1. Engine Oil Filters (Part V): Magnet filtration-The next
generation of filters
By Paul Dilger
Before we proceed with our series on oil filters, let’s briefly recap the topics we have covered in the past four
issues of OPE. In part one, we learned about the history of canister-type spin-on filters, the basic filter
components and the various base plate designs. In part two, we looked at solutions for removing filters from
engines, the filter thread types and their specifications, anti-drain back membrane seals and their problems,
base plate to element couplings, and different types of springs. Part three covered bearing clearances on
contemporary engines with respect to particle size filtration, SAE filter standards, the beta factor, filter
efficiencies, research findings from micro-micron (smaller than a micron) filtration, and differences between
industrial and consumer standards. In part four, we discussed concerns with environmentally friendly oil
filters, oil pump priming failures, filter by-pass relief valve problems, and center tubes. As stated in the
headline above, part five will explore magnetic filtration.
Based on my research on oil filters, I have come to the conclusion that most
engine manufacturers specify oil filters that have an effective average efficiency
of around 25 microns (plus or minus 5 microns) in particle size for warranty
purposes. This does not mean everything above 25 microns is filtered out —
far from it! Laboratory test data reveals that a percentage of the particles
greater than 25 microns (like 40 and 50 microns) passes through most filters to
some degree. Tests show the majority of normal wear on an engine comes
from particles 2 to 10 microns in size that pass freely through oil filters that
meet the manufacturer’s recommendations and are sold by all the filter
companies. Also, keep in mind that if an automobile manufacturer specifies a
particular filter, that same specification remains today. As the technology
develops, the specifications for older model engines do not seem to be updated
with the new technology. Some aftermarket manufacturers, however, do
update their product lines for the older engines. It is the responsibility of the
engine owner to do the research on older engines and never assume that new
technology has been incorporated into the original specifications.
Figure 1: Magnetic
Magnetic filtration, where a magnet is added to the oil filter to pull out very fine filtration is used in
iron and other particles, is a very inexpensive solution to the problem of filter
media deficiencies. Industry has historically used magnetic filtration to process industry to filter
engine oil, hydraulic oil and diesel fuel (see Figure 1). In my opinion, magnetic engine oil, hydraulic
filtration is the key to effective filtration and the preservation of newer engines oil, gasoline and
that are built to finer tolerances. As long as the maximum-sized particles in the
oil are even close in size to engine tolerances, engine wear will occur. diesel fuel.

2. In part three of this series, I mentioned that General Motors had performed
tests on oil filter efficiencies (SAE 881825). A summary of the test “Correlating
Lube Oil Filtration Efficiencies with Engine Wear” was written by David R.
Staley of General Motors. The significance of this test is far reaching since it
affects oil, air and hydraulic filters on all engine-driven equipment from small
riding mowers to automobiles, line-haul trucks, and large industrial equipment
(see Figure 2).
Mr. Staley wrote the following analysis and conclusions:
• “Analysis — The researchers found clearances in the diesel and Figure 2: Magnetic
gasoline engines varied between 2 and 22 microns during engine
operations. That should specifically mean particles in the 2- to 22-
filtration is used in
micron size range are the ones most likely to damage engine parts. applications from
Particles smaller than 2 microns will slip through the (bearing) small landscape
clearances without damaging bearing surfaces.”
tractors to large
• “Conclusions — Abrasive engine wear can be substantially reduced
with an increase in single-pass efficiency. Compared to a 40-micron agricultural and
filter, gasoline engine wear was reduced by 50 percent with 30- industrial equipment.
micron filtration. Likewise, wear was reduced by 70 percent with 15-
micron filtration. Controlling the abrasive contaminants in the range of 2 to 22 microns in the lube
oil is necessary for controlling engine wear.”
As was also mentioned in part three of the filter series, “Microscopic (micro-
micron) filtering gravimetrically reduced the particulate contamination from
0.016 percent to 0.0025 percent, which reduced the number of particles by a
factor of 6. It also reduced normal engine wear by a factor of 14.” Magnetic
filtration is the only practical method of achieving this microscopic level of oil
filtration at a low cost. Below are the laboratory tests on two magnetic filtration
products.
Magna-Guard oil filter magnet manufacturer used Titan Labs in Denver, Colo.,
to analyze the effectiveness of its magnetic center tube insert.
Figure 3: Oil pan drain These statistics are impressive for particle sizes so small that they are not
even harmful to the engine!
plugs were the first
applications of magnet
FilterMAG oil filter manufacturer used Predictive Maintenance Services, Inc. in
filtration. Uhrichsville, Ohio, to analyze the effectiveness of its external semi-circular
filter.
Where Magna-Guard measured particle types in its testing, FilterMAG measured particle count in 6
submicron-sized groups. By studying both types of analyses, we get a better picture of the value of magnet
filtration.
You may ask whether just any magnet will work for this
application. The answer is no. Regular store-bought magnets are
more for toys and crafts, etc. Also, non-industrial magnets have
a tendency to lose their magnetism when heated to around 200
degrees F, so their service life would be very short. Trying to use
a magnet that is not specifically designed for this purpose could
cause you to lose a magnet into your oil galley!
Figure 4: Kubota uses a circular
After looking at the list of particles that were removed in the
Magna-Guard test, you might wonder how magnetic filtration magnet on the base plate of its
removes particles other than ferrous (iron) metals. Remember filter to clean iron filings out of
that everything in the universe, regardless of its size, has an new engines (after super cleaning
electrical charge and a gravitational force. Therefore,
microscopic, non-metallic particles that would not normally have during assembly).
any detectable attraction will become slightly electrically

3. polarized as they pass through an extremely strong magnetic field. This small polarization then develops a
very small temporary magnetic field as it passes through the magnetized filter.
As these slightly polarized microscopic particles circulate, they have a tendency
to conglomerate just like a pile of small magnets would. As the particle clump
grows, its field becomes stronger since it continually passes through the filter
and magnetic field, until it is finally drawn into the magnet. The smaller the
particle, the weaker its field and the less chance of the particle being separated
from the moving fluid. So, conglomeration of non-metallic particles only occurs
very slowly over time and after many circulations within the system.
Figure 3 shows a magnetic oil pan drain plug. This type of plug was the first
Figure 5: Magna- application of magnetic filtration and has been used in engines, transmissions
Guard magnet being and differentials to remove harmful wear metal.
installed in a spin-on
filter. The only oil filter I could find that uses “built-in” magnetic filtration is a Kubota
tractor filter that is factory installed and used on its new engines during break-in
(see Figure 4). Kubota uses a circular donut filter that overlaps the base-plate holes to ensure all oil passing
into the filter passes very close to the magnet. Figure 4 shows the amount of iron collected during the break-
in on one of its engines.
Magna-Guard sells rectangular magnets that are placed in the center tube of
a spin-on filter (see Figure 5). The magnet is inserted into the tube through
the large thread hole and then pushed back to the far end of the tube. I found
that it is almost impossible to get one out once it’s properly installed. Be sure
not to just drop it in the hole, as some tubes are plastic, aluminum or stainless
steel, and are not magnetic material.
Figure 6 shows a Magna-Guard magnet after an oil change and illustrates the
amount of iron wear particles that are circulating through the average oil filter
without being removed.
Figure 6:
FilterMAG molds a series of neodymium very strong magnets into a semi-
circular band that is installed on the outside of spin-on filters (see Figure 7). It
Contamination
manufactures 10 different sizes of semi-circular magnetic molds to fit almost accumulation after 40
any filter. hours of collecting a
conglomeration of
This concept of the semi-circular magnet arrangement develops an extremely debris with the Magna-
powerful magnetic field. Because the magnets are arranged in a semi-circle,
the magnetic force gets focused toward the center of the circle, similar to the Guard filter.
way an optical lens focuses light to a point.
Concentrating the strength of the magnetic field into a small area creates a
super magnet. Figure 8 demonstrates how powerful this magnetic assembly
really is. The attraction is so strong that this heavy, half-inch Craftsman ratchet
is being held up off the workbench by the magnet assembly.
The larger the filter, the harder it is to remove the FilterMAG. The FilterMAG
shown in Figure 9 is so strong that you cannot pull it off the canister with your
fingers. A pusher screw is provided to pry the filter back far enough to get your
fingers into the gap and rotate the magnet off the filter.
Figure 7: FilterMAG
magnetic filters
Figure 10 shows a cut-away of a spin-on oil filter, with its accompanying
assembled on spin-on FilterMAG magnet, and the conglomeration of debris contamination collected
filters, ranging from and deposited on the inside of the filter canister. Keep in mind that all this
lawnmower tractors to contamination normally passes through OEM filters and is the primary wear
material that needs to be removed.
heavy industrial
equipment.

4. Figure 11 is a close-up, cut-away view of conglomerations of particulate
contaminating materials that were separated out using a FilterMAG on a
racecar engine filter.
There are also internal and external magnetic filters for automatic
transmissions. They are designed to be inserted in an oil cooler line or applied
to a flat portion of the transmission pan. Figure 12 shows an internal magnet
and paper filter combination sold by Wix and manufactured by Filtran for use in
automatic transmissions. Personally, I do not recommend this filter in automatic
transmission cooler lines after seeing how much debris is generated in
automatic transmissions. This small filter could become restricted and starve
the transmission for oil.
FilterMAG also makes a flat super-magnet in three sizes, shown in Figure 13,
Figure 8: FilterMAG
that easily attach to the flat portion of an automatic transmission pan to provide supporting a heavy,
visual identification of wear metal when servicing the car ’s transmission oil half-inch Craftsman
filter.
drive ratchet.
These super-magnets are also very helpful with hydraulic systems, as well as diesel and gasoline engines. I
was also told that the magnetic field created by these super-magnets reformats the molecular structure of
distorted fuel molecules, causing them to burn more efficiently and effectively, improving fuel mileage. This
may be difficult to understand, but testing by General Motors ’ engineers proved it.
There are a few other types of magnets that work on oil filters, but I don’t think they will be as effective as
Magna-Guard and FilterMAG. I came across magnets attached to an elastic strap, a magnetic end cap that
fits on the end of the spin-on canister, and magnetic ball bearings. They may work fine, but I don’t think they
can develop as strong a magnetic field as the ones we’ve discussed.
Figure 13: Automatic
transmission exterior
Figure 12: Filtran’s pan magnets
in-line filter for
Figure 9: To remove a Figure 11: Illustrates automatic
5-inch FilterMAG, a
Figure 10: A cutaway the conglomerate of transmissions
special pusher screw
view of the abrasive particulate
is required
conglomeration of material separated by
metallic and non- magnetic filtration
metallic extracted by
a super-magnet