|
RICO TALKS MIATAS (Continued)
With peace,
came the explosive growth in the number of automobiles. This also put a
demand on the production of lubricants. While jet aircraft engines
continued to use synthetic oils, good old, out of the ground petroleum
based oils dominated the automotive market for the next fifty years. The
reason was simple. Compared to synthetics, petroleum oils were far
cheaper, and most drivers never kept their car more than two or three
years. Synthetics were around, but almost exclusively at the
airport. After a while even reciprocating piston aircraft engines began
using synthetic oils exclusively. Did the aviation industry know
something the automotive industry did not? Then again, why would
an industry promote a product that did not come from the oil wells they
had spent millions of dollars to drill?
It was not all that long ago when an engine with 80,000 miles on it was
expected to need an overhaul of some sort in the next ten to twenty
thousand miles. Then the gas crisis of the 1970's put major pressure on
the automotive industry to make cars more gasoline efficient. One of
these things was the oil in the engine. Research led to petroleum oils
with a much lower coefficient of friction; this not only gave better gas
mileage, but also increased engine longevity. The motoring public became
knowledgeable about the fact that which oil you used, and how often you
changed it, really made a difference.
Then about 1979, the Mobil Oil Corporation decided to mass market one of
the oils they had developed for racing. It was called Mobil One, and
Synthetic oils had a foothold in the mass market. There were some major
stumbling blocks in the way. One was cost. In 1980 a quart of Mobil One
went for $4.75 in 1980 dollars. A quart of very high grade petroleum
based oil went for about seventy-five cents a quart. Then there were
problems with compatibility with different materials internal gaskets
and o-rings were made of. An adventuring spirit that got a synthetic oil
change might find your engine leaking like a sieve. Cars made after 1985
don't have these problems, since there have been major changes to the
materials that were subject to compatibility problems.
What are some of the major operational differences between synthetic and
petroleum based oils? First off, when subjected to long periods of
internal engine temperatures, petroleum based oils literally change
chemically. It's not a far stretch to say that you can "scorch"
petroleum based oils in your engine much as you would in a frying pan.
Synthetic oils on the other hand are much better suited for higher
operating temperatures. This was one of the reasons synthetics worked so
well in jet engines. In scientific terms, petroleum oils are "pyrophobic";
they migrate away from heat. Synthetics are "pyroscopic" they literally
migrate toward heat. A neat experiment is to heat up a nail with a
propane torch. Then immerse the hot nail into a beaker of petroleum
based oil. Upon removing the nail you would find that little or no
petroleum oil adhered to the hot nail. Do the same with synthetic oil,
and the nail comes out wet. Now imagine the nail is the stem on your
exhaust valve. Which kind of oil would give better protection there?
My best example came when we changed the timing belt on my Miata.
Removing the valve cover, I found absolutely no sludge, varnish, or
other deposits. All that was there was oil wet metal. This after 110,000
miles. I took a magnifying glass and inspected the cam lobes.
There was still a factory "mirror" finish. No etching, galling, or wear.
Jackson Racing's dynamometer still shows 127 horsepower at the rear
wheels. Mileage is still dead on at 30 M.P.G.
So what is the "best" oil for your Miata ? Like I said, it depends on
what you use it for. I am sold on synthetics, should you be? All
depends. Corvettes and Porches require the use of synthetics. But it's
only a car. The cheap stuff will work just fine. Won't it?
Do you feel lucky?
Copyright 2001, Enrico Massagali
|
|
