Carb upgrade 1947 sedan

[al3xcooktattoos]

So I drove home last night and noticed a strong fuel smell.. I started the car this morning and have fuel dumping from front of the carb. I figure it’s most likely the float.
I’ve done a little reading, and while I plan do do a quick rebuild anyway, I think I’m going to upgrade to something more efficient than the Carter bb. I’ve heard the w-1 is a popular choice, but I’m wondering if any of you know of a bolt-on carb that’s readily available that you can recommend

thanks!

[soth122003]

For these old cars, efficient carbs are not really a thing. All carbs are not really efficient. Fuel efficiency came by way of weight reduction and airstream resign. A two barrel carb might be a bit more fuel efficient maybe. What the 2 and 4 barrel carbs did deliver was more power, but at the cost of fuel efficiency. The real fuel mpg came with the advent of fuel injection. To put one of these systems on the flathead might be doable but it will cost BIG BUCKS. For all that, the Carter BB's were the best at the time they were used. This is born out by how long they were in service. 1930's to the late 60's. You also had the  Ford-Holly, Rochester, and Stromberg. Most car companies didn't take fuel efficiency into account until the very early 70's due to the oil crisis.  Early car companies were all about HP and speed. 

 

That's why a lot of owners will change the carb, to get a little more power out of them. These old cars got a respectable 17-19 MPG. If you look at todays cars and trucks (mainly trucks due to weight) the MPG has not increased that much. Mainly due to weight reduction and gear addition in the tranny's and diiferential's. Unibody, aluminum and major plastic component parts and fuel injection. Driving habits also play a big role in fuel efficiency. Lead foot and speeding are the big downside to driving with fuel in mind. Also when these cars were built 50mph was about the max speed limit. 

 

My Carter BB1 just started leaking like yours did. Someone had over-torqued the bowl screws and warped the top a bit. It might be fixable by using a flat piece of glass and some sand paper to take the warp out enough to let the gasket seal again or by using a thicker gasket material. Check out the thread Carter BB leaking and you'll find this to be a more common issue than thought. My advice, rebuild your Carter or use Ebay and replace it. Almost any Carter will fit the mount studs but the linkage will be the problem. You can get a scrapped Carter for between $50 and $80 for parts. 

 

Sorry for the lengthy rant/advice, but I felt like being a writer today. Also if this is not your intent just ignore the post. A lot of people try to make these old cars into something they are not just by using todays cars as an example to compare against these old cars. For their time these were the best engineered cars on the planet. Prime example being their long life span. Todays cars will not last like these classics. The sun kills them by degrading the plastics and the elements kill the metal because it is so thin. You can also buy a fully restored classic a lot cheaper than you can buy the cheapest new car out today, and the only thing you will miss is the A/C and cruise control. You can retro these cars with seat belts and radio for next to nothing. A/C is a bit more costly but doable. Cruise control... there is always some ******* in front of you doing 1-2mph slower than you meaning pass or drive slower. 

 

While these cars are meant to be driven, they are not meant to be speed demons. Plus with the population growth towns, cities and interstate are way more crowded than even 10 years ago. I don't even drive on the interstate due to the amount of trucks and yahoo's trying to get someplace fast and when there is a wreck plan on adding 1-3 hours to your drive. The old U.S. highway is so much more comfortable to drive and the scenery is great along with the food. 

 

Sorry, got way off topic there. Anyway, I would stick with the Carter and rebuild it. It is cheaper and you know what your working with.

 

Joe Lee

[nonstop]

You can certainly increase your mileage with one of these cars.  But it also involves some money.  I DD my cars.  If you take a look, early 80’s Ford trucks got over 20 mpgs and it is also been purported some 472 and 500 cube Cadillacs also got similar mileage.  Todays trucks are getting in the teens with FI and a bunch of computers… over 40 years later.  Now, there are certainly trade offs.  The trucks I referred to were 300 cid 6 cylinders, with SROD overdrive transmissions and 2.73 rear gears.  They also had lightened frames, manual windows, no airbags, etc.  Still, in over 40 years you would think mileage would have increased.

 

As noted above, weight certainly plays a part.  I recently weighed my truck and it was 2600 pounds - or less than half the weight of a new truck.  I recently changed my gearing from 4.10 to 3.73.  I certainly noticed an improvement in mileage.  After consulting with some of the fine members here, my next upgrades were a dual carb set up (with the B&B carbs) and dual exhaust.  There was another mileage improvement - and the engine is much happier!  The mileage improvement is said to be from better fuel distribution.  I am happy with it, but ultimately, you need to decide how much money do you want to put into it vs how long would it take to recoup that in savings at the pump.  Will the mileage savings be worth it to you?  How far do you drive?  
 

A simple carb rebuild might be your most cost effective alternative instead of experimenting with different carbs, OR putting out the money once to get it professionally rebuilt with a warranty by a reputable company.

[Sniper]

4 hours ago, soth122003 said:

The real fuel mpg came with the advent of fuel injection. To put one of these systems on the flathead might be doable but it will cost BIG BUCKS.

 

I don't know that i would agree that EFI was a real improvement in economy so much as it was a real improvement in meeting emissions standards.  As for costs, well I have been putting together a dual throttle body injection setup for my 51.  I have a spreadsheet with the costs, Just about a thousand dollars all in. 

 

Edit, I added in the ignition parts.

EFI parts.xlsx

Edited September 11, 2023 by Sniper

[soth122003]

6 hours ago, nonstop said:

The trucks I referred to were 300 cid 6 cylinders, with SROD overdrive transmissions and 2.73 rear gears.  They also had lightened frames, manual windows, no airbags, etc.  Still, in over 40 years you would think mileage would have increased

You can only due so much with a truck and still be used as a truck. The 1/4 ton sorta didn't exist back in the day (think station wagon) but it gets pretty good mileage. The 1/2 and 3/4 tons were the main stay for work trucks and had to be built tough to handle the work required of it. Hard to go with light metal bodies and take the stress of some of jobs they did. That's why (IMHO) they stress torque and HP over fuel economy. Nowadays The people that buy trucks for other than work trucks won't really take them off road or work them hard, they want the new shiny thing that looks pretty.

 

6 hours ago, nonstop said:

I recently changed my gearing from 4.10 to 3.73.  I certainly noticed an improvement in mileage.  After consulting with some of the fine members here, my next upgrades were a dual carb set up (with the B&B carbs) and dual exhaust.  There was another mileage improvement - and the engine is much happier!  The mileage improvement is said to be from better fuel distribution.

Don't know for sure, but changing the ratio of the diff changes the torque and power available for carrying and towing loads. Now with an older truck like yours I don't think you'll be using it like a work horse so the changes are a benefit to you. The dual carb set-up is an improvement as well as it means one carb per 3 cylinders and you adjust the carbs to match what is needed for 3 instead of 6. I believe the fuel will distribute better and you won't have as much excess in the intake manifolds. Granted were talking a little bit, but that adds up over a tank thus increasing the mileage.

 

4 hours ago, Sniper said:

I don't know that i would agree that EFI was a real improvement in economy so much as it was a real improvement in meeting emissions standards.  As for costs, well I have been putting together a dual throttle body injection setup for my 51. 

I think the throttle body was the interm between the carb and EFI. The TB mixed the air and fuel at a more regulated rate than the carb, but the EFI was designed to help atomize fuel and to use what was needed in the cylinder and not any more. That was why the computer for EFI was more advanced than the TB. The TB is either good or could develop flat spots on the electronic part of the TB and when it does it means replacing the TB. Fuel injectors can be cleaned to be made right again or replaced individually if bad. The EFI was developed to help cars meet emission standards and the mileage was a part of that process.

 

As for the cost, the TB is the cheaper way to go. EFI would include changing the intake manifold, fuel pump, convert to 12vdc and the wiring and the computers to run it. Very costly. When I wrote the above post I didn't even think about the TB, but I could see that as doable and not too expensive. Then again, expensive is relative. You make 200k a year some projects are cheap by that standard. 50k a year and the budget comes into play at that point. The OP might be a millionaire so any improvements could be considered cheap. 

 

My RV has a 454 chevy in it and a TB. It gets about 9MPG but weighs in at 12,000lbs dry. Before the TB most of the rigs my size got about 5-6MPG, hence the large fuel tanks (mine is 60 gals and not cheap to fill) but if you can afford the cost of it you can afford the gas for it too. That's why a lot of owners wanted the diesel pushers for the extra 4-5MPG, lower maintainance costs and the diesel at the time was cheaper than gas. 

 

Mr. Scott once said "The more complicated the plumbing, the easier it is to stop up the drain". That's the reason I like these old cars and trucks, they were simple, easy to maintain and fun to drive. Also as stated in my prior post, I could by a fully restored Chrysler product for about the same as a new cheap POS that won't last nowhere near as long. Since I don't have the vim and vigor I used to, I might sell my P-15 SD and buy a restored  coupe. Still thinking that one over though. 

 

Joe Lee

(man, that's like my second novel of the day).

Edited September 11, 2023 by soth122003

[Sniper]

9 hours ago, soth122003 said:

I think the throttle body was the interm between the carb and EFI.

 

Throttle body injection is EFI.  EFI means electronic fuel injection.  There are many types of EFI, TBI, MPFI (batch fire and sequential), Direct injection, etc.  All of them a form of EFI. 

 

TBI could be regarded as essentially an electronic replacement for a carb, one that uses pressurized fuel thru a metered solenoid controlled by a computer to replace the vacuum operated fuel delivery system of a carb.  This injection delivers a predetermined amount of fuel to the intake, based on programming and sensor feedback, without regard as to when the intake valve opens.

 

Batch fire multi port fuel injection is very similar to TBI with the major difference being that there is an injector at each intake port rather than upstream of the intake.  Other than new holes in the intake, and associated plumbing, there is not much to adding this to any intake.  All the sensors and such are the same as TBI.  This system delivers an identical, or as identical as humanly possible, shot of fuel to each cylinder.  This injection delivers a predetermined amount of fuel to the intake PORT, based on programming and sensor feedback, without regard as to when the intake valve opens.

 

Sequential Multi Port Fuel Injection (which is what I think you are calling EFI here) is almost the same as batchfire with the exception of being able to time when the injection happens, usually just before and as the intake valve opens.  Still delivers the same amount of fuel for each cylinder and still uses the same sensors and such as TBI would, with the exception of the timing of the injection which requires more resolution in regards to crank and cam position and a more sophisticated computer to do those calculations.  Theoretically, not sure if any production system did this, you could tailor the fuel delivered to each cylinder based on need.  This would essentially require the computer to be able to monitor each cylinder's needs.  Doable, but right now very complicated, essentially a wide band O2 sensor for each cylinder though there has been some research into using the spark plugs as a sensor., they are fragile and expensive so I am not holding my breath.

 

Direction injection is similar to sequential MPFI, but delivers the fuel directly into the cylinder, after the intake valve is closed.  My 2015 BMW has this, makes 300 hp and make 36 mpg at 80 mph.  However, that is beyond the scope of a DIY type, the head has to have provisions for the injectors, I guess someone could cast or mod a flathead head easier than an OHV/OHC head.  Again, there has been research into making a combination spark plug and direct injector for retrofitting, though I am not holding my breath there, lol.

 

10 hours ago, soth122003 said:

As for the cost, the TB is the cheaper way to go.

 

The only real difference in cost would be the added injectors and intake mods needed to fit them if you wanted batch or sequential fire MPFI.  Though in our specific applications it would be more difficult to run this as there are 6 cylinders being fed by 3 intake ports.  Which means you'd need an injector twice the size as you'd normally need (remember you are feeding 2 cylinders per injector).  When injectors get too large they tend to lose fine control for less than WOT applications.  Not sure how or even if that would apply here but I suspect fuel distribution would be horrible with the first intake valve to open after the injection even to be too rich and the second intake valve to open being too lean.  This might be ameliorated by injecting twice per cycle rather than once, but some fine attention to detail and maybe even tying the injection timing more closely to the  engine timing being needed, much like sequential does it.  Not sure though if the ECU I am using is capable of double firing the injectors in sequential mode or not. 

 

10 hours ago, soth122003 said:

EFI would include changing the intake manifold, fuel pump, convert to 12vdc and the wiring and the computers to run it.

 

You really need to clarify what you mean by EFI, but other that intake mods, no need for a new intake as any reasonably competent machine shop can add injector bungs and fab a fuel rail for just about any intake manifold.  Not to mention there is no multiport intake available for our engines.  All the rest is going to cost the same regardless of what version of the 4 EFI types you want to run.  To be honest, my EFI setup is a hybrid TBI and batch fire setup.  Most TBI systems use a lower fuel pressure and physically larger injectors than the other setups, but my setup is using MPFI pressures and injectors with the injectors being in the throttle body upstream of the intake rather than being in the intake at the other end.  Simply to deal more easily with the odd ball three intake ports but six cylinders arraignment we have.  I could, if I chose to, have my intake modded to fit three injectors, one for each intake port and go to batch fire MPFI, some added wiring and computer tuning needed as well, but that would be it.  But, see my above concerns about fuel delivery in our siamesed intake setup.

 

Yes you could replace the entire stock fuel delivery system with new parts, tank, lines, fuel pump and carb for much less that I am spending and no I will never make the difference up in fuel "savings".  So why am I doing it?  When was the last time you saw a fuel injected MoPar flat head?  Basically, it's the same answer given by the man who was asked why he wanted to climb the mountain.  Because it is there, lol.

 

[soth122003]

19 minutes ago, Sniper said:

Sequential Multi Port Fuel Injection (which is what I think you are calling EFI here)

That's what I was thinking of. The TBI to me just does not quite (to me) seem like EFI, though I see your point. It is electronic and fuel injected, but it flows through the manifold instead of directly into the cylinders. To me EFI is direct injection into the cylinders.  I will admit most of my post is from a layman's understanding and I do not really keep up with the EFI types with the exception of when I worked on engines with a TB. Your understanding is more in-depth than mine due to your deeper research and I believe your are an actual engineer where I am just the mechanic, and I have been out of that business for about 10 years now.

 

31 minutes ago, Sniper said:

My 2015 BMW has this, makes 300 hp and make 36 mpg at 80 mph.  However, that is beyond the scope of a DIY type, the head has to have provisions for the injectors, I guess someone could cast or mod a flathead head easier than an OHV/OHC head.  Again, there has been research into making a combination spark plug and direct injector for retrofitting, though I am not holding my breath there, lol.

Your example here is what I was trying (poorly in this case) to articulate. I saw your price list and while it is fairly inexpensive, what about the time involved to install and test it? I look forward to what you can do with it and hope you'll post the results as well as a vid of your project. I don't think we have to much of a divergent thought process on this, just what each of thinks what a certain thing is. In my case I was ignorant of the different types of EFI and did not explain very well.

Basically "I DOER NOT THINKER" as I pick my knuckles up off the ground to take another step forward. Plus i like simple. No need for me to over complicate things by doing something that will land me in trouble with myself (or the wife) by fixing something that ain't broke. I wished we lived a little closer together as I would love to spend a day just chatting about these kinds of subjects. Hard to post facial expressions and hand gestures to get the point of understanding across. 

 

Joe Lee

[Sniper]

2 hours ago, soth122003 said:

I believe your are an actual engineer

 

Not hardy, lol.  I'm just a car guy that has an inquisitive mind and not a fan of formal schooling.  So I read, a lot.  Then I try to do monkey see, monkey do and then I figure out that half of what the car magazines print just shows they are journalism majors, not mechanics.  So I read real engineering papers on the stuff, with a dictionary at hand. 

 

2 hours ago, soth122003 said:

what about the time involved to install and test it?

 

Lol, it's a hobby.  If we added up the time and labor any of us puts into whatever we are doing on these old cars and assigned a cost to it we'd all just buy something new.  It'd be cheaper that way.

 

2 hours ago, soth122003 said:

hope you'll post the results as well as a vid of your project.

 

Oh I will, when/if I ever get it up and running.  Right now I am mentally locked because I have a 230 to rebuild to replace my 218 and I figure it'll be easier to just do it all to the 230, but there is so much I could do to the 230 to "improve it" and then there is the OD trans swap I want to do and the rear drums, add AC, etc, etc.

 

I need to just cut it up into chunks and do it one bit at a time instead of seeing everything and freezing up due to the scope.

 

Yeah, I know, I'm mental, lol.

 

[soth122003]

8 hours ago, Sniper said:

Lol, it's a hobby.  If we added up the time and labor any of us puts into whatever we are doing on these old cars and assigned a cost to it we'd all just buy something new.  It'd be cheaper that way.

You're tight about that. Reminds me of that saying about a fool and his money... Course i just dropped over $350 on 2 carbs from ebay.

 

8 hours ago, Sniper said:

Not hardy, lol.  I'm just a car guy that has an inquisitive mind and not a fan of formal schooling.  So I read, a lot. 

Helicopters and airplanes were my trade. I read a lot as well mostly fiction, (2-3 novels a week) but way back when, I read a lot of theoretical physics, aircraft engine design and flight principals. Scram jet engine as could be applied to aircraft. Then I got old and worn out (40 years stomping flight line around the world), and now I like to read and slowly tinker on my P-15. Trouble is while I can get down and bend over to work on things, I need a crane to get back up. 

 

22 hours ago, soth122003 said:

Since I don't have the vim and vigor I used to, I might sell my P-15 SD and buy a restored  coupe. Still thinking that one over though. 

 Found these on ebay last night....and I'm thinking.

https://www.ebay.com/itm/235185223940

https://www.ebay.com/itm/145291999590

https://www.ebay.com/itm/394869371954

https://www.ebay.com/itm/166320062887

No I don't think I can afford this next one but man what I wouldn't give.

https://www.ebay.com/itm/166318508531

 The first 4 are almost cheaper than the lowest model brand new POS, and will last 10 times longer.

 

Joe Lee

 

Just got an email from the 4th car on the list. They say they will knock off $500.00 for me. Makes it even more irresistable.

Edited September 12, 2023 by soth122003