Myth or Fact?
I have !@#$%^ 94's on my engine (Flathead/SBS/Nailhead/etc.), and
it just wants to run rich even at idle, I rebuilt them (or a competent
shop) and they still do it can you help? - We get at least 4 to 6 calls a
day with this most common question. We prefer Strombergs (97s
couple of reasons especially on multi-carb installations. One is in the
throttle base and the other is the power valves. The Stromberg
throttle base seems to have better machine work on the throttle
valves and the throttle bores in that they don’t stick when coming off
idle at a stop light. This makes for smooth throttle openings besides
returning to idle without sticking. The other advantage and biggest, in
our opinion, is the Stromberg’s power circuit. Strombergs use
mechanically operated brass power valves instead of vacuum
operated diaphragm power valves as found in the
Ford/Holley/Chandler Grove carbs (94's). When using multiple carbs
the manifold vacuum is usually low. This contributes to premature
opening of the vacuum controlled power valve. It’s not uncommon to
find these valves opening with less than partial throttle applications
since almost any drop in vacuum is enough to make them operate.
As can be envisioned, this leads to a rich condition when it’s not
needed. It’s impossible to compensate for this over rich condition by
reducing the main jets because when these vacuum power valves
open it’s the same as increasing the main jet size 10 whole numbers~
No wonder they always run rich! The Stromberg’s mechanical power
valve operates mechanically and is relatively unaffected by low
vacuum. This eliminates the over rich conditions that are caused by
the power valve opening too soon or when it’s not needed. Yes you
can "block" the power valves on 94's but at what cost? Power when
you need it! That doesn't make a whole lot of sense does it?
For these 2 reasons alone we do not rebuild, re-manufacture, or sell
94's. We would be happy to quote you replacement Strombergs for
your application, regrettably we do not take 94's in on trade/core.
Kitting a carb is as good as reconditioning / rebuilding it - In most
cases kitting a carb will do little for it. Keep in mind these carbs
originally were produced in 1932 (so 75+ years ago). If the carb
hasn't been run much in that time then all kinds of things have built
up in the passages of the carb (we have seen wasps nests, mouse
droppings, spider webs, dirt, amongst other things). If the carb has
been run its entire life then most likely there is a film build-up of
varnish on everything inside the carb. The emulsion tubes are
probably clogged. This is the most overlooked item in rebuilding
Strombergs. It does require a special tap and puller, but it is a
necessity 75% of the carbs we rebuild have these either partially or
totally blocked. These are fairly large passages, just imagine what
the smaller ones are like that your can't see. This is why we fully
disassemble the carbs for reconditioning / rebuilding and
ultrasonically clean them. Boiling the carbs does damage to them by
warping the castings. Ultrasonically cleaning them gets them clean
even in the most minute crevasses.
All Strombergs leak - not true, they are by design not leak proof, as
no carb is. The felt around the airhorn/accelerator pump is made of
felt and thus is not a gasket per se. However leaks anywhere else is
probably either due to the gasket surfaces not being clean / level to
the mating part. Tighten the screws can possibly make this problem
worse since you are warping the air horn by tightening them more
than the Stromberg recommended 2-3 INCH pounds (not foot
pounds)....This explains why so many carb bodies have stripped
threads. Many leaking problems can be traced back to running to
much fuel pressure. All Stromberg 97/48/81 should only be run at 2 -
2 1/2 lbs of pressure. Even a stock flathead fuel pump will put out
4lbs at high rpm. Stock small block Chevy's fuel pumps put out 6-
8lbs, way to much for Strombergs. A good quality fuel pressure
regulator and gauge should be used with all Stromberg carbs.
Tightening the air horn screws will stop it from leaking - if might
temporarily but ultimately it will warp the air horn and cause more
Multi-Carb setups are problematic - Only to the uneducated. Our
2x2v4 and 3x2v4 setups are as simple as it gets. Unbolt your 4
barrel carb and bolt on 2 or 3 deuces. In most cases you will even
get better gas mileage. Stromberg 3x2 setups for SBC will in most
cases result in better mileage (using progressive linkage), if you keep
your foot out of it! Getting the proper adjustment to the progressive
linkage is the hardest part. Honestly this has more to do with how
you drive than the carbs.
Strombergs and Ford / Chandler Grove / 94's are almost identical -
FALSE! Nothing could be further from the truth. They don't flow the
same CFM. 94's use a rubber based "power valve" and 97's don't
have a power valve (per se), they have a power-by-pass valve that is
mechanical not invoked based on vacuum. 94's rubber power-valves
get brittle over time and leak (blew the power valve). We have had
more people replace their 94's with 97's than have bought new
setups. Why? Because they keep blowing the power-valves, they
are a pain to replace, their cars are running rich because of the blow
valve, or vacuum is causing the 94 power valves to actuate. Multi-
Carb 94's will draw to little vacuum and activate the power-valve in
most applications (the carb thinks its under a load), thus causing a
run rich condition, even at idle. This problem gets worse the more
you "build" your engine, inasmuch as high performance engines tend
to have low vacuum at idle. 97's do not have this problem, and thus
are considered by hot rodders the premium carb for multi-carb
94's are better than 97's - This all depends on your setup. We
believe there are more multiple applications that meet with the
requirements of 97's/48's than 94's. If you are trying to go "stock"
then by all means be sure you put the matching carb to you car. If
you are going to drive your car and not worry about authenticity then
Chroming Carbs ruins them - Depends on the chromer. Most do not
do a good job of chroming carbs to start with. Secondly the chrome
builds up in the air and gas passages within the carb...it is almost
impossible to remove. This reduces air / gas flows at idle and high
speed, it also reduces the actual venturi opening thus reducing
1 is OK, 2 is better, 3 is great, more is better - See our CFM
calculator page. The most common / biggest mistake people make is
"Over-Carbing" an engine. Remember an engine is a big pump, if
you have to much going in you won't get it out. The result is a rich
running engine. Be honest with yourself when using the CFM
calculator. Most engines don't run 100% volumetric efficiency they
run more around the 80% mark at best. If you aren't going to run the
engine at 5,000 rpm don't fool yourself in to thinking you are. Most
common run between idle and 3,500.
6x2's are a pain and hard to get to work right - So not true! Not only
do you get great looks, but the performance is outstanding. Worried
about gas mileage? Then block off the corner carbs and then you
have economy and looks
Sure you can use and HEI with 3x2's and 6x2's - Not true period.
You must use an older style points distributor. You can then convert
it to electronic ignition via a Pertronix kit. The HEI distributors are
just to large to fit between the rear carb and housing.
Straight Linkage vs. Progressive - In most cases - Straight linkage for
Flatheads and progressive linkage for SBC's. Most flathead intakes
are not of an open plenum design, if you run progressive in this case
you are starving the cylinders above the secondary carb most of the
time. You will be running lean on the rear cylinders and rich on the
front cylinders...this doesn't make for a long lasting engine. In
addition Flatheads don't really "breath" that well to start with so you
are choking half the engine.
In all 3x2 cases that we have run across for the street a SBC should
always be run with progressive linkage. Keep in mind progressive
linkage is adjustable, if the need truly arises that you need straight
linkage (all opening at the same time) you can adjust the linkage
"simply" to get the effect of straight linkage.
On our 2x2 setups for a SBC, we suggest straight linkage.
Why do you ask about elevation on your Get Your Quote Page? -
Actually its pretty simple. The jets in a carb are a metering device.
The carbs are "standardized" at sea level. At higher altitudes the air
is thinner and thus the carb/engine needs more air / less gas to
maintain performance. Thus we use smaller numbered jets at higher
than sea level altitudes.
Do you have more questions, myth to dis-spell email us, we promise to answer!
|Carbs - Quality re-manufactured / rebuilt carbs and
setups. Specializing in Stromberg 97 / 48 / 81's