Air cleaner cover and base for dual carburetor assemblies

A universal air cleaner cover base plate assembly for mounting standard size ring shaped air filters on closely spaced dual carburetors includes a pair of circular base plates formed with eccentrically located circular openings. The openings enable the base plate to be mounted upon the air cleaner flange of the carburetor body for rotative adjustment and their eccentric relationship to their base plates enables the center to center spacing of the filter elements to be adjusted independently of the fixed center to center spacing between two adjacent carburetors. The cover is of a generally rectangular configuration dimensioned to cover the tops of both air filters.

BACKGROUND OF THE INVENTION 
This invention relates generally to air cleaners for internal combustion 
engines, and more particularly to means providing adjustability of 
mounting a single air cleaner cover on separate air cleaner elements such 
as in a "2.times.4" carburetor installation. 
As used herein, the term "carburetor" is not limited to a fuel control 
device technically known as a carburetor; rather, it means and includes 
any fuel control device such as a fuel injection throttle body, which may 
have a flange means and by which it is mounted to the engine intake 
manifold, one or more air induction flanges or bores each having a 
throttle valve to control the flow of air to the engine and means for 
mounting an air cleaner thereon. That is, the invention is adapted for use 
with any air induction devices requiring an air cleaner cover. 
The modification of a standard internal combustion engine to achieve 
maximum performance for racing purposes normally involves the replacement 
of the original equipment intake manifold and carburetor (or fuel 
injection throttle body) package with specialized intake manifolds and 
carburetors specifically designed for various competitive usages. Where 
feasible, the modified engine will use two four barrel carburetors, a 
configuration conventionally identified as "2.times.4". 
Specialized 2.times.4 intake manifolds are marketed by various 
manufacturers for mounting upon the more popular stock engine blocks, such 
as the small block Chevrolet engines. The location of the intake openings 
of the manifold establishes the assembled relationship of the two 
carburetors to each other. Due to differences in manifold design between 
different manufacturers, the distance between the center lines of the two 
carburetors may vary, and in some instances the carburetor center lines 
may be offset from each other relative to the longitudinal center line of 
the manifold. 
The typical air cleaner employed with these carburetors includes an annular 
ring type filter mounted within a holder or filter housing on top of the 
carburetor so that air flows radially through the filter to the 
carburetor. Such ring type air filters are sealed at their top and bottom 
sides by the housing and must be of an inner diameter which is greater 
than that of a circle enclosing the four barrels of the carburetor. For 
maximum air flow, the outer diameter of the filter should be as large as 
possible, however, this diameter is limited by the center line spacing of 
the two carburetors. 
The air filter element is conventionally mounted upon the main body of its 
carburetor upon an upwardly facing shoulder on the main body provided with 
an outwardly projecting flange which supports the air cleaner housing with 
its ring-like filter element centered coaxially of the carburetor center 
line. The top of the air filter element is sealed usually by a circular 
plate or cover which is detachably held in position by means of a bail 
mounted bolt secured to the carburetor main body. In this arrangement, the 
ring-like filter element is coaxial with its carburetor center line, and 
the maximum possible outer diameter of the filter element and its housing 
is dictated by the center line spacing of the two carburetors. 
The present invention is especially directed to universal air cleaner 
mounting assembly for dual carburetor systems in which annular air filter 
elements of a single standardized maximum size may be mounted upon dual 
carburetors located at center line spacings varying within presently 
encountered limits. A single one piece cover is employed to cover the tops 
of the two air cleaners. 
SUMMARY OF THE INVENTION 
An air cleaner mounting assembly embodying the present invention includes a 
pair of like circular base plates and a single one piece cover of 
generally rectangular configuration. Each of the circular base plates may 
be formed with an upwardly projecting flange extending around its outer 
periphery dimensioned to engage the outer periphery of an annular 
ring-like air filter element of standardized dimensions to locate the 
filter element on the upper surface of the base plate. The base plate is 
formed with an eccentrically located circular opening dimensioned to 
receive, with a sliding fit, the air cleaner flange on the main carburetor 
body. The minimum distance between an edge of the eccentrically located 
opening and the outer periphery of the base plate is at least equal to or 
slightly greater than the radial thickness of the standard annular air 
cleaner element. By adjusting the rotative position of the base plates 
upon their respective carburetor main bodies, the eccentric location of 
the main body receiving opening in each base plate allows an adjustment of 
the radial distance of the base plate periphery measured along a line 
connecting the center lines of the two carburetors over a range determined 
by the eccentricity of the opening to the base plate periphery. This 
enables air filter elements of a maximum outer diameter usable on 
carburetors of a maximum center line spacing on carburetors of smaller 
center line spacings--which may be less than the outer diameter of the 
filter--so that a single standardized dimensioned air cleaner is usable 
with assemblies whose center line spacings may vary over a substantial 
range. It also enables filters mounted upon carburetors whose center lines 
may be respectively offset from the longitudinal center line of the intake 
filter with the filter center lines lying along a line parallel to the 
longitudinal center line of the intake manifold. 
Other objects and features of the invention will become apparent by 
reference to the following specification and to the drawings.

Referring first to FIG. 1, there is shown a somewhat simplified perspective 
view of a typical high performance 2.times.4 carburetor-intake manifold 
assembly which includes an intake manifold designated generally 10 and a 
pair of like carburetors designated generally 12. The manifold 10 is 
designed to be bolted to the engine block of a specific engine and is 
drilled and tapped at its top to receive mounting bolts such as 14 which 
fixedly bolt the two carburetors 12 to the top of the manifold. The 
spacing between the two carburetors 12 is thus determined by the 
configuration of the intake manifold. High performance manifolds are of 
very sophisticated design and the spacing between the two carburetors 12, 
normally measured in terms of center line to center line spacing, may vary 
depending upon the specific engine involved and the specific manifold 
design. In general, the center line spacing between the two carburetors 
provided by present day commercially available 2.times.4 intake manifolds 
will range from a minimum of 7.25" to a maximum of 9.375". 
While the designed center line spacing between the two carburetors is 
sufficient to provide the necessary clearance between the two carburetors 
and their associated operating linkages, etc., problems are frequently 
encountered in providing adequate clearance between air cleaner assemblies 
mounted at the top of the respective main carburetor bodies. Frequently, 
where the carburetor center line spacing is near the low end of the range, 
standard sized air filter elements cannot be used because of inadequate 
spacing. 
The replaceable air filter elements employed with such carburetors may take 
the form of a replaceable ring-like annular filter 16 (FIG. 2) having a 
ring-like member of filter material 18 closed at its top and bottom as by 
flanged annular plates 20. The upper portion of the body of each 
carburetor 12 is formed with an annular air cleaner flange 22 projecting 
outwardly from the carburetor body slightly below its top to form a seat 
which would sealingly support a housing 26 having a central opening in its 
bottom dimensioned to seat upon flange 22. The housing may be constructed 
with an upwardly projecting perforate sidewall dimensioned to receive and 
retain the replaceable filter element 16 and a detachable cover 28 closes 
the top of the holder. The housing 26 and cover 28 are held in assembled 
relationship with the carburetor by means of bolts 24 (FIG. 1) coupled by 
a bail to the associated carburetor body. 
This arrangement found the filters 16 and their enclosing housings mounted 
in concentric coaxial relationship to the vertical carburetor center line 
and the standard 9" diameter filter elements thus were unusable in systems 
where the center line spacing was less than 9.375". This center line 
spacing problem was overcome in some instances by using specially designed 
oval shaped filters and covers or in some instances by using specially 
designed ring-shaped filters of smaller diameters. The specially designed 
filter configurations in turn required matching housings. Because each of 
these specially designed parts was, in effect, custom designed for use 
only in a limited number of applications, they were frequently available 
only on a special order basis. 
The present invention is especially designed to enable the usage of larger 
filter elements such as standard 9" ring type filter elements, in dual 
carburetor systems in which the center line spacing between the 
carburetors may be substantially less than 9". 
In accordance with the present invention, an air cleaner base plate-cover 
package includes a pair of circular base plates 30, best shown in FIG. 3, 
and a single unitary cover of generally rectangular configuration 
designated generally 32. Each base plate 30 is of circular configuration 
and formed with an upwardly projecting filter retaining flange or lip 34 
which extends around the outer periphery of the circular base 36. 
A circular opening 38 is formed in each base plate and is eccentrically 
located with respect to the center of the circular plate 36. The opening 
38 is adapted to slidably fit onto the top of the body of carburetor 12 so 
that the base plate 30 can be seated upon the air cleaner flange 22 while 
the plate may be rotatively adjusted relative to the carburetor body. The 
flange 34 will receive and locate a standard 9" air filter element 16 upon 
base plate 30. 
Plates 30, filter element 16 and cover 32 are assembled upon the dual 
carburetors 12 as best seen in the cross-sectional view of FIG. 4, with 
the retaining bolts 24 of the respective carburetors projecting upwardly 
through slots 40 in cover 32 and through a bore in a sealing plate 42 
dimensioned to seal the top of slots 40. As can best be seen in FIG. 8, 
the slots 40 may be eliminated by the use of an offset mounting stud 41 
which has its lower end threaded and adapted to engage the carburetor air 
cleaner stud hole. The upper offset portion of the mounting stud 41 is 
designed to be equal to the offset of the air cleaner eccentric base 
thereby allowing the use of a single round upper mounting hole 43 with a 
variety of carburetor spacings. The parts are clamped in the assembled 
position shown in FIG. 4 in any suitable manner, such as by wing nuts 44. 
The eccentric location of openings 38 in base plates 30 enable the base 
plates to be rotatively adjusted upon their respective carburetor bodies 
to provide clearance between the two filter elements 16 when the center to 
center spacing indicated at C in FIGS. 5 and 6 is less than the outer 
diameter of filter element 16. In cases where the spacing C between the 
carburetor center lines is a minimum, the two base plates 30 are 
rotatively oriented as shown in FIG. 5 with the high points of 
eccentricity of the respective plates being 180.degree. offset from each 
other. FIGS. 6 and 7 show respectively a center line spacing greater than 
that of FIG. 5 and a mounting arrangement where the center lines of the 
carburetor are offset from the longitudinal center line CL (FIG. 7) of the 
intake manifold. When the offset mounting stud 41 is used, the stud is 
rotated to the desired location with the lower end of the stud at the 
carburetor center line while the upper end of the stud is at the center 
line of the base OD. 
Opening 38 is so located that the minimum distance between the edge of 
opening 38 and the radially interior surface of flange 34 is at least 
equal to or slightly greater than the radial thickness of the replaceable 
filter element 16 so that the element does not block any portion of 
opening 38. 
Cover 32 is preferably formed with an integral downwardly projecting 
peripheral flange 46. The dimensions of the generally rectangular cover 32 
are such that its width exceeds the outer diameter of a filter element 16 
and that its length is such that it can overlie two filter elements 
regardless of the rotative orientation of base plates 30 upon their 
respective carburetors. It is believed apparent that the base plate 30- 
cover 32 package described above provides a universal mounting arrangement 
for mounting standard sized ring shaped filters 16 on dual carburetor 
assemblies whose carburetor center line spacing may vary within reasonable 
limits. 
While exemplary embodiments of the invention have been described in detail, 
it will be apparent to those skilled in the art the disclosed embodiments 
may be modified. Therefore, the foregoing description is to be considered 
exemplary rather than limiting, and the true scope of the invention is 
that defined in the following claims.