TheSamba.com :: View topic - Alternative carburetor for 34-PICT

Sat Apr 24, 2010 8:27 am

I'm looking to totally replace my Solex 34-PICT that has bad throttle bushings with a "inexpensive" carburetor where I can remove my 34-PICT and bolt on the new carburetor with near zero modifications. A carburetor other than the Bocar. Something like a Weber or Holley. I would like to have a choke, but if not, a chokeless carburetor that doesn't take 10 minutes to warm up in cold weather. If there is an inexpensive 2 barrel, that would be nice too. I have a dual port 1600cc with manifold heat risers. Any input would be greatly appreciated. Please, no dual carb setup suggestions. Thanks! :D

Sat Apr 24, 2010 10:01 am

Why no dual carbs?much more efficient than a single two barrel...

Sat Apr 24, 2010 10:22 am

johnnypan wrote: Why no dual carbs?much more efficient than a single two barrel...

I may have to do this. Can I run a SVDA distributor with dual carbs, or do I have to use an 009.

Sat Apr 24, 2010 10:25 am

Most dual carbs perform better with a SVDA, but they need to be properly tapped for ported vacuum. Most new ones already are.

What dual carbs are you running or intend to run?

Sat Apr 24, 2010 10:27 am

I notice on the back of the Weber dual carbs there is a vacuum port. Can an SVDA be hooked up to one of these ports? Otherwise, changing over to duals is pretty simple. I have a synchrometer and know how to balance duals pretty well.

Sat Apr 24, 2010 10:29 am

Randy in Maine wrote: Most dual carbs perform better with a SVDA, but they need to be properly tapped for ported vacuum. Most new ones already are.

What dual carbs are you running or intend to run?

I think I can a used set of Weber duals from a friend of mine and they are 31's. Approximately a year and a half old.

Sat Apr 24, 2010 1:12 pm

RobbyK wrote: Randy in Maine wrote: Most dual carbs perform better with a SVDA, but they need to be properly tapped for ported vacuum. Most new ones already are.

What dual carbs are you running or intend to run?

I think I can a used set of Weber duals from a friend of mine and they are 31's. Approximately a year and a half old.

I run my distributor vacuum off of the left intake manifold...no problem... if you run a balance tub between the carbs you can take it there as well.An easy way to see your distributor advance is ok (besides driveability) is to slowly rev your engine with the timing light hooked up,the timing mark should go up with the engine rpms graudually and smoothly.The power and "seat of the pants"improvement from dual carbs is the best bang for the buck for a stock engine

Sat Apr 24, 2010 5:23 pm

johnnypan wrote: RobbyK wrote: Randy in Maine wrote: Most dual carbs perform better with a SVDA, but they need to be properly tapped for ported vacuum. Most new ones already are.

What dual carbs are you running or intend to run?

I think I can a used set of Weber duals from a friend of mine and they are 31's. Approximately a year and a half old.

I run my distributor vacuum off of the left intake manifold...no problem... if you run a balance tub between the carbs you can take it there as well.An easy way to see your distributor advance is ok (besides driveability) is to slowly rev your engine with the timing light hooked up,the timing mark should go up with the engine rpms graudually and smoothly.The power and "seat of the pants"improvement from dual carbs is the best bang for the buck for a stock engine

The balance tube can run between the carbs? It doesn't run between the manifolds? If the manifolds have vacuum tubes on them? This is a great thing to know that I could run a balance tube between the carbs.

Sat Apr 24, 2010 5:42 pm

johnnypan wrote:
I run my distributor vacuum off of the left intake manifold...no problem... if you run a balance tub between the carbs you can take it there as well.An easy way to see your distributor advance is ok (besides driveability) is to slowly rev your engine with the timing light hooked up,the timing mark should go up with the engine rpms graudually and smoothly.The power and "seat of the pants"improvement from dual carbs is the best bang for the buck for a stock engine

you do realise the massive problem with that dont you?

proper ports on a carb for a vac advance are tied into the progression ports ABOVE the throttle plate
that way the advance only works when its needed, ie cracking the throttle under load

having it connected below the throttle plate means it will see vacuum all the time but most of concern is when engine braking down hill the manifold vacuum is the highest you will see as the throttles shut
so the engine would get full advance under that condition when it really needs 0 vacuum advance, only what the mechanical provides (on an SVDA dist anyway)

Glenn will be able to straighten you out on that one

Sat Apr 24, 2010 5:45 pm

30/31 pict carb.

Sat Apr 24, 2010 5:50 pm

the balance tube,which is basically a vacuum line run between both manifolds equalizes the vacuum to allow for a smooth idle...carbs synchronized correctly can run without them. Randys point about vacuum signal is valid,a good clear vacuum from below the throttle body is necessary for proper SVDA function..but dont let this stop you...

Sat Apr 24, 2010 7:27 pm

Buggin_74 wrote: johnnypan wrote:
I run my distributor vacuum off of the left intake manifold...no problem... if you run a balance tub between the carbs you can take it there as well.An easy way to see your distributor advance is ok (besides driveability) is to slowly rev your engine with the timing light hooked up,the timing mark should go up with the engine rpms graudually and smoothly.The power and "seat of the pants"improvement from dual carbs is the best bang for the buck for a stock engine

you do realise the massive problem with that dont you?

proper ports on a carb for a vac advance are tied into the progression ports ABOVE the throttle plate
that way the advance only works when its needed, ie cracking the throttle under load

having it connected below the throttle plate means it will see vacuum all the time but most of concern is when engine braking down hill the manifold vacuum is the highest you will see as the throttles shut
so the engine would get full advance under that condition when it really needs 0 vacuum advance, only what the mechanical provides (on an SVDA dist anyway)

Glenn will be able to straighten you out on that one

So are you saying the vacuum ports on the dual carburetors is tied in above the throttle plates? I think that is what you are saying.

Sat Apr 24, 2010 7:28 pm

perrib wrote: 30/31 pict carb.

Perrib, what do mean by your comment? Thanks.

Sat Apr 24, 2010 10:53 pm

Install a Solex 30/31 carb. At one time they came with an adapter plate to replace the Solex 34 pict. There are two Samba members who will rebuild either Solex (yours or one of theirs) to new condition sometimes better than new. One is Mharney and the other someone else will have to chime in as his name eludes me at this time.

Sun Apr 25, 2010 8:39 am

Buggin_74 wrote: johnnypan wrote:
I run my distributor vacuum off of the left intake manifold...no problem... if you run a balance tub between the carbs you can take it there as well.An easy way to see your distributor advance is ok (besides driveability) is to slowly rev your engine with the timing light hooked up,the timing mark should go up with the engine rpms graudually and smoothly.The power and "seat of the pants"improvement from dual carbs is the best bang for the buck for a stock engine

you do realise the massive problem with that dont you?

proper ports on a carb for a vac advance are tied into the progression ports ABOVE the throttle plate
that way the advance only works when its needed, ie cracking the throttle under load

having it connected below the throttle plate means it will see vacuum all the time but most of concern is when engine braking down hill the manifold vacuum is the highest you will see as the throttles shut
so the engine would get full advance under that condition when it really needs 0 vacuum advance, only what the mechanical provides (on an SVDA dist anyway)

Glenn will be able to straighten you out on that one

Good point.. never made the connection for vacuum retarding on deceleration will try it..imagine it helps with engine braking and a cleaner burn....

Sun Apr 25, 2010 2:28 pm

RobbyK wrote: I'm looking to totally replace my Solex 34-PICT that has bad throttle bushings with a "inexpensive" carburetor where I can remove my 34-PICT and bolt on the new carburetor with near zero modifications. A carburetor other than the Bocar. Something like a Weber or Holley. I would like to have a choke, but if not, a chokeless carburetor that doesn't take 10 minutes to warm up in cold weather. If there is an inexpensive 2 barrel, that would be nice too. I have a dual port 1600cc with manifold heat risers. Any input would be greatly appreciated. Please, no dual carb setup suggestions. Thanks! :D
Why do you want to replace your solex carb with something different? There is no such thing as a carb that just bolts on and works. They ALL need to be adjusted and dialed in to work properly.

Your original Solex is a high quality carb. Why would you want to replace it with something that is probably cheaper and lower quality? This makes no sense. If your original Solex is worn out, just have it rebuilt. http://www.krustykarbsrestoration.com/

Also, why all this talk about going to dual carbs if you are so sensitive to cost? Dual carbs are not inexpensive at all.

Mon Apr 26, 2010 4:51 am

RobbyK wrote: Buggin_74 wrote: johnnypan wrote:
I run my distributor vacuum off of the left intake manifold...no problem... if you run a balance tub between the carbs you can take it there as well.An easy way to see your distributor advance is ok (besides driveability) is to slowly rev your engine with the timing light hooked up,the timing mark should go up with the engine rpms graudually and smoothly.The power and "seat of the pants"improvement from dual carbs is the best bang for the buck for a stock engine

you do realise the massive problem with that dont you?

proper ports on a carb for a vac advance are tied into the progression ports ABOVE the throttle plate
that way the advance only works when its needed, ie cracking the throttle under load

having it connected below the throttle plate means it will see vacuum all the time but most of concern is when engine braking down hill the manifold vacuum is the highest you will see as the throttles shut
so the engine would get full advance under that condition when it really needs 0 vacuum advance, only what the mechanical provides (on an SVDA dist anyway)

Glenn will be able to straighten you out on that one

So are you saying the vacuum ports on the dual carburetors is tied in above the throttle plates? I think that is what you are saying.

when running a vac advance dist with duel carbs you only need the vac signal from one carb, but wherever it comes from it has to be above the throttle plate so it only gets vacuum under engine load

but if your talking about the balance pipe between the carbs then no those are just between the manifolds, below the carbs

Mon Apr 26, 2010 5:34 am

perrib wrote: Install a Solex 30/31 carb. At one time they came with an adapter plate to replace the Solex 34 pict. There are two Samba members who will rebuild either Solex (yours or one of theirs) to new condition sometimes better than new. One is Mharney and the other someone else will have to chime in as his name eludes me at this time.

The other is Kiefernet, I believe.

Tue Apr 27, 2010 5:13 am

Hey all, I appreciate your feedback & didn't want to post again until I lined up all my ducks and decided what to do.

I am going to a set of Weber 34 PICT duals (same set I had on prior to going to a PICT-34 Solex). My manifolds don't have vacuum ports & I was running these type duals without manifold ports before. Is it necessary to have the port on each manifold, then run a balance tube linking the ports? I would have to drill out the manifolds to install a port, which isn't a big deal, but what size thread should I make it and what ID port fitting? Reason I ask is because I want to run my SVDA distributor with these duals and I know I need to plug into the left carb vacuum fitting at the bottom. Any input is greatly appreciated.

Tue Apr 27, 2010 6:25 am

perrib wrote: Install a Solex 30/31 carb. At one time they came with an adapter plate to replace the Solex 34 pict. There are two Samba members who will rebuild either Solex (yours or one of theirs) to new condition sometimes better than new. One is Mharney and the other someone else will have to chime in as his name eludes me at this time.

Mharney is no longer doing it. Your other options are as above.