here, I really doubt that running inappropriate oil is going to cause a spectacular failure. More likely, the damage will be very subtle in the beginning and the engine might even make TBO. But, things like spalling lifters don't happen overnight and camshaft rust forms slowly. Personally, I can think of a lot better ways to "save a few bucks" in the airplane game.

John Clark
RV8 N18U "Sunshine"
KSBA
 
Hi Bob,

I have no personal experience using auto oil in a Lyc, but I've talked to people who have, & they haven't reported problems. Obviously, that's 3rd hand info so take it for what it's worth.

The most reasonable argument *against* auto oil is that air cooled engines run so much hotter than water cooled engines, with water cooled heads at maybe 250 degrees vs aircooled at well over 400 degrees in some situations. That's where synthetic should really shine, but when it was tried there were serious problems with lead not being handled properly by the synthetic oil.

I run premium mogas in my O-320/160, & it would be really tempting to run synthetic if it didn't cost more than Aeroshell....

Charlie
 
I don't think that anyone is going to flame you (or at least they shouldn't) for asking the question. That being said, let's take a look at some fact/$$;s.

1) Many of us run Philips X/C 20W50 at about $5.00/qt.. Other oils range from $4-$8/qt.

2) With the exception of the cheapest "store brand" oils in a 20W50 weight, most good motor oils also run about $4-$8/qt with synthetics being even higher.

Net savings = ZERO

Yes you can get more expensive aircraft oil and cheaper auto oil (and the other way around), but overall it's flatly a wash so to me a rather moot discussion.

Experimenting for the sake of experimenting when there is no real gain (safety, price, reliability, etc..) to be had is fine in something that you can pull over to the side of the road if it quits. Airplanes, not so much....

Took about 30 seconds of google to find current oil prices, and another 30 seconds to find:

http://www.swaviator.com/html/issueja02/Hangar7802.html

My 2 cents as usual!

Cheers,
Stein
 
Flame away, but I know guys that have run Amsoil in Lycomings. Purpose not being to save money but to run a superior oil. And those engines have been torn down and everything inside was clean like new. How does a 200 hour oil change sound?
 
oil

thanks for the replies so far
now heres a thought motorcycles are air cooled do you use a special oil
i never did
heres a thought on multi grade oils you crank up and taxie out to take off i let my engine warm to 100f and take off
if your running 15-50 at the point of take off the oil is close to 15w because it has to heat up to increase weight this is the hardest you run you engine
on the whole flight and it was designed for 50w
now throw in a bottle of avblend and it is cutting the oil even more to a lower weight and no ones thinks twice about it
aircraft oil is made to saej1899
the next ? is auto oil made to saej1899 or better
 
Here is a Google Lubrication Fundamentals book link. Found it searching for SAEJ1899. Looks like more info than I want to know about lubricating oils.

Lycoming Service Instruction 1014M talks about recommended oils for our Lycoming aircraft engines. The summary is that it needs to meet SAEJ1899 or SAEJ1966.

I now have three questions:

1. Why not start a POLL to keep track of who has used automotive oil in their air cooled aircraft engine?

2. What does the FAA have to say about using a NON-recommended oil in an aircraft engine on EXPERIMENTAL Aircraft?

3. What does the insurance company say when non-recommended oil is used in an aircraft engine when an accident occurs? Is my coverage still valid?
 
This is almost

like the old "can you run autofuel in a Lycoming". The resounding result of that poll is "Yes of course you can and it runs very well".

But it took along time to get there and its not without its concerns. But eventually all the nonsense about lubricating valve guides with lead etc went away.

i strongly suspect the same is true with running auto oil..as one poster said, I never used a different oil in my air cooled motorcycle engine..Ok there is AD..which primarily scavanges lead..Well what if you hardly ever run 100LL in your Lyc?

I bet auto oil is just fine probably better than what we use. but as Stein pointed out, the savings are much smaller than using mogas, so there are likely a ot less folks willing to try it.

Even if you could get a 200hr oil change, would you really run it longer than 50 hours?..I'm not sure i would.

Bottom line, there is not much motivation to experiment.

Frank
 
rocketbob said:
Flame away, but I know guys that have run Amsoil in Lycomings. Purpose not being to save money but to run a superior oil. And those engines have been torn down and everything inside was clean like new. How does a 200 hour oil change sound?
Click to expand...

That I can see...same with lots of racers, hotroders, harley guys, etc... In that case price/cost is obviously not the driving factor, because Amsoil (while good stuff) is proud of it! :)

Cheers,

Stein
 
There used to be an old "wives' tale" that since automotive oils (and air-cooled motorcycle oils too) had a lot of zinc phosphate compounds in them, and that aircraft engine main/cam/rod shell-type bearings were made with a fair amount of silver in them (different alloys from auto bearings), and that the zinc would attack the bearing and slowly leach out the silver, resulting in long term bearing damage.

I don't know if that's even true, or if it would even be the case anymore, since the EPA ordered the zinc phosphates to be removed or dramatically reduced in automotive engine oils, but I've heard the story from several old timers.
 
I'm not a big fan of
"I don't want to know, and I don't want you to know either". Those posts are not helpful.
Oil companies list their oil specs in hand books and on web pages, so you can spec it for yourself. Periodically someone does an independent lab test of several oils at the same time. That takes a bit more searching, but it's worth the time.
Oils are reformulated all the time, including Aeroshell. They have to because oil base stock changes from day to day. Addetive packages change because of this as well. (blended whiskey comes to mind, made to taste)
New automotive oils have less ash (or ashless) because ash damages catalytic converters, and leaves deposits on piston crowns. So the latest oil spec is probably more acceptable to your aircraft engine.
If you were low on oil and the FBO was closed, but the auto parts store open, I don't think it would do any harm to add a few quarts of 20-50, or 15-40 and fly home.
As for cost effect, oil at the auto parts store is not very cheap these days, certainly not 1/3 the price of aviation oil for the quality of oil you might find acceptable.
As for lead scavanging, 100LL does not have very much lead in it anymore, and most of us change oil @ 50 hours give or take. Many of us have oil filters on our engines, so a detergent oil theoretically would be called for?
It Is worth discussing.
I use aviation oil in the Cessna, automotive oil in my RV-8, but then again, it's got an auto engine. :D
 
Last edited:
SHIPCHIEF said:
--- snip ---
As for lead scavanging, 100LL does not have very much lead in it anymore, and most of us change oil @ 50 hours give or take.
--- snip ---
:D
Click to expand...

Please provide the SOURCE of this statement. IMHO, the amount of LEAD in 100LL is very high.

My source is:
http://en.wikipedia.org/wiki/Avgas

"As of Jan 2010, 100LL has a TEL content of 1.2 to 2 grams TEL[6] per US gallon (0.3?0.5 g/l) and is the most commonly available and used aviation gasoline. One gram of TEL contains only 3/5 of a gram of lead."
 
Not exactly a Lycoming but years ago I overhauled a A-75 and it ran on Delo 400 15-40 for over 300 hours on mostly 100LL. Never a stuck valve, compression loss or any other abnormalities that I could see. The engine almost never saw 10K' elev. but was almost always run hard (over 2600rpm) and with frequency. Oil changes at 20-25 hours, no filter.

At the time I worked as a mechanic for a trucking fleet so the cost, or lack thereof, was a factor.

Things and times change, now I use Aeroshell exclusively in both Lyc. & Cont. not because I had a failure but because I can almost afford it now.
 
oil

talked with an oil company today and tech said he had no way of checking specs on sae j1899 but he said all bearings have copper silver chormium so thats not a problem
bob
 
IIRC motorcycle oil has an additive to prevent slipping in the clutch pak. I dunno how that would affect our engines and am not willing to find out.
I'll stick with my Phillips XC.
 
turbo super rv-10 said:
ok i know i will get flamed on this but i want some comments on this i purchased a case of 100w and the prices was over $54
so my ?
is anyone out there running a heavy weight auto oil in there Lyco its about 3 times cheaper
i know there is additives that are not in 100w but the base should be close
its not all that long ago that auto fuel had lead also
id like to here from any car oil users
bob
Click to expand...

bob,

A case of oil for $54 comes in at $4.50 a quart. Compared to what you have invested in the RV-10, that $54 isn't pocket change nor will cover the cost of a hamburger on a typical week end flight. Sure you can save a couple bucks using mo-oil. But with a RV-10 and its expensive engine? It would be appropriate with a Pietenpol - not a RV-10.

Treat an aircraft engine like king and it won't let you down. My engine gets a shot of AVBLEND at $16.95 plus the $4.50/qt for the oil plus $16.95 for the filter. It is money well spent.

To experiment with mo-oil has very little up side (what, $2/qt ?) and could have a huge down side if it doesn't work. It certainly would void a warrantee.
 
One thing more:
I buy Aeroshell from National aviation because he's a good guy and services the local aviation community.
It's not much, but keeping Don in business is good for all of us.
 
Steve said:
IIRC motorcycle oil has an additive to prevent slipping in the clutch pak. I dunno how that would affect our engines and am not willing to find out.
I'll stick with my Phillips XC.
Click to expand...

the way i've always heard it is that motorcycle oils have less additives than current car oils. The newest car oils have additives that make things have less friction to try and increase gas mileage, and those additives can ruin clutch action in a wet bath motorcycle.
 
Hey -- wait a minute!

rocketbob said:
Flame away, but I know guys that have run Amsoil in Lycomings. Purpose not being to save money but to run a superior oil. And those engines have been torn down and everything inside was clean like new. How does a 200 hour oil change sound?
Click to expand...

Hey Bob:

I went 150 hrs, not 200. The top end upgrade tear down @ 150hrs revealed an amazingly clean engine inside, and this engine is still running with approx 1400hrs (?) on it? The second owner did not follow my oil use -- straight Av oil for him, so the data can't really be used for comparison. For the 700 (?) hrs I had that engine, no problems.

Yes, Amsoil allows extended oil change intervals -- about 3x what mineral oils use.

FWIW, Amsoil is an AD oil. Mobil 1 had the lead sludge problems, not Amsoil, which by the way was designed 1st for aircraft piston engines. The Mobil 1 problem led them to abandon marketing to aircraft owners, and remove their aviation oil from the market.

Following the lead of another more experienced fellow, I now mix Amsoil with Phillips X-CY 50/50 to get the benefits of both. YMMV.

BTW I also use auto filters on my engine (IO-550N).

Carry on!
Mark
 
You must log in or register to reply here.
Back
Top