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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