richm

hey Matt, good to see you back - u been a bit quiet here lately.. I was hoping to catch you at Castle Combe last month. Hope things are sorting out for you now? is that moby number your primary contact at the moment?
Cheers
Rich

Paul J

pugo,
Loads about it all over the place so its a fuck-off conspiracy


nooilchange:
Here's what happened, according to a detailed account published in the trade magazine Lubricants World. Late in 1997, Castrol changed the formula of its Syntec "full synthetic motor oil", eliminating the polyalphaolefin (PAO) base stock (that's the "synthetic" part, which makes up about 70% by volume of what's in the bottle) and replacing it with a "hydroisomerized" petroleum base stock.

Mobil Oil Corporation, maker of Mobil 1, "Worlds Leading Synthetic Motor Oil," said no fair and took its complaint to the National Advertising Division (NAD) of the Council of Better Business Bureaus. NAD often arbitrates between feuding advertisers on their conflicting claims.

The notion behind synthetic motor oils as we've known them is an elegant one. Instead of relying on the cocktail of hydrocarbons contained in crude oil, why not go into the laboratory and build the perfect base stock from scratch, molecule by molecule, and builds it till it gets 10-carbon molecules, then combines three of those to form PAO. The result is a fluid more stable than the usual base oils derived from crude. It keeps flowing at low temperatures. It's more resistant to boiling off, and more resistant to oxidation, which causes thickening with prolonged exposure to high temperatures.

Still, there's more than one road to the point B of improved stability. Petroleum refiners in recent years have learned how to break apart certain undesirable molecules - wax, for example, which causes thickening of oil at low temperatures- and transform them by chemical reaction into helpful molecules. These new hydroisomerized base oils, in the view of some industry participants provided properties similar to PAO's but only cost half as much," Lubricants World reported.

The argument before NAD tiptoed around the obvious- does the consumer get four bucks' worth of value from each quart of synthetic oil?- and plunged straight into deep semantics. Mobil's experts said "synthetic" traditionally meant big molecules built up from small ones. Castrol's side held out for a looser description, defining "synthetic" as "the product of an intended chemical reaction."

What do unbiased sources say? It turns out that the Society of Automotive Engineers (SAE) and the American Petroleum Institute (API) both have technical standards covering motor oils, and both of these organizations in the '90's backed away from their old definitions of "synthetic," leaving lots of room for new interpretations.

In the end, NAD decided that the evidence constitutes a reasonable basis for the claim that Castrol Syntec, as currently formulated, is a synthetic motor oil, said Lubricants World.

The obvious question now: Has the term "synthetic motor oil" been opened up to the point that it no longer means anything? Maybe. But here's a better question: Did synthetic ever mean what we thought it meant?

"Great oil" is what most guys think it means. "At that price, it's gotta be great stuff!"

Okay, but how great? Your cars manual tells what motor oil you should use, and with few exceptions, that description will consist of only two specifications. One is for viscosity, such as 10W-30; and the other is for the API service grade, SJ being the current one for gasoline passenger cars.

The buck-a-quart multi-grades meet these standards, as do the synthetics.

The synthetics, on the back label, claim compliance with more standards, but even if you know what they mean, they seem beside the point for U.S. passenger cars. For example, should you care about diesels if you drive a gasoline burner? API service CF is the oldest of the current specs for light-duty diesels; some synthetics list that one. Synthetics may also list ACEA A1 and B1, which are European specs roughly equivalent to API gasoline and diesel specs. The Europeans grad their oils by level of performance, so that A2 and A3 are tougher specs than A1. Same for diesels. Usually the date of the spec is omitted, but A1-98 is newer than A1-96.

Completely absent is the one performance claim that would have some real meaning for all of us- some indication of longer oil life. (except for AMSOIL which clearly states 25,000 miles/1-year or 35,000 miles/1-year for their Severe Service 0W-30 synthetic). Automakers hold synthetics to the same oil change intervals as conventional oils. And the oil companies, promise even less. "To give added protection and life to your engine, change your oil every 3000 miles." This same language appears on the back of both Pennzoil Synthetic and conventional oils. Valvoline synthetic makes a similar recommendation. (commentary: Since 1972 AMSOIL is the ONLY synthetic oil manufacturer in the world to guarantee 25,000 miles or 35,000 mile oil change intervals and utilizing full PAO synthetic technology exclusively).

Synthetics do get one unambiguous endorsement: Corvettes, Porsches, Vipers, and all AMG models from Mercedes-Benz come with Mobil 1 as the factory fill.

Most synthetics mention GM 4718M in their list of claims; that's the unique spec created by General Motors for Corvette oil. It's a high-temperature requirement that tolerates less oxidation (thickening) and volatility (boil-off) on a standard engine test called Sequence 111E according to engineer Bob Olree of GM Powertrain. (note: AMSOIL 0W-30 far surpasses GM's 4718M spec).

But don't expect to learn such details on any label (again, except for AMSOIL which clearly states test results on the back of every bottle of Series 2000 0W-30 and 20W-50 synthetic). Mobil 1 at least uses straight forward declarative sentences. Most of the others read as though they were written by a lawyer looking for an escape clause. Why else would the following claim be so rubbery? "Pennzoil Synthetic motor oil is recommended for use in all engines requiring ILSACGF-1, GF-2, API SJ, SH, or SG, and in engines requiring oils meeting GM 4718M." Okay, but does it actually pass those standards?

"Yes" says James Newsom, Pennzoil's motor-oil product manager.

Castrol Syntec, on its label, "exceeds" every standard it mentions. Hmm. Now that the meaning of "is" is in play, I have to wonder, does Syntec meet those standards as well?

"It does" says Castrol's Julie Ann Oberg. While I have her on the phone, I ask if there will be a Syntec price reduction now that the lower-cost base stock has been substituted for the old synthetic. She says no.

End of article.

oilman

To clear up some points.

1. It is not bullshit, it's fact there is a good summary here:
http://www.1st-in-synthetics.com/articles60.htm

2. Castol RS 10w-60 is still available, I sell it!

3. Synthetic lubricants are superior (read this if you want to know why)

SYNTHETICS vs MINERALS

Oil is the lifeblood of your vehicle's engine. For decades conventional petroleum
oils have been providing adequate protection for all of our vehicles.

The key word here is adequate. Petroleum oils, for the most part, have done an adequate job of protecting our engines from break down. If you change it often enough, you can be relatively sure that your car will last 100,000 to 150,000 miles without a serious engine problem - maybe even longer.

The real question is, why settle for adequate when something better has been available for about 30 years?

Today's engines are built for better performance, and, although petroleum oils are designed for better protection and performance today than they were 10 or 20 years ago, there is only so much that can be done. Today's engines need high performance lubricants, and the only true ones available are synthetics.

Conventional petroleum oils are insufficient for use in today's vehicles primarily because they are manufactured from a refined substance, contain paraffins (wax), sulfur, nitrogen, oxygen, water, salts and certain metals. All of these contaminants must be refined out of the basestock in order for it to be useful for use within a lubricant.

Unfortunately, no refining process is perfect. Impurities will always remain when any refining process is done. It simply isn't economical to continue to refine the oil again and again to remove more impurities. If this was done, petroleum oils would cost as much as synthetic oils do.

There are many components of petroleum oil basestocks which are completely unnecessary for protecting your engine. They do absolutely nothing to enhance the lubrication properties of the oil. In fact, most of these contaminants are actually harmful to your oil and your engine.

Some of the chemicals in conventional petroleum lubricants break down at temperatures well within the normal operating temperature range of your engine. Others are prone to break down in these relatively mild temperatures only if oxygen is present. But, this is invariably the case anyway, especially since oxygen is one of the contaminants within petroleum basestocks.

These thermally and oxidatively unstable contaminants do absolutely nothing to aid in the lubrication process. They are only present in conventional petroleum oils because removing them would be impossible or excessively expensive.

When thermal or oxidative break down of petroleum oil occurs, it leaves engine components coated with varnish, deposits and sludge. In addition, the lubricant which is left is thick, hard to pump and maintains little heat transfer ability.

In addition, petroleum oils contain paraffins which cause dramatic oil thickening in cold temperatures. Even with the addition of pour point depressant additives, most petroleum oils will begin to thicken at temperatures 10 to 40 degrees warmer than synthetic oils.

As a result, petroleum lubricants will not readily circulate through your engine's oil system during cold weather. This may leave engine parts unprotected for minutes after startup. Obviously, significant wear can occur during this time frame.

Even when all conditions are perfect for conventional oils to do their job, they fall far short of synthetic oils. Part of the problem is that (because of their refined nature) petroleum oils are composed of molecules which vary greatly in size. As the oil flows through your vehicle's lubrication system, the small, light molecules tend to flow in the center of the oil stream while the large, heavy ones adhere to metal surfaces where they create a barrier against heat movement from the component to the oil stream. In effect, the large, heavy molecules work like a blanket around hot components.

There is also another effect of the non-uniformity of petroleum oil molecules which reduces their effectiveness. Uniformly smooth molecules slip over one another with relative ease. This is not the case with molecules of differing size.
Theoretically, it might be somewhat similar to putting one layer of marbles on top of another (if this could easily be done). If the marbles were all of the same size, they would move over one another fairly easily. However, if they were all of differing sizes, the result would be much less efficient.

In the case of petroleum oils this inefficiency leads, ironically, to added friction in the system (the very thing that lubricants are supposed to reduce). Hence, petroleum oils are only marginally capable of controlling heat in your engine. Considering that motor oil does nearly 50% of the cooling of your engine, that's not a good thing. But,

This being said, petroleum oils are “adequate” for the purpose of protecting your engine, if you don't mind a shorter vehicle lifespan, inconvenient oil changes, or decreased engine
performance. Under normal circumstances, most vehicles lubricated with petroleum oil should run satisfactorily for 100,000 to 150,000 miles without serious incidence.

If you like the hassle of changing your oil regularly, and you are only looking for marginal
performance for the next 100,000 miles or so, petroleum oils are definitely the way to go.

Assuming that you don't relish the idea of changing your oil every 2,000 miles or and are looking to keep your “pride and joy” in tip-top condition then these are the main areas where synthetic oils surpass their petroleum counterparts.

Oil drains can be extended
Vehicle life can be extended
Costly repairs can be reduced
Fuel mileage can be improved
Performance can be improved

Synthetic basestock molecules are pure and of uniform size. This is because synthetic basestocks are designed from the ground up with the sole purpose of protecting your engine. Nothing is added if it does not significantly contribute to the lubricating ability of the oil.
In addition, in top-quality synthetics, no component is added which might be contaminated with any substance that might lessen the lubricating qualities of the oil. In other words, manufacturers of these premium synthetics implement very strict quality control measures to insure no contamination.

Not only that, synthetic basestocks are designed so that the molecules are of uniform size and weight. In addition, synthetic basestock molecules are short-chain molecules which are much more stable than the long-chain molecules that petroleum basestocks are made of. This significantly adds to the lubricating qualities and stability of the oil.

EXTENDED OIL DRAINS
Stable Basestocks
Synthetic oils are designed from pure, uniform synthetic basestocks, they contain no contaminants or unstable molecules which are prone to thermal and oxidative break down.
Moreover, because of their uniform molecular structure, synthetic lubricants operate with less internal and external friction than petroleum oils which have the non-uniform molecular structure. The result is better heat control, and less heat means less stress to the lubricant.

Higher Percentage of Basestock
Synthetic oils contain a higher percentage of lubricant basestock than petroleum oils do.
This is because multi-viscosity oils need a great deal of pour point depressant and viscosity modifying additives in order to be sold as multi-viscosity oils.
Synthetic oils, require very little in the way of pour point depressants and viscosity
modifiers. Therefore, synthetic oils can contain a higher percentage of basestock, which actually does most of the lubricating anyway. More basestock leads to longer motor oil life.

Additives Used Up More Slowly
Petroleum basestocks are much more prone to oxidation than synthetic oils, oxidation inhibitors are needed in greater supply and are used up very quickly. Synthetic oils do oxidize, but at a much slower rate therefore, oxidation inhibiting additives are used up much more slowly.
Synthetic oils provide for better ring seal than petroleum oils do. This minimizes blow-by and reduces contamination by combustion by-products. As a result, corrosion inhibiting additives have less work to do and will last much longer than within a petroleum oil.

Excellent Heat Tolerance
Synthetics are simply more tolerant to extreme heat than petroleum oils are. When heat builds up within an engine, petroleum oils quickly begin to burn off. They volatize. In other words, the lighter molecules within petroleum oils turn to gas and what's left are the large petroleum oil molecules that are harder to pump.
Synthetics are resistant to this burn-off. They will tolerate much higher engine temperatures.

EXTENDED VEHICLE LIFE WITH FEWER REPAIRS
Heat Reduction
More often than not, vehicle life is determined by engine life. One of the major factors affecting engine life is component wear and/or failure, which is often the result of high temperature operation. The uniformly smooth molecular structure of synthetic oils gives them a much lower coefficient of friction (they slip more easily over one another causing less friction) than petroleum oils.
Less friction, of course, means less heat in the system. And, since heat is a major contributor to engine component wear and failure, synthetic oils significantly reduce these two detrimental effects.
In addition, because of their uniform molecular structure, synthetic oils do not cause the "blanket effect" which was mentioned earlier. Since each molecule in a synthetic oil is of uniform size, each is equally likely to touch a component surface at any given time, thus moving a certain amount of heat into the oil stream and away from the component. This makes synthetic oils far superior heat transfer agents than conventional petroleum oils.

Greater Film Strength
Petroleum motor oils have very low film strength in comparison to synthetics. The film strength of a lubricant refers to it's ability to maintain a film of lubricant between two objects when extreme pressure and heat are applied.
Synthetic oils will typically have a film strength of 500% to 1000% higher than petroleum oils of comparable viscosity. In fact, believe it or not, even though heavier weight oils typically have higher film strength than lighter weight oils, a 0w30 or 5w-40 weight synthetic oil will likely have higher film strength than a 15w40 or 20w50 petroleum oil.
Thus, even with a lighter weight oil, you can still maintain proper lubricity and reduce the chance of metal to metal contact when using a synthetic oil. Of course, that means that you can use oils that provide far better fuel efficiency and cold weather protection without sacrificing engine protection under high temperature, high load conditions. Obviously, this is a big plus, because you can greatly reduce both cold temperature start-up wear and high temperature/high load engine wear using the same low viscosity oil.

Engine Deposit Reduction
In discussing some of the pitfalls of petroleum oil use, engine cleanliness is certainly an issue. Petroleum oils tend to leave sludge, varnish and deposits behind after thermal and oxidative break down. They're better than they used to be, but it still occurs.
Deposit build-up leads to a significant reduction in engine performance and engine life as well as increasing the number of costly repairs that are necessary. Since synthetic oils have far superior thermal and oxidative stability than petroleum oils, they leave engines virtually varnish, deposit and sludge-free.

Better Cold Temperature Fluidity
Synthetic oils and other lubricants do not contain paraffins or other waxes which dramatically thicken petroleum oils during cold weather. As a result, they tend to flow much better during cold temperature starts and begin lubricating an engine almost immediately. This leads to significant engine wear reduction, and, therefore, longer engine life and fewer costly repairs.

IMPROVED FUEL MILEAGE AND PERFORMANCE
As indicated earlier, synthetic oils, because of their uniform molecular structure, are tremendous friction reducers. Less friction leads to increased fuel economy and improved engine performance.
Any energy released from the combustion process that would normally be lost to friction can now be transferred directly to the wheels, providing movement.
Vehicle acceleration becomes swifter and more powerful while using less fuel in the process.
The uniform molecular structure of synthetic oils has another performance enhancing benefit as well. In a petroleum oil, lighter molecules tend to boil off easily, leaving behind much heavier molecules which are difficult to pump. Certainly, the engine loses more energy pumping these heavy molecules than if it were pumping lighter ones.
Since synthetic oils have more uniform molecules, fewer of these molecules tend to boil off.
More importantly, when they do, the molecules which are left are of the same size and pumpability is not affected.

Cheers
Guy (Simon is my brother)

Jon ERST S2

But if you change your oil every 3000 miles or less. I heard Mineral oil is better for the engine.

Obviously synthetic increases service life etc on normal cars, but when we throw ours away all the time, does it matter much?

oilman

Synthetics are still better all around (the real thing that is) ester/pao is the way to go for ultimate protection.

Cheers
Simon

oilman

That is because there is two of us. Simon and Guy.

We are still the oilman though!

Cheers.

XRTypeRS

So in summary what should we be buying??, Castrol RS 1-60 or Mobil Motorsport, both are about the same price and both are hard to get hold of now (i.e. u cannot pop round to your local motor factors for) due to the fact that modern cars which make up most of the UK fleet these days dont have the "large" operating clearances in their engines that our now "ancient" RSs have!.

Im personally always gone for RS as it seems to keep the old CVH just a tad quieter but I could be swayed to try something else!

swerv

ive used castrol RS 10/60 and mobil 15/50 for a long time now , ive known a few people to have probs with the castrol making the engine noisey but never with the mobil.

I used the castrol in my cossie since it was run in and had no probs what so ever!!

also i havnt read all the above yet but ive been told by various turbo specialist's that you should not use a mineral oil on a turbo car

oilman

We supply them all delivered to your door and more!

Just email us: sales@opieoils.co.uk

Cheers
Guy

Fast Guy

You get around the forums abit Oilman, is there a sales drive on at work?

If synthetics are better (and I don't doubt it, cos I use them) then why don't all engines use them as standard?

Christian and Beccy

iTrader: (14)

I digested some of that, but to be honest, most went over my head.

I have got on well with Castrol RS 10w60. It gives good oil pressure, noticeably better than others. I found that Mobil Motorsport 15w50 made my VERY lowe mileage engine rattle.

I also rate Valvoline VR1 Racing 5w50 (formally Valvoline Synpower 5w50). What the verdict on this oil??

Also, whats the deal with Royal Purple oils? They seem to have a pretty interesting slant on it.

POPEYE

i use the valvoline 5w50 and love it

oilman

No sales drive on yet. Trying to educate as there is so much misinformation regarding oil on the net.

Most modern cars benefit from a fully synthetic, however its down to cost.

A manufaturer is only going to factory fill the car with an adaquate oil to keep costs down, along with many services when they change your oil, if your not charged for it and they dont give you a choice then they are unlikely to "give" away top quality expensive oil.

And back to my misinformation, a lot of the general public are unaware of the benefits of synthetic oils, so if you dont know why they are more expensive why would you buy one.

Cheers

Guy.

weegaz22

as said above bike oil has friction modifiers in it to allow the clutch plates(which are in the engine oil) to grip instead of slip, if you put car engine oil into a bike it will slip its clutch as there is less friction in that oil....so the moral of the story is dont use it in your car as it may wear other things out prematurly

oilman

More and more people do these days and so do many OEM's for factory fill now.

It's a question of developments in the oil industry and the fact that synthetics are coming down in cost so they are more affordable these days.

Yes they are here to stay and are the future of engine lubrication.

Cheers
Guy

CossieRich

iTrader: (1)

im not going to pretend that i understand this tech talk on oils. All i really want to know is what oil is the best for a cossie?

Ive been using castrol rs 10w 60 for 2 years now (on the recommendation of M.A Developments) and had no problems and neither has Mark AFAIK.

So which oil is to be used?

Disabled Account

Oilman,

Could you clear one thing up please.

For my Escort Cossie I would choose your best reccomendation "Silkoline PRO S 10W-50" as I understand it this is a fully Synthetic oil.

However, also in your price list you describe Castrol RS 10W-60 as being a fully Synthetic oil.

My question is: Is the Castrol RS 10W-60 NOT actually a true synthetic oil and therefore not as good at protecting an engine as the Silkoline PRO S 10W-50?

Malc50

Hi Oilman...

For an Escort Cosworth...What oil do you recommend and how much can you supply it for...

Thks Malc

oilman

You will have no problems with the 10w-60. However you could do better in terms of quality and grade. I have always maintained the SEA60 is too thick and I feel an SEA50 is better. Reasons for this have been discussed at length on this forum.

Castrol 10w-60 is Hydrocracked mineral oil, not even close to an ester/pao fully synthetic of a similar grade.

For me it would be the Silkolene Pro S 10w-50 all the way as it is ideal for hot turbo charged engines, that require high temp protection.

Cheers

Guy.

Christian and Beccy

iTrader: (14)

CossieRich

iTrader: (1)

Have you got a web-site with all the oils you stock?

oilman

Doug,

Unfortunatly the Castrol RS10w-60 is not a true PAO/Ester fully synthetic. Its a Hydrocracked Mineral Oil.

They can call it synthetic because of the court case a few years ago which resulted in the oil companies being able to describe a modified mineral oil as synthetic when in the true sense of the term it is not.

However in Germany, the rules are different, Manufacturers there have to be precise about what the oil is. Like Ronseal "does exactly what it says on the tin".

Hope this clears it up a bit.

Cheers

Simon.

CossieRich

iTrader: (1)

Website?

oilman

For the Cosworth I would consider the Silkolene Pro S 10w-50 ester based fully synthetic.

Email me at sales@opieoils.co.uk and I will forward you on some prices.

Cheers

Simon.

Disabled Account

Thanks Simon,

Clears up the slight confusion.

From now on I will be using a TRUE synthetic oil....will be in touch soon about some Silkoline PRO S 10W-50

oilman

Ok website.

http://www.opieoils.co.uk/lubricants.htm

Specs on all the oils we stock here.

cheers.

CossieRich

iTrader: (1)

Cheers Simon

oilman

We dont know much about valvoline, it is difficult to get the tech data on it. Royal Purple though we are having tested at the moment. The rusults should be good. Will let you know.

Cheers

Simon.

Mike Rainbird

iTrader: (3)

I used to use the Mobil Motorsport 15w50, but found at high temperatures (above 110°C) that the Mobil would give much lower oil pressures (5-6psi lower) compared to the Castrol RS 10w60.

Could you please clarify, why if the Castrol RS is an inferior oil, that this might be the case?

Stating that Castrol RS is too thick is a joke - it has a lower viscosity rating at cold than the Mobil Motorsport, perhaps the higher rating when hot gives it the better oil pressure ?

JAP CRAP

Make sure you let us know of the results

AlexD

iTrader: (3)

Features / Benefits
Castrol Formula RS 10W-60 is formulated with fully synthetic base oils and an advance additive package to
provide the following benefits:

· Specially suitable for high performance applications.
· Provides improved acceleration for safer overtaking.
· Maximum wear protection and deposit control assured.
· Reduced friction allows easier cold starting and faster oil pressure build-up.
· Engine deposits are kept to the minimum possible to preserve engine life and reduce ownership costs.

Seem o.k to me

Al..

CossieRich

iTrader: (1)

improved acceleration. How?

Disabled Account

Alex,

I dont think that we are doubting that Castrol RS 10W-60 is a good oil to use in our Cosworths..........BUT is it the very best oil that is available for our cars?

If you read the first posting on this thread it becomes clear that IF Castrol had lost that court case, then they WOULD NOT be able to market Casrtol RS10W-60 as a fully snthetic oil. Essentially, i'ts a hybrid oil, not a true synthetic oil

oilman

When I say it is too thick, I am talking about the viscosity when hot the SEA60, I should have been more clear.

Yes it gives great oil pressure, however this is a measure of resistance not flow, and flow is whats important.

If you have too much resistance you engine is using up power from elswhere to push against the resistance to make the oil flow.

Hope this helps.

Cheers.

oilman

Spot on!!!

oilman

A lot of oils say this just to make you buy it.

You can achieve better power delivery though!

Cheers.

turbinator

oilman .. what do you think of this ??

http://www.torcoracingoils.com/produ...sGroupIDPK=110

St3V3_C

I wondered that "and don't worry about that high volume, low margin shite, sell the EXPENSIVE stuff"

Price.

Oilman, Thanks for the information mate, good reading.

oilman

Cheers,

Went and had a look at the site. They dont give measurments on their VI indexes, however with a few calculations from what is there, we have worked out the VI index is quite low, Lower than european oils this suggests poor base stocks.

The low flash points indicate it is not ester based.

I would like to see a proper data sheet on this one.

In addition to this, being a US oil it is likely to cost you an arm and a leg!

However there is another problem with US oils.

It may be best that all fans of U.S. oils close their ears or look away at this point, you may not like what you read!

Some basics first.
A good oil must be quite low in viscosity even in the cold, so that it gets around the engine in a fraction of a second on start-up. On the other hand, it must also protect engine components (piston rings for example) at temperatures up to 300 deg C without evaporating or carbonising, and maintain oil pressure.
Unmodified thin oils simply can't manage this balancing act. The answer is to use a mixture of thin oil and temperature sensitive polymer, so as the thin oil gets even thinner with increasing temperatures as the engine warms up, the polymer expands and fights back, keeping the viscosity at a reasonable level to hold oil pressure and film thickness on the bearings.
All oils have a viscosity index which is the number indicating that rate of change in viscosity of an oil within a given temperature range. Higher numbers indicate a low change, lower numbers indicate a relatively large change. The higher the number the better. This is one major property of an oil that keeps your bearings happy. These numbers can only be compared within a viscosity range (10w-40 vs 10w-40) but here it the important thing...............
They do not give an indication of how well the oil resists thermal breakdown! (The oil film tearing or shearing)
This is all down to a very important additive called a Viscosity Index improver and it is critical that this is shear stable.
VI improvers like all other things in life vary in quality and this is down to cost and availability.
In other words, an oil can look great on paper and make impressive claims but, unless all the components are of high quality it will fail to perform under the most arduous conditions.
I asked John Rowland the Silkolene/Fuchs Chief R&D Chemist for 40 years to give me his opinion on U.S. oils for another car club and below was his reply:

Quote,

Guy,

The main problem with the majority of American Oils is that they have “low grade" Viscosity improvers in them. Good ones are just not available in the states due to the fact that they are just not required for the majority of American engines.

The consequence of this is, although the oils look good on paper with high VI indexes etc the low grade inprovers mean that they have a tendency to "shear down" causing a lack of oil pressure , after a couple of thousand miles hard use in a stressed engine. .

For example, the oil you are using may be a 10w-40 when first put in but could be operating as a 10W/20 after a few thousand miles! It’s the use that sorts them out.

JR

Unquote:

I was intrigued by Johns answer and wanted to know how he knew it was the case in the U.S. that good quality VI improvers were not available. His reply was as follows:

Quote:

We have found it is impossible to source shear stable VI improvers
in the U.S.A. even for ready money!

Unquote:

Bear in mind here that Fuchs/Silkolene is the largest independent Lube Oil Manufacturer in the World and has facilities in the U.S.

Mis-information abounds in the oil world and looking behind the marketing hype and claims is impossible unless of course you are a chemist and able to look deep into the oils make-up which neither you nor I can do!

Hope this helps.

Cheers

Guy

Chick

So, what you're syaing is you wouldn't reccomend any oil with a viscosity rating of as high as 60 because it's too thick at high temperature?
When you see that peolpe get a higher oil pressure at high temp with a 60 it's because the oil is thicker, i.e the molecules have more mass so when the pressure (which is a measure of force over an area) the force is higher due to the heavier molecules and not due to the velocity of them?
Am I on the right track?