5.0 and 5.7 Discussion, Amsoil... in Cadillac Engine Discussion; Diesel oils have higher levels of ZDDP which is a key antiwear additive. Cars with cam driven distributor gears and/or ...
- 11-04-06 09:21 PM #16
Diesel oils have higher levels of ZDDP which is a key antiwear additive. Cars with cam driven distributor gears and/or flat tappet cams NEED this additive. Modern SM spec oils have ZDDP dropped to dangerous levels for these type engines. Diesel oils have sufficient levels of ZDDP to ward off this wear.
Read more on M1 and Amsoil here: http://neptune.spacebears.com/cars/stories/mobil1.html and http://neptune.spacebears.com/cars/stories/amsoil.html
Search for ZDDP on the Deville and HT4100 forums.
- 11-04-06 10:01 PM #17
Interesting reads. They seem to be all about M1 lasting longer and being more consistent in testing. Why is everyone so hyped up on Amsoil? Although the TBN in the M1 seems to be pretty low compared to Amsoil. Of course they do say that the Amsoil was better over all as far as insolubles found but what's up with the major viscosity changes. I imagine that's not cool for the N*.
Just rambling at this point, it's all pretty interesting.
- 11-04-06 10:33 PM #18
Amsoil is a fairly well engineered oil, and they are forthcoming in the product. Most synthetic oil companies are not, they, in many cases, do NOT even have a synthetic oil, yet they claim they are synthetic (Syntec, Syntron, etc all those garbage names that are meaningless) and are nothing more than a Group III oil and not anything synthetic at all.
Mobil 1 is also fairly good, not quite as forthcoming as Amsoil, but they do make good product. Testing oils side by side for wear has shown that in almost every case, with direct metal to metal contact wear (again, ONLY the camshaft and distributor gear have the harshest wear here), Amsoil was best. Especially in 60kg pressure. Havoline Formula 3 SL 5W30 oil outperformed most synthetics in 40kg wear except for Mobil 1 5W30 and Amsoil 0W30.
So how does this all have meaning to an engine? Hard to make a 100% judgement of it.
Edit: After looking at some of the data, it does seem the Mobil 1 performed better in the TBN catagory. Now, what I don't see if time of year. Temps. The temperature determines how rich/lean the AFR is and that will very likely have some significance in the acid levels as there is more fuel that is needed to crank over and start the engine. As I drive 600+ miles per week, I see 33K+ miles per year, I can do a test similar and have one oil in the winter, one in the summer easily.
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- 11-05-06 09:57 PM #19
Corvette C5 AMSOIL Series 2000 0w30 Used Oil Analysis Report
Note: the 6/24 and 5/6 test were AMSOIL, the 3/11 test was German Castrol 0w30.
Many people recommend diesel oils because they haven't been subject to the new API SM standard applicable to gasoline motor oils. Of note, the API did just come out with a new diesel standard for 2007 and later diesel engines, the API CJ-4 standard which does severely limit the additives allowed. API CI-4 diesel oils such as the AMSOIL Series 3000 Synthetic 5w30 Heavy Duty Diesel Oil do have very robust levels of anti-wear, detergent and dispersant additives.
Though the new API SM standards have higher performance standards than older standards, they actually severely restrict ZDDP additives (by limiting phosphorus to 0.08%). This was done at the behest of the automotive industry to help them meet EPA requirements, not necessarily protect the engine.
And you can read the history, including the why the auto industry and the EPA wanted the new standard here:
Here is a short primer on the AMSOIL line for gasoline motor oils:
- Group IV PAO synthetic basestock
- API SM compliant but does not carry the API Starburst certification
- Rated for 35,000 miles or 1 year of use in normal service, 17,500 miles or 1 year in severe service
AMSOIL Series 2000 0w30
- Group IV PAO synthetic basestock
- API SM compliant but does not carry the API Starburst certification
- Rated for 25,000 miles or 1 year of use in normal service, 15,000 miles or 1 year in severe service
AMSOIL SAE Synthetic 10w30
AMSOIL SAE Synthetic 5w30
Most Affordable Tier
- Group III highly hydroprocessed synthetic basestock
- API SM compliant and API Starburst certified
- Rated for 7,500 miles or six months of use. With Oil Life Monitoring Systems (such as most current GM vehicles) can be used as recommended by the manufacturer (normally change the oil at one year or per OLM whichever comes first)
AMSOIL XL Synthetic 5w20
AMSOIL XL Synthetic 5w30
AMSOIL XL Synthetic 10w30
AMSOIL XL Synthetic 10w40
For an older car where you want improved performance over regular oils, I'd suggest the XL line which is what I use in my wife's 2003 Chevy Trailblazer which has the 5.3L V-8. For my 2006 CTS-V I'll be using the Series 2000 0w30 when I get to my first oil change.
- 11-05-06 10:41 PM #20
Do you recommend a 0W-30 oil even for a high oil consumption engine such as the N* or should we stick with a 10W-30 flavor. Seems to me I saw people eliminating oil consumption by switching from 5W-30 to 10W-30 so it stands to reason, in my mind, that using a 0W-30 oil would increase oil consumption. My car is just under 40k
- 11-08-06 09:41 PM #21
An SAE 30 grade oil is an oil with a 100C (212F) viscosity in a band of viscosity: 9.30 to 12.49 cSt. It is commonly believed that a 10w30 is "thicker" than a 5w30 or a 0w30, but at 100C (212F) all of them have viscosities in this range. However, some oils have a viscosity higher in the range than others. To actually determine what you are getting you need to look at the product data sheet for the individual brand and grade of oil you are buying. For example, Mobil Clean 5000 10w30, a conventional oil, has a viscosity of 10.4 cSt at 212F per Mobil's website. Conversely, the AMSOIL Series 2000 0w30, a group IV synthetic oil, has a viscosity of 11.2 cSt at 212F per AMSOIL's corporate website. The 0w30 actually has a higher viscosity than the 10w30 and this will contribute to less not more oil consumption.
To achieve multiviscosity ratings, conventional oils need to add viscosity improvers (VIs). To make a 5W-30 oil, one starts with a 5W oil and adds viscosity improvers. These VIs have the property that in cold temperatures their polymers coil up, contributing little to the base oils viscosity measurements. At higher temperatures they uncoil to reduce the base oils loss of viscosity as it heats up. So when the VIs break down (shear down) one is left with properties of the original base oil (the 5W stuff). Thus over time, a low quality 5w30 could over time shear down to a 5w20, or worse. The higher the spread of the multiviscosity oil, the more VIs are needed and the more susceptible to viscosity shear down the oil is. Thus a conventional 10w30 will have less VI and will remain "thicker" longer, which contributes to the common perception that a 10w30 will do better with oil consumption.
However, good synthetics do not need as much VI as conventional oil so in general don’t shear down as fast. Since a 10w30 will need less VI than a 5w30, again in general it will perform better since there is fewer VI to shear down and there is proportionately more basestock in the 10w30 since it isn’t being displaced by VI. That said, there are other higher costs additives that can offset this effect. FYI, most high quality synthetic 10w30 actually have no VIs and 5w30 and 0w30 synthetics have little VI.
- 11-08-06 10:23 PM #22
This is why I love this place.
So basically a synthetic 10W-30 is a lot more stable because there are no or very little Vi in it making the viscosity true to rating throughout the temp range?
Do I understand that correctly?
Thus the Synthetic 0W or 5W -30's are fine because the viscosity is also more stable and doesn't get as thinned making it less susceptible causing the burn off or leaking associated with the N* as a conventional oil would?
Did I get that right? Sort of.
- 11-08-06 11:47 PM #23
Like Amsoil's (10W)30 diesel oil? No VI or low VI is common place with Amsoil isn't it?
- 11-10-06 12:23 PM #24
You did that right... sort of.
With regard to the understanding of VIs and synthetic vs conventional viscosity shear down, you have it.
But, I did qualify my statement to "good" synthetics. There are a huge variety of synthetics on the market. I've posted a description of the various oil basestocks below. Most synthetic oils on the market are Group III. A few such as AMSOIL's SAE Synthetics and currently Mobil 1 are Group IV. Redline, predominantly a racing oil is the only Group V I'm aware of.
Not all synthetics respond the same to viscosity shear down. The below quote is from this AMSOIL commissioned motor cycle oil which demonstrates the issues surrounding viscosity shear down. You can see the actual graphs if you download this file:
AMSOIL Motorcycle Oil “White Paper” (1 MB pdf file)
"Viscosity Shear Stability (ASTM D-6278)
An oil’s viscosity can also be affected through normal use. Mechanical activity creates shearing forces that can cause an
oil to thin out, reducing its load carrying ability. Engines operating at high RPMs and those that share a common oil sump
with the transmission are particularly subject to high shear rates. Gear sets found in the transmissions are the leading cause
of shear-induced viscosity loss in motorcycle applications.
The ASTM D-6278 test methodology is used to determine oil shear stability. First an oil’s initial viscosity is determined. The
oil is then subjected to shearing forces at 30 cycle intervals. Viscosity measurements are taken at the end of 30, 90 and
120 cycles and compared to the oil’s initial viscosity. The oils that perform well are those that show little or no viscosity
change. Oils demonstrating a significant loss in viscosity would be subject to concern. The flatter the line on the charts
below, the greater the shear stability of the oil. Each SAE grade was split into two or more groups to make the charts easier
The results point out significant differences between oils and their ability to retain their viscosity. Within the SAE 40 group,
41.6% of the oils dropped one viscosity grade to an SAE 30. Within the SAE 50 group, 43.8% dropped one grade to an
SAE 40. Most of the oils losing a viscosity grade did so quickly, within the initial 30 cycles of shearing. Testing revealed that
Lucas 10W-40 High Performance Motorcycle oil was the only oil to shear to an SAE 20.
It should be noted that both high and low viscosity index oils exhibited significant amounts of shear and viscosity loss. Two
of the oils with the highest viscosity index, Torco T-4SR in the SAE 40 group and Yamalube 4R in the SAE 50 group, had
the largest drops in viscosity of all the oils in their respective groups. Torco T-4SR sheared to an SAE 30 and Yamalube
sheared to an SAE 40. Valvoline 4-Stroke SAE 50 and Castrol V-Twin SAE 50 had a comparatively low viscosity index and
they too lost significant viscosity, shearing down to an SAE 40."
The API has not come out and defined the term "synthetic." Instead, they have classified oils into the following groups:
Group I base oils are the least refined of all of the groups. They are usually a mix of different hydrocarbon chains with little or no uniformity. While some automotive oils use these stocks, they are generally used in less demanding applications.
Group II base oils are common in mineral based motor oils. They have fair to good performance in the areas of volatility, oxidation stability, wear prevention and flash/fire points. They have only fair performance in areas such as pour point and cold crank viscosity. Group II base stocks are what the majority of engine oils are made from. 3000 mile oil changes are the norm.
Group III base oils are subjected to the highest level of refining of all the mineral oil stocks. Although not chemically engineered, they offer improved performance in a wide range of areas as well as good molecular uniformity and stability. By definition they are considered a synthesized material and can be used in the production of synthetic and semi-synthetic lubricants. Group III is used in the vast majority of full synthetics or synthetic blends. They are superior to group I and II oils but still have limitations. Some formulations are designed for extended oil changes. AMSOIL XL Motor Oils, Castrol Syntec and many others fall into this category.
Group IV are polyalphaolefins (PAO) which are a chemically engineered synthesized basestocks. PAOs offer excellent stability, molecular uniformity and performance over a wide range of lubricating properties. AMSOIL SAE Synthetic Motor Oils and Mobil 1 primarily use group IV basestocks. PAO is a much more expensive basestock than the highly refined petroleum oil basestock of Group III.
Group V base oils are also chemically engineered stocks that do not full into any of the categories previously mentioned. Typical examples of group V stocks are Esters, polyglycols and silicone. Redline uses an ester basestock.
In the 90s, Mobil filed suit against Castrol for falsely advertising Syntec oil as synthetic, when in fact it contained a Group III, highly hydroprocessed mineral (Dino) oil, instead of a chemically synthesized (group IV or V) basestock. Due to the amount that the mineral oil had been chemically changed, the judge decided in Castrol's favor. As a result, any oil containing this highly hydroprocessed mineral (Dino) oil (currently called Group III basestock by the American Petroleum Institute) can be marketed as a synthetic oil. Since the original synthetic basestock (polyalphaolefin or PAO) is much more expensive than the Group III basestock, most of the oil blenders switched to the Group III basestock, which significantly increased their profit margins.
- 11-10-06 12:25 PM #25
- 11-10-06 01:13 PM #26
Amsoil used to be Ester/DiEster base stocks (90's). They are not now? So they were Group V and are not Group IV?
- 11-10-06 01:25 PM #27
I do know that PAO and ester basestocks effect seals differently. PAO shrinks seals, ester expands them. I've read that the mixture AMSOIL uses results in a slight (on the order of a few percent) expansion of seals. This provides the benefit that in higher mileage cars when the higher levels of detergents in AMSOIL remove sludge exposing potentially older dried out seals to fresh oil, the oil replenishes and expands the seals so that leakage problems are minimized or non-existant. I've got hundreds of AMSOIL customers and not one has ever reported a seal leakage problem to me. If there is an actual mechanical fault with the seal (e.g. a crack) the slight expansion probably won't correct the problem.
- 11-10-06 01:29 PM #28
So which is better? Ester or DiEster stocks or PAO's?
Are PAO's still 100% synthetic? Are all Amsoil's addtives still synthetic? That was Amsoil's claim to fame at one time.
- 11-10-06 05:47 PM #29
You can read more about the benefits of PAOs and Esters in this article I found on another automotive forum:
"Esters: Diesters (dibasic acid esters)
During World War II a range of synthetic oils was developed. Among these, esters of long-chain alcohols and acids proved to be excellent for low temperature lubricants. Following World War II, the further development of esters was closely linked to the aviation gas turbine. In the early 1960s, neopolyol esters were used in this application because of their low volatilities, high flash points and good thermal stabilities.
Diesters are prepared by reacting a dibasic acid with an alcohol containing one reactive hydroxyl group. Note that the hydrolytic stability of diesters is not as good as mineral oils. Hydrolytic stability refers to how the lubricant reacts in the presence of water. Hydrolytic degradation can lead to acidic products, which, in turn, promote corrosion. Plus, hydrolysis can also materially change the chemical properties of the base fluid, making it unsuitable for the intended use. Systems that can contract high levels of moisture include systems that operate at low temperatures or that cycle between high and low temperatures and also certain fuels such as racing engines running alcohol, which has a cooling effect in the engine. Racing engines using ester based lubricants should have the lubricant changed regularly.
Diesters have good lubricating properties, good thermal and shear stability, high viscosity indexes and have exceptional solvency and detergency. Diesters are superior fluids for aircraft engines and compressors, although mainly older jet aircraft. Diesters are also used as a base oil or part of a base oil for automotive engine oils and in some low temperature greases (note: modern military and commercial jet aircraft almost universally use lubricants formulated with polyol esters as the base fluid now).
Diesters are incompatible with some sealing materials and can cause more seal swelling than mineral oils. The scientific reason for this is as follows: diesters have a low molecular weight that results in low viscosities. This combined with their high polarities makes them quite aggressive to elastomeric seals. This can be reduced by using better elastomers or by carefully blending with PAOs to nullify their swelling effects, since PAO base stocks are nonpolar.
Esters: Polyolesters (Neopentyl Poly Esters)
Polyol esters are formed by reacting an alcohol with two or more reactive hydroxyl groups. These fluids are used primarily for aircraft engines, high temperature gas turbines, hydraulic fluids and heat exchange fluids. Polyol esters are much more expensive than diesters. Lubricating greases with polyol esters as the base fluid are particularly suited to high temperature applications. Polyol esters have the same advantages/disadvantages as diesters. They are, however, much more stable and tend to be used instead of diesters where temperature stability is important. In general, a polyol ester is thought to be 40-50 deg. C. more thermally stable than a diester of the same viscosity. Esters give much lower coefficients of friction than those of PAO and mineral oil. By adding 5-10% of an ester to a PAO or mineral oil the oils coefficient of friction can be reduced markedly.
Polymerized alpha olefin: Polyalphaolefin, Olefin Polymers, Olefin Oligomers- a synthetic hydrocarbon
PAOs are commonly used to designate olefin oligomers and olefin polymers. The term PAO was first used by Gulf Oil Company (later acquired by Chevron), but it has now become an accepted generic term for hydrocarbons manufactured by the catalytic oligomerization of linear alpha olefins having six or more carbon atoms. PAOs are gaining rapid acceptance as high-performance lubricants and functional fluids because they exhibit certain inherent and highly desirable characteristics. These favorable properties include:
A wide operational temperature range.
Good viscometrics (high viscosity index).
Hydrolytic stability. *
Compatibility with mineral oils.
Compatibility with various materials of construction.
Manufacturing flexibility that allows tailoring products to specific end-use application requirements.
* Of particular interest in relation to demonstrating superior hydrolytic stability of PAO fluids is a test that was conducted to find a replacement for a silicate ester based aircraft coolant/dielectric fluid used by the U.S. military in aircraft radar systems. The test method required treating the fluids with 0.1% water and maintaining the fluid at 170 or 250 deg. F. for up to 250 hours. Samples were withdrawn at 20- hour intervals, and the flash points were measured by the closed cup method. A decrease in flash point was interpreted as being indicative of hydrolytic breakdown to form lower-molecular-weight products. The PAO showed no decrease in flash point in any of the test conditions, while the silicate ester based fluid showed marked decreases. The PAO fluid maintained started out with a flash point of 300 deg. F. and only dropped to 295 deg. F. at 80 hours into the test, while the silicate ester fluid, which started out with a flash point of 270 deg. F., ended up with a flash point of 220 deg. F. at only 55 hours into the test.
PAOs are used extensively as automotive lubricants (engine, gear, transmission, grease, hydraulic). PAOs are also super premium oils for automotive applications operating in temperature extremes. PAOs are a synthetic hydrocarbon that is compatible with mineral oils. In industrial applications, they may be combined with organic esters to be used in high temperature gear and bearing oils, as well as gas turbines. They are also used as a base fluid in some wide temperature range greases.
The general manufacturing process used to form PAOs is performed by combining a low molecular weight material, usually ethylene gas, into a specific olefin which is oligomerized into a lubricating oil material and then hydrogen stabilized. There are a variety of basic building block molecules used to form the finished lubricant, which are dependent on the range of requirements of the specific lubricant.
Seal compatibility is an important factor for any lubricant. Unlike mineral oils, PAO does not have a tendency to swell elastomeric materials. Early commercial PAO products were not formulated properly to allow for this difference in behavior. Consequently, early PAOs gained an undeserved reputation for leakage. Extensive tests have since shown that the addition of small quantities of an ester to the formulation easily alleviates this problem.
Recent work has indicated that the proper choice of other performance additives may eliminate the need to employ esters, but this approach is not yet in practice for crankcase applications. In a test of a PAO vs. a mineral oil for seal compatibility, four seal materials were studied: acrylate, silicone, nitrile and fluoroelastomer. The seals were evaluated at the end of the test for changes in tensile strength, elongation, volume (seal swell), and hardness. The PAO performance fell within the specification limits for all four elastomers. The mineral oil failed with silicone. Similar tests have been carried out with fully formulated part- and full-synthetic PAO oils. In all cases the fluids met the specifications.
Recent data shows that PAO-based fluids provide superior performance for the high-tech cars and trucks being built today. Todays engines are smaller and more demanding and operate at higher RPMs and under hood spaces is limited which causes increased operating temperatures. Both the thermal conductivity and heat capacity of PAO fluids are about 10% higher than values for comparable mineral oils. The net result is that PAO-lubricated equipment tends to run cooler.
There is clearly no doubt that synthetic lubricants are superior to petroleum based oils. An excellent summary of in-depth studies that were conducted on the benefits of synthetic lubricants is presented in Appendix B of the Society for Automotive Engineers, Progress in Technology ****** 22 and was conducted during the 1970s and 1980s. The nine superior performance features of synthetic engine oils that were documented by extensive laboratory and field testing are listed below:
Nine Superior Performance Features of Synthetic Engine Oils
Improved Fuel Economy (4.2% average increase)
Oil Economy (lower consumption)
Excellent Cold Starting and Low Temperature Fluidity
Outstanding Performance in Extended Oil Drain Field Service
High Temperature Oxidation Resistance
Outstanding Single and Double Length SAE-ASTM API SE and SF Performance Tests (note SE and SF specs were the latest at the time of the testing)
Excellent Wear Protection
Extended drain capability for heavy-duty diesel trucks and gasoline powered trucks. Note: this particular test was based on truck fleet testing, however extended drain capability holds true for passenger cars as well.
These same superior performance features of synthetic engine oils hold true today just as they did when this extensive testing was conducted and has since been verified by many more studies and testing as well as countless millions of miles of field service in every possible type of vehicle and equipment application."
- 11-11-06 12:08 AM #30
Ok, wow my brain is now on oil info overload. Thanks so much for all the good info. My next oil change will be to Amsoil 10W-30
This will be my first synthetic venture.
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