Technical Carter WCFB tech

So I did some more searching, and according to this list, the 2622S carbs were used on a bunch of different Makes/Models, including American Motors, Buick, Cadillac, Chevy (265, 283, single carbs and dual carb applications), Chrysler, Desoto, Diamond T, Dodge (including the D-500), Dodge Truck, Ford/Mercury, Hudson, Lincoln, Oldsmobile, Owens Marine, Packard, Plymouth, Pontiac, REO, & Studebaker. And they all used the same size Primary (.0945) & Secondary (.067) jet sizes. So I'm confused. Am I reading the chart wrong? Or is the chart itself wrong?

https://www.carburetor-blog.com/knowledge-base/carter-wcfb-carburetor-jets/

 

The good news about the internet.................................anyone can post.

The bad news about the internet....................................anyone can post.

Jon.

 

I would also question that chart. Those cars listed have way different linkages. Externals jetting however could be the same and usually is when compression ratios are a consideration. I bow once again to the Carb King.

 

I missed this post earlier. Thank you @carbking So it looks like the 1956 Dodge 315 cu in D500 is correct. Cool, that's good to know. Not that I have D500 to run them on, but at least now I know.

 

I have posted this before, but:

Virtually EVERY original equipment carburetor used on a U.S. produced car, truck, tractor, boat (inboard), or industrial application from about 1920 to 1974 is listed on my website. This includes, Autolite, Carter, Detroit, Holley, Marvel, Motorcraft, Rochester, Schebler, Stromberg, Zenith, and a host of other makes. A little research, and fairly easy to identify O.E. carburetors. There are currently about 99,000 records in the database.

Using your favorite search engine, use this string:

thecarburetorshop.com nnnn where nnnn is the carburetor number.

In this case, the string would be thecarburetorshop.com 2622

This will bring you to a number of pages. Try each one by clicking on it, and then use the "find on this page" tool on your browser. In this case, the first page I found had brand other than Carter, but both the second and third pages listed gave the answer for a Carter 2622.

For Autolite and Motorcraft, ignore the 9510; thus a typical Autolite EDB-9510-AA would use the string EDB-AA (try looking this one up in your Holley listing, remember that many Autolites were other manufacturer's design, this one is a Holley).

Jon

 

I just wanted to report back on my experimenting with those 2622SA carbs. I picked up this pair of matching carbs cheap, real cheap ($50 for the pair). Freshly rebuilt. I installed them on a 283 SBC, with an Offy 360 hi rise 2 x 4 manifold using adapters to match up the smaller carbs to the larger bolt pattern on the manifold. Due to interference between the rear carb and the distributor cap (WCFB's have a bulge on the rear side of the carb that doesn't exist on the AFB) I had to use a 1" spacer to raise the carb up and get some clearance over the distributor. I connected them up to run progressive linkage with the rear carb as primary, but they idle on both carbs. The engine runs excellent. May not be perfect, but damned close to it.

The biggest issue I have is I cannot get the idle speed down as low as I would like it. I can run each carb alone (with the other carb blocked off) and it idles great at around 700 rpm's. I set the idle air/fuel mixtures on each carb one at a time, and the engine ran great with either carb installed alone. But when both carbs are installed together the idle speed increases to about 1000 rpm's, and will not come down. I have the idle adjustment screws backed all the way off, not touching the linkage at all. But the throttle shaft will not close any further, something is holding it open. On both carbs. I didn't snap any photos to share, but IMO there is just a hair too much of the transfer slot showing below the throttle plates, but the plates will not close down any further. I have a pair of cores I've looked at and I don't see anything internal in the cores that would hold the throttle plates open, I suspect there is something in the linkage on the carbs themselves that is causing this. The problem is not the linkage from the pedal to the carbs, I can have that completely disconnected at the carburetor and still cannot get the idle speed down. The issue is at the carb(s) themselves.

Other than that I love the way it runs, excellent smooth transition from idle to acceleration, part throttle response, cruising, full throttle, everything is tits. I love it. It's far superior to the dual 2GC's I was running on the engine prior to this. Everything except the idle speed is better. The installation looks great, good eye candy. Everything but the idle speed is excellent. It's not anything I can't live with, but it would be nice to get that idle speed down to around 700 - 800, I would be a happy man with that.

 

GUESSING: Since you are using Chrysler carbs, you might need a stronger throttle return spring. Chrysler used a really weird throttle return setup on lots of their carbs.

But you might also look at fast idle cam position.

Jon.

 

Good thoughts Jon, thanks for the reply.

I cannot manually force the throttle closed by hand. It is being held slightly open mechanically. On both carbs. And I did make sure it is not on the fast idle cam, that's not what's holding it open.

 

You might take a look and be sure that the secondary blades are closing properly too.

 

If checking the secondaries (post above) don't find the issue, try disconnecting the pump operating rod from the pump intermediate shaft. Occasionally, these rods get bent, and might prevent one of the throttles from closing. The rod can be bent at the angle (that is why the angle is present) to adjust.

Another possibility would be the secondary throttle operating link. These also have an angle for adjustment.

Jon.

 

Your comment about idle on either at 700, but both at 1000 illustrates why I recommend SOLID linkage rather than progressive for the street.

Whatever is causing the problem is still present; but the RPM is dropping 300 RPM due to the uneven cylinder fill density at lower RPM leaning some of the cylinders. It does get better as the RPM (and runner velocity) increase; but will never be as efficient as using solid linkage.

Jon.

 

^^^^ Ahhhhh, that makes sense.

 

I have found on a number of occasions that the previous rebuilder did not properly center the throttle blades (butterflys) during the rebuild, especially on the secondary side. You may have to remove the bases and hold them up to a bright light and see if there are any excessive gaps around the butterflys. You should be able to slightly loosten the screws and move them around usually by just slapping them closed a couple of times and gently retightening the screws. Be very careful if you attempt this as the screws are staked and will only allow you to slightly loosten them, any more than that they will break off unless you grind the staked end of the screw off.

 

Saltracer - agreed, or put them in upside down!

Jon

 

Jon, what historical carburetor do all other carbs aspire to be when they grow up? What's your favorite design?

 

Yes, I also have seen that done.

 

I am going to partially pass on this one, as my overall favorite street carburetor is not H.A.M.B.-friendly. As far as H.A.M.B.-friendly street units:

Single barrel - Carter W-1
Two barrel - 3-way tie Carter WCD, Rochester 2-G, Stromberg WW; if I have to pick one, then the WCD
Four barrel - genuine Carter AFB

But there are designs for performance (power), performance (economy), low initial price, beauty, tunability, etc.

Some words in the English language to attempt to avoid would be first, last, best, worst, favorite, etc.

And before someone jumps in with the typical "my dog is bigger than your dog", please remember Truck64 asks for my favorites. There can probably be as many opinions as there are H.A.M.B. members, and there is no wrong answer on favorites.

Jon.

 

Did you ever find your issue? I am having the same exact issue on my 2x4 cadillac set up with wcfbs and leaning towards butterfly adjustment issues from the rebuilder

 

I haven't messed with it. It's a "one of these days" type of thing for me. If it were a bigger issue I'd be more prompted to work on it, but I can live with it as is.

 

Try disconnecting ALL linkage (both the linkage from the footfeed, and the progressive linkage) from both carburetors; and see if you can make it idle. The fact it will idle on either, but not on both, points to linkage.

Also, and I don't believe this is your issue, you might try disconnecting the secondary throttles from the primary throttles. When one well-known (but not to be named here) carburetor manufacturer started restoring carburetors, we sent a WCFB to them just to see their work. The WCFB came back with the secondary linkage over center such that the secondary side was cracked open at idle.

Jon

 

the issue that I’m having is that I’m unable to get mine under 1000 rpm’s as well. The idle screw is complete backed off and the air bleeds do not have much effect. With the linkage off as well. I haven’t ran it on a single carb to see if it goes down but I have checked the metering rods to make sure they are closed at idle, checked vacuum leaks and all the basics. My next check will be confirming closed butterflies. Caddy 331 with dual quads and solid linkage

 

IF:

(1) the throttle plates are correctly centered, and right side up
(2) the secondary throttle linkage is disconnected
(3) the throttle positioner screw is completely backed out
(4) there are no vacuum leaks and the correct mounting gasket is used
(5) the idle mixture control screws SHOULD have effect (maybe 1/2 turn from thumb-tight).

With the above conditions, turning all 4 idle mixture screws into thumb-tight should completely stall the engine (unless your name is Schrader )

The only time I have seen this not to be true, is when a customer bought an dual quad intake of a popular manufacturer (not to be named here) which I told him NOT to buy, and the angles of the ports to the cylinder heads were incorrectly machined for an internal vacuum leak (but this obviously is quite rare).

EDIT: granted it is a larger engine, but (2) 625 CFM genuine Carter AFB's on an Offy running solid linkage (choke on both, idle on both, run on both) on my 390 will idle smoothly at 550 RPM after about 5 minutes. Before that, a wee bit of choke (at least if the ambient is below 40) is required.

Jon

 

Since we're on the subject of fine tuning a WCFB, I bought one at a swap meet one time that someone had ground or milled down the weight on the secondary air valve, drilled a hole through it, and had several flat washers attached to it with a machine screw. Seems like a reasonable way to tune the air valve for a special application; add or subtract washers until it opens precisely as it needs to.

 

I have seen air valves with chunks of lead screwed to the weight. I have also seen them ground down to almost nothing.

I am not saying this won't work; but generally I find the wrong carburetor was applied (or was attempted to be applied) to the application.

Carter only used 2 different weights for the WCFB (at least to my knowledge). There were more on the AFB. But the tuning item most folks ignore are the attack angle of the air valve plates. In my opinion, these are much more important than the weights.

If one studies the calibrations the Carter engineers used, one will find that "screamer" engines used a more aggressive angle than "torquer" engines.

I have repeatedly found that doing one's homework PRIOR to the purchase (or use, if you already have a carburetor) reaps more benefits than trying to recalibrate the incorrect carburetor.

Jon