vfm@ihu1f.UUCP (08/23/83)
In response to questions about automobile engine oils. To quote from the publication "Petroleum Motor Oil Guide", American Petroleum Institute (API) Division of Marketing 1801 K St., N.W. Washington, D.C. 20006 "The "W" (for winter) after the SAE number indicates an oil suitable for use in colder temperatures and the viscosity of these "W" oils must have the proper value when measured at zero degrees F. Those SAE classifications which do not include the "W" are suitable at higher temperatures such as are in the summer months. The viscosity of these oils must have the proper value when measured at 210 degrees F." end quote. Oil longevity! A problem with these extended drain intervals is than no matter what the brands or manufacturing techniques of lubrication products they "do not" keep dirt out of the oil. Synthetic oils in general are almost indestructible in a properly running engine, in fact they may last indefinitely providing you keep out (or filter out) the contaminants. The problem with this is not so easily and inexpensively performed. The best way to tell whats in it is to have an oil analysis done (many large trucking outfits do it that way), but for you and me that can be too expensive (~$10) for our 4-5 quart engines, change instead. One thing that you can do is filter it better. The following is an excerpt from Popular Science, April 1976, (which "appeared" to be paid for by Mobil). Quoting Mr. Ray Potter at that time chief of lubrication research at Ford, "Potter says regular oil filters won't hold up to this kind of service. He uses special depth filters, made by many of the leading filter makers." The depth filter which Mr. Potter referred to does a much better job than a conventional pleated paper "surface" filter, even the so called "double filter". These filters (although the quality of these may differ) are comprised of a uniformly packed, select cotton fibers (no junk parts from the cotton plant so "channeling" doesn't occur). Typically they filter particles out that are three times smaller than a good normal surface filter plus they provide substantially more cubic filtering media and and dirt-holding capacity than the paper media. Because of their design, these filters are not meant to be used in cars built specifically for racing. AMSOIL Inc. which markets (and by the way was the FIRST company to market an automotive synthetic lubrication) a multitude of synthetic products, religiously attempts to sell their depth filter with their oil. Installing this filter with the initial change and replacing the filter at 6 months or 12,500 miles, this combination will provide superior protection to 25,000 miles or one year. Which one to use ? Before making my reccomendation I'll give you some background on them. Mobil 1: It is a synthetic hydrocarbon (Polyalphaofin). This type of product can/is manufactured from petroleum oil, coal and etc. Up to about a year ago it was API classified as a 5W-20 oil, now is a 5W-30. Some car manufactures stated in their owners manual that 5W-20 oils were "not" to be used with sustained speeds over 50mph. AMSOIL: It is diester (dibasic acid ester), which is produced from a reaction between alcohol and acid. It is a 10W-40, but other viscosities are available. AMSOIL is used extensively in the racing proving grounds, including dragsters, road racing, truck and tractor pulls, motorcycles, boats (they make a synthetic 2-cycle oil also), snowmobiles, go-carts airplanes and etc. You name the competition and they are using and winning with it and not just in the engines. They are the only ones out with a 100% synthetic ATF, piston engine aircraft oil (FAA certified) plus many other products including gear lubes, hydraulic fluid, recip and rotary air compressor oil, wheel and chassis grease and several others synthetic products. Then on the other hand, Mobil 1 with a megabuck backing company just is not used in competition, look for yourself! There are several other manufactures of synthetic lubes and by number, the majority are of the diester type. Cost, AMZOIL runs ~$6./qt and Mobil 1 about half that at Monkey Wards or other high volume, multiproduct distributor. To justify your expense, I could get more detailed with the MPG claims and other controversial subtleties, but I think you have enough to chew on for now. Break-in period? At one time AMSOILs reccomendation was 6,000 miles before making the switch. I recently read somewhere (which I can't confirm) that they are using a new type of rings or manufacturing process of them that requires no additional break-in period after the factory installed oil is changed. Maybe someone else out there can answer that.