OIL for older cars--is zinc being taken out by the oil companies ???

[Mopar Al]

When you speak of "old cars"  What would you consider olod?    That's not meant to sound as a wise crack.      Mine is a 61 Belvedere   318 cid.    My local auto mechanic recomended   valvoline 10 - 30  when I bought the car, and I haven't ever had a problem.      Mopar Al

[12905]

I don't think you can go wrong using DELO. I started using it when our company leased out the service facilities to Chevron in 1955, and I have used it ever since - in all my vehicles.

[POC-Admin]

Look for a rating beginning with a "C" - from a website about motor oils -

"API Oil Standards

The additive package is made to make the finished oil product meet one of the certifications. There are two classes of certification: S, for Service, and C, for commercial. The certification standards are maintained by the API, the American Petroleum Institute. Over the years, the API has improved and changed these standards. The most current S standards are SL and SM. These standards differ from earlier standards like SH by lowering phosphorus to improve catalytic converter life, and increasing molybdenum to lower internal engine friction and improve gas mileage. Phosphorus was originally added to oils to help protect high pressure areas like cam lobes and crankshaft bearings, so lowering phosphorus levels is a compromise of lower pollution, perhaps at the expense of engine life. Molybdenum is added to improve fuel economy due to the federal CAFE (Corporate Average Fuel Economy) standards, thereby helping GM and Ford keep selling large V8s to the American public, but can perhaps cause problems in engines with wet clutches. Most S additive packages are also designed to be inexpensive so that the resulting oil can be sold at a low price. SL and SM oils are both low phosphorus; SM oils which are labeled "energy conserving" are high molybdenum.

About every three years or so, the API releases a new S standard. The new standard supercedes the old standard, so, for example, the SH standard included extra high temperature deposit protection due to the popularity of turbo engines in the early '90s; SJ oils did not have this high temperature protection, as that portion of the standard was dropped. This means that for some cars, oils made to the older rating systems are sometimes better than oils made to the new standards. SH certified oils are probably the best of the S oils for motorcycles and high- performance sports cars, but you pretty much can't buy them anymore. Oils which are labeled "energy conserving" are bad for any vehicle with a wet clutch, meaning most motorcycles. Essentially all 0w-20, 5w-30, and 10w-30 oils are energy conserving and should not be used in your bike.

Most people blending S type automotive oils are buying their base oils from a company who is most likely using the Chevron Iso- DeWaxing process to make their oils, then buying their additive package from another company that is highly constrained by the API standards. The cost of getting an API certification for a single S motor oil formulation is from $125,000 to $300,000. The cost for C certification is $275,000 to $500,000. Once testing is complete, the oil can be licensed for $825 per year, plus a small royalty fee per gallon sold for all gallons over one million. The length of time between new specifications is now approximately 2 to 3 years, which does not allow a great deal of time to recover testing costs.

Additive companies, such as Lubrizol, Ethyl, Infinium and Oronite develop licensed additive formulas that they offer to oil companies to re-license. It is inexpensive to re-license one of these formulas, and the majority of oil companies choose to do this to avoid the costs associated with testing. Thus, the same chemistry is being sold under many brand names. Because of this, S type automotive oils have pretty much turned into a commodity. Although the people selling a particular brand may wish you to believe their oil is superior to any other, in fact if it's got the API seal on it, it's probably about the same as any other similarly rated automotive oil.


Commercial (Diesel) Oil

The additive packages for C (commercial) certification are designed to promote engine life. The additive packages for C rated oils contain extra buffers and detergents to keep the engine clean and free of acids. C rated oils are far better than S oils at holding and dispersing combustion byproducts and other contaminants, and at not becoming acidic. Traditionally these oils are primarily used in diesel motors, which are very expensive and are expected to last a million miles or more. When an engine rebuild costs $10,000 - $15,000 and puts you out of work for a week or three, you don't mind paying a bit more for your oil. The C certification tests have been largely developed by Mack, Caterpillar, Detroit and Cummins to provide the additives necessary to keep these engines running a long time. The latest commercial certification is CI-4 Plus, which includes extra protection for high temperature high revving motors. Since it's designed for diesel motors, they don't care about no stinkin' catalytic thingies, and CAFE is a place where you get a cup of joe and a donut. CI-4 Plus differs from CI-4 with higher detergent requirements and better sheer stability. The shear stability is exactly what motorcycles need due to running the engine oil through the transmission.

Although C standards are changed every few years, the older standards are enhanced, not superceded. So, newer higher rated C oils are simply better than older lower rated oils.

Although few car owners test their oil regularly, most large trucking companies routinely do oil analysis on their diesel trucks. Used oils are checked for viscosity breakdown, for detergent and dispersant function, and for metal contamination that would indicate engine wear. C oils that don't measure up are quickly run off the market place. To prevent engine wear, the best strategy is to keep deposits off the pistons, rings, and bearings. Therefore, diesel oils typically contain half again more detergents, double the dispersants, and a much more expensive and robust VII package than S type oils. If you go to an auto parts store, convenience store, or grocery store, you'll see that there are dozens of brands of automotive oils, all claiming to be the best. If you look at truck stops, you'll see there are only a very few diesel oils sold, typically Rotella, Delo, and Delvac. Trucking companies find what works for them and won't switch. They're not interested in saving a dollar a gallon on some unknown oil.

The C certified oils are all also S certified, just as some S certified oils are also C certified. The best C certified oils are SG, usually SH, sometimes SJ. I don't know of a C certified oil which is SL. The best S certified oils are CF, which is a relatively old and obsolete C standard, and does not include the tests for high speed high temperature engines that CG, CH, and CI have. In fact, CF oil does not meet the current factory standards for Volkswagen or Mercedes diesel passenger cars.

The API charges serious money to test an oil and certify it. If the API really tested the oil in their independent lab, and the oil company pays their royalties on time, the oil company gets to display the API seal on their product. Some smaller companies don't pay the API to test their oils and certify them. In these cases, you won't see the API seal, instead you'll see some words like "Meets or exceeds all manufacturers warranty requirements. API Service SJ, SL, CF." It's up to you to decide if you trust this manufacturer to actually test their oil themselves and tell you the truth about the results. "

[plymfury]

I recently heard about this too. I telephoned the Castrol company and spoke with a technition who said the same thing in the article. The 20W/50 oil is suitable for the older engines which is what I have been using recently. I also called Valvoline and thier technition said to use thier VR1 racing oil for the older cars. I have not been able to find any oils that state that they are suitable for Diesel engines. Does anyone know which oils are rated for Diesel engines and can be used for the older engines? Thanks for posting this info.
plymfury

[Richard Dryman]

The following is one of several making the rounds that oil companies are being forced to reduce the zinc additives in the oil and that causes scuffing on flat valve tappets, camshafts, etc.; even GM has a zinc additive because of that.???

This is fairly long but you may find it very interesting and it seems logical -----in fact, I think I am going to run diesel oil or Valvoline racing in my old cars from now on.

Anyone else seen anything that says this is NOT true.

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