Sythetics: The Auto Industry's
Getting the most out of
your 5.0 starts by using the best oil.
Muscle Mustangs &
Fast Fords - May 1992
by John Hunkins
Have you ever heard the story
about the light bulb that doesn't burn out or the
razor blade that never dulls? Sure, these stories
get exaggerated, but sometimes there's an element
of truth to the rumors leaking out of a manufacturer's
skunkworks. One particular rumor that sounds too
good to be true is "an experimental motor oil
that increases horsepower, practically stops engine
wear in its tracks and improves fuel efficiency."
Well, synthetic motor oil is not
a rumor. It's been in use ever since World War II
(the Germans used it on the cold eastern front because
conventional oil wouldn't flow in the arctic-like
weather). Even though it sounds too good to be true,
synthetics do reduce engine wear, improve gas mileage
and, most important for us gearheads, increase horsepower.
This is because synthetic oil molecules are superior
in a number of ways to their mineral-based brethren.
To spare you the technical jargon,
we'll just say that synthetics have a higher resistance
to heat than mineral-based oils. Because synthetic
oil is composed of molecules that are uniform in
weight and shape, its heat of vaporization is much
higher (more than 600 degrees F. compared to conventional
oil, which begins evaporating at temperatures as
low as 350 degrees F.). This added stability at
high temperature means that your hard-working 302
HO won't burn up as much oil-and that means less
sludge and fewer varnish deposits inside the engine.
Added slipperiness is another
attribute of synthetics. The uniform length of synthetic
oil polymers allows them to more easily slide over
one another. The resultant reduction of friction
shows up as more horsepower at the flywheel. What
you do with it is up to you; you can reduce throttle
~ pressure and save at the gas pump, or shave a
tenth off your ET.
Higher film strength. however,
is the real mother lode of synthetics. Film strength
is what keeps oil molecules from being pushed away
from each other under pressure. Mineral-based oil
has a film strength of about 500 psi, while synthetics
are closer to 3000 psi. In an area where two metal
surfaces meet, the film of oil between them prevents
them from rubbing and wearing away at each other.
Synthetics do a better job of this than conventional
mineral oils. (Remember, it takes six times as much
pressure to squeeze synthetic oil from between two
surfaces than conventional oil.) Consequently, synthetics
are much better at keeping your engine like new.
All this boils down to one thing:
It makes more sense to buy a $5 quart of oil than
a $1900 engine rebuild.
Film strength is important in
another way - cold start protection. Regular mineral-based
oil will not remain as a boundary layer (a uniformly
thin coating) on metal surfaces when an engine is
turned off. Mineral oil drains oft parts and out
of passageways into the oil pan. No big deal-until
you crank your stallion and go hoofing into the
sunset. There are some mighty important metal surfaces
crying out for lubrication in the time it takes
for your oil pump to fully pressurize all of those
bearings, lifters and passageways. Synthetic motor
oil, on the other hand, will stay on engine parts
and coat them uniformly because of its high film
strength and greater heat affinity (it adheres better
to hot metal parts). Also, because of its higher
heat of vaporization (reduced volatility), the synthetic
can stave off engine wear when your engine is basically
running with no oil (which can be as long as 30
seconds after cranking the motor). Wouldn't it be
nice to have a strong-running mill after 100,000
miles instead of a used-up chunk of iron?
As an extra benefit, synthetics
have a longer drain interval than mineral oils.
The added cost of synthetic oil is offset by the
need to change it less frequently. The environmental
dividend is that you don't generate as much waste
oil (a toxic waste) over the lifetime of the vehicle.
On this note, please remember to dispose of waste
oil properly. If you change it yourself, bring it
to a reclamation center or a garage (which should
have a large waste oil tank for reclamation).
Okay. Synthetics are great. The
real question is: Why doesn't everybody use them?
Automakers don't use synthetics in production vehicles,
they want to sell you a new car every five years
and synthetic motor oil would significantly reduce
their chances of doing that. Also, the maintenance
intervals can be greatly reduced.
Major racing teams don't appear
to use synthetics, but things aren't always what
they seem. The racing team's sponsor might want
you to believe there's a certain kind of motor oil
in the race car's crankcase, but the majority of
successful race efforts use synthetic lubricants
throughout the car.
Most big oil companies do not
market synthetic lubricants because of the tremendous
cost involved. The manufacture of synthetic hydrocarbons
requires a totally different technology than the
refining process widely in use. (This is about to
change as several large oil companies are jumping
onto the synthetic bandwagon, but until products
are officially introduced, expect the facts to remain
obscured.) Understandably, major oil companies want
to sell you their product.
Interestingly enough, the biggest
reason that synthetic lubricants are not in widespread
use is because the would-be consumer is ignorant
of the benefits provided by synthetics. Even though
people have known about them for years, consumers
continue to be brand- and price-driven. The rationale
continues to be, "My grandpappy used brand
V in his model T, so I won't use nothing else."
Or, "I been usin' brand Q in my IROC for years.
If I change brands now, it'll blow the motor."
Or, "I ain't payin' no five dollars a quart,
no sirree, Bob, I ain't that stupid." (We'll
see who's stupid at the ol' Chrondeks!)
As you can see, for various reasons,
people don't use synthetic motor oil (and if you
use it, you'll be glad that the guy in the other
lane doesn't). However, most people don't drive
fuel-injected, roller-cammed, heavy-breathing, high-output,
The topic of oil consumption should
not be strange to the owners of late-model 5.Os.
For years, the engineers at Ford have used low-retention
oil rings in High Output 302s. Low-retention oil
rings reduce cylinder friction considerably. This
increases power and prolongs engine life. It also
increases oil consumption. This is because the oil
rings used in recent 5.Os allow more blowby than
in other 302s. Synthetic motor oils can reduce the
rate of oil consumption in high-output Windsors
(302, 351) because they have a higher film strength.
However, even synthetics cannot totally eliminate
When switching to a synthetic
motor oil, it is important to keep several things
in mind regarding oil consumption. Have an extra
quart of your synthetic handy. Although many synthetic
oil manufacturers tout the compatibility of their
oils with mineral-based fluids, adding mineral oil
to synthetic oil will drastically reduce the mileage
to your next oil change (remember, synthetics last
Also, as the mineral oil breaks
down, it will pollute the rest of the oil, leaving
sludge and varnish deposits in the engine (this
is because mineral oil is made up of many chemically
dissimilar hydrocarbons, including waxes, all of
which react differently under various conditions).
By adding a mineral oil to synthetic oil, you may
also see a reduction of engine efficiency, depending
on how much, and when, the mineral-based oil was
There are a growing number of
companies that currently offer synthetics. Because
this overview is intended to give readers a general
idea of the benefits of synthetic lubricants, we
have not discussed the specific differences between
individual brands and their unique formulations.
Keep in mind that there are differences between
brands of synthetics, which may affect the performance
of your engine.
There is nothing secret about
the benefits of synthetic lubricants. They are for
real, and I can personally testify to their effectiveness
in my daily driver/drag car). The added benefits
of synthetics are so great that the extra cost is