The Stovebolt Site Forums The Shop Area Engine Shop What's this port? Auto Choke Rochester Carb

I 'm just continuing the assembly of my rebuilt 235 and have a question about this port on my Rochester Carb's Auto Choke. Is it another vacuum advance port for the Distributor? There is already a vacuum port at the bottom of the carb. If it's not also a vacuum port, what's it for?
http://i1236.photobucket.com/albums/ff441/AZ59apacheguy/IMG_0995-1.jpg

It looks like a fitting for a heater tube that runs from the automatic choke to a "stove" on the intake manifold. Maybe someone who is familiar with heated thermostats will confirm or correct this.

Hy AZ59apacheguy, the top port in your picture is the hot air tube connection for the automatic choke, the bottom port in your picture is your fuel inlet port. The hot air tube is a 1/4" tube which fits into a hole in a piece of light gauge steel which surrounds the exhaust manifold (sometimes these are deteriorated and missing) Hot air is drawn into the tube to heat the bymetal spring in the choke housing, this is accomplished with manifold vacuum through drilled passages in the carb, hope that helps

What they said. I might add that you need to make sure to connect it. I tried my carb without hooking it up. In warm weather it worked fine, but in the cold weather, it sucked in enough cold air to keep the choke on all of the time. When I hooked it up, the problem disappeared.

Hi, thanks for all the replies. You mean this port on the exhaust manifold?
http://i1236.photobucket.com/albums/ff441/AZ59apacheguy/IMG_1007.jpg
Looks like mines buggered, was wondering what that was for. Does anyone sell replacements?

I think the picture in my last post is wrong. Does anyone have a picture of this " tube which fits into a hole in a piece of light gauge steel which surrounds the exhaust manifold "

Nope. That is a vacuum port for your original vacuum wipers. Unless someone else does, I'll get you a pic of the heat stove setup in a day or two (my truck isn't at home right now).

That would be GREATLY appreciated. I would hate to have to sell this carb to get a different one.

I have the tube and manifold stove for a 1954 Rochester BC. However, your later BC is a different design and the tube comes out of the choke at a different angle.

I think this is like yours.

This stove on eBay should work on a 235 manifold. You would need to make a tube (metal brake line or gas line) and get a fitting for the carb-thermostat end.

Here is a universal kit from Dorman. You'd need to find a fitting to the choke.

Thanks tclederman! Bought and paid for ( ebay item ),hopefully I get it in a few days. Thanks again

Still need pics?

Hi. I definitely would like to see a pic of how you have it set up. Thanks

Ok...here you go. Just please disregard the peeling paint on the intake. I have an Offy dual just waiting to replace it.

This one shows where the heat stove mounts on the exhaust manifold.

This one shows the routing of the heat tube. Yours will be different than mine, since I'm running a Carter which has the choke on the back of the carb.

I hope this will help you out.

Thanks for the pics. How is the tube that runs to the carburetor secured in the opening of the manifold section? I bought the stovepipe system shown on the first page of this thread, it did not come with the tube. Is that something I can make on my own with break hard lines?

The port is for the automatic choke.

My stove plate and heat tube are original to the 1956 Chevrolet 235 powerglide passenger car engine.

The stove plate clamps onto the manifold and secured wit one bolt. stove plate
The routing of my heat tube to a Rochester BC carburetor. heat tube

Tim

The tubing pushes through the back (manifold) side of the stove. Flare the end of the tube, and it sits in the dimple on the stove and won't pull through. I used standard metal brake/fuel line from my FLAPS.

Thanks for the explaination. Do stores sell brake line with a female style connector? I've only seen male style connectors on the end of brake lines.

Not that I know of. Its been long enough ago, I don't remember what kind of fitting I used.

You might have to obtain the appropriate connector. Weatherhead-Eaton would most likely have the appropriate connector. What is the outer diameter of the tube? What is the size and type of fitting to the thermostat?

Hy AZ59apacheguy and guys, I believe that attachment at the carb is 1/4" male compression (7/16" X 24 U.N.F. thread) you'll need to buy one 1/4" compression sleeve (ferrule) Weatherhead p/n 60X4, and one nut Weatherhead p/n 61X4, and an appropriate length of 1/4" brake tubing, hope that helps.

Thanks for ALL the help. I used the above components and after a little tube bending, I'm pleased with the results:
http://i1236.photobucket.com/albums/ff441/AZ59apacheguy/IMG_1018.jpg
http://i1236.photobucket.com/albums/ff441/AZ59apacheguy/IMG_1017.jpg

Looks great!

Nice job !!

Thanks for those kind words