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(1)
Title: “Oil filtration
and lifter wear “ SAE paper No.
650865 by Pfeifer & Finnigan
(Pure Oil Company, a
division of Union Oil Co. of California, conducted tests on an 8
cylinder Oldsmobile engine to determine lifter wear using a full flow
filter and a bypass sub micron filter.)
The
report revealed
particulate contaminate 1 micron and under contributed to engine
wear. The highest wear rate occurred with oil contaminating
particles in the 0.45-micron range and finer. The majority of the
contaminates were located in the crankcase oil containing particulate
less than 5 micron with a substantial proportion under 1
micron. Studies
conducted by a large manufacturer of heavy trucks using sub
micron filtration concluded that a filter that can filter under 1
micron results in an 80% reduction on compression rings and a 50%
reduction on oil rings.
(2)
Title: “A modern
approach to piston ring bore assembly wear determination”
SAE paper No. 650316 by DenBeston, Leverenze & Bloom,
International
Harvestor Company
Eight
hour radio tracer tests
were conducted on a six cylinder engine to establish the relationship
between wear rates and filtration levels on the piston-bore assembly.
The wear rates were determined with clean oil, unfiltered used oil, 5
micron filtered and 1 micron filtered oil. The wear rates were measured
using radiotracer techniques; i.e., the chrome plated compression rings
and standard bottom rings were activated and the oil was surveyed for
radioactive chromium Cr 51 and iron Fe 59. The wear rates observed on
the test with unfiltered used oil were 6-10 times higher than the wear
rates with the new oil, i.e., 6 times higher on the oil rings and 10
times higher on the compression rings. When filtering
the used
oil through a 5 micron filter the wear remained almost unchanged, but
the 1 micron filtration significantly reduced the wear rate by
½
on the oil rings and 1/5 on the compression rings.
- SAE
paper 710813;
“The
use of good full flow filtration, combined with bypass oil
filtration, will result in the extension of engine wear up to two to
three times the wear life obtainable with only good full flow
filtration”
- U.S.
Bureau of Standards states in Bulletin No. 86;
“Oil
does not wear out mechanically, it only becomes dirty”
- Lubrication
Engineering, Vol. 17; “Oil does not
wear out”
- Standard
oil of New York “Many
times the question has been asked ‘Does lubricating oil wear
out?’ The question should be answered in the negative”
- Mobil
Oil Bulletin No. 863;
“Oil
does not wear out, breakdown or otherwise deteriorate to
such an extent that it needs to be changed. It becomes
contaminated with water, acids, carbon particles and sludge.”
- Theory
and Practice for Engineers, 2sd edition, pg. 590-591;
“Oil
is like any mineral and can not wear out. Oil can
become dirty and contaminated but, like copper, iron or silver, when
they are reprocessed, they are as good as new. Studies have
shown
that oil significantly improves lubricating qualities as it is exposed
to heat during use in the engine”
(16)
(3)
Tribology International, 1991, pg. 329;
“New oil right out of the can is not as good one might think
but
contains metallic and non metallic particles in various
amounts”.
Fact
No. 1:
When engine oil is replaced, the new oil becomes dirty the moment the
engine is started. This is because approximately 18% of the
old
oil remains in the engine. The 18% old oil instantly
contaminates
the ‘new’ oil.
Fact
No. 2: Test
results from engines equipped with full flow filter elements have shown
that 4% of the oil drained from the engines was solid particles
consisting of carbon, dirt and metal particles.
Conclusion:
Since used oil typically contains 4% solid abrasives then the following
formula is used:
Average
contaminate = Initial contaminate + final contaminate
In
this case, 2% of the oil
circulated to the engine during this period was dirt. By way of
example, if an engine is driven 12,000 miles per year, in excess of
100,000 quarts weighs approximately 212,000 pounds or 106
tons.
If 2% of this is abrasive solids, then over 2 tons of solids are
passing through the engine per year.
SAE
881827
“Within the 10 to 20 micron dynamic clearance size range,
particles less than 10 microns generated about 3.5 times more wear than
particles greater than 10 micron”
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Soot is a major
problem,
contributing to engine wear. New
emission-controlled diesels will
put .0048 oz. of soot into the lubricating oil for every gallon of fuel
burnt. At 7 mpg., a truck will burn 1,786 gallons of fuel every 12,500
miles. During that interval, more than half a pound (8.57 oz)
of
soot will enter the oil.
I.
SAE 912344 “Some soot is
hard. Its abrasive action wears cams, rings, bearings, cylinders and
valves"
II.
SAE 810449/810499 “
Debris from the wear process promotes more wear, which, in turn,
generates more debris in a deepening cycle”
“Soft
soot, like activated charcoal, has a large specific surface
area.
It is very active chemically. It absorbs the oil’s
main
anti-wear ingredient, Zinc Dithiophosphate (ZDP), onto its
surface. Oils anti-wear properties deplete quickly when soot
is
present. Also, particle near the 1-micron size will abrasively remove
the anti-wear coatings formed on metal surfaces by oil additives to be
deposited, thus depleting the oil"
III.
SAE 852126 “Soot
thickens oil, reducing oil circulation during cold
starts. It can even gel motor oil. Soot also acts
as a
catalyst to accelerate oil oxidation and sludge formation"
(17)
I.
SAE 881825/Brown “Significant wear reduction
is realized when filter cut-off size is reduced”
The removal of soot
that
causes abrasion and spalling, the wear particles
can virtually be
eliminated. Since no large particles are present
to absorb oil
additives or to abrade the engines protective coating, the demand for
oil additives is significantly reduced. As a result, oil
drains
can be safely extended.
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