The Carburetor Shop LLC
204 East 15th
Street Eldon, Missouri 65026 Home | History | F.A.Q. | Orders | Contact Us | SELL TO US Carburetors | Repair Kits | Other Parts | Literature | Tools | Articles | Troubleshooting | Carburetor Identification Passenger Kits | Truck Kits | Tractor Kits | Industrial Kits | Marine Kits | Multi-carb set-ups Car Comics | Car Records | Stamps and Coins | Car Trading Cards | Subscription Cards | Oakland and Pontiac Aftermarket carburetor adapters (updraft) General In the 19 teens and twenties, many
carburetor companies made aftermarket carburetors for many applications for
which they had not sold the original carburetor. As many companies either
ignored, or blatantly defied, S.A.E. standards, it was necessary to sell a
flange adapter with the aftermarket carburetor. I have lists of adapters originally
produced by Carter, Marvel, Rayfield, Schebler, Tillotson, and Zenith (and
probably others). No, I will not publish these lists for a number of reasons;
the primary reason being they would be mis-interpreted by many. How? These adapters were made to adapt a
SPECIFIC carburetor to a SPECIFIC application. So a Zenith adapter to adapt a
Zenith size 2 type 105 carburetor to a specific application MAY NOT adapt a
Zenith size 2 type 63AW carburetor to the same application. Why? Because the
63AW is physically wider than the 105. So looking at any of the lists for a
cross-flange size 2 to size 3 adapter would get an enthusiast a part number
for an adapter that would bolt to the carburetor and bolt to the intake, but
maybe NOT allow the carburetor to fit in the allotted space between the
engine block and the fender. Fabrication So, the way we suggest to proceed: (1) Determine which carburetor to use to
properly run the engine. (2) Determine which type of adapter will
be necessary to adapt the carburetor to the engine:
(A) straight
(B) cross
(C) rotated
(D) offset Each of these will be discussed in detail
below. (3) Determine the dimensions of the
carburetor with the adapter connected, and measure to see if it will fit. Types of carburetor
flanges: (1) straight - a straight line drawn from
center to center of the mounting studs would run from bumper to
bumper on the vehicle (2) cross - a straight line drawn from
center to center of the mounting studs would run from fender to fender on the
vehicle (3) rotated - a straight line drawn
from center to center of the mounting studs would not be parallel or
perpendicular to a straight line from bumper to bumper. Good examples would
be 1929~1931 Chevrolet 6 cylinder and virtually all single barrel Marvels
produced after about 1925. The Chevrolet is rotated 30 degrees. The Marvel
rotation varies. Types of adapters: (1) straight - the straight adapter will
allow a carburetor with a straight flange to mount to an intake with a
straight flange. Often this is quite easy. From a swap meet (or salvage yard
if you are lucky enough to still have a salvage yard), acquire two unloved
carburetors (we used Tillotson type JR, Holley 1904, and Rochester type B and
BC) with cast iron flanges with the appropriate center to center
spacing, place the throttle body in a power hacksaw such that the saw will
cut the throttle body parallel to the flange just on the side of the throttle
plate opposite the flange, acquire a short piece of steel pipe of the
appropriate diameter, and weld it (or if you are me, take it to someone that
CAN weld) all together. The completed adapter should resemble a capital
letter "H" that fell over on its side. The cross-bar in the
"H" is the pipe with an I.D. equal to the smaller of that of the
carburetor or the intake. There must be sufficient distance between the legs
of the "H" to allow nuts to be installed.
(2) cross - the cross adapter will allow
a carburetor with a straight flange to mount to an intake with a cross
flange. Theoretically, the reverse is possible, but cross flange aftermarket
carburetors are very rare. Because of the orientation of the nuts, often a
cross adapter may be made as above but without the pipe; just weld the
two flanges together.
(3) rotated - the rotated adapter will
adapt a straight flange carb to a rotated intake manifold. Often, like (2)
above, it may be fabricated simply by welding two flanges together.
(4) offset - the offset adapter,
virtually always identified with Marvel applications may be necessary because
using another adapter will cause interference with something (generator,
steering box, etc.). The most common requirement for these is the 1926~1929
Buicks where one needs a rotated adapter WITH an offset. Basically, the
offset is a small "S curve" in the pipe connected the two flanges.
All of the above assume a two bolt
flange. There were a few applications with 3, 4, 5, and 6 bolt flanges. The
procedure is the same. S.A.E flange sizes (cheerfully ignored by Marvel, and
some others): (5) Special
Carburetor
and flange sizes (link to a listing of
S.A.E. and other flange sizes). |