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MG MGA - Aviation Motor Oil in an MGA?

This if for you guys that understand the nuances of motor oils, especially the differences between an motor oil sold for aircraft (Like AeroShell) and a typical automobile motor oil, like Castrol 10-w-40.

In this month's issue of Sport Aviation Magazine (p.19) AeroShell had a blurb about the additives in their piston engine oil:

"The anti-wear additive reduces wear on start-up by forming a mircroscopic layer on the engine's moving parts to prevent metal to metal contact when there is little oil present."

The oil was designed for "pilots who fly...less frequently."

Snake oil? Any different than what most quality oil manufacturers might have in their formulas? If this is something different, exactly what is the difference in aviation piston motor oil and our Castrol that prevents us from using the AeroShell (i.e., is AeroShell W80 really 80 weight oil and thus too heavy for our engines?) Or if this is something different, could it be used in an MG engine?

It would be nice to know that there was something protecting our rings and bearings when we crank up our A's after they have been sitting a week. I don't know about you, but to me it is painful to watch the tach rev before I can push the choke back in as the oil pressure builds to 50 or 60 lbs.



Frank Nocera

Hi Frank. I know nothing about Aviation motor oils, but I DO know that synthetic automotive oils provide vastly superior protection over natural petroleum motor oils. There is a lot of information available on the Internet about the advantages of synthetic oils, and they are worth a read. In short though, synthetics dont thicken in cold weather, dont thin out in hot weather, and do not form sludge no matter how hot the oil gets. Synthetic oils also have incredible longevity, and dont have to be changed near as often as regular oils. Synthetics also bond molecularly to metal parts, preventing dry starts. I use synthetic products (motor oil, and chassis grease) in both of my vehicles, including my MGA, and highly recommend such products because they really are better than their natural counterparts! Cheers, Glenn
Glenn

I am not an expert on aviation oils, however, aircraft piston engines are air cooled and run at low and relatively constant RPMs, so the design goals for aviation oils are a little different. They are also limited in their additives since any additives are required to be ashless which according to Castrol means no metalic compounds in the additives. Aeroshell may have additives to reduce wear on startup, or it may be marketing hype, but either way, it would be relative to other aviation oils. I would stick with a good automotive oil.
Jeff Schultz

In general, you can halve aviation oil viscosity to compare it to automotive oil viscosity. In other words, 100W aviation oil equals 50W automotive oil, 80W = 40W, etc. Don't ask me why, that is just the way they do it. For your MG, I would just run a good detergent multigrade automotive oil. Unless your engine has relatively new, modern seals I would stay away from synthetic oil.
Del Rawlins

Most probably aviation engine manufacturers specify aviation oil in their engines for warranty coverage. I am not an aviation mechanic, but it wouldn't surprise me if federal regulations restrict the oils used in the aviation industry either.
mike parker

My MGA ran pretty well on 115/145 AVGAS in the early 60's and while a pilot in the Army. It was free (so to speak). I also used aviation motor oil but I can't remember what grade. When I rebuilt the engine a few years later, it was a clean as could be. The valves were a bit burned as you would expect, from the high octane, but all of the bearings etc. were in good condition from the oil. All of that after 30-40,000 miles.

Joe
Joe Wiley

Thank you Glenn!
Finally, someone who 'believes in' synthetic lubes.
Really though, why would anyone want to 'believe' in something that should be scientific?

SF
Dwight
DCM McCullough

Hi Dwight. I was honestly quite against synthetic motor oil and synthetic lubricants and products in general, until I read about them, and then tested them myself. A quart of synthic oil and a quart of regular petroleum oil were placed in my deep freeze for about a week. On removal, the synthetic oil ran like water, but the regular oil was like thicl like molasses. I then heated a coke cap full of petroleum based oil. It gradually thickened to sludge, and eventually burned to ash. I heated the synthetic oil for an extended period of time, and it did not even thicken significantly! After my crude tests, I became a complete believer in not only synthetic motor oils, but in synthetic lubricants and products generally. While I change my synthetic motor oil once a year, I believe that is actually unnecessary. I believe synthetic motor oil would probably be good for at least 250,000 miles without a change, if the oil filter was changed a few times a year. Given the extended drain period of synthetic oil, I find it less expensive to use than regular petroleum based motor oil! I now use synthetic motor oil, synthetic transmission fluid, and synthetic grease in all of my vehicles. I will also be looking into synthetic lubricant to replace the 80 W 90 hypoid lubricant in the MGA's rear axle! Cheers, Glenn. PS I'm not sure if silicone brake fluid qualifies as a synthetic product, But I use it also, and am highly impressed by it's excellent properties also.
Glenn

Glenn,

Do you use a synthetic oil in your MGA transmission? If so, what brand and wt.?
Mark

Hi Mark. Yes I use synthetic oil in my MGA transmission. It is made by Red Line auto products. I don't know what weight it is, but the stuff is sold specifically for manual transmissions, and replaces the straigt 30 wt motor oil that was originally recommended by the factory. Do a search for Redline synthetic oil and check out their website.
Cheers, Glenn
Glenn

I also use Redline. I have seen a few people say they use synthetic 20w50 engine oil in their gearbox, but most reports say that synthetic engine oil is too slick for the synchros to work properly. Redline MTL and MT-90 are designed for manual gearboxes and have friction modifiers to allow the synchros to work properly. MT-90 is slighty heavier than MTL. I use MT-90 in mine.


Jeff Schultz

i rebuilding my engine at the moment and also consider to use synthetic motor oil after a running in periode with running in oil.soneone told my that when i don't want oil leaks (i now most of them have some oil leaks , i think he ment less oil leaks )i shoud use normal oil 15w40, because this is a bit thicker.


http://users.pandora.be/mga_world/

serge

Sadly, I have known about synthetics since 1972, when a Amsoil dealer came into the MB dealership I worked at.
I did try it in my '76 Plymouth Volare, [sorry] but Valvoline was $.49 a quart, and regressed back to 'cheap' oil'
Many independent tests have been done comparing oils, but not Redline, or Royal Purple.
Sure would like to see that.
I do know these tests show Amsoil to be superior to Mobil 1.
The only petroeum oil that comes close is Castrol.

Now Asmoil is selling syntheic fibre oil and air filters. The oil filters are warranteed for a year or 25,000 miles. the air filters are 'dry' and are warranteed for 4 years or 100,000 miles. They should be cleaned annually with a vacuum cleaner, or low pressure shop air.
They filter down to 15 microns, and flow like crazy. Also available are 'cone' filter elements.
They have a very big range of lubricants.

I suppose I will be chastised for 'advertising'

But I'm not trying to sell anything, except the concept.

Now don't give me any of these 'belief' arguments.
Just do the research, and find out for yourself.

SF
Dwight
DCM McCullough

Like most things, the real determinents are the parameters of use vs. the parameters of the materials used. If an engine is not highly stressed, as most of ours are not, many parameters of oils designed for certain stresses are never really approached.

Most oils suffer more from simply sitting and short running periods which do not eliminate contaminants than they from the usage most of us give our cars. Race prepped/used engines are more likely to test the limits of oils. Remember, that our engines were designed at a time when engines were not as stressed as modern engines are and most likely never approach the high limits of modern oil's operating parameters.

This is not to disparage the notion that we should use the best we can afford, but the return on investment may well be a lot less than we able to realize. JMHO
Bob Muenchausen

Hi Bob. I think that synthetic motor oil is an excellent choice for our MGA engines, if for no other reason than it's vastly superior anti wear properties. Synthetic oils protect moving engine parts better than any conventional oil can. As I stated earlier, with the longer drain interval possibilites available using synthetic oil, it is actually cheaper to run the synthetic product in my MGA than it is to use regular petroleum motor oil! I therefore see no advantage to using petroleum based motor oils, only a lot of disadvantages! Just my two cents worth. Cheers, Glenn
Glenn

Castrol makes semi and fully synthetic 20W-50.
Mark

I would agree with you mostly, Glenn, but I simply see it as a matter of choice. I think you are probably right about the cost-over-time factor. I am not convinced, however, that for most of our cars, given their typical usage and the hope of routine maintenance with quality products that it will make too great of a difference in our lifetimes.

But then again, you have to remember that I am one of those nuts who thinks that there may come a time when we might be forced to change our "antique car's" drivetrains from fossil fuels to electrics just to "keep 'em on the road". That may not happen in my lifetime, but you never know.
Bob Muenchausen

Hi Bob. You state that: "I am not convinced, however, that for most of our cars, given their typical usage and the hope of routine maintenance with quality products that it will make too great of a difference in our lifetimes." I am not sure that I agree with your statement. I have seen many MGA and MGB engines with significant internal engine wear, even when given decent routine maintenance, such as regular oil changes and grease jobs. Since the anti wear properties of synthetic products is vastly superior to regular petroleum products, I personally feel that it is sheer folly to use ANYTHING but synthetic products. If using synthetic products did in fact cost more than using petroleum products, a reasonable argument would then exist. However the synthetic products last considerably longer than their petroleum couterparts, thus offsetting their greater initial purchase cost. In the end, of course, each owner must decide what is best for his or her own vehicle, and personal requirements. Cheers, Glenn
Glenn

Frank

Because of lead fuel mineral oil is used together with a good anti corrosion package, bike oils also tend to have a good anti corrosion package.

The anti-wear additive reduces wear on start-up by forming a mircroscopic layer on the engine's moving parts to prevent metal to metal contact when there is little oil present.

Same as car oils mostly Zinc and moly, they are load/temp sensitive.

No doubt you have seen Castrol "Start Up" advertised with unique molecular attraction. This is a mineral oil with 5% synthetic ester oil. Esters are polar unlike PAO synthetic. Most synthetics use esters 10-15% and race oils use greater amounts and are termed ester based but esters are expensive.

A lot of aviation oils are still straight weight mineral oils because multi grade mineral oils use viscosity improvers. Synthetics oils because they naturally flow when cold and thin less when hot use minimal amounts of viscosity improvers.

At cold starting temps oil is still 10-20 times thicker than when at operating temperature. At start up flow of oil is important and oil that is too thick may generate good pressure but a proportion will be dumped via the relief rather than circulate.

For the older style engine Zinc is a very important additive which is being reduced in modern oils due to CAT poisoning, race and bike oils are still have high zinc additives.
Paul Wiley

Glenn,
I think our "disagreement" probably hinges more on our perceptions of how these cars being used. For myself, I do not see that many restored or even "driver" MGAs putting enough service hours on them or driven hard enough for wear, per se, to matter. However, I do think that if they spend most of their time just sitting, then additive packages to fight corrosion and the ability to produce a hardy film of lubrication to protect between start ups are very important. And for those cars I am thinking of, perhaps even more important than wear reduction potential, since much, if not most of the wear seems to take place when oil of any sort is in short supply to the wear surfaces. However, for an owner who engages in many cross country journeys, or autocrosses or races alot, it would be hard to beat synthetics. That is where it seems to shine the most.
Bob Muenchausen

Bob

Page 20&21

http://www.performanceoiltechnology.com/mc_oils_white_paper_g2156.pdf

Esters can build a 1 micron layer on metal sufaces which stay in place when the engine is shut down.
Paul Wiley

Paul:
A very interesting study. I wish there was a similiar exercise for the common engine oils we use and talk about- synthetic/mineral. It would resolve a lot about the assumed qualities of each oil.
J H Cole

Thanks, Paul. I like a good report over opinion any day, even my own. I agree with JH that a good and similar report accomplishes more than opinion, and sometimes even empirical experience.
Bob Muenchausen

JH

If you consider the latest oil specs that oils are required to pass, mineral oils have to use more refined base stock ie Group II and Group III. As Group III can be considered Synthetic, I doubt that there is much to resolve.

However as Bob mentioned above, if you only do 3k miles a year a wish to change oil each year, paying a high price for Synthetic is perhaps not economical. Add to this to possible "leak" issue with Synthetics then a good mineral
with the correct additive pack tends to suit most owners.

However the study had minerals and synth bike oils that failed the anti corrosion test, so finding a quality oil that suits your purpose is not easy.
Paul Wiley

Tha main difference between avaiation oils and automotive oils, is that automotive oils don't have to maintain their specifications when the engine is up-side-down, like when an airplane like a 747 is in a roll. Unless of course your MG is sometimes up-side-down.

Ya know what I mean?

Mystery BB respondent
Gordon A. Clark

>Ya know what I mean?

No, not really.

Del Rawlins
Certificated A&P Mechanic currently working on B747 aircraft.
Del Rawlins

Del

I understand the base oils for jet engine lubricants and gearboxes are 3-7 cSt pentaerithyritols or Trimethylol propanes or a combination depending on the appliation, and for the most part contain small amounts of anti-oxidants, corrosion inhibitors.

Complex esters are usually added to improve certain characteristics of jet engine oils (bond to metal when upside down!).
Paul Wiley

Well, not to get too far off topic, but there is enough happening inside a turbine engine and its gearbox that those attributes would be needed even for straight and level flight. The 747 is not exactly an aerobatic aircraft however.
Del Rawlins

I am sure that 747 and such use turbine oil rather than the oil used in internal combustion engines.
mike parker

A turbine engine IS an internal combustion engine. (Sorry for the waste of bandwidth if this has nothing to do with MGs).
Barney Gaylord

Hi folks. Here is a URL that discusses the advantages of synthetic oil over conventional oil. It is interesting reading.

http://organicanews.com/news/article.cfm?story_id=211

Cheers, Glenn PS. Apparently jet engines use synthetic engine oils exclusively as they are the only type of oils that can withstand the extreme heat that is generated.

Glenn

Glenn, that is exactly right. And unlike automotive oils, different brands/grades of turbine oil are not to be mixed. Bad Things can happen.
Del Rawlins

Barney,
I apologise. I should have said, Otto cycle engine, referring to the standard four cycle gasoline engines that we commonly use for automotove applications. I realize that gas turbine engines are internal combustion, but they are really continuous combustion engines rather than the four cycle type that we see.
mike parker

That synthetic oil may be something other than crude oil base is a public impression.
The (second) meaning of synthetic = resigned on synthesis. And synthesis means: the join together on an orderly manner of small molecules to big molecules.
So called synthetic oil has ordered, organized big molecules. So called mineal oil has unordered, disorganized small molecules.
Good to known in this thread (I thought)
Walter
Walter Tange

http://www.hatcocorporation.com/pages/about_esters.html
Paul Wiley

This thread started out as a question "Can I use Aero-Shell in my MGA? This question was never really addressed. Personally I would use only car oil in cars. The specific additives packages are different between water cooled cars and air cooled airplanes. For example car oils are "detergent" airplane oils are not, they are ashless dispersant instead.
The thread then went off on a synthetic tangent implying that they are better. Tying back into aviation Mobil made a synthetic oil for airplanes years ago. The oil was found to damage aircraft engines and was recalled.
Mobile bought a lot of aircraft engines because of the problems useing pure synthetic in aviation engines.
R J Brown

The problem with the Mobil AV-1 was, simply, an inability to deal with lead from av gas blowby and misuse.

Mobil AV-1 could have been merely tweaked to achieve a very high level of performance in lead dispersion capabilities. It was in fact accomplished in the lab, however, the cost of re-certification of the oil with FAA would have taken much time/money and not cost justified.
Paul Wiley

So Paul, if I take your post correctly, oil may be oil, but to be used in an aircraft, it must be certified by the FAA?
mike parker

Mike

Oil is subject to tests/certification and audit

http://www.swri.org/4org/d08/GasTests/home.htm

http://www.imakenews.com/lng/e_article000487916.cfm?x=b11,0,w

http://www.imakenews.com/lng/e_article000401358.cfm?x=b11,0,w

Paul Wiley

I have flown light aircraft of all types for over 20 years and used areoshell 15w50. There are some differances in the properties of the detergents in aviation oil. As a rule aircraft run in a very clean inviroment except on dirt strips.
I can't quite remmember why but it is not recommended for use in automobiles.
Synthetic oil seems to find leaks and as the saying goes if it's not leaking wait a minute and it will.
Synthetic oil was designed for cold starts. and I beleive Mobile first brought it out for use in the artic
L E Marchand

One thing I forgot to mention on AreoShell 15w50
There was a engine in the cessna 172 that had a bad camshaft and the lobes would wear out very quickly.
The FAA put out and AD airworthyness directive that the camshafts had to be replaced. Later on the AD was changed as long as you used areoshell 15w50 because of the superior qualities in the oil.
But it still is not recommended for auto use.
Lar
L E Marchand

PAO basestocks is used for the majority of our synthetic oils today. Their first use was in steam turbines, but, in possibly the first ever use of synthetic oil in automobile engines, saw use during the second world war in tank engines. In the African desert, where enormously stressed Sherman tanks, using standard Chrysler car engines were frying their engine oil and seizing engines solid, these special lubricants were tried out very successfully.

The DFV engine revved very high and it needed an oil that would not break down at these revolutions and it needed oil additives that were not going to fall apart at these high speeds. Long chain polymers such as oil viscosity modifiers have a tendency to straighten out whilst under load in a rotating bearing. The viscosity of oil actually in the bearing, at that time, is thus lower than the value of the oil when tested externally. Whilst there is no immediate load change, this is not detrimental. The polymers when leaving the bearing regain their original form and viscosity is regained. However, as bearing loading is increased, the polymers literally break up.

With dry sump oil aeration is an issue mineral oil will absorb air, sometimes as much as 25%. Poly alpha olefins (PAO), used as an oil base, retain far less air than a mineral oil, therefore significantly reducing this problem. Poly-ol ester lubricants really came into their own with the advent of the F1 turbo engine. 1500cc developing 1200 bhp.
Paul Wiley

RJ Brown wrote,

"This thread started out as a question "Can I use Aero-Shell in my MGA? This question was never really addressed."

Agreed--except that Del Rawlins, the certified airframe and powerplant mechanic, partially did in the third post of the thread. Viscosity is double.

As to the compatibility, RJ helped explain in his latest post, 7 above this one. "Detergent vs. ashless dispersant."

So I would conclude also, that aviation oil is for aircraft engines and car oil is for cars.
Paul Hanley

100 = SAE 50 same viscosity

As far as I am aware Group 1 mineral is used and the blend is prob 50/50 PAO/Mineral. However, it is the additive package, or lack of one is of most concern. According to Shell, it is a non-metallic "polymeric" anti-foam and dispersant additive, known as "ashless dispersant". There is no calcium and no zinc. This oil is mainly intended to burn off cleanly without fouling the spark plugs and to scavenge and hold lead from the fuel. It is likely that none of the detergent, anti-oxidant, acid-neutralizing or anti-wear additives that are normally in car oil are used in aviation oil. The head runs hotter than on a car engine and pre ignition needs to be avoided.

Oils may need changing every 25 hours or 4 months whichever occurs first.

Two major reasons for frequent oil changes are:
(1) Flush out metal particles.
(2) Flush out acid contamination.

Oils are blended for their use (Redline do not use detergents in their race oil) and aviation use is totally different from car use.
Paul Wiley

Lar

This may be of interest to you
http://www.exxonelite.com/Lubes/Exxon/elite/pdfs/wear.pdf

A bit old and avoids the cold start wear issue with most road cars
http://www.mr2.com/ARTICLE/Mobil1.html
Paul Wiley

This thread was discussed between 20/08/2006 and 03/09/2006

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