rebuilding the holley 94 / 2100 / 2110
REBUILDING THE HOLLEY 94 / 2100 / 2110
The original Holley 94 carburetor had a venturi size of 94/100. Later versions
of this same carburetor include the 2100 and 2110 with one-inch and 1 1/16
venturi sizes in three-bolt base configurations. We found many carbs in salvage
yards for under $20 and online for under $40. Be prepared to purchase more
carbs than you’ll need as many of ours had incorrect or damaged parts.
Stuck throttle plates, rusted throttle bores, cracked housings, and
plenty of dings left by shade tree
mechanics over the years are just
some of the issues you’ll discover.
The disassembly process was pretty
straight forward, though some gentle persuasion was necessary to remove the 50-plus year old screws.
Let’s face it, carburetors contain
lots of parts, so keeping them organized in clearly labeled bags
made the assembly process easier.
The choke lever plunger and spring
often require extra effort to remove.
We removed them early to avoid
having to find them later.
After removing the choke plate, we
slid the choke shaft out from the
carburetor’s top housing.
After removing the jet access plugs,
we used a standard screwdriver to
remove the jets. A jet tool can also
THE HOT RODDER’S OTHER VINTAGE CARBURETOR
BY MARK SIMPSON
Before the introduction of the four-barrel carburetor, single and two-barrel carburetors
prevailed. Naturally, when early hot rodders
needed more cfm for their engines the solution was simply adding more carbs. The aftermarket soon responded with a wealth of
intake options. For most, adding multiple
carbs meant a trip to the salvage yard where
there was a cheap and plentiful supply of
them. Strombergs were the early choice
for many, but as the supply of
Strombergs began to dwindle, hot rodders turned to the Holley 94.
In 1934, Henry Ford set out
to build a carburetor that
was more efficient than the
Stromberg units he was currently using. He contracted
Chandler-Groves Company to
design and build this new carburetor, and in exchange for the
one-year contract to build them,
Ford was granted the design and
patents for this new carburetor. After
the first year of production in 1938,
Ford awarded the contract to Holley
when their bid came in just under
ten cents per carb less. Even though
the design and first production was
all Chandler-Groves, this carburetor
soon became known as the “Holley 94.”
The Holley 94s were used on Ford production cars and trucks from 1938-’57 and
were produced in the aftermarket into the
early ’70s. In short, there are a lot of them,
unlike their Stromberg counterparts. The
“94” designation for the carburetor refers to
the venturi size of 94/100-inch. Later versions would boost the venturi size to oneinch and 1 1/16-inch. These later versions
were also referred to as the Holley 2100 and
the 2110, but all shared the same design
and basic operation as the original Holley 94.
After locating several good cores, we set
out to give our vintage engine some real hot
rod flair with a trio of Holleys mounted atop
an Edelbrock intake. Visit your Club website
(streetmachineclub.com) and follow along
as we rebuild our 94s.
The choke plate is screwed to the
choke shaft. To remove the screws,
we used a drill bit to remove the
staked portion of the screw.
It’s important to disassemble the
carb as much as possible for thorough cleaning, including parts
within parts like this idle tube.
The power valve was easily removed from the base of the mid
section using a one-inch wrench.
At the base of the accelerator pump
well there is a small check valve
spring and ball, this must be removed before the cleaning process.
The accelerator pump piston should
also be replaced; compare them
carefully them to the original as
they can sometimes vary in length.
The throttle body is made of cast
iron and is the most suseptible to
the effects of corrosion; replace this
section if heavily rusted.
Once the carburetor was completely
disassembled, we set about to remove the corrosion from the various components.
The second component of the check
valve is a small ball. Often times
this can be stuck in place if the
carb has been sitting dry.
We removed the throttle shaft and
blades in the same manner as the
choke. Some of our bases were
equipped with a plug on one end.
To remove the plug, we simply
tapped it out using a narrow punch.
For the smaller parts, we used a vibratory tumbler from
the Eastwood Company. We started with an aggressive
compound called Green Pyramid to remove the rust.
After derusting our parts, we further polished them in the
tumbler using Eastwood’s Dri-Shine media. We used a different method to clean and polish the large carb sections.
After cleaning and polishing, we inspected the parts again
for wear. All passages should be blown out using compressed air to remove any remaining polishing media.
We soaked the carburetor sections in a cleaning tank before using a fine glass bead media to remove any corrosion. All gasket surfaces were then checked and filed flat.
It’s always a good idea to replace
the float when rebuilding a carburetor and to take the time to inspect all
parts closely for damage and wear.
Not all power valves are created equal. Pictured on the left is a standard power
valve available from Holley that works well for current production carburetors;
however, the tall larger diameter valve can get hung up on the inside of the fuel
bowl. The center power valve is from our local NAPA store and is the right size,
though the radiused seat can prevent good sealing in the early Holley carburetors. On the right is a Vintage Speed power valve, which has the correct size
valve end as well as a machined seat area for positive sealing.
All gasket surfaces should be
checked and filed. Here the effects
of excessive corrosion can be
remedied in short order.
Eastwood’s Tripoli and White Rouge
greaseless buffing compounds
made short work of putting a shine
on the zinc cast carb body.
Further detailing of the carbs was
accomplished with cone shaped
buffs also available from Eastwood.
A pair of retainer straps are used to
hold the spray bars and squirter
nozzles in place. Gary suggests
using a small amount of anti-seize
on these screws.
The accelerator pump cups come in
rubber or leather, depending upon
the kit. A small amount of oil will
help ease assembly and prevent
damage to the cup as it is inserted.
The choke plate is assembled in
much the same manner as the
throttle plates. Don’t forget to stake
these screws as well.
We measured the float drop in the
same manner as the rise, with the
air horn turned right side up. Bend
the small tab to adjust the drop.
Next, we reinserted the choke lever
plunger and spring into the air horn
before reattaching the choke lever
itself. The plunger aids in retaining
the choke in either the open or
Because worn throttle shafts are
very common, we replaced ours with
extended shafts from Vintage Speed
to accommodate the new progressive linkage. It’s important to stake
the screws to prevent them from
It’s important to install the throttle
butterflies correctly, matching the
bevel on the edges of the blades.
When held to the light, a small but
even amount of light should be visible around the edges.
Next, we dropped the accelerator
check valve ball into the pump well
and rolled it into position, before
sliding the retainer spring into place.
Completely assembled, the accelerator check valve should look like
this. The end of the spring clip rests
on top of the check ball.
Spray bars with the idle tubes were
installed next. Gary at Outcast Kustoms warns to check them to ensure
they are the same size, especially if
you plan a multi carb setup, and
don’t rely on the fact they originally
came out of the carburetor.
Different sized squirter nozzles
were used throughout the history of
this carburetor design. If your plan
is to build a multi-carb setup, make
sure to use a matched set.
Two small tabs near the hinge point
on the float are used to adjust the
float’s rise and drop. With the air
horn upside down, we took a
measurement from the gasket surface to the top of the float. Follow
your kit’s recommendation for setting the correct float rise, although
some recommend tuning the rise to
1/16 to 1/8-inch higher to reduce
the risk of vapor lock by allowing
more fuel to be present in the bowl.
Bend the small tab until the correct
measurement is achieved, making
sure not to press on the float while
making this adjustment.
Rebuilding early carbs is a task
many of us can handle with the
payoff every time you turn the key.