[stude8]

I have a 1928 Studebaker Commander Big 6 (354 CID) that was fitted sometime in its past with a Carter BB-1 updraft carburetor. The car has not been regularly driven in many years and only recently I have done brake work to get it driveable. After running in the driveway a few times it started to die mysteriously from what was discovered to be lack of fuel.

After checking lines and fuel pump it was found to be the carburetor needle valve being stuck closed. After disassembly much "Silt" was found accumulated in the carb float chamber that prevented the float to fail to sink when the bowl ran dry. I completely disassembled the carb and cleaned all passages and blew out all openings until sterile. Reassembled the carb and the car started and ran better than ever, even had a nice smooth idle for the first time since idle circuit was previously clogged with dirt.

The first drive down the drive to the road ended at mail box when it suddenly died, again no fuel in carb bowl? I pulled the float needle seat fitting and the needle (regular brass arrow head style with synthetic (Viton?) tip seems to have a slight friction in the inet fitting (it lays parallel to the ground so gravity doesn't help it move in anyway) so I polished the three flutes the needle slides on to improve motion ability. This only worked 5 minutes and carb again ran dry from the needle not opening from fuel flow?

My research shows the Carter BB-1 was common to 1939-48 Chevrolet Cab Over trucks and some Chrysler Marine applications.

I don't know if it is correct or not, but later carburetors (1950-60's vintage) often had a small wire form spring affair to link the needle to the float so when the float sank with lack of fuel it actually withdrew the needle from the seat to allow more fuel to enter the bowl. *THIS CARB HAS NO LINK FROM NEEDLE TO FLOAT?

My question is "Does anyone have knowledge if this it is correct for the needle to simply get motivated by the flow of gas past it?"

A second question would be should the needle be all brass without a synthetic material tip?
Attached are before and after photos of the contaminated bowl and the complete carb reinstalled on engine with temporary plastic inline filter for protection until problems are cured.

Any suggestions are welcomed to find a way to get this carb operating correct.
Stude8

[carbking]

As to the float valve clip, Carter did not use clips on the fuel valve on the BB updraft series carburetors. Given the placement of the fuel valve seat in relation to the operating tang on the float, I would doubt that one could be custom-made for this series carburetor.

As to a solid brass needle, one could be produced, but do not think it would work any better than the neopreme. Carter did use both Monel steel needles and thermoplastic needles; both of which were rejected in favor of the neopreme, which effects a better seal than either. You certainly do NOT want an updraft carburetor to leak. Also, the steel needle would become magnitized, causing rust particle to stick to the needle and leak profusely. Also, contrary to popular opinion, the Monel steel will rust, and this condition is accelerated by the ethanol in todays fuel. We would try making needles from the thermoplastic, but to date have found no available source (on the shelf) for the triangular or square rods.

My guess as to the cause of the problem would be insufficient fuel flow to the carburetor. I am assuming your Studebaker is equiped with a vacuum tank. For testing purposes, try bypassing the vacuum tank, and (if you have one) use a portable outboard engine tank hung at the same height above the engine as the vacuum tank. Also, since the Carter is non-original; consider the use of an electric pump (the Carter will work with up to 4 1/2 psi).

Jon.

[DeSoto Frank]

If the Stude has a vacuum tank, there may not be enough height differential between the outlet of the vacuum tank and the carb inlet for gravity to overcome the friction of the horizontal needle.

Carter used a horizontal needle valve on the BB downdraft carbs used on MoPars from c. 1934 through 1952.

Just about every US auto & truck manufacturer went to mechanical (or other ) fuel pump after 1932, so the BB-1 updraft applications for COE trucks (Dodge used this carb too) were all designed to operate on pressurized fuel systems.


And now that I went back and looked at your pics, I see a fuel-pump right next to the carb...

Would suggest doing a pressure-check on the fuel-pump; if you found that much crud in the float-bowl of the carb, I wouldn't be surprised if there's similar crud collected in the check-valves of the fuel pump, preventing them from sealing completely - this would allow some fuel flow, but not enough pressure to open the needle ?

When I resurrected my '48 New Yorker from a 20 year nap in a field, I had all sorts of issues during the first months of driving, stemming from "crud" in the fuel system, including debris catching in the pump check-valves, holding them open.
I was able to remove the pump, open it up, clean-out the crud, and get going again. On the side of the street, downtown, in mid-day traffic, in the rain.

The needle-valves I've seen that work with a clip usually have a groove machined in the float-end of the needle... if you're ambitious, and nothing else helps, I think you could fabricate a "hair-pin" spring to hinge around the float pin, one leg grabbing the needle-valve, the other leg resting against the tab on the float arm...

Check the fuel pump first.

[stude8]

Thank you Jon & Frank for the responses, the car does have a mechanical fuel pump (AS Frank observed in the overall engine / carb photo).

I am happy to learn from your replies that a "return spring" or other wireform was not original to the Carter BB-1 float system. This sort of points at the volume of fuel flow to dislodge the seated needle when bowl level becomes lower. I had a suspicion that possibly the "Wafer" type check valves in the fuel pump might be sticking related to the amount of silt found in the carb bowl.

The fuel pump diecast metal shows several fractures in the aging body and cover flange area so I had hesitated to disassemble it without good reason.
It looks like I have good reason now so that will be the next job on the schedule.

Prior to the carb disassembly the engine has run well (except for idle mixture adjustment) for 2 years since I acquired the car. So the volume of fuel pump output wasn't a consideration until now. Factory literature says the correct carburetor is a Ball & Ball SV-43 but the Carter BB-1 has served the car for a long while from appearances.

I appreciate your knowledgable input in this matter, Stude8

[DeSoto Frank]

VERY nice car ! ( I love that "French-style" visor that was in vogue in the mid-'20s !)

Sounds like the fuel pump is suffering from "early pot-metal syndrome" (cracking, and probably warping). I would recommend looking for a replacement pump, hopefully one made after WW-II, which would be made from a better alloy.

The Pre-War pot-metal issue is one of the reasons many pre-Depression engines have replacement carbs fitted to them...

The Carter BB1 is a "stable", reliable carb.

[Mark Shaw]

Just a note that the BB1 carb manufold gasket must have a slot open to vacuum. Otherwise it will not perform correctly.

[wk66]

There are 2 different needle and seat assemblies for the BB-1 One for the fuel pump which has a #38 drill hole that feeds the needle and one for the vaccuum tank which has a #31 drill hole which feeds the needle. The larger hole gives more hydrauic pressure to push the needle open.

Attached parts list shows that there are 2 different ones.

Jerry Szostak

[hwellens]

Here is some more info

[stude8]

Thank you WK66 & Wellens for the technical data for Carter BB-1 carb's. Unfortunately the 21K file from WK66 is too small to be legible and when blown up it pixelates to a checker board, the PDF from Wellens is very legible and gives some interesting dimensions for the float needle inlet sizes.

My car has an AC fuel pump not vacuum tank but the inlet fitting measures only #44 drill (.086" ID) much smaller than the #38 or #31 sizes specified. This seems a possible reason why the horizontal needle fails to open reliably from too low of a fuel flow pressure.

In the meanwhile I am in process of acquiring a new fuel pump due to die cast metal disintegration of the present unit and other reasons like the lever arm condition with metal welded on the cam lobe contact pad in an attempt to correct cumullative "Slop" in the internal linkages by unknown previous owner.

I'll report in the future how it all works out when new pump is installed.
Stude8

[hwellens]

I think this is the sheet that WK66 was trying to add: