two carb setup

[4ford]

hello all.
just got this motor running and runs well thanks to all that helped ! I have a few things to ask, as you can see in pic the fuel lines is there anything anyone can share about different ones maybe pics of yours? to give me some ideas. second the carbs the carb that is closest to the alt seems to have more vacuum then the one close to the fire wall. the primary one is that one closest to fire wall and has the choke hooked to it is this right? or should it be the other way? it has 400 heads and 1090 offy intake. 1941 ford 46 motor 59ab....any thoughts??

thanks

[adileo]

4Ford - your choke is correct

Here is my pic004.jpg

[Tony, NY]

Reports are that small air filters are too restrictive. I have taller ones.

[30-9]

I like taller ones - where u get them?

[Kahuna]

Andy
I like the 2 carb setup
Looks great
Jim

[adileo]

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Thanks Jim! -

Hope all is well with you and yours

[Scott H in Wheaton]

Yes, air cleaners can be restrictive.
I have a Cobra dual carb setup for a 289.
I had the carbs airflow tested with and without two small air filters. There was almost 100cfm less with the two small air fliters. Large oval filter with K&N showed little to no cfm loss.

[bk53]

nice clean look on the fuel lines adileo.4ford, do you mean like a throttle body vacuum leak or just trying to get them adjusted. I got one of those unisyn jobs and kept tweaking away at it.

[Tony, NY]

Originally Posted by 30-9

I like taller ones - where u get them?

http://www.otbgear.com/Fin-Top-2-Bar...r-Tall-P6.aspx

[Pete]

Originally Posted by 4ford

hello all.
just got this motor running and runs well thanks to all that helped ! I have a few things to ask, as you can see in pic the fuel lines is there anything anyone can share about different ones maybe pics of yours? to give me some ideas. second the carbs the carb that is closest to the alt seems to have more vacuum then the one close to the fire wall. the primary one is that one closest to fire wall and has the choke hooked to it is this right? or should it be the other way? it has 400 heads and 1090 offy intake. 1941 ford 46 motor 59ab....any thoughts??

thanks

Your fuel lines will be ok for putting around on the street.
A better setup can be seen in the pic.
Most street setups fall short in the fuel supply volume at wide open throttle.
Whatever pump setup you have, it needs to be able to maintain 2 lb or more at wide open full load throttle.
You can observe the fuel pressure with a TEMPORARY mounted fuel pressure gauge on the cowl OUTSIDE the cockpit. Never mount the commonly available fuel pressure gauges in the cockpit. Potential fire hazard.

Most "hot rod" air cleaners are restrictive. A good rule of thumb is the filter area for each carb should be at least 4 times the carb throat area.
This is hard to achieve with individual cleaners. Most hot rodders don't like the look of the modern "covers all the carbs" type cleaners but it is about the only way to get adequate area with no restriction. Here again it depends on how fast you want to go or how old you want to look.

Your variation in vacuum between the 2 carbs is probably due to the choke in only one. It will probably won't hurt anything if it is just a small difference.

[4ford]

The vacuum I can feel it when I have both chokes open just buy putting my hand over carb. I think it's a notesable difference

[4ford]

Adiulo....
Where did you get your fuel lines. Home made?

[adileo]

Speedway but I have also seen them on mr gasket and ebay

[Tony, NY]

Originally Posted by 4ford

Adiulo....
Where did you get your fuel lines. Home made?

You can get them from Stromberg.
http://www.stromberg-97.com/linkage/...ts.asp#prodfrm

[funrunr]

I bent my own fuel lines using brake lines from Napa

[4ford]

how about something like this for an air cleaner? more air?? what do ya think. would it make any difference to make the choke on # 2 closer to the alt. then the stock choke rod will work well?

[bk53]

the choke on my forward carb is straight up and down, and fixed in place. I'm running 97's though. you maybe could choke that out somehow though and work on the back carb. make sure there are no leaks, use propane or whatever. if no vac leaks, vac hopefully can be evened out with idle set screws. I did have issues with linkage being interfered with make sure the linkage between the carbs is loose so you can set both carbs up with idle, then lock em down. I apologize if this is all second nature to you. I'm not a good judge sometimes of peoples skill sets. I'm pretty new at this, couple years running duals. K&n makes an air cleaner that is unrestricted and 4 1/2 inches tall. I don't have pics online. those are free enough that they make no difference on or off. Can't remember if the top and bottom and bolt /wingnut came with them.

[4ford]

so if I hear this all right..... the primary carb should be closest to fire wall. with the choke also on that one? or could it be the other way?

[blucar]

From my prospective, I think the average "close mount" dual carb manifold setup is more for looks, as compared to actual performance. A single four barrel would work better.
I have a Offy Super wide mount manifold on my 59AB with a pair of 97's, of course this application requires a side mount generator.
The front choke is wired open, the rear carb choke is attached to a modified choke cable.
Fuel is delivered via a fuel block on the firewall supplied with fuel from an original type of fuel pump backed up with an electric pump near the tank that is switched separately.
The air cleaners are stock type oil bath that have been modified to hold disposable paper filters.
The whole setup might not be to pretty, but it is functionable.. I drove the car to work everyday for years through summer heat and winter blizzards.

[adileo]

4ford ur last post is correct as shown in my pic

[Tony, NY]

Originally Posted by 4ford

so if I hear this all right..... the primary carb should be closest to fire wall. with the choke also on that one? or could it be the other way?

Sounds like you have progressive linkage in order to have a primary carb? Or because it has a choke?

[tubman]

I have never run a regular dual manifold (just "super-duals" and 4BBL's), but it seems obvious to me that using the rear carb as the primary would seriously starve the front cylinders. I may be wrong, but if I am, I'd like someone to explain why.

[V8 Bob]

Originally Posted by 4ford

hello all.
.........the carbs the carb that is closest to the alt seems to have more vacuum then the one close to the fire wall. the primary one is that one closest to fire wall and has the choke hooked to it is this right? or should it be the other way? it has 400 heads and 1090 offy intake. 1941 ford 46 motor 59ab....any thoughts??..thanks

I would choke the carb closest to the alternator, as it is more centrally located on early regular dual intakes like yours, because of greater generator space back set. The later 8BA regular dual can have both carbs centrally located because of the longer overall length of these engines and more forward generator placement..
You want to run straight linkage with dual carbs, so there is no primary or secondary carb.
You have to sync the carbs to attain equal air flow and proper operation. This starts with the two air/fuel adjustments on each carb, followed by using a Uni-Sync or something similar to dial in the butterflies.

[tubman]

From what I am reading, it sounds like he (like many others) is running a progressive linkage. I think we have to go back to a more basic question : "Can a 'regular' dual carb setup be made to run satisfactorily with progressive linkage?" Anyone know for sure?

[scicala]

To me, progressive linkage on a two carb set up is asking for trouble as in poor air/fuel distribution and some cylinders running leaner or richer than others. While running on the primary carb only anyways.

Sal

[scooder]

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Originally Posted by tubman

From what I am reading, it sounds like he (like many others) is running a progressive linkage. I think we have to go back to a more basic question : "Can a 'regular' dual carb setup be made to run satisfactorily with progressive linkage?" Anyone know for sure?

Probably can be made to "work" but pointless, and never as good as a properly set up dual manifold with carbs opening in sync. A complete waste of time and energy in my opinion. A properly setup dual in my experience has better throttle response and better mpg than a single on a stock manifold, plus the obvious more power and greater urge in the higher rpm range.
Probably setup includes addressing the ignition curve, and if it's a 8BA type, deep sixing the loadamatic. I learnt from JWL's dyno testing that two carbs want less total timing.
Any re jeting and power valve sizing for 97 style or opening vacuum for 94 style needs to be looked into aswell. Jet sizing normally ends up damn close or same as stock. The rule I use when buggering about with carb jets is, too far from right is wrong. If you think it wants much smaller or bigger jets, something else is wrong. The word much used here would be used if you pulled out (of a 94) 51 jets and plunked in 55 or 46, that's to far from right.
In my experience.
JWL's book confirms I've not been barking up the wrong tree with the carbs
Martin.

[bk53]

so if I hear this all right..... the primary carb should be closest to fire wall. with the choke also on that one? or could it be the other way?

I'm not sure primary is the right term. I have the choke full open and fixed on my forward carb as I received it from a very reputable fellow.All i'm saying is you may need to get one carb running in order to adjust the idle settings. then get the second one going or do em both at once. don't connect the direct linkage until you have similar vacuum going on both. also, make sure nothing is interfering with the linkage once you have it.

[scooder]

On a regular dual if I had one, the front carb would have the working choke, the back one (firewall end) would have the choke wired open.
Good advice on making sure they both work properly, in this instance I'd use a blank off on the back, and verify operation of each carb when bolted to the front carb port.
Martin.

[4ford]

thanks guys!!! the set up is not a progressive. its solid, I am going to try to use the front choke and remove the butterfly on the other. sync both carbs then hook up linkage and drive like hell

[chap52]

I tried small air cleaners which restricted air flow and made it impossible to tune in. Then switched to scoops with filter foam and wire mesh to keep the carb from eating the foam. Works great.
I am running electric fuel pump with pressure regulator set to 2#.

[chap52]

OOPS, Also. I have rear carb as primary with a choke and front choke wired open.

[funrunr]

I'm running chokes on both my carbs, helps with starting too.
Is there a reason someone should only run one?

[scooder]

Originally Posted by funrunr

I'm running chokes on both my carbs, helps with starting too.
Is there a reason someone should only run one?

Oftentimes just having the choke working on one carb is enough for starting. If it's found one is enough, it saves making up something to link the two chokes together.
Essentially it's easyer if you cam get away with one choke.
Martin.

[scooder]

Originally Posted by 4ford

thanks guys!!! the set up is not a progressive. its solid, I am going to try to use the front choke and remove the butterfly on the other. sync both carbs then hook up linkage and drive like hell

No! Don't remove the other choke plate, just wire it open.
Removing the plate (butterfly) upsets the fuel metering in the carb. Johns book shows this with 97's with dyno proof. I'd say it's also relevant with 94's. Think about it, the carb was built and designed with the choke plate fitted and worked properly.
Leave it in.
Martin.

[Terry,OH]

This is Stromberg fuel inlets pictured below. Choke can usually be on either Carb. One choke will work fine and eliminate excessive linkage. Just block the other choke plate open so it can not close (do not remove). Use a Carb synchronizer to set the Carbs so at idle both have the same flow and contribute equally during throttle operation. Adjust the idle RPM up or down to match each.
Looks like you will have to change throttle shafts for extension to hook linkage.

[funrunr]

Originally Posted by scooder

Oftentimes just having the choke working on one carb is enough for starting. If it's found one is enough, it saves making up something to link the two chokes together.
Essentially it's easyer if you cam get away with one choke.
Martin.

Thanks Martin, well said.
Mark

[Ralph Moore]

Originally Posted by funrunr

I bent my own fuel lines using brake lines from Napa

I've been trying to make a fuel line doing the same, but I'm having a heck of a time bending them. Seems every time I get to a 90, it kinks on me.
I have a nice bender, and it worked great on my brake lines, but the larger 5/16" lines are just not working. Any secrets?

[30-9]

Once heard fill with sand and then bend

[4ford]

terry.
looks like you have linkage on drivers side is that what you have the two carbs running on not the pass side? if that's the case I can do that real easy and not have so much junk on pass side of the carb. you say to match idle of each carb? I do have a sync tool and this weekend will be trying all this.

[4ford]

ralph.
I used the spring type to bend mine it seemed to work the best

[the cooch]

Too cold up there Ralph! A little heat helps the fuel lines bend. I put the little guys in the oven for a few last time. Torch is overkill and would make thin spots, i think, but I get easier, better looking bends by hand with the lines hot than with any tool I've tried. I do like the spring style for big curves, but always get a kink from the plier style with the wheel on small corners. Could be a placebo effect, haha, but theres a nice feel to it.

[blucar]

A very clever body man showed me a neat trick to loosen frozen/stuck nuts, bend tubing, etc.,
Use an electric heat gun. The heat can be controlled without distorting the metal. Works great on pot metal/cast trim pieces that have been bent. Heating the piece with a heat gun will allow the piece to be straightened without it breaking.

[funrunr]

Originally Posted by Ralph Moore

I've been trying to make a fuel line doing the same, but I'm having a heck of a time bending them. Seems every time I get to a 90, it kinks on me.
I have a nice bender, and it worked great on my brake lines, but the larger 5/16" lines are just not working. Any secrets?

I have a couple benders, however I used the cheap one. Notice the lines I used are the softer metal ones that they sell in shorter lengths. It has some coating to prevent rust and bends easier. I cannot remember the name as this was a few years ago. However I took a close-up for you. When you go into Napa you will recognize by the different color. If you cannot find it I will stop in our location here and get the name for you.
Good luck, Mark

[V8COOPMAN]

It's Kunifer Brake Pipe. DD

[Ross F-1]

Originally Posted by V8COOPMAN

It's Kunifer Brake Pipe. DD

Cunifer

[Mike51Merc]

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It's not a good idea to remove your choke plate, even if you don't use the choke. Air flow studies have shown that these carbs flow less with the choke plates removed.

As far as running two carbs with progressive linkage, it depends on your manifold. Most manifolds have equalization tubes between the two plenums, meaning that both carbs feed all eight cylinders, not each feeding four cylinders. I've set up engines with both direct and progressive linkages successfully.

[Mike51Merc]

Originally Posted by tubman

I have never run a regular dual manifold (just "super-duals" and 4BBL's), but it seems obvious to me that using the rear carb as the primary would seriously starve the front cylinders. I may be wrong, but if I am, I'd like someone to explain why.

As I posted above, most multicarb manifolds have equalization tubes inside that join everything together.

As far as starvation from distance away-- just look at any six cylinder manifold and how far the carb is from the end cylinders compared to the middle cylinders. Do they starve?

[V8COOPMAN]

Originally Posted by V8COOPMAN

It's Kunifer Brake Pipe. DD

Originally Posted by Ross F-1

Cunifer

You're absolutely correct Ross, and I did know there was a difference. I've even written about it in the past. I grabbed the wrong straw this morning without properly checking myself. DD

[tubman]

Originally Posted by Mike51Merc

As I posted above, most multicarb manifolds have equalization tubes inside that join everything together.

As far as starvation from distance away-- just look at any six cylinder manifold and how far the carb is from the end cylinders compared to the middle cylinders. Do they starve?

All well and good, but how many six cylinder intakes have you seen with the carburetor on the end? Everything is a compromise, but we are better of with the best configuration we can find.

[Mike51Merc]

Originally Posted by tubman

All well and good, but how many six cylinder intakes have you seen with the carburetor on the end? Everything is a compromise, but we are better of with the best configuration we can find.

No, the carb's in the middle and it has to feed cylinders at the ends!

[Ralph Moore]

Thanks Cooch, your probably right about the cold, I turned the heat off in my shop a couple weeks ago( no longer freezing), but it's about 45 degrees in there now, unless I build a fire.

[4ford]

just did the sync and seems to run ok. the linkage sucks its from speedway and has cotter keys I the ends and feels tight. any one have a different source of a better one its a solid linkage....

[flatjack9]

The linkage isn't the greatest. I've had to open up the slots to make them work or they bind on the carb levers.

[PeterC]

My setup is solid linkage with single active choke and one locked choke plate front - carbs are 48's. starts great when cold and runs very nice throughout the spectrum of demands. Fuel line is old school as noted in the picture.

[4ford]

look at the air cleaner set up. here's the linkage I have...not so good... the air cleaners seem to work well.. like to find better linkage. question on the driver side of the carbs there's levers for throdell rods can you hook up linkage there also?

thanks

[scicala]

"It's not a good idea to remove your choke plate, even if you don't use the choke. Air flow studies have shown that these carbs flow less with the choke plates removed"



I worked 12 years on carburetor development and flow box work. I would love to witness that test or do it my self in order to believe it. Right now I don't.
The same air flow...., maybe. Less, I don't believe.

Sal

[4ford]

sal.
just taking some advice from some of the guys out there... kind of a backyard why of doing it. but there seems to be no difference with or with out the cleaners on??

[scicala]

4ford,

I've never done any flow box work with and without air cleaners. I would imagine most of the smaller air cleaners (dual and tri power type) are pretty restrictive. Especially the $10 ones you see. Would stay away from those all together. Use the taller ones with more filter area. It's hard to say about larger more quality type air cleaners. I would say on a flathead there would be very little or no restriction with a large air cleaner, especially the K&N type filters.

Sal

[4ford]

its two filters put together and one is K&N wanted to see if it was working first b 4 getting 4 of them

[Walt Dupont--Me.]

I'm running 4 - 97's on my 276 in a 40 coupe. Direct linkage, I got the ball bearing linkage from Uncle Max, it works good, Walt

[estout81]

Here's how I did mine.

[Terry,OH]

Mine are Stromberg's and not Holley's. Yes, only the linkage tying the two Carb.s together is on the drivers side, the rest is on the passenger side. I believe, with the Holley's the throttle shafts are not long enough on the drivers side so some replace the shafts with extended length shafts. I am not recommending any place but "Vintage speed" web site has photos as well as the Stromberg web site, if your looking for ideas on the linkage.

[4ford]

thanks Walt!!! and thanks again for all your help on this rebuild you helped a lot!!

mike