synthetic oil vs. dino - A refresher

[boxermania]

I found this article while searching for a related item and thought it would be of interest to this forum as the author is well versed on the subject matter, enjoy.


Ok... so here's info from a friend named Phil Hall... he studies lubricants at NASA. I *really* don't think there can be a better source of unbiased info AT ALL... I'll break this up into several posts here.. and then eventually add it to the FAQ (or maybe ask him to write up something more technical for the FAQ)
____________________________________________

PART 1:
Today's topic seams to be motor oil related. I am a NASA Engineer at
Marshal Space Flight Center in Huntsville, Alabama. My field of work is
Tribology which is the study of friction, wear, and lubrication. In our
spare time, our group collects and tests different motor oils using the
Shell Four Ball tester. This tester tests the extreme pressure properties
of oils. These areas in a motor are cam to lifter contacts, valve stem to
guild, and piston skirts. Over the years we have found synthetic bases oils
to out perform mineral based oils by a large margin. We test the oils new,
after 1000 miles, 2000 miles, and up to 10,000 miles. In a nut shell, we
found that synthetic oils have better wear properties after being run 10,000
miles then mineral grade oils new. Which synthetic do we use? First any
you will benefit from any synthetic, but we use Mobil 1. Mobil by far puts
more research dollars in motor oils then any other company. They are also
aggressive in racing.
Other notes on motor oils.

Do not run a multi grade oil (10w-30) more then 1000 to 2000 miles -
depending on your driving habits.
This is because a 10w30 oil starts its life as a 10 weight oil and large
polymer chains are added to get the 30 rating. These chains break down very
quickly which produces small chains with an open electron charge at the
ends. These ends attract grim and form sludge.

Do not run synthetics in a new rebuild. A new engine needs the added
friction allowed by mineral oils to set the rings properly. Chevy found
this out on the corvette. These cars came from the factory with Mobil 1 and
owners brought them back because of smoking and oil consumption (rings did
not seat). Run a good single weight oil for the first 2000 miles. We found
Havaline 30 to be a good mineral oil - in fact we use it for our standard.

The reason Mobil 1 can safely be run for 10,000 miles is because the
additive package is well engineered to isolate grim and hold it in
suspension. This also is why Mobil 1 is expensive. You know - you get what
you pay for.

I know there are a lot of questions on motor oils. You can e-mail me for
more information or search the web for more details on synthetics. Your
Roadster deserves the best - run synthetic oils.

Phil Hall

Part 2:

I listed multi grade oil break down at 1000 to 2000 miles. This is for the
junk oils found at circle K for a dollar. A good name brand oil will last
3000 miles without too much break down. This is for mineral grade oils -
synthetic oils meet government viscosity tests for ratings without adding
thickeners like polymer chains.

Guys here at work run synthetics in motors that have 140,000 to 170,000
miles on them without any more oil consumption them normal. I believe that
you will get a slight increase in consumption in older motors because the
synthetic are very slippery and can get by old rings easier. In these cases
going to a 15w-50 may help, but this is not a reason not to use synthetics.
Older motors need the extra protection. At running temperature a synthetic
will maintain its viscosity, where a mineral oil viscosity is DRASTICALLY
REDUCED.

A test on how well synthetics work at different temperature can be done in
your home. Get a quart of your favorite mineral oil and a quart of a
synthetic. Put a cup a each oil in a glass or paper cup and stick in the
freezer over night. In the morning try and pour the oils out. Next test:
DO THIS OUTSIDE. On an old camp stove put a ¼ of the synthetic oil in an
old frying pan and put it on the stove on the highest heat setting. Cook
for 30 minutes. Now cook your oil for 30 minutes. At this point you will
see why you cooked the synthetic first. As the oil cooks pour some out to
see the changes in viscosity between the oils.

Part 3 on oil additive coming soon. I need to back to NASA work.

Phil Hall

Part 3:

The question of change intervals and synthetic oil has come up. As a side
at work we run oil tests using the Shell Four Ball test rig. This tester
was developed by Shell oil to test the extreme wear properties of motor oils
- cams, piston skirts etc. It consists of three, = inch balls held in a
triangular pattern in a cup with oil heated to 165 degrees. A forth ball is
lowered to the center of the three balls and loaded to 40 KG. The ball is
then rotated 600 RPM for one hour. After the test the wear scar is measured
on the three stationary balls. The bigger the scar the lower the extreme
wear property of the oil is. We use Havoline 30 wt for a base line. We use
this oil because engineers from the past liked this oil, so we have a large
data base.

Looking at data shows new Havoline 30 wt has a wear scar of .0165 inches.
New Mobil 1 has a .0145 inch scar. May not seem like a lot of difference,
but it is. Havoline 30 at 3000 miles has a wear scar of .020 inches and
Mobil 1 at 4000 miles has a .0164 scar. Remember - the bigger the badder.
3000 miles is as long as anyone was willing to run Havoline 30 wt, so its
data stops here. Mobil 1 at 6000 miles is .0167, at 8000 miles is .0188,
and at 10,000 miles is .0194. So, at 10,000 miles Mobil 1 has better
lubrication properties in the critical areas in your motor then a good 30
wt. All mineral oils follow Havoline pretty close - major brands. Some off
brands have a .020 wear scar new. Multi-grades generally have a larger wear
scar as well. This data was from a 5.0 Ford Mustang. Every motor will be
slightly different, but not much.

So, synthetic can handle long run intervals. But, that is part of the
story. You have contaminates to deal with. This is where the additive
package comes in play. This is the expensive part of oils and the reason
synthetics are high priced. Because of the long run intervals of synthetic,
they must have a vastly superior additive package - and they do. Proof of
this is to take 3000 mile dino oil and look at it in a glass jar - then do
the same for Mobil 1. The Mobil 1 will look new compared to the dino oil.
I run Mobil 1 in my new cars to the longest manufactures oil change interval
- usually 7000 miles. This will keep the warranty happy. In my Roadster I
change it once a year regardless of mileage. It run my Roadster about 5000
miles a year. Most people at work run synthetics and do the same. We have
a bunch of cars in the lot that have over 200,000 miles on them and going
strong. I (my wife) never keeps one that long.

I run 10w-30 Mobil 1 in my new Roadster motors (after break-in). Older
motors get 15w-50 because the tolerances are larger. Because synthetics
don't thin down like mineral oils do at temperature, I would be careful
running 15w-50 in a motor with a high volume oil pump. By doing so you may
run into cavitation problems - oil gage jumping wildly. Drag racers
experience this often at high RPM. Drop a wt and it will clear up.

I checked the auto parts stores last night and could not find a zero wt
Mobil 1. It was about 2 years ago they were talking introducing this oil,
so apparently they have in some markets. I stand corrected.

Testing another "magic" oil additive today. It looks and smells like
linseed oil! This should be fun. Additives are another subject all
together. Another day, but never tested a good one - none- zip - zero -
don't waste your money.

Sorry for being soo long. I like synthetics (obviously). If you have been
to the conferences, seen all the tests and data, and read the lubrication
journals you would run nothing other then synthetics.

Phil

It does support my position that the rings need to be seated, this takes place when the engine stops consuming oil, before moving on to the synthetics.....ride like you stole it.

[owldaddy]

Thanks for posting this info. I have read many things about lubricants the last 30 years, this boils it all down in a simple to understand quick reading text. I have been using synthetics for years, and in fact change the oil yearly now on all my vehicles, regardless of mileage, not that I put that many miles on any of them any more (retirement is grand ) It has been my experience that if you don't mind changing oil every 3k miles/4 months (over 300k miles on an engine is not uncommon with this schedule if your putting the miles on quickly), that you can get excellent results in a water cooled engine with dino oil. I'm not into doing that much maintenance these days, so synthetic is the way to go, especially in an air cooled engine. Thanks again boxermania. Once again, what I believe to be true has been validated by you and your sources.
Don

[Beemeridian]

11

[Sunbeemer]

Thanks for posting this excellent review, but it doesn't address seal seepage by synthetic oils. I don't know why synths get past seals easier than dino oils do, but it makes me wonder if the seal materials are incompatible with the base stocks from which synths are made? Any thoughts?

[owldaddy]

I don't know why synths get past seals easier than dino oils do, but it makes me wonder if the seal materials are incompatible with the base stocks from which synths are made? Any thoughts?

I have heard of this being a problem in the past. The only oil I have had a problem with getting past seals was Arco graphite way back in the 70's. That was some nasty stuff, since it was already black, it really showed up when it leaked past the seals. It didn't take long to make a mess of your engine either, I only used it once......... The 20-50w Amsoil or Castrol full synthetic have not been a problem for me, at least not yet, I'm keeping my fingers crossed that they won't be a problem in the future.
Don

[boxermania]

Sunbeemer

I'm not a Tribologist by training, however, synthetics are relatively new products. That being said, I think the leakage cases would have to be tabulated as there could be many instances where the leakage has nothing to do with the oil.

Instances like older engines with worn, hardened or ill fiting seals or oil level too high, as seals are designed to control splash, no direct contact with the medium.

Synthetics are, in general, slicker than dino oils so that could in answer to your question account for some of the leakage cases, but i hardly think so, at least in regards to todays engines, since most OEM's are going to the synthetics on all new engines.

[Sunbeemer]

Thanks again, Boxermania. The only synth I've used in the bike was Castrol's semi-synth blend (20W-50), and that was the only time I've seen oil leaking from the left cylinder cam cover and filler neck. When I changed the filler neck and oil fill cap o-rings, they appeared greenish-grey and were harder than the new ones. I never did replace the cam cover seal, and it has not leaked again with the oil I usually use - regular Castrol 20W-50.

The only other time I've seen leaks from my boxer is when using Valvoline 20W-50, when I saw slight weepage at the block-tranny junction (just a few greasy smudges along the lower right side seam between the engine and tranny cases). Since switching back to regular Castrol 20W-50, they have not reappeared. BTW, I noticed front and rear seal weepage also occurred in my Chevy van's 5.7L V-8 when I used Valvoline 10W-30 in it.

I have also changed my tranny and FD to Castrol Hypoy C 80W-90 recently (from Valvoline's 80W-90) and have eliminated the grease stain that occasionally occurred under the front of the FD boot. I'm hoping this change will also eliminate the tell-tale stench of gear oil I've detected in my clutch's hydraulic fluid the last two times I bled it. We'll see.

And I agree that, depending on the conditions of use, regular oil doesn't always hold up for 3000 miles in these engines. With hot summers, and/or lots of short trips, I change mine in as little as 1700 miles (based on subtle hot-engine knocking noises). My manual specifies this interval when operating under these conditions, too.

Oil threads....

[philbytx]

On some older motors, seal seepage was due to the better detergent action of synthetic oils cleaning out the gunk around the seals. Synthetics are way superior for air/oil cooled motors.

[Beemeridian]

11

[boxermania]

+ 1 Beemeridian

Synthetics are "slicker" oils and therefore a bit harder to "seal"

[sweatmark]

The NASA guy's info is refreshingly concise. Nice to see some scientific data in support of lubricant performance claims.

The "synthetic & seals" thing is more complicated than previously noted. There's an array of factors to consider, in particular: (1) effects of synthetic lubricant chemistry -both base fluid(s) and additives- on seal materials; and (2) effective kinematic viscosity over range of operating temperatures.

The latter is IMO the issue (bad pun) for current-day seal leakage attributed to use of synthetic crankcase oils when compared to conventional refined crude paraffinic oils. At low temps, eg. starting conditions, synthetics can have better (lower) viscosity for higher flow rates within a motor's oil circuits, hence providing improved performance over conventional oil. That same benefit of lower cold-starting synthtic lube viscosity becomes a potential liability for cold seals that gap a little before closing with thermal expansion.

Some of the leaking seal problems of the past were due to the first consideration: material incompatibility. Excessive seal swelling and/or deterioration of deal integrity due to chemical breakdown were (and can still be) a problem if mismatch between synthetic lube and seal material occurs.

I'm not a NASA tribologist, but did receive training from Mobil Oil for my job as industrial lubricants sales engineer, including hands-on testing with the 4-ball EP apparatus. My knowledge of this topic is however outdated.

[owldaddy]

Do seals work with synthetic lubes? Look under your machines, does it look like an old Harley was parked there? If not, then the seals are working. My garage has an oil free floor, as does my driveway. The seals must be working with synthetic lubes. My old Nissan has almost 270k miles on it, and it is oil tight. Don't have to be a rocket scientist to do that test.
Don

[rbertalotto]

The only problem I have with all of this...............Is what oils are "TRUE" synthetics and what are quasi synthetics. I understand the government allows other types of oils to be labeled synthetic even if they are not 100% synthetic.

Can anyone elaborate on this?