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Dual SOLEX carbs on a 230 flat six?


papajohn

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I've never used a flow meter to sync carbs, but I've always had good luck so it seems. Also have dual carbs on my BMW motorcycle, and I seem to get them on through sound, feel, and perhaps a little voodoo or ju-ju something. !!! But normally I can find the sweet spot.

 

My vacuum meters come off the manifold, just below each carb, and will show a difference if they are way off. My distributor vacuum advance line comes off the manifold, from a port that is equally between the two carbs. I did play around with them (gauge lines) on the carb ports, but I don't remember how they behaved. I don't think that worked well, and taking them off the manifold, just below the carb seems to work best, for me. I guess that my reason is that if the engine started running badly, I'll know which carb to start trouble shooting. And they look pretty neat waving back and forth in perfect harmony. :)

 

One of my many springs goes to one of my chokes. For starting when it's somewhat cold, or colder, I usually pull that one full on, then the other one about halfway. When it starts, then the spring and the airflow kind of automatically opens it again. But don't ask me why, it just worked out that way. When it is halfway warm or warmer, I just use one choke, and generally speaking Lumpy doesn't like a lot of choke. Once the car is warmed up, I just look at the starter button, and she fires. Well....just about! I guess my choke system comes under the heading of: "why keep it simple, when it's so easy to make it complicated"?

 

ken.

Edited by Lumpy
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Yes, good question. Now just in my opinion, I don't think a flow meter is absolutely required. However, it would be interesting to try it, and see. But again, maybe I can't, but I believe I can sync carbs pretty good....

I could run my vacuum advance line to a carb port, but engines can be pretty individualistic as to how they like their advance curve, when it drops out or in, etc. So...I don't know. Just from experimentation, coming off the manifold seems to be where this engine likes it. I have found over the years that one specific type of engine will vary quite a bit as far as how much total advance it likes....such as the small block Mopar V8, or which I've had many.

 

I also know from my drag racing days, that sometimes when an engine feels like it's running good, you find out differently when you go through the traps. I think my engine runs close to perfect, whatever that is. She's smooth and puts out lots of power, in L6 terms.

 

Just some thoughts, and I value everyone's opinion. I love brainstorming on this stuff, and one never knows when one is wrong, I try to keep my mind open to that.

 

Okay...g'night all.

 

k.

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  • 1 year later...

Believe it or not, those aren't studs and bolts, those are bolts which have threads in the bolt heads. ?? That's what was on the engine when I got it. That is actually a Chrysler ACE marine engine, so maybe that has something to do with it. ?? The engine was found in a warehouse in Pullman Washington, someone had ordered it for a boat, perhaps an old Chris Craft or something, and never paid up. Then it found it's way into Lumpy.

I promise I would never run short studs on an engine.

So...??

ken.

PULLMAN, Wa, That's my neck of the woods.  By the way, a lot of times those double headed studs are used for mounting spray shields or shrouds, not sure if that is the reasoning for your application.  I just got a Shanafelt Dual intake with two carbs mounted on it for my 48 this past weekend at the Portland Swap Meet via a friend who was looking out for me. 

Edited by mlozier76
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I've used the Uni-syn device to do a dual carb tune & I found having 2 helped, and it also helped to have an assistant, (& a pair of short "stacks" to raise them, if your air horn has a bolt in the middle.) To do my VW with twin Solex carbs I used to use tomato sauce cans with the ends removed & some gasket foam on the ends. Tiny air leaks will goof the readings, so however you fit it up, get it to seal. With a dual Weber (de Brazil') carb set I didn't need the cans, as they have a horn like the B&B.

 

It's harder to balance a multi-carb engine with these but I've used a bank of ported vacuum gages to do 2, 3, & 4-carb engines & that usually works better (especially for sidedrafts, though the Uni-syn works with a sidedraft too.)

 

The thing is that you want to see how the other carbs react too, when you twiddle the mix on the carb with the Uni-syn on it, (though the difference may not be so evident on log-manifold or plenum setups as a straight side-draft setup.) With only one device you can tell something but IMO you can't tell enough.

 

Say you have a 4-carb setup: If you see carb 1 gets a different reaction than carb 2, when you twiddle carb 3, but carb 4 gets the same reaction as 1 & 3, then you know something's up with cyl 2.

 

BTW, I thought those Brazilian Webers were real good carbs, and 2 of them would supply a 100 HP+ VW engine. All the jets were removable, so tuning was very flexible. Mine did not leak like the Solex carbs did.
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