Tips for tuning dual Carbs?

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Ken_B

Ken_B

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Just about finished buttoning up the install of a new to me /6 in my Valiant along with an Offenhauser dual 1bbl intake, Ive played with carbs before so they arent completly foreign to me but this is a whole nother bal game. The carbs themselves are identical brand new Daytona 1bbls, an improved ethanol resistant autolite 1100 design supposedly. So I guess my question is, anybody have any advice on where to start with tuning/syncing these things? Tips? Tricks? Etc...? Thanks!
 
get a motorcycle sycronizer gauge set up /or just play with everything a little at a time until you are happy.
 
If it will fit the carburetors, these work very well. I had one when I had my Triumph Spitfire years ago. Works like a charm.

[ame="http://www.ebay.com/itm/Uni-Syn-Carburetor-Synchronizer-Carb-Synchronizing-Balancing-Tool-/331265092831?pt=Motors_Car_Truck_Parts_Accessories&hash=item4d20f02cdf&vxp=mtr"]Uni Syn Carburetor Synchronizer Carb Synchronizing Balancing Tool | eBay[/ame]
 
You can MAKE a manomemeter. The reason you need something like the old uni-syn device is for carbs that don't have individual vacuum ports which isolate vacuum from one to the other

Here.......

Down at the bottom, 'uni-syn instructions'

http://www.aircoolednut.com/erkson/ttt/engine/carbs/

Here

http://www.aircoolednut.com/erkson/ttt/engine/carbs/uni-syn-1.jpg

and

http://www.aircoolednut.com/erkson/ttt/engine/carbs/uni-syn-2.jpg

You can get pretty close by carefully LISTENING to each carb, if necessary use a length of scrap hose as a stethoscope
 
I have used the uni-syn to adjust dual 2 barrels on a 4 cylinder bug motor. You first want to get all the idle stops set the same. That can be done by going equal amount on throttle stop screw from fully closed. Then make sure the linkages are corrrect such that all return to stops at the same time and open fully at WOT. All this assumes the the throttle plates are correctly aligned on each carb. The best way for me to do that is look how light leaks around the bore, throttle closed.

On the Dellortor carbs there is an air volume screw that controls air bypass of the throttle. Use uni-syn and tweek those to give equal readings on each bore. In your case slight tweeks to idle speed, then re-tweek linkages..... repeat till all is well.
 
a long time ago. i helped a guy with a early hemi with duel carbs. it would not come off of idle. the trouble was that the connection from one carb to the other carb was sloppy. just be sure the carbs have a good tight connections. and reach wide open together.
 
Have a nice tight linkage setup, came with the manifold. Definitely a long way from where I want to be but I was able to take the car for a drive tonight! :burnout:
 
Something I was going to mention, then forgot...............this IS a simultaneous dual carb setup, as opposed to progressive?


If progressive, you don't NEED to really sync them.
 
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