Synthetic Oil good or bad for Model A ?

[luckyal]

Hemmings Motor News is marketing their own brand of synthetic oil in the April 2013 edition. Avalable in SAE 20W50 and 15W50. They state the advantages for Classic and older cars but obviously no disadvantages. Is it good or bad for a Model A ? Is it worth the investment ? 6 quarts full synthetic $ 70 dollars, shipped.
Thanks Al

[Mike V. Florida]

Use whatever you like. Some swear by synthetic, some swear at it. You will find that every weight oil, by every manufacturer, detergent and non detergent oil will work and has worked for years.

Not one engine rebuilder on this site has ever said no not use XYZ because it will damage your engine.

So with that I always recommend vehicle oil for Model A's.

[BRENT in 10-uh-C]

After seeing some test results here in my shop from Schaeffer's Oil against the Rotella 10w-40 that I was using, I am now using Schaeffer's mineral 30 wt Racing oil. The additives packaging that Schaeffers in putting in that oil that fights friction seems like a plus in our engines, and the thing I learned is any mineral oil can better absorb moisture and small contaminents than a synthetic can. This isn't a benefit on an engine that has an oil filter or one that reaches higher temps that can evaporate the condensation but when given a choice, the engineers felt the mineral oil would be a better choice. There are other oil companes that manufacture oil of equal quality to what Schaeffers is so that is not what I am saying, but the shear tests and the friction tests they do in front of your eyes are amazing.

[Purdy Swoft]

We use synthetic oil in the modern vehicle. The word is that synthetic oil leaks badly when used in the model A. Original model A engines don't have a rear oil seal but depend on a rear slinger on the crankshaft. Though I feel that synthetic oil is a better lubricant, I figured it was too expensive to be allowed to leak out on the ground. I use Walmart brand 20 W 50 with good results in my model A's. Opinions vary.

[Joe K]

The advantage of synthetic oil over natural mineral oil is "consistency." It holds it's viscosity much better under increasing temperature.

Thus, it can be "optimized" for the engine application.

I don't think anyone except perhaps Hemmings supplier has analyzed the Model A engine for optimal oil. Hemmings is a magazine and NOT automotive engineers. And magazines are VERY close to marketing - which I expect this is all this is.

Still, it may be possible to do the optimization. The Model A has a couple of challenges, however, these being a cylinder wall temperature (with OEM cooling) that is not optimal for sliding/ring seated friction, and hydrodynamic bearings in the crankcase (rather than pressure lube).

And given the disparity between these two major functions (cylinder walls tend to like 5W oil at temperature and hydrodynamic tends to like SAE30) one wonders if synthetic could bring any additional advantage over the cheap stuff. The Model A engine is simply NOT that engineered a machine. Not that you can't make it more so with pressure lube and thermostats.

Some say synthetic is more "slippery." This not so if you look at viscosity v. temperature alone and realize the curve is simply "flatter." "Clingy" is another term and not so fully described in the literature and perhaps what Brent above is getting to.

I probably will keep using my SAE30 detergent oil since it is relatively cheap and I won't have a financial heart attack every 500 mile interval.

Joe K

[P.S.]

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Originally Posted by Purdy Swoft

We use synthetic oil in the modern vehicle. The word is that synthetic oil leaks badly when used in the model A. Original model A engines don't have a rear oil seal but depend on a rear slinger on the crankshaft. Though I feel that synthetic oil is a better lubricant, I figured it was too expensive to be allowed to leak out on the ground. I use Walmart brand 20 W 50 with good results in my model A's. Opinions vary.

I read the same thing many times. However, after switching to synthetic oil in our car (at the demand of a Model A guru whom I listened to), it began to leak less. Completely stock motor except for a valve job with a lot of miles on it now, it rarely leaks more than 2 or 3 drops after a day of driving.

Also, after flushing the motor out, the oil stays pretty clean. Looks like it will probably make it way, way past the 500 mile mark before it gets dirty enough to prompt changing it.

[Model A Man]

I put synthetic in my 2004 dodge ram pick up and I started getting oil leaks, the next time I went back to regular oil and the leaks stop. I don't know what this means but just reporting what happened to me.

[MikeK]

I run Mobil 1 synth 15W-50 with a rear slinger. Not a single drop leaks. When I ran straight 20 detergent for the first 100 as break-in, both the front and rear dripped a little.

I think some of the modern engine reports of leakage with synth may relate to it having less of a swell effect on elastomeric seals than the oil it replaced. Any switching between brands or types, natural or synth, may give you a new oil with less swell effect resulting in leakage. That happens all the time with automatic trans rear seals, especially if anyone has ever added leak stop to it. The new fluid has less swell effect, the seals shrink back toward their metal outer shells.

[luckyal]

Thank you to all who have offered advice. I have been working on these old girls for 63 years. I was 80 years old last week. Unfortunatly I did not keep up with new technology so I have to ask for advice. Obviously I came to the right spot and I very much appreciate and respect your opinions. You are today's experts and sit in the chair I did 40 years ago. Thanks again !
Al

[BRENT in 10-uh-C]

I have a queston, ...is the term "viscosity" the same with either type oil? For example, is 10w-30 synthetic more "fluid" or 'flowing' than 10w-30 mineral oil? If the synthetic oil is "less thick", then maybe that accounts for the leaks?

The only oil that I have ever experienced that created leaks from the moment it went in was that Graphite Oil that ARCO developed back in the '70s. That stuff would darn near leak out of the sealed can you bought it in, --and heaven help you if you put it in an engine as it would leak out every pore in the casting or ever gasket! Otherwise, I have not really experienced any leakage with synthetic being the cause.

[Mitch//pa]

I run 15/50 synthetic in mine no leaks and if you look up the specs on Mobil 1 web site it is high in zddp.

[takomaned]

I think the biggest advantage to synthetic oil is it can be run for a much longer period of time before it starts to break down. The additives in conventional oil will leave some nasty deposits if not changed often enough. I would guess it depends how long and far you drive your A between oil changes to determine if it's worth the additional expense.

[Mitch//pa]

Originally Posted by takomaned

I think the biggest advantage to synthetic oil is it can be run for a much longer period of time before it starts to break down. The additives in conventional oil will leave some nasty deposits if not changed often enough. I would guess it depends how long and far you drive your A between oil changes to determine if it's worth the additional expense.

I don't use synthetic to pinch pennys and prolong the intervals. It still gets changed just as frequent

[Joe K]

I have a queston, ...is the term "viscosity" the same with either type oil? For example, is 10w-30 synthetic more "fluid" or 'flowing' than 10w-30 mineral oil? If the synthetic oil is "less thick", then maybe that accounts for the leaks?

Viscosity is measured in various units depending on the application. The "w" designations (10w-30) are roughly equal on two differing sources. I.e. if both named 10w-30 they will have similar properties at some temperature, tyically 40C or 100C.

But this only that temperature. For differing temperatures the viscosity may vary widely.

Chart of viscosity targets for various oil grades shown at http://www.machinerylubrication.com/.../oil-viscosity

This one in particular of interest...



One of the reasons for the sudden rise of "5W-30" oil is synthetic oil. They can maintain that 5W temperature above for starting, and yet have an oil of sufficient viscosity at operating temperature (ISO VG 100 - SAE 30) that contains sufficient "lubricity."

The page is a little technical but brings one away with an appreciation of engine oils and their application. The oils available today are MUCH more thermally stable than oils available during the Model A period. Part of this being synthetic oil which while a lot of oils are called non-synthetic, actually contain a fair proportion of synthetic oil in the mix. This being driven by the vagaries of fractional distillation AND the need for a place to put non-optimal feedstocks. (what you buy as "mineral" oil may in fact be simply dregs left over from non-conforming synthetic oil production - too sloped a viscosity curve and didn't meet spec.)

Joe K

[redmodelt]

If you don't have a filter and change your oil at the recommended intervals does it even have time to break down? If the oil is not breaking down then you are speending more money for fake oil and changing it just as often.

[steve s]

It's curious to me how it's turned out that a certain fraction of the glop produced when layers of ancient plankton are subjected to immense geologic pressure should be perceived as the gold-standard lubricant for metal-on-metal friction, while molecules scientifically custom designed, purified, synthesized, tested and proven superior for just that purpose are considered as somehow suspect or "fake." This, in spite of the fact that the synthetic oils are so superior that the extensive additive package that must be added to make the petroleum, or mineral, oils reasonably useful is largely unnecessary.

Steve, scientist emeritus

[Jim/GA]

JoeK's table has an important detail that most people will not pick up on, so I have highlighted it.






The SAE viscosity specs are not a single number of measured viscosity, like you would measure something to be exactly 12 inches long. They are a range. Any oil that has a viscosity that falls between "min" and "max" at 100 degrees C can be called that SAE viscosity. The W numbers are "winter" (cold temperature) measurements. Until multi-grade oils were produced, there were just single-grade "summer" and "winter" oils.

So one company's oil may in fact be thinner (and leak more than) another company's oil with the same SAE number.

IMHO, it is better to replace conventional oil more frequently in a Model A than it is to run synthetic for a longer time. But it's your call and your money.

[Jim/GA]

Originally Posted by steve s

It's curious to me how it's turned out that a certain fraction of the glop produced when layers of ancient plankton are subjected to immense geologic pressure should be perceived as the gold-standard lubricant for metal-on-metal friction, while molecules scientifically custom designed, purified, synthesized, tested and proven superior for just that purpose are considered as somehow suspect or "fake." This, in spite of the fact that the synthetic oils are so superior that the extensive additive package that must be added to make the petroleum, or mineral, oils reasonably useful is largely unnecessary.

Steve, scientist emeritus

I agree, Steve. The uniformity in properties and thermal stability of synthetic oil is second to none. I find it amazing in all of my modern cars how clean the engines are under the valve covers and in the crankcase. The engines look new inside after 150,000 miles.

There is nothing fake about synthetic oil. It is really amazing stuff.

[Joe K]

Jim/TX thank you for that clarification. I wish I had an online reference to a "family" of curves to show the difference in viscosity between two spec equivalent brands of oil: one synthetic and one non-synthetic.

But you brought out the point. Oil marking on the can is a "this range only" comparison. Cheap oils may have a very "tilted" viscosity curve and may be unsuitable for your engine. Synthetic oils a lot "flatter" curve. Now whether this makes a difference to the Model A is the subject of this thread, and I can't really tell EXCEPT to say that oil is getting continually better in it's basic properties.

Thanks!
Joe K

[dwollam]

Back when oil came in cardboard cans I owned a motorcycle shop. I grew up in a Havoline preferred family. I stocked that and others in the store. One shocker I found was every morning when I came in, I had to wipe the oil off the shelf and floor under the Castrol Oil. It leaked right through the cans. I soon found out it leaked through the gaskets on 4cyl Honda motorcycles and also other similar bikes. Switched them to Havoline (and others brands) and the leaks stopped on the same bikes.

Dave

[pat in Santa Cruz]

I suspect Hemmings' oil is repackaged Mobil one 15/50. Mobil recommends their 15/50 for classic cars because it has zinc and other additives best suited to them.

I have been using it in my cars for a long time. The slant window sedan just clicked over 40K miles on Mobil one. It does not leak any more than with regular oil, which is practically none.

I had the valve covers off my Toyota truck recently, with 278,000 miles and its clean as a whistle, passed smog with .005 ppm contaminants ( allowable is 20 ppm). The smog guy said its cleaner running than a new car. It has always run on synthetic oil. I'm convinced it is better oil.

[Special Coupe Frank]

I am going to quote annecdotal "evidence" here, but I also seem to recall hearing / reading that synthetics are less affected by crankcase dilution, and are less likely to burn-up in the combustion chamber.

I do not know if there is sceintific evidence to back this up.

[ronn]

You can buy synth oil at walmart for around 7.00 a quart. Just head over there and
put the extra cash in your pocket.
I run synth in everything.
Old engines, I add a quart a year to the regular oil, which most probably wouldn't advise, but I prefer the added protection and never had a problem.
Runs much cleaner then reg oil.

[takomaned]

I'm not a science major (didn't do well in organic c.)but I do know that synthetic oil offers better long term protection. Any oil is subject to fuel contamination in slow speed/ stop and go situations. Unless the oil achieves enough heat to evaporate fuel and moisture, the only solution is to change it if you want to protect your engine.

[steve s]

Originally Posted by dwollam

Back when oil came in cardboard cans I owned a motorcycle shop. I grew up in a Havoline preferred family. I stocked that and others in the store. One shocker I found was every morning when I came in, I had to wipe the oil off the shelf and floor under the Castrol Oil. It leaked right through the cans. I soon found out it leaked through the gaskets on 4cyl Honda motorcycles and also other similar bikes. Switched them to Havoline (and others brands) and the leaks stopped on the same bikes.

Dave

Dave,

I would bet that a more likely explanation than leaking right through the cans is that the seal between the cardboard sides and the metal base just wasn't very good on the Castrol cans. If the oil really went thru the paper, the whole can would have been a soggy mess, not just the shelf.

Steve

[Mitch//pa]

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mobil 1 15w50

[Duffy1]

Synthetic oil has no sulfur in it .

[Ljamz]

I have a1929 PU that I run Shell Mobil One and the engine seems to start faster in cold weather, the oil also seems to stay clean longer. I have an old Harley shovelhead that always used the old 50WT Harley oil, when ever I changed the oil it would always smell and look dirty. A few years ago I switched to Mobil One 20W-50WT and it is always a lot cleaner and never has that burnt smell to it. I changed out the Cam about 6 months ago and when I opened up the engine there was none of the sluhge that I always found when using the old non-synthetic oil. I am an aircraft mech and the airplane industry is dominated by the synthetic oils, even the piston engines now that the FAA approved it's use, they took 20 years to finally apporve it so you know they didn't rush into it.

[59mgaguy]

Boy! You guys sure put a lot of thought into this. But let's makes this a little more simple. Synthetic oil cost around $7 per qt. Regular oil about $3.00 something. You change oil every 500 miles. Synthetic is well known to find it's way through little crack or crevice. Now cost wise is it good for your engine? Maybe but not for the pocket.

[luckyal]

Heh 59 Yes it is simple. If you only drive 500 miles ( like me ) a year and change the oil once. Synthetic times 4 quarts is 28 dollars Regular oil at 3 dollars is 12 dollars. I don't think the extra 15 bucks is going to break most of us on this site and if it helps the engine that is a bonus ! The old saying was and still is pay me now or pay me later.
Al

[Mike V. Florida]

Originally Posted by luckyal

Heh 59 Yes it is simple. If you only drive 500 miles ( like me ) a year and change the oil once. Synthetic times 4 quarts is 28 dollars Regular oil at 3 dollars is 12 dollars. I don't think the extra 15 bucks is going to break most of us on this site and if it helps the engine that is a bonus ! The old saying was and still is pay me now or pay me later.
Al

At 500 miles a year if you were to use the worst oil out there and your engine only lasted 10,000 miles that's still what, 20 years?

And if you're only driving 500 miles a year, I would think you would have more to worry about with gas going bad then any problems with the oil.

[Terry, NJ]

All the things that aren't gonna break me are slowly breakin me!
Terry

Originally Posted by luckyal

Heh 59 Yes it is simple. If you only drive 500 miles ( like me ) a year and change the oil once. Synthetic times 4 quarts is 28 dollars Regular oil at 3 dollars is 12 dollars. I don't think the extra 15 bucks is going to break most of us on this site and if it helps the engine that is a bonus ! The old saying was and still is pay me now or pay me later.
Al

[V4F]

hmmm , very interesting thread . i change my oil spring / fall . i use vr-1 20-50 (valvoline racing oil) for the zddp . about 7$ quart , but i really like my lil motor so it gets what i consider the best for it ......... thanks .. steve

[luckyal]

V4F We think a lot alike !
Al

[Rock Hornbuckle]

V4F and luckyal...Right on the money.

Running oil for 500 miles won't even begin to breakdown its' viscous qualities, so why bother? In the study of physical chemistry I learned that all things, gases, liquids, and solids have viscosity. Which is the speed of its' internal molecular dynamics. This simply means that you want an oil that "hangs in there", gets to work on time, and doesn't flow away to quickly, so it keeps two metal sufaces from rubbing together under pressure. ALL modern oils will do this for at least 500 miles. The dirt and crud in the oil from a non-filtered engine is far more harmful than the minor loss of viscosity in 500 miles. If you notice your seals and gaskets don't like a certain oil...switch brands or type of oil.

[Tom Wesenberg]

With only 500 miles on the synthetic oil, you could use it in your modern car with it's filter, and it should be good for a few more thousand miles.

[ronn]

my mistake-went over to Walmart this afternoon and full syth Pennzoil is 4.50 a qt-22.50 for a 5 quart container, which I bought.
so reg oil is almost the same price.... how'z them apples?
Full synth will last 15,000 miles if you want it to.

[Rock Hornbuckle]

Originally Posted by Tom Wesenberg

With only 500 miles on the synthetic oil, you could use it in your modern car with it's filter, and it should be good for a few more thousand miles.

Or, run it for 4,000 miles in your modern filtered engine, then 500 miles in the A. It certainly will not have broken down, and should be clean enough to run in a non-filtered engine.

[Mitch//pa]

i change my synthetic oil every drivng season since i do less than 500 miles a year. i then burn the old oil in my wate oil heater to keep warm.

[Allanw]

Originally Posted by V4F

hmmm , very interesting thread . i change my oil spring / fall . i use vr-1 20-50 (valvoline racing oil) for the zddp . about 7$ quart , but i really like my lil motor so it gets what i consider the best for it ......... thanks .. steve

Originally Posted by luckyal

V4F We think a lot alike !
Al

Originally Posted by Rock Hornbuckle

V4F and luckyal...Right on the money.

I use the 10-W40 version of the same oil - it actually leaks less from the rear "seal" than whatever was in there before.

I run this same oil in my aircooled VW Beetle, Dad's classic E30 BMW and the Subaru engine in my VW Van...... I'm thinking about buying it in bulk

[59mgaguy]

Originally Posted by luckyal

Heh 59 Yes it is simple. If you only drive 500 miles ( like me ) a year and change the oil once. Synthetic times 4 quarts is 28 dollars Regular oil at 3 dollars is 12 dollars. I don't think the extra 15 bucks is going to break most of us on this site and if it helps the engine that is a bonus ! The old saying was and still is pay me now or pay me later.
Al

The advantage you get for the engine is minor. and with they way synthetics creep through any crack. Let me know about the pays statement when you to replace you clutch plate when the rear rope seal leaks.

[Tom Wesenberg]

Originally Posted by 59mgaguy

The advantage you get for the engine is minor. and with they way synthetics creep through any crack. Let me know about the pays statement when you to replace you clutch plate when the rear rope seal leaks.

The front of the crank has a rope seal, which does an excellent job, but the rear has an oil slinger and no other seal. This has worked well for me using regular oil.

[msmaron]

Originally Posted by MikeK

I run Mobil 1 synth 15W-50 with a rear slinger. Not a single drop leaks. When I ran straight 20 detergent for the first 100 as break-in, both the front and rear dripped a little.

100% agree same as i run and no worries at all. I change every 1500 miles

[Mitch//pa]

Originally Posted by msmaron

100% agree same as i run and no worries at all. I change every 1500 miles

Me 3

[Allanw]

Synthetics don't actually leak more, the moecule size is more consistent, so if you already HAVE a leak, it MAY leak more.

So far, I've never had the problem - like I say, our real "seal" leaks less, and my aircooled VW's have leaked less too, both using semi-synth.

[hefty lefty]

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Originally Posted by takomaned

I think the biggest advantage to synthetic oil is it can be run for a much longer period of time before it starts to break down. The additives in conventional oil will leave some nasty deposits if not changed often enough. I would guess it depends how long and far you drive your A between oil changes to determine if it's worth the additional expense.

In an engine that has a full flow oil filter AND a bypass oil filter extended intervals are possible with a synthetic oil if the fuels don't contaminate it. But in an old engine you need to change it just as often as the particulates will build up.

Synthetics are better at very cold and hot temperatures but they do not hold contaminants in suspension very well and a low compression flathead engine like an A Ford is going to foul its oil more than a modern one. Plus it has babbitt bearings. I would not spend extra money for synthetics in an antique engine not operated in extreme cold or hot weather.

[31 A4door]

Just switched over to Shaffers Way lube oils on our machines at work..Unbelievably more slippery than other oils we have always used........I may try some of their motor oils myself.

[tiger.1000]

Using detergent oil in an oil engine is NOT a good idea. Any long term build up of gum and carbon will be fairly rapidly dissolved and often resulting in lubricant weeping past the rings.....result = heavy oil consumption and blue smoke. SAE 30 low or non detergent oil works well in my experience but we're all different......

[johnsor]

There are many advantages of a synthetic oil in a modern engine. However it would not be of much value to a Model A engine with their short drain periods, and often consumption, thus don't justify the high cost of a synthetic. A synthetic will have much better thermal stability at high and low temps. and lack of oxidation. There are a number of synthetic base stocks, but the most common for automotive use are a di-ester (di trideckle adapate), or a PAO (poly alpha olefin) such as Mobil I. Both are very good synthetics for thermal stability and extended drain periods. I won't discuss the other advantages here, but your fine with most any name brand petroleum oil of the viscosity you prefer in your Model A and change it every 500 miles or so.

[Jim Huseby]

I had never heard of Schaeffer oil until Brent's post. I just looked at schaefferoil.com/million . Amazing!