carter bbs float adjustment

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Slantsix64

Slantsix64

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Was wondering what your guys float levels are on your carter bbs i currently have mine to 7/32 i was messing with it the other day and set it lower due to my car running at 180 degrees instead of the 195 degree that's installed in my thermostat finally my car would reach 195 degrees and run a lot smoother has anyone ever had this problem or any ideas? would running the float level a little leaner be bad in the long run? Could this because of too much advance on my distributor that i have to mess with the float?
 
That must be the oddest thing I ever read.

While a lower than normal float level setting,will affect the A/F slightly, at idle, it's common to just, adjust the Mixture screws a little richer to compensate. Cuz if you don't, the engine will idle crappy. But if it doesn't idle crappy then the screws were probably too rich in the first place.
Then theres the main and power circuits; These circuits are probably the least affected by a slightly reduced float level.
And the Transition circuit. This circuit is likely the most affected. If the level gets too low, you will introduce driveability issues ;such as hesitation on tip-in, perhaps a bog, or poor transition between circuits.

Now, I have no idea where SGV is, or what your altitude is there. But the thing is this; if your altitude is different than what the carb was calibrated for, then a float-level tweak may actually be beneficial to your engine.
And the clincher; changing the float level should have absolutely nothing to do with the minimum engine running temperature. That is the job of the stat.
However;If the float level was very much too high, I suppose it could be possible for fuel to get into the engine elsewhere than through the proper circuits. If this happened, then the extra fuel will, for sure, suck heat out of the chambers. It will also cause; a poor idle, a lazy engine, cylinder wash, terrible fuel mileage, an ever increasing "oil" level as the gas ends up in the pan, and makes-your-eyes-water exhaust stink.
Finally; just as retarded timing can put heat into the exhaust pipe, due to the charge continuing to burn there, an over-advanced timing can put extra heat into the cooling system, due to the extra work being done trying to compress an already expanding charge.
Bottom-line is this; it's a poor practice to try and control cooling system temperature with float level changes.
My experience with my slanties has been that they naturally run cool. A new stat may not run at its advertised temp. They have a fairly broad working range. And you can't mod them. You may have to buy several and boiling-water test them. Do not let them fall to the bottom of the pot during testing, to sit there next to the heating element. Stants are usually pretty good.
And, of course, timing. Give that baby what she wants. Idle timing, Power timing, Rate of advance, and most especially the vacuum advance. Oh, and make sure the valve lash is adequate. A tight lash will make a rough idle.
 
I agree w/ post #2. I would get an IR gun (cheap at HF) to verify temperatures and useful on many cars. Mine gives good agreement w/ the dash gage in my M-B and the T-stat stamp. Of course, Dart dash gages have no numbers on the tics.

In this day, it is simpler in the long run and much better to install an O2 sensor in the exhaust to determine rich/lean, so at least have a bung welded in when re-doing the exhaust or if you have the pipe off. I put two bungs in my cars so I can install a wideband O2, plus a regular on/off to verify calibration of the wideband. To get started, you can get a cheap rich/lean indicator (~$20 used ebay). Widebands are dropping greatly in price, so can screw one in the same hole later. Much better than trying to judge from viewing spark plug tips, over-heating, max vacuum, etc. I wouldn't try tuning a carb today without one.
 
I just rebuilt my BBS last Sunday while watching the Browns game. That way I didn't feel guilty about wasting time on the Browns.

Anyway, I set mine to spec at 1/4". It will be awhile til the mighty 225 is running so I don't have results.

I was thinking about it later, here I am setting up a carb with a ruler doing the best I can bending linkage rods, tabs, whatever, and a modern F.I system does that automatically and can vary it hundreds of times every minute.
Talk about driving a horse and buggy....
 
AJ/FormS said:
That must be the oddest thing I ever read.

While a lower than normal float level setting,will affect the A/F slightly, at idle, it's common to just, adjust the Mixture screws a little richer to compensate. Cuz if you don't, the engine will idle crappy. But if it doesn't idle crappy then the screws were probably too rich in the first place.
Then theres the main and power circuits; These circuits are probably the least affected by a slightly reduced float level.
And the Transition circuit. This circuit is likely the most affected. If the level gets too low, you will introduce driveability issues ;such as hesitation on tip-in, perhaps a bog, or poor transition between circuits.

Now, I have no idea where SGV is, or what your altitude is there. But the thing is this; if your altitude is different than what the carb was calibrated for, then a float-level tweak may actually be beneficial to your engine.
And the clincher; changing the float level should have absolutely nothing to do with the minimum engine running temperature. That is the job of the stat.
However;If the float level was very much too high, I suppose it could be possible for fuel to get into the engine elsewhere than through the proper circuits. If this happened, then the extra fuel will, for sure, suck heat out of the chambers. It will also cause; a poor idle, a lazy engine, cylinder wash, terrible fuel mileage, an ever increasing "oil" level as the gas ends up in the pan, and makes-your-eyes-water exhaust stink.
Finally; just as retarded timing can put heat into the exhaust pipe, due to the charge continuing to burn there, an over-advanced timing can put extra heat into the cooling system, due to the extra work being done trying to compress an already expanding charge.
Bottom-line is this; it's a poor practice to try and control cooling system temperature with float level changes.
My experience with my slanties has been that they naturally run cool. A new stat may not run at its advertised temp. They have a fairly broad working range. And you can't mod them. You may have to buy several and boiling-water test them. Do not let them fall to the bottom of the pot during testing, to sit there next to the heating element. Stants are usually pretty good.
And, of course, timing. Give that baby what she wants. Idle timing, Power timing, Rate of advance, and most especially the vacuum advance. Oh, and make sure the valve lash is adequate. A tight lash will make a rough idle.
Click to expand...

thanks for your reply yes it is very odd when i have the float set to 7/32 the car will idle a little rough and i can smell carb stink and motor is very poor at acceleration but when i set the float a little lower at say 3/8 i would get better throttle response and a very smooth idling engine. my car would not have those hard starts and would be properly warmed up thats what i did not understand at all.
 
my 1967 dart, charger factory service manual. shows the BBS carb float level to be 1/4 inch. except the taxi to be 9/32. and the 2 bbl BBD to be 1/4 inch. i have had and worked on the BBD a lot and never found it needed to set it any different.
 
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