BB1 Updraft Rebuild

[Taylormade]

I'm rebuilding a Carter BB1 updraft carb for my 1932 Dodge Brothers DL sedan.  The old carb, also a BB1 was slightly different than the one I have now.  I believe it was designed for a Chevy truck and it used to work fine when I drove the car 45 years ago.  I tried to restore it, but the threads in the housing were stripped and there were some corrosion problems, so I bought another carb.  It arrived, with a rebuild kit, cleaned, but not rebuilt as the seller said he won't take responsibility for a rebuild on his part gone wrong.  Anyway, overall the carb seems to be in reasonable shape.  It is also made specifically for The Chrysler Corporation, as stamped on the top housing, so I'm hoping this one will work even better than the last.  The old and new carb below.

 

 

 

 

As I'm going through the rebuild I've come across a couple of minor problems and I need a little help.

 

First is with the Step Up Valve.  When I took this apart to clean it and replace the ball bearing, everything naturally fell out - luckily into the pan I was working over.  I'm pretty sure the reassembly has the ball bearing going in first, then the spring, and then the top cap, but I'd like confirmation to easy my troubled mind.  There was also no new spring in the rebuild kit, just the ball bearing.  Is it okay to use the old spring?  Are replacement springs available?

 

 

Then the idle passage tube.  The one in the new carb was in rough shape with the top torn up when someone got a little too zealous with a screwdriver in the slot.  I thought I could use the one from the old carb, but since the top casting on that carb is longer, the tube didn't match.  Does anyone have replacement tubes?  I suppose I could turn off the top of the longer tube on my lath, but the shorter tube is so ripped up, I'm not sure of the exact length - or if the length is that important.  Threads on the longer tube seem a bit longer, but it screws in place with no problem.

 

 

The next puzzle involves the needle and seat.  The new needle and seat I got in the rebuild kit are on top and the old units are on the bottom.  Totally different.  Is this a problem?  Should I use the old parts, or go with the new ones?

 

 

Next up, the nozzle.  In the picture you can see the black washer that was on the nozzle when I removed it.  I didn't find anything quite like it in the rebuild kit (more on that below.)  I hesitate to use the old washer, but I'm not sure if the correct washer is in the kit.  Since the Carter book mentions that Model 289S uses two gaskets, I assume the thickness of the gasket is important.

 

 

Finally, the matter of the rebuild kit.  I have two, one I bought when I was trying to rebuild the old carb and one that came with the new carb.  Take a look at the gasket sets on this split photo..  Somewhat different, plus I'm sure this is a universal rebuild kit and some of these gaskets don't go with my carb.  But there was no parts list in either kit, so I'm lost.

 

 

Are the three gray washer/gaskets on the far left for the three screws that hold the top to the bottom of the carb?  These did not come with the kit on the right.

 

I can't find anything like the four thin rubber washer/gaskets in the center of both kits.

 

Then the thicker washer/gaskets at the bottom.  The kit on the left has two, the other three.  Can't find a spot for these, either.

 

Of the three red washer/gaskets at the right of each kit, one seems just a bit bigger than the others.  Is this the one for the nozzle?  Any idea what the other two do?

 

Finally, the top two large washer/gaskets seem to be the same as those that cam in the bag with the needle and seat.  Are these extras, or do they go somewhere else?

 

 

Thanks for any information you can provide.  I've gone through the Carter Carburetor Service Procedure Book for the BB Updraft and in their parts group photos they seem to have the washers already on the parts, so it's very difficult to make out what is what.

[carbking]

OK - will take a stab at this:

 

The power valve - as you surmised, first in is the ball, then the spring, with the jet covering everything. It is not a cap, rather a jet. Note there is an orifice in the center. Different size orifices are used in different carburetors. You can test (to a degree) the spring. Once assembled, the spring should hold the ball closed with the mass of the step-up pushrod resting on the ball. The springs are in the better rebuilding kits. When the engine is in a low vacuum condition, the heavy spring in the top casting under the piston, pushes the pushrod down, opening the ball, and allowing fuel to flow, augmenting the main metering system.

 

The fuel valve - there are at least 12 DIFFERENT fuel valves used in the various BB1 carbs. If you use the new one, reverse the plunger. The flat neopreme goes into the seat. The better kits have the correct valve for the specific carburetor.

 

The idle tube - there are several different. Depending on the tag number of your carburetor, one for your carburetor may or may not be available. The internal orifice differs, as well as the length, from model to model.

 

The fibre washers - as there are dozens of different BB1 carbs, there are a number of gaskets which may be in the kit which will not be used in your carburetor. If you get the generic kit, try to match them up. The better kits have the specific gaskets for your carburetor by tag number.

 

I would suggest you NOT interchange parts from two different carbs; UNLESS you have the Carter bill-of-material for each carburetor and the part numbers are the same.

 

Jon.

Edited August 2, 2016 by carbking (see edit history)

[Taylormade]

Thanks, Jon.  You've  been helping me out since you rebuilt my carb on my 1929 Plymouth Model U.  I know you don't rebuild anymore, but I'll give you a call tomorrow to see if we can find the correct idle tube.  The really bad news is the tag on this carb is missing, so the vital information we need is not readily available.

[carbking]

Try cleaning the tube with Scotch-brite. It should have the part number stamped somewhere on the outside of the tube. It will be small, so a strong glass, a strong light, and a pair of "young eyes" are essential  Wish I still had the last item  

 

If you cannot find the number, chances are your best bet for a new tube would be take the old one to a local machine shop and have one made, as you do have a pattern.

 

Incidentally, there are THIRTY-ONE DIFFERENT BB updraft carburetors made for Chrysler! These include models for Plymouth, Dodge, Dodge Truck, Dodge Truck military, DeSoto, Chrysler, and Chrysler Marine.

 

Jon.

Edited August 2, 2016 by carbking (see edit history)

[Taylormade]

I spent a lot of time with Jon (carbking) on the phone today and he really helped me through some of my problems.  I ordered a part from him, and as soon as it comes in, I'll continue this post and show how I rebuilt the carb.  It turns out there were a few more problems I never saw coming.  i was also relieved when Jon told me this was a very good carb if properly rebuilt and maintained.

[Swenster]

Hello,

 

I have a 1929 Plymouth Model U.  Vintage Carburetors LTD sold me a rebuilt Carter BB-1 for it and I had my mechanic reassemble it as Vintage Carb does not fully assemble due to insurance reasons.  The car will start briefly when fully choked but then kills.  It does not want to stay running no matter the choke position. Not sure if it is an adjustment issue or something else.  I am including a picture just to make sure it is a carb that should work for my car.  Please let me know any thoughts and thank you in advance.  Any thoughts on initial adjustments would also be great.  Hopefully it is the right carb for it.

[keiser31]

2 hours ago, Swenster said:

Hello,

 

I have a 1929 Plymouth Model U.  Vintage Carburetors LTD sold me a rebuilt Carter BB-1 for it and I had my mechanic reassemble it as Vintage Carb does not fully assemble due to insurance reasons.  The car will start briefly when fully choked but then kills.  It does not want to stay running no matter the choke position. Not sure if it is an adjustment issue or something else.  I am including a picture just to make sure it is a carb that should work for my car.  Please let me know any thoughts and thank you in advance.  Any thoughts on initial adjustments would also be great.  Hopefully it is the right carb for it.

Don't know if this will help....

 

Edited September 7, 2022 by keiser31 (see edit history)

[Taylormade]

Not sure if that is too much carb for a four cylinder.  The DL is a six.  Some of the info posted above should help.

[Peter R.]

18 hours ago, Swenster said:

I have a 1929 Plymouth Model U.  Vintage Carburetors LTD sold me a rebuilt Carter BB-1 for it and I had my mechanic reassemble it as Vintage Carb does not fully assemble due to insurance reasons.  The car will start briefly when fully choked but then kills.  It does not want to stay running no matter the choke position. Not sure if it is an adjustment issue or something else.

The original carburetor on your car was not a Carter BB-1 but your car should run fine with a Carter BB-1 245S as a replacement (Carter BB-1 Universal Carburetor, SAE 1-1/4" flange, drilled for 1" manifold). From your picture I can tell that the upper half of your BB-1 is a 245S but the lower main body might be from another BB-1. Can you take it apart and provide some picture from the inside of the carburetor? The venturi size should be 1".

 

Here's a Carter BB-1 245S:

 

[Peter R.]

[Swenster]

thank you for all the information.  I do have the original 156S too but was advised that the BB-1 would be an improvement.  I will try to take it apart to show the two halves too.  Thnks to all for responding and taking the time to assist me.

[Swenster]

This is the original carb that came with the car.  I was told the BB-1 would be a better carb overall.

[Swenster]

Hello Peter,

 

Here are a couple pictures of the inside with measurements.  Does this look ok?  Please advise.

 

 

[Peter R.]

13 hours ago, Swenster said:

Here are a couple pictures of the inside with measurements.  Does this look ok?  Please advise.

Judging from the pictures I can tell the venturi size is correct. Everything is in place and nothing seems to be missing. What I can‘t tell from the pictures is whether or not the nozzles and jets are sized correctly. Let‘s assume they are and nothing is clogged up. Check the float level setting (1/16“ below top of casting when needle valve is closed). Put the carburetor back together and make sure the gasket seals up properly the idle tube passage between the upper and lower carburetor body halfs. Then reinstall the carburetor and make sure there is no air leak around the flange. Now turn the adjustable main metering screw all the way in (turn right) and then open it one revolution (turn left). Turn in the idle adjustment screw all the way in (turn right) and then open it one revolution (turn left). Don’t apply force when you turn in the screws. Set the throttle stop screw so the throttle valve is slightly open. Now give it a try. If the engine runs you will have to do idle rpm, idle mixture and high speed mixture adjustments.

 

As far as I understand your engine starts up for a short time when the choke is pulled and then dies. So it doesn‘t even run at idle speed.

 

An air leak will result in a too lean mixture, which can prevent your engine from running. If the main metering screw is all the way in, the main metering jet is closed, which blocks off the fuel for the idling and high speed circuit.

 

Do the above basic adjustments to get the engine running, and proceed with the fine adjustments.

 

Give it a try and if you get the engine running that way, we take it from there.

 

[Peter R.]

Adjustments to perform once engine is running.

 

Edited September 10, 2022 by Peter R. (see edit history)

[Peter R.]

17 hours ago, Swenster said:

I do have the original 156S too but was advised that the BB-1 would be an improvement

I agree, besides the flooding issue the BB1 was a good and advanced carburetor for its time. Just don‘t step on the gas pedal when the engine is not running.

 

On the other hand the Carter brass bowl updraft carburetor wasn‘t a bad carburetor either (my opinion). I counted over 50 different brass bowl updraft Carters. The later ones included all circuits of a modern carburetor back in the days. The brass bowl Carters I have restored so far performed very well. The real problem with these carburetors seems to be availability of parts.

Edited September 10, 2022 by Peter R. (see edit history)

[carbking]

Peter - actually about 225 different (and most parts for most of them are available, but not cheap).

 

Jon.

[Peter R.]

Jon….😳

….are we talking about the same carburetors….? 🤔 If there are 225 Carter brass bowl carburetors (and I have no doubt about it when you say so) I’m missing a lot of Carter info….😶

I have listed 53 different Carter brass bowls with numbers from 4S to 248S. I was sure there would be some more but I did not expect that many in total….wow….

 

Parts for Chevrolets (150S etc.) and bits and pieces for other more common car makes still do surface every once in a while. But other than that the market for Carter brass bowl carburetor parts seems to be dry. 
May I assume the those parts are mainly in your hands…? 🙂 Did you reproduce some of them…?

 

Peter

 

 

Edited September 10, 2022 by Peter R. (see edit history)

[carbking]

Peter - Carter started numbering with number 1.

 

The highest brass bowl number was 256.

 

Scattered among the brass bowl units were 2 or 3 U-1, a couple of W-2's, a couple of DW-1's half a dozen W-1's; and the rest from 1 to 256 were brass bowl units.

 

There are quite a few that most enthusiasts never see documentation, as the carburetors were sold to car companies for their export models. Chrysler, Dodge, DeSoto, Plymouth, and Nash all had several export versions that would be one number different from the domestic versions. There were also some variations for export left hand drive and right hand drive.

 

Here is a listing of about 130 different. Early Carter carburetor list

 

EDIT: PM sent.

 

Jon.

Edited September 10, 2022 by carbking (see edit history)

[Swenster]

thanks everyone for all the help.  I will try these adjustments and report back to the group.  I appreciate all the helpful information and all the time each of you have made to provide detailed information, very helpful.

[Swenster]

Thank you for all the information.  I set the adjustments as noted above and replaced the spark plugs.  I replaced the NGK AB-8 spark plugs with Champion D6 plugs.  I noticed the PO had the gap way less then .027.  I gapped them to .028 which I believe is in the correct range.  The engine started and had way more rev power.  I will likely need to richen the high mixture a bit as it wanted to run with the choke slightly pulled but at least it was running and revving now.  Perhaps the prior plugs were fouled even though they appeared to spark when i tested them.  I will need to go thru the ignition as the wires look old and the distributor likely needs some attention to properly advance.   I appreciate everyone's guidance.  Looking forward to driving it but unfortunately I had to run it in the garage with the doors open tonight for a short time as my driveway was just seal coated.

[elkhorne]

I am new to the forum but have a 1929 Plymouth Model U sedan and have had a lot restored on the car. The carburetor that came on the car was a Carter BB1 and ran for a while. It was discovered that the BB1 on the car was leaking fuel at the main metering screw and below the main body. We decided to replace the original BB1 with a NOS from Vintage Carburetors LTD. We received it and did final assembly after checking and double checking all gaskets and fittings. Last night we re-installed the new BB1 with no real problems. We set the idle adjustment screw one turn out from the closed position. We set the main metering screw I turn out from the closed position. My wife started the car and it ran but at a very fast idle. Turning the idle adjustment screw in or out seemed to have no effect as with the main metering screw also had no affect. Due to the very fast idle we turned the car off. Thais morning we went back out and tried to start the car and it ran for about a minute then died. We noticed there was fuel leaking from the main metering screw and I tightened the main metering screw assembly on the washer to the lower carburetor casting. My wife tried to start it again and it did did not start! The next thing I noticed was that there was gas draining from the drain hole in the choke intake lower main body. I would appreciate any help anyone can give to help me get this car properly running! Thanks in advance,

[Akstraw]

A few thoughts from somebody admittedly not an expert.  I have, however, been able to get the BB1 to perform rather well on my 1930 Franklin.

 

1.  Regarding idle speed, have you check to see that your throttle plate is all the way closed in the idle position?  This would be a linkage adjustment.

2.  Check float position adjustment.  I used an off-the-car setup to check mine (see photo).

3.  On these updrafts, do not touch the throttle/gas-pedal until the car has started.  Use only the choke.  Otherwise the accelerator pump will pump excess fuel, and without engine vacuum pulling it upward, it will leak down and out of the carb.