two carb setup

[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