"SYNTHETIC
OIL: Rx FOR LONG ENGINE LIFE
by Curt Scott,
an article from: "The Complete Guide To Specialty Cars".
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"Those
naysayers who only a decade or so ago prematurely dismissed synthetics
as, "snake oil", are now among the staunchest devotees of laboratory-manufactured
lubricants. Among these believers are top lubrication engineers, race
car drivers, vehicle fleet operators, and millions of private motorists
around the world. What factors have contributed to the growing enthusiasm
for synthetic lubricants? Simply put, synthetically-produced lubricants
have demonstrated beyond doubt that they are far superior to their conventional
petroleum counterparts in fulfilling the many and varied tasks demanded
of oil by today's modern engines and powertrains. Indeed, synthetic lubricant
technology is swiftly progressing to a point where it is possible that
engine wear may no longer continue to be the major limiting factor in
the expected life span of motor vehicles."
"The
first question demanding an answer is: Just what is synthetic oil? Technically
speaking, synthetic lubricants are made by chemically combining, in a
laboratory, lower-molecular-weight materials to produce a finished product
with planned and predictable properties. Don't be confused by this technical
double-talk. What this means is that synthetics are custom-designed products
in which each phase of their molecular construction is programmed to produce
what may be called "the ideal lubricant." This process departs
significantly from that of petroleum lubricants, whose physical components,
both desirable and undesirable, are inherited from the crude oil from
which they are refined.
Crude oil
possesses thousands of varieties of contaminants, depending upon the oil's
geographical and geological origins, which no amount of refining can entirely
remove. Corrosive acids, paraffins and other waxes, heavy metals, asphalt,
napthenes and benzenes, as well as countless compounds of sulfur, chlorine,
and nitrogen, remain in the finished product.
Equally
as important, petroleum oil molecules, as contrasted to uniform-sized
synthetic oil molecules, vary significantly in size, shape and length.
When your engine heats up, the smaller molecules evaporate, while the
larger ones tend to oxidize and become engine deposits. As a result, refined
petroleum lubricating products differ widely in their overall quality
and performance. The presence of and the resulting drawbacks of these
undesirable constituent elements lie at the very root of the considerable
performance differences between synthetic and petroleum based motor oils."
"Chief
among the areas in which the pre-planned and predictable properties inherent
in premium synthetic lubricants significantly surpass those of premium
petroleum oils are: low-temperature fluidity...and thus improved ambient
startup protection; low volatility, (higher boiling point...greater resistance
to evaporation); high-temperature thermal stability; oxidation resistance;
lubricity; fuel economy; film strength and wear protection; extended drain
capabilities; water stability; and high natural detergent characteristics,
(resulting in a cleaner engine with less additive content)."
"For
the purposes of comparison, we have taken a well-known synthetic engine
oil, Amsoil 10W-40 synthetic oil, and contrasted its characteristics with
those of several prominent 10W-40 conventional motor oils. Below is a
condensed summary of the results of several closely-monitored field and
laboratory tests:
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Amsoil
10W-40
100% synthetic
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Petroleum
10W-40
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1.
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Effective
lubrication range |
-60
F to +400 F
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0
F to 300 F
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2.
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Viscosity
increase after single sequence, (64hour), Olds III-D Test |
9%
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102
to 400%
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3.
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Wear,
(mg. weight loss Falex test) |
1.1
mg.
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3
to 6mg.
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4.
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Fluidity
@ - 40 F |
Flows
freely
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Solid
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5.
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Volatility,
(evaporation @ 300 F for 22 hours) |
1%
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28%
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6.
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Crankcase
Temperature (Track test) |
240
F
|
290 F
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7.
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Flash
Point (D92 Test) |
470
F
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400
F
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8.
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Oil
consumption, (50,000 mile test) |
42%
less than
petroleum
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|
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9.
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Intake
valve deposits, grams measured at 50,000 miles. |
32.1
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75.5
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"From
this data it is readily apparent that synthetic lubricants
have substantially broadened the horizons of engine lubricant
protection. Simply by comparing the lubrication-temperature
range comparison, the limits of petroleum lubricants become
evident. On both ends of the relavent temperature spectrum,
synthetics demonstrate conclusively the ability to significantly
extend the thermal regions in which the engine is protected.
This has a special significance for those automotive power-plants
which normally work harder and produce higher internal
and lubricant temperatures...that is to say: high-performance
engines, smaller high-RPM engines, air cooled engines,
diesels and rotaries. Furthermore, climactic conditions
in which synthetics allow operation with full engine protection
are for all practical purposes boundless, whereas with
a petroleum oil the protective capacity significantly
diminishes with temperature extremes. Note particularly
the comparative viscosity, (oil thickening), increases
after the 64-hour Olds III-D test, (Item 2)... 9% for
the Amsoil synthetic VS 102-400% for the
multigrade petroleum oils; the reduced wear, (Item
3), and the reduction in crankcase temperatures,
(Item 6). These favorable results are quite typical of
virtually all similar test comparisons between petroleum
- and synthetic-based motor oils."
"Underhood
temperatures also take a quantum leap with the use of power options, especially
air conditioning, and because of emissions devices and emissions-related
design. It is important to note that, even though the dash gauge
may register only a 200 deg. F or so water/coolant temperature,
the temperature of the sump and of all the assorted bearing surfaces significantly
exceed the water temperature, and often surpass 500 deg. F on the
piston ring and cylinder wall areas. These high-temperature
surfaces serve to rapidly decompose petroleum oil and additives, as
well as contribute to their shorter service life, while the synthetic
is largely unaffected. Beyond the protection afforded an engine during
these particular instances of high-operating temperatures, high-temp thermal
stability moreover permits an engine oil to deliver overall extended service
life, (significantly longer drain intervals), in all driving conditions,
because it prevents the phenomenon of sludge and carbon formations
on critical engine parts, (valves, valve guides, oil channels, lifter
assemblies, piston rings, etc.), due to oil thickening, a problem
commonly attributable to petroleum oil breakdown at high temperatures.
As these deposits accumulate in the oil circulatory system, oil flow drops,
thus accelerating engine wear. To the user of synthetics, the benefits
are, (1) reduced wear of critical engine components; (2) significantly
reduced sludge and varnish...a cleaner engine; (3) reduced engine
drag due to uniform viscosity; and, (4) increased fuel economy
due to reduced component wear."
"Film
strength", refers to the amount of pressure required to force out
a film of oil from between two pieces of flat metal. The higher the film
strength, the more protection is provided to such parts as piston rings,
timing chain, cams, lifters, and rocker arms...wherever the lubricant
is not under oil system pressure. Synthetics routinely exhibit
a nominal film strength of well over 3,000 psi, while petroleum
oils average somewhat less than 500 psi. The result is more
lubricant protection between moving parts
with synthetics."
"Viscosity
is a crucial consideration when improvements in fuel economy are desired.
It stands to reason that the freer an engine turns, the less
fuel it will require to accomplish a given amount of work. Studies
have demonstrated conclusively that engine drag is directly related to
the viscosity of the motor oil. Generally speaking, the lower the viscosity,
the better the fuel economy of the engine. In formulating lower
viscosity oils, it has become clear that the synthetics are
the base stock of choice. This is because
it is possible to produce a synthetic oil of a given low viscosity without
incurring the excessive oil consumption, (due to evaporation),
and resultant thickening of the same low-viscosity petroleum oil. Indeed,
the U.S. Department of Energy in its pamphlet entitled, "An Assessment
Of The Effects Of Engine Lube Oils On Fuel Economy", states: "It
is evident that low-viscosity oils will help minimize engine friction
losses in the prevalent hydrodynamic region and thereby achieve better
fuel economy. In addition, such oils help to reduce friction during ambient,
(cold), start by increasing the oil flow rate to critical engine parts.
However, low-viscosity engine oils, blended from conventional petroleum
base stocks, may have problems with high oil consumption and engine wear.
There is also the possibility of decreased catalytic-converter life and
efficiency due to the increased levels of phosphorus in the exhaust gas
from the oil additives. One solution is to mix some synthetic with the
mineral, (petroleum), oil, or use a synthetic base stock entirely...(end
of quote). This low-viscosity, low volatility character of synthetics
has become increasingly important because many automobile manufacturers
are now recommending lighter-weight, (chiefly 5W-30), oils for use in
their products, and because the trend toward smaller engines creates substantially
more heat and stress on the oil used. In these smaller, high-output powerplants,
enough heat is generated to cause a lighter petroleum lubricant to evaporate
and significantly increase viscosity within weeks of its introduction
into the crankcase. High-temperature stability, as well as oxidation-resistance,
is of absolutely paramount importance when it comes to turbocharged engines.
Because it must both lubricate and cool the turbo unit, the oil MUST be
specifically formulated to withstand the turbo's extremely high operating
temperatures. Oil film temperatures often exceed 450 deg. F
in the turbo unit during operation, and can surpass 650 deg.
F, (!!!), during a short period immediately following engine shutdown...both
figures far exceeding the thermal limits of petroleum oil. Synthetics,
with their capacity to maintain proper, (low), viscosity and lubricity
under these high heat and stress conditions, and with their natural resistance
to oxidation, have risen to the fore. It is also important to note that
the high-temperature-stability properties of synthetics are designed primarily
into the base-stock oil itself, rather than being achieved primarily with
additives. The advantage of this approach is twofold:, (1) Additives,
which may account for as much as 24% of the volume of a can of
petroleum oil, by themselves have little or no
lubricating properties per se. Thus the more the additive content
in an oil, the less lubrication is available to the engine; and, (2) Most
additives tend to volatize, (evaporate), and deteriorate
with heat, age and use, so that the overall effectiveness of
the lubricant itslef is significanlty diminshed within only a few thousand
miles of driving.
It is also
important to note that, contrary to what many take for granted, higher
viscosity in and of itself does not translate into better engine protection.
Extensive testing has shown the opposite to be in fact true. As long as
a lower-viscosity oil is formulated to resist evaporation and provide
high film strength, this lighter oil will actually deliver more complete
protection to the engine parts, since its more rapid circulation delivers
both better lubrication per se, and far better cooling characteristics...a
critical advantage, given that oil flow furnishes up to 30% of an engines
cooling requirements. Prior to the introduction of synthetics, however,
the problem of evaporation, (and the resultant thickening of the remaining
oil), was addressed primarily by increasing viscosity. In short, don't
be concerned with the relatively lower viscosity ratings of some synthetics.
Syn lubes are a whole new ball game.
The remarkable
ability of synthetic oils to reduce internal operating temperatures is
far too important to ignore, since high operating temperatures contribute
directly to premature failure of mechanical components and gaskets and
seals. Coolant, (i.e. water/antifreeze), cools only the upper regions
of an engine. The task of cooling the crankshaft, main and connecting
rod bearings, the timing gear and chain, the camshaft and its bearings
must be borne entirely by the oil. There are three identifiable reasons
why synthetics do a better job of cooling an engine: (1) Because of both
the oil's lubricity, (slipperiness), and its stable viscosity, less friction
- and thus less heat - is generated in the first place; (2) The molecular
structure of the oil itself is designed to more efficiently transfer heat,
even compared against the thermal conductivity properties, (ability to
absorb and dissipate heat), of an identical viscosity petroleum oil; and,
(3) As mentioned in the preceeding paragraph, the more rapid oil flow
of these lower-viscosity synthetics contributes significantly to the efficient
transfer and dissipation of heat. Because of all these factors, oil temperature
decreases of from 20 deg. F to 50 deg. F are quite common with the use
of synthetic oil. One might even say that the heat-reduction properties
of synthetics are synergistic...by helping to reduce its own temperature,
the synthetic oil is simultaneously enhancing the lubricant's overall
performance characteristics."
"In
the same Popular Science article on synthetic oils, veteran race car driver
Smokey Yunick was quoted: "When you disassemble an engine that's
been run on petroleum oil, if you examine the rings and cylinder bores
with a glass you'll see ridges and scratches - that's the wear going on.
With a polyol, (a variety of synthetic), when you take the engine apart
everything has the appearance of being crome-plated. In the eninge we
ran at Indianapolis this year we used a polyol synthetic. When we tore
the engine down, you could still see the original honing marks on the
bearings...no wear at all. We put the same bearings back in because the
crankshaft never touched the bearings. I've never seen that before."
"Another example of the capacity of synthetic oil
to deliver exceptional engine protection and performance
is a recently-completed demonstration involving the Amsoil
Corporation of Superior, Wisconsin, a major manufacturer
of a wide range of premium synthetic oils, automatic transmission
fluids, chassis lubricants, and related products. This
demonstration involved the use of its 100% synthetic engine
oils in a New
York City taxi fleet. The test, sponsored
and supervised by a major lubricant additive manufacturer,
compared the overall performance of Amsoil's 10W-40 synthetic
oil with a number of leading petroleum motor oils. The
demonstration was scheduled to encompass 60,000 miles
of New York taxi service on each car. With the high levels
of idling time typically encountered in such service,
the total number of, "engine miles", of each
car was estimated to be about double the miles registered
on its odometer.
Initially
the demonstration was to have required that each taxi, equipped with a
Chevrolet 229 CID V-6 engine, have its oil and filter changed every 3,000
miles. But Amsoil insisted that an alteration of the test procedure be
instituted. The company's intent was to push its synthetic oil to the
extreme and evaluate how it compared to the petroleum oils drained at
the originally specified, 3,000 mile intervals. The twelve Amsoil-lubricated
vehicles were thus divided into three goups of four taxis each. Group
1, (Amsoil), would double the control interval, with oil and filter drain
at 6,000 miles; Group 2, (Amsoil), would quadruple the control interval,
with oil and filter drain at 12,000 miles; and group 3, (Amsoil), would
not change the oil for the duration of the test ; thus multiplying the,
(petroleum), Control Group's drain-control interval by twenty times. In
place of changing the oil, these, (Group 3), cars would be equipped with
Amsoil's By-Pass oil filter, claimed by the company to keep, (synthetic),
oil analytically clean for up to 25,000 miles of driving, without replacing
the element. The by-pass filter element was changed at 12,500 mile intervals
for the duration of the test.
Following
the year-long demonstration, each of the engines was disassembled, both
to determine the levels of sludge, varnish and rust that had accumulated
inside the engine, and to carefully measure the amounts of wear experienced
on critical engine components. Pictured on the previous page are representative
samples of various components of the test engines. In the first example,
the pistons and intake valves of the petroleum Control Group, (oil and
filter changes every 3,000 miles), are illustrated. The lower set of photos
represent the same engine components from an Amsoil Group 3 vehicle. Note
the substantially reduced varnish and sludge deposits on the synthetic-oil
lubricated components, and the remarkably good overall condition of the
Amsoil group 3 pistons and valves.
To summarize
the findings and conclusions, the test facility responsible for the demonstration
submitted this statement: "The data presented in this report indicates
that the Amsoil synthetic SAE 10W-40 passenger-car motor oil formulation...provided
protection of the test engines from excessive wear and deposit formation,
far beyond the normal 3,000-mile oil change interval." In fact, the
level of protection was such that those engines in which the original
synthetic oil was run for the entire duration of the, (60,000 mile), test
showed less wear than did the Control Group vehicles using premium petroleum
oil and 3,000 mile drain intervals."
"Renowned
race-car driver Bobby Unser stated in an article in, "The Family
Handyman", magazine: "I've had tremendous success with
synthetics; both grease and oil, in all my cars. In several instances
where we have compared petroleum-lubricated engines with those which used
synthetics, the latter were cleaner, with less carbon and sludge.
And the engines produced more horsepower, which meant better
mileage and longer life."
"But",
you say, "if synthetics are so good, why aren't even
more motorists using them?" First and foremost, many
folks simply aren't aware of synthetics.
Others who are aware are deterred by the higher purchase
cost, without investigating the advantages. Even
many professional mechanics haven't kept abreast of the
advances that have occurred in the field of synthetic
lubricants, and frequently tend to dismiss them without
bothering to check the wealth of current literature and
impressive test results regarding them. Secondly, garages
and dealerships often hesitate to recommend any extended-drain
lubricant, perhaps because their livelihood is to a large
degree dependent upon frequent servicing and repairs.
We learned of one, (probably common occurring), instance
where a dealership mechanic told a customer:
"You can't use synthetic oil in your car...the eninge
wasn't designed for it!" Still another reason is
that many of the advantages and cost savings provided
by synthetic lubricants are difficult to quantify, and
thus difficult for many consumers to appreciate. For instance,
how does one place a precise value upon such benefits
as..."cleaner
engine; lower operating temperatures; fewer oil and filter
changes; less oil consumption; lowered octane requirements;
longer battery/starter/alternator/spark plug/turbo unit/PCV
component life; increased fuel mileage; the convenience
of exceptional four-season performance with
a single motor oil...and so on." On the other hand,
it is quite simple to compare the purchase costs of conventional
vs synthetic, and to ignore the real cost-and performance
comparisons in actual operation. Do you prefer to save
$12 or $15 per oil change by using a petroleum oil,
even knowing that it should be changed six
or seven times as frequently
as a premium synthetic? Or are you
more interested in the bigger picture, irrespective of
the fact that many of the very real benefits of synthetics
cannot be precisely quantified in terms of dollars and
cents? All available evidence indicates that synthetic
engine oils offer performance advantages not achievable
with any refined-petroleum product.
Does all
of this mean that synthetic motor oils are superior
to conventional petroleum oils? If you value your
automobile engine and would like to keep it in peak, trouble-free
operating condition year after year and
far beyond its normal expected life,
our conclusion is, "Yes,
without question".
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