Thoughts on synthetic oil by Bob Woods
Let me preface my ramblings by stating that I use synthetic oils and I have for years. Not because I save any money on the oil/filter changes, but because I tow a fifth wheel and like the added thermal protection. My first experience with synthetic oil resulted in reduced oil consumption (as compared to the previous years trip) while towing an RV through the Southwest in July. I have been reading alot about synthetic oils lately, It seems there is a lot of hot air available, but one fact shines through. Polyalphaolefin (PAO) based oils are the best, ester and diester based oils are hard on engine seals. The reason PAO's are the best, all the molecules are the same size and the increased thermo stability. However ester and diester is added to PAO stocks for the solvent action to cause seal swell. The biggest farce is the hype that synthetic oils don't come out of the ground, while its true that synthetic PAO base stocks can be made from renewable sources; corn, apricot pits and other fruit stones,etc, the best base stock is a synthetic aliphatic hydrocarbon, polyalphaolefin (pao) that is a petrochemical product ( such as CPChem synfluid or SpectraSyn by Exxon). PAO's are refined from, 1-decene, decane, ethylene, propane, and a few other light hydrocarbons, all so called fossil fuels. Ester and Diester is primarily cracked from animal and vegetable fats and meanwhile the source of crude is still being debated, dead dinos or rotted plants? Or as one page on the Amsoil site suggests it might be continueously generated from deep inside the earth. PAO's are safe for use in food preparation equipment and are considered kosher, EPA allows drilling lubricants (yeap you gotta lube that drill bit when drilling for oil) that are PAO based to be dumped on or in the ground or the sea floor. But no matter how safe the base oil is once you dump in the additives and use it in an internal combustion engine its a bio-hazard. The product data sheets and MSDS's on automotive synthetic oils I have been able to find list the POA's at around 80-90% with the remaining 10-20 percent esters and zinc and other compounds. All the aircraft turbine oil I found data sheets on was made up of ester and/or diesters(90-95%), but jet engines have different oil seals than automobiles, they use carbon seals and special o-rings. Jet engines are also operated at 80-100 degrees Celsius oil temp, exceeding 100 degrees for too long requires an inspection. We hardly ever changed oil on jet engines, 3,4,5000 hours on oil was and is common.
