little67stang
New member
There is a line that runs between the two, it has vacuum from the carb but why? ???Fuel economy??? what would happen if I took it off and capped the holes?
Carb to exhaust manifold?
- Thread starter little67stang
- Start date
It's an auto choke heat tube. Where this passes through the exhaust it is supposed to be sealed against exhaust gases, and just drawing air. Many corrode open to the exhaust, causing damage to the carb as hot gases are drawn in.
If you plan to keep the automatic choke, make sure this is working to spec.
If you plan to keep the automatic choke, make sure this is working to spec.
little67stang
New member
Not even Chiltons could tell me what it was!
little67stang
New member
These are a couple pics of the attachment points, how would you get a seal on the exhaust manifold? The previous owner just had the tube ground down and shoved in the hole. The carb is easy! EXCEPT the threads are bent, cracked and stripped ! Thanx in advance!
The exhaust manifold would have originally had a small part, a recepticle of sorts for the end of the pipe.
There is a "HELP" kit made by Motormite to repair these things:
http://www.partsamerica.com/ProductDeta ... yCode=3111
This one is for a header, but there is more than one type of kit.
Tried to find a link with a good picture...
They come with new fittings and tube.
There is a "HELP" kit made by Motormite to repair these things:
http://www.partsamerica.com/ProductDeta ... yCode=3111
This one is for a header, but there is more than one type of kit.
Tried to find a link with a good picture...
They come with new fittings and tube.
My favourite version of this setup is as found on the 289s and such.
Filtered air is drawn from inside the air cleaner housing (or upper flange of the carb) down one tube, through the exhaust manifold passage (English name I know it by is "stove pipe") and back into the auto choke housing. The tubes must be reasonable gauge plated steel to last any duration.
I don't like the open-ended (albeit crimped for a controlled leak) type as airflow is less - possibly increasing the fussiness of choke settings - and the risk of dust getting in, somewhat greater. Wrapping a tube several times around the exhaust manifold is possibly the easiest fix.
Regards, Adam.
Filtered air is drawn from inside the air cleaner housing (or upper flange of the carb) down one tube, through the exhaust manifold passage (English name I know it by is "stove pipe") and back into the auto choke housing. The tubes must be reasonable gauge plated steel to last any duration.
I don't like the open-ended (albeit crimped for a controlled leak) type as airflow is less - possibly increasing the fussiness of choke settings - and the risk of dust getting in, somewhat greater. Wrapping a tube several times around the exhaust manifold is possibly the easiest fix.
Regards, Adam.
little67stang
New member
Found this from your recomendation, thanx
http://www.metropartsmarket.com/catalog ... _4446.html
The V8 version does seem like a better idea though.
http://www.metropartsmarket.com/catalog ... _4446.html
The V8 version does seem like a better idea though.
well, from the pics, that's a 1940 holley, which I had 1 on my car ( '67 200 ) but I never had a choke tube, and altho it took a while for the choke to pull off, it did work. the coil just has to get warm inside the choke, dosn't need the choke tube to get it warm, just gets it warm faster
I used to run a 1940 carb on my car, loved that carb. It ran like a champ! Liked it better than the 1100
The choke is controlled by a bi-metalic spring. As warm/hot air is drawn thru the choke tube and thru the housing the spring will "unwind" and cause the choke flap to open. Without the flow of warm/hot air the choke flap will stay closed causing the car to run rich, which wastes gas and make the car perform slugishly. The end of the tube is stuck down the hole so it will not draw in dirt, plus it helps in heat transfer. When I rebuilt my 1940 there was dirt and sand and stuff plugging the passages in the carb, and especially the small cut out in the manifold pad. The tube end needs to be open so air can be drawn thru.
I also found out (the hard way) that the insulation is needed around the tube. If not used, the heated air going up the tube is cooled by the air flow from the fan or driving, and it again delays the opening of the choke.
The choke is controlled by a bi-metalic spring. As warm/hot air is drawn thru the choke tube and thru the housing the spring will "unwind" and cause the choke flap to open. Without the flow of warm/hot air the choke flap will stay closed causing the car to run rich, which wastes gas and make the car perform slugishly. The end of the tube is stuck down the hole so it will not draw in dirt, plus it helps in heat transfer. When I rebuilt my 1940 there was dirt and sand and stuff plugging the passages in the carb, and especially the small cut out in the manifold pad. The tube end needs to be open so air can be drawn thru.
I also found out (the hard way) that the insulation is needed around the tube. If not used, the heated air going up the tube is cooled by the air flow from the fan or driving, and it again delays the opening of the choke.
little67stang
New member
What type of carb that was.
But how can you tell?
But how can you tell?
. Or just ask here! 
.little67stang":7hjqw859 said:What type of carb that was.
But how can you tell?
that is a 1940 holley. if you look around on it, you will see HOLLEY stamped into the side the exhaust manifold is on, right on the float bowl. mine didn't have numbers on it, NAPA had to X refrence it as the replacement carb, for me to get a rebuild kit ( if you need to rebuild at any time, Napa part # 2-5743 and the float is 2-449 )
little67stang
New member
It's always good to know what you got and the numbers will help alot. Most parts stores around seem a little unwilling to help, or they tell you the wrong thing.
