Whos running 4 carbs on a Flatty?

Well, that is what I was worried about since 1 carb is directly feeding 2 cylinders. Would a multi-carb synchronizer be a good investment then? If it turns out to be more than I can handle, I'm looking at an original Navarro 3 deuce for next to nothing...

 

No info but here's a picture I took when I was 12.......

 

You'll definitely need a "Uni-Syn" or similar device - on any multi-carbed setup.

Keep in mind, all they really do is enable you to hopefully get the air volume the same, they know nothing about fuel. I'd rebuild the carbs and maybe even replace all the emulsion tubes, jets, and the accel-pump valve with all new stuff from the same manufacturer (thank gosh for new 97 parts!). I'd also rework the bases with the same oversize throttle shafts, new plates, etc.. Try to get everything the same.

If you can pickup a 3-deuce Navarro . . . I'd do that for insurance. It not - I'd sure love to have it!

Dale

 

Good luck with your quest. I set up a Man-a-fre back in the 70's. Same deal...1 carb for 2 cylinders with no plenum. It takes some serious time to get them balanced and idling nicely. I got them to work...OK but they don't work well on the street.

They sure look good but there is a reason you don't see them on the street in the real world. To work right each carb needs to be adjusted to one fourth of what they were designed to work at. Carbs need air velocity to work right. The engineers designed the carb for a given C.I. and air velocity. When you devide that by 4 things don't work the same way on the street any more. The 4 carb manifolds were made for WOT racing. Plenty of air velocity at WOT. They don't have intersections at Bonneville. They don't have to worry about sitting at a light.

I don't want to rain on your parade but you are in for a real PITA. You might get it to work with the smaller 81s...they use 2 of them on the 4 bangers but 4 corner 97's will really be tough.

The inline type can be set up for progressive linkage or 2 of them can be blocked off in a way that can't be detected with the eye.

Good luck with your quest. If you get it to idle and perform in a streetable way please do a U tube for us to enjoy.



I bought this syncronizer to set up the Man-a-fre. All 8 idle mixture screw and all 4 idle speed screws will change the idle every time each one is adjusted just a tad which means that all the other 11 screws now need to be readjusted...etc. etc. etc. Race cars don't worry too much about idling. They tune for WOT. All this****umes you really want to drive the car.

I don't want to be negative. Just some real world experience. I was going to have the baddest 62 Corvette on the east coast. I ended up driving it with a Carter AFB.

 

Not running it,but i got one.......

 

Sorry wrong pics,
these might be better ?

 

Hey Tommy,

Do you know if these are still available?

Danny

 

Yeah I think so. Try a Google.

 

I run 4 97's on a 59ab. Drove a lot of miles on it this year. Also spent a lot of time soldering and orifice drilling the jets because I couldn't find small enough ones. Had to play with idle tubes as well. Here's pix

 

Hello...Here is a way to run four 97s with progressive linkage..somebody said you need to put oversize throttle shaft in the bases of 97s..why....How can a brass shaft wear cast iron?????? Correct about all the jets, emulsion tubes, idle jets,should be the same..Most important don't starve your 97s for air with fansy(sp) air cleaners..Put a screen over the top of the air horn and leave the choke plate in to direct the air..
..Duane

 

Hi Mate,

Was this strictly for the looks value with that set up? I'm thinking that trying to shoe horn two carbs worth of air/fuel through the opening designed for one wouldn't be the best performance wise. Or is it the carbs that are the restriction , not the passge (ie. in a stock 2x2 the 97 will run out of air/fuel before the opening for the carb reaches its limit flow wise?)

Danny

 

Mine ran better with 97s .I first ran it with 81s.When my kid comes home from school I will post pics.

 

Hello...Why would it be just for looks value?????How did the slingshots work, just fine..The Y's has been indexed to match the venturies of the 97s the intake is indexed to match the Ys and the intake is indexed and slight ported to match the block..
It is progressive linkage and the secondaries will not make the engine run rich..Again, What goes in must come out..need good headers..
Enjoy..
Duane

 

one carb for every two cylinders? sounds overkill to me

 

Hi Mate,

What I'm interested in is finding out where the bottle neck performance wise is on a common intake/induction set up. If a sling shot works, then it must be the carb that gives out before the ability of the intake passage to flow more air/fuel. My concern I guess, was that with a dual intake design like your running, at WOT the intake may only be able to channel two carbs worth one carb running at 100% for each passge you have two running at 50% each).

Danny

 

I'm with you, Danny.

I'd believe the intak becomes the bottleneck - even if it wasn't before with only 1 carb...

 

It does, regularly, I have been restoring carbs, for 34 years and have found this is the most common problem with all brands of carbs it's not just 94s and 97s.
Soft metals will wear when rubbed against a harder metal, but the hard metal will wear too and the abraisive particles soaked in oil and gas make a great grinding compound in carbs.
When you cant get a car to idle no matter what you do, check the throttle shaft and base for wear.
I bore out and teflon bush nearly all carbs and put in a new standard size shaft , exceptions are carbs that cannot be bushed or those which already have bushes.
In fact carbs with steel shafts in alloy bases wear less than brass in cast iron , over strength throttle return springs, compound the problem.

 

The original Synchrometer is made/distributed in USA by Redline, they are originally a Weber carb tool .
The Aussie distributor is Hardimans


Victoria distributor is
E.T Performance.


I think the Weber Carb Shop on Burwood Highway at Vermont
probably has them.

You could always make yourself a balance tool with a set of homemade water or oil manometers.....one for each carb . They are much more accurate than anything else, and only cost a few bucks.

 

Thanks mate,

Whats the proceedure for the water /oil manometers?

Danny

 

I have tried to write this a couple of times . It takes too long to describe it properly for V8 multi carb applications. here and I don't have any pics. Here is how it is built but it won't work properly on a V8 as it's use is described here. There are a couple of other parts that need to be made .
I will sort it out, get the pics and email it to you, I suppose I could possibly make a tech post .

There is another way to balance carbs which is even simpler, it's the way it was done "back in the day " by all the old carb tuners, and is every bit as accurate as any instrument.
It takes practise and a good ear .
You put one end of a piece of plastic tube in your ear and use the other end to listen to the inside of the carbs at idle. One carb at a time and adjust the idle speed screws to give even sound. When the*****ing sound is the same in all the carbs the idle is balanced.

 

Here is a post that may help. The last post has a link to someone selling the tool.

PS the inline manifolds are more forgiving. I was driving it like this(as purchased). It wouldn't run near as nice on the manifold in question.

 

my bro detroitdraggin is running 4 carbs on his flatty. took a little tuning and patience but the car runs awesome! there is a vid or two on youtube........


http://www.youtube.com/watch?v=qr610QyLTL0

http://www.youtube.com/watch?v=NlpL971rnW4

Steve

 

One helpful way to tune 4 carbs is to put a stock intake on a motor and do a quick setting on each carb running seperatley on the motor. After you tune 1 at a time you may have a better starting point. I was also thinking that there are those devices where you point it at an object and it tells you the tempature, I wonder if one of those would help by keeping track of tempatures of two cylinders at a time. If you see bigger differences between certain cylinders this may direct you to fine tune that corner a bit. I have never tried that way so I have no idea if the tempature reader will work. And if it does it wil only work on intakes like this. E & S also made a 4 carb staggered intake.

 

DAMN! got enough intakes???