...yep, interesting stuff Ron. Think back... years back.... Remember
when oil change intervals (as stated in owners' manuals) were many
thousand miles. What happened? Did oil get "worse", engine materials
"softer"... or what. OR.... did the oil companies [and filter
manufactures] figure out a way to quadruple their sales????!!!!!!??????
That's my guess.
Ron Soave wrote:
> Per several requests (and a request AND reminder from
> the great Wide F'ing Open one) I dug out the synthetic
> oil article I mentioned yesterday. It was in Feb 1993
> Road and Track, pg. 98, ugly purple Vette on the
> cover. I don't want a copyright lawsuit, but if
> possible, Just Ed offered to post it on his site. Til
> then a brief summary:
>
> * It's written by Dennis Siminaitis, former SAE
> president, a sharp cookie.
>
> * All lubricants, synth and natural, are made by
> refining. A conventional is refined relatively
> broadly, within economic and physical limits.
> Viscosity Index improvers (VI's) are added to get the
> range needed. DS compares this broad refining to
> spectrum "white light".
>
> * Synths can be more precisely refined. DS compares
> this to a laser. Far fewer VI's are need. VALVOLINE
> synthetic (not Castrol, as I stated yesterday) is
> refined to where it needs no VI's. This is a good
> thing. Less deposits.
>
> * Synths are made from alphaolefins, which are made
> into heavier polyalphaolefins (PAO), and ethylene is
> blended in. The result has excellent heat transfer
> and thermal stability. As mentioned to a lister
> yesterday, the LT-1 Corvette engine did away with its
> oil cooler by switching to synthetic. Chevy says any
> oil that meets its standard can be used, but the only
> ones meeting the standard are synthetic.
>
> * Synths according to DS pour well at -60F. I did
> viscosity tests on PAO at -40F (and C), and PAO
> COOLANTS, not oils, mind you, turn to mud real quick.
> Either way, better than natural oils.
>
> * Don't use synths in a production Mazda rotary
> engine. It's not compatible with oil injection
> systems.
>
> * Rockwell Int'l trucks extends its oil service
> intervals on axles from 100,000 mi for conventional to
> 500,000 miles for synthetics.
>
> * DS recommends keeping your oil change interval as it
> is. Stretching it out with a synth is false economy.
> If you have to go an extra 1,000 miles, you know you
> have margin if you really need it.
>
> * DS says new standards in 1995 ill (did?) improve
> conventional's properties all around, but DS agrees
> with Daniel1312 - the synthetics are far beyond even
> the best of the natural refined oils.
>
> Homework's done. Can I watch TV now?
>
> Ron
>
> =====
> .
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