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| General Filter Facts - Oil Filters |
| Since 1954 when we patented the first
spin-on oil filter, NAPA Filters has been at the forefront of
oil filter technology and performance for passenger cars, light
trucks, heavy trucks and buses, and off-highway vehicles. SAE
J806 tests prove that NAPA Filters oil filters hold 45% more dirt than
the leading national brand - meaning we keep filtering long
after the competition has completely quit. Use our Filter
Look-up feature or consult your NAPA Filters Distributor, to find the
best NAPA Filters filter for your needs. |
| What
the Oil Filter Does... |
You may take your oil filter for granted,
but this small, inexpensive part of your vehicle's lubrication
system plays a vital role in protecting the engine from premature
wear. Each moving part in the engine and the cylinder walls
requires clean oil for proper lubrication and lasting life.
The oil filter cleans the oil as it passes through the filter
element or filtering media. This prevents abrasive contaminants
in the engine lubrication system from damaging engine parts.
The better you understand your engine's lubrication system,
the more you'll appreciate the vital role your oil filter plays.
When the engine is running, oil enters the oil pump through
a screened intake. The screened intake -- or oil pick-up --
is located in the crankcase near the bottom surface of the oil
pan. The oil is drawn through the screen intake and forced by
the oil pump through the oil filter.
Oil from the main gallery is also fed through vertical passages
to the crankshaft main bearings and through the crankshaft to
the rod bearings. Oil thrown from the crankshaft, or sprayed
from the connecting rods, lubricates the pistons and cylinder
walls.
In a typical full-flow type oil filter, the oil flows into an
inlet passage and then through the filtering element. After
flowing through the filter element, the filtered or "clean"
oil passes directly to the main oil gallery. In a partial-flow
type filter, the oil returns directly to the oil pan.
Oil from the main gallery lubricates the camshaft and the camshaft
bearings (and feeds hydraulic valve lifters if used in the engine).
On non-overhead cam engines, oil is metered through the valve
lifter to a hollow push rod that carries oil for the lubrication
of the push rod pivot point, rocker arm pivots and valve guide.
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| Oil Filter
Media |
The media is the filtering material in
the oil filter element. It essentially determines the efficiency,
performance and useful life of the oil filter.
There are two basic types of filter media: the "paper" media
and the "depth" type media. The primary features of the filter
elements are:
Particle size retention (filtration efficiency)
Particle size retention is the measure of the degree to which
the filter can retain particles of various sizes. NAPA Filters has developed
optimum particle size retention quality in filter media by extensive
engine wear tests including exhaustive testing of filters used
in racing, and sophisticated laboratory tests. NAPA Filters media in
the automotive full-flow oil filter is able to trap and hold
essentially all the contaminant particles larger than 25 microns.
(A human hair measures approximately 70 microns in diameter.
An object that is 1 micron in size is .000039 inches in diameter.)
Our filters also capture a high percentage of even smaller particles.
Dirt-holding capacity
Dirt-holding capacity is the amount of contaminant that can
be removed and held by the filter until the filter ceases to
function. The capacity of NAPA Filters filters is significantly larger
than the minimum requirements to efficiently filter all the
oil during the oil and filter change periods as specified by
vehicle manufacturers.
Resistance to oil flow
NAPA Filters full-flow oil filters for automotive applications use arch-pleated,
prescription-blended media. When new, the media with a maximized
number of pleats has less than 2 psi pressure drop when filtering
oil at a rate of 4 g.p.m. at normal operating temperature. This
low initial restriction to oil flow protects the vital engine
parts more effectively. |
| Parts
of an Oil Filter |
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Gasket - provides exterior seal
between the filter and engine at the engine mounting surface.
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Mounting Plate - prevents deflection
(movement) at the gasket sealing surface. Heavy gage steel
plate provides for threaded attachment to the engine.
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Inner Element Support - provides
inner element stabilization and a positive seal between
the inner element and the mounting plate to prevent the
bypass of unfiltered oil. |
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Upper End Cap - retains element
end sealant and filter media, provides an outlet for clean
oil, and provides structural rigidity to the pleated media.
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Lower End Cap - retains element
end sealant and filter media. |
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Arch-pleated, Prescription-blended
Filter Media - provides a more than adequate filter area.
The element has a controlled porosity blended media to
assure complete filtration of the oil. |
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Spiral-wound Center Tube - provides
internal element support. The spiral design greatly reduces
initial flow restriction when compared to other designs.
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Coiled Spring - ensures a constant
load on the inner element to maintain the seal between
the upper element end cap, the inner element support,
and the mounting plate even during pressure surge situations.
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Filter Canister - encloses the assembly
with a mechanically-locked double seam. The canister provides
"flutes" at the closed end for ease of removal with an
oil filter wrench. |
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Silicone Anti-Drainback Valve - Stays
flexible in extreme temperatures, improves oil flow and keeps
oil in filter to prevent engine destroying dry starts. Also
provides lasting protection to meet new vehicle manufacturers
longer recommended oil change schedules. Nitrile valves can
harden and become ineffective over time. |
Some NAPA Filters full-flow filters include anti-drainback and/or filter
by-pass valves. These types of filters are identical to full-flow
filters, except that a by-pass valve replaces the inner element
support and an anti-drainback valve has been added. The Anti-Drainback
Valve prevents oil from draining out of the filter inlet holes
when the engine is shut off. It also provides seal between clean
and dirty oil at the upper end cap. This is necessary in applications
where the oil filter is mounted in a horizontal or inverted
position.
The Filter By-Pass Valve
If a NAPA Filters full-flow filter becomes "clogged", or excessively
restrictive to oil flow, the filter by-pass valve ensures continued
engine lubrication by allowing the oil to by-pass the filter.
Some vehicle manufacturers have the by-pass valve built into
the oil filter mounting unit (located on the engine).
Other vehicle manufacturers require full-flow filters have the
by-pass valve built into the filter itself. All NAPA Filters oil filter
types recommended for these particular applications include
the by-pass valve assembly in the filter.
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By-pass Valve Assembly -- spring
loaded valve assembly that allows oil to by-pass the element
under high-differential pressure conditions such as cold
oil and/or excessively contaminated media. This allows
lubrication of the engine, but without full-flow filtration. |
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