silverriff

I just received my rebuilt Q-Jet for my 455. It is so nice. I got it with an electronic choke conversion and my question is about the 2 provisions for the original hot air/cool air choke pipes. Do I need to block off or plug up either one of these? Or just let them run open? Anyone?

joe_padavano

You can just leave them. The two holes are the ends of the choke stove, which is a U-shaped tube inside the crossover. Unless the choke stove has rusted through, it is sealed from exhaust gasses.

silverriff

I'm sorry, I should have been alittle more clear. I meant the provisions on the carb itself....the screw in hot air line on the side of the choke case, and the rubber slip on fit on the back of the carb. I actually made alittle plate to close off the manifold because I wanted to keep the whole choke stove in one piece. But I wanted to know if I needed to close them off on the carb end.

Olds64

You can get a plug at the hardware store. Just use a little bit of teflon tape when you put the brass plug on it.

joe_padavano

The port at the back of the carb needs to be capped to prevent dirty air from bypassing the air filter. The port on the choke housing also needs to be capped. You will need a brass female flared pipe fitting cap. These are straight threads and the seal is the flare. You can also use the nut that was on the hot air pipe and fashion a flared seal inside it.

ReallyWildStuff

I am doing the same thing as OP (7 years after their post)...I recently got the 77 QJet back w/ an electric choke conversion, and desire to plug the hot air inlet on the original choke housing.

It is a simple matter to plug the hot air inlet at the top rear of the carb (that receives one side of the hot air "loop" off the manifold) but I'm speaking about the threaded port on the trailing edge of the choke housing.

Above, Joe calls for a "brass female flared pipe fitting cap". What are the other additional specifications for this part to plug the hot air inlet on an <unused, converted to electric> hot air choke housing?

Without this info I'd basically have to bring the carb to the plumbing store for sizing...

I looked here, I also called them: http://www.carburetion.com/quadrajet.asp

The "carb rebuilder" they passed the phone to similarly recommended "plugging that with something" but he could not recommend what that something would be.

Seems weird to me that a part like this is so hard to find. Maybe I didn't look in the right places? Anybody can sell you the black plastic part with the included electric element + 3 stake screws/washers but there's not a "brass female flared pipe fitting cap" included.

The answer just can't be "most people just don't plug it", can it?

RetroRanger

i capped the threaded portion of the choke housing w a vaccum cap, i also siliconed the port inside the choke houseing. I admit a brass female flared pipe fitting cap would be a more elegant solution.

Fun71

It's a simple flare tubing cap. I don't know the exact size right off but there aren't more than maybe three different sizes that are even close, so it won't be hard to figure out which one you need from the hardware store.

deadeyejedi

i agree it should come with the kit .they did have it at my local hardware store as stated above flaring tube cap.the pic is a little decieving but i believe 3/8 .

Olds64

Correct. If you don't want to take the entire carburetor into the hardware store; something I've done many times, you can remove the choke housing and bring it with you.

ReallyWildStuff

I took the carb into U-Plumb-It and got great service (like always) - and the part for free.

It is brass. It was described by the master plumber as: 1/2" plumbing compression cap.

It's a weird thing because the OEM design of the choke housing/hot air tube "pressure seal" includes the flared end of the hot air tube (as well as the threaded fitting). Without the flared end of the tube in-place, the cap (replacing the fitting) "threads all the way up the choke housing" until it bottoms out - I don't think it is truly vapor or water tight.

Since there's no pressure coming out of the choke housing there's no issue - but that's not normally the way "plumbing" works.

Perhaps this explains why the cap is not included in electric choke conversion kits.


Also, "I am not a plumber".

Olds64

Good to hear that you got what you needed.

Fun71

Hmm. I used a tubing cap on mine and the inside of the cap has a beveled surface to mimic the flared tubing end. This is the type of cap that would go onto a flared tubing so it has to seal very well.

It's not a big deal on the carb choke, though, since the hot air choke has a "vacuum leak" built in for proper operation. All that may happen with an electric choke is a small amount of air may enter and have a very tiny cooling effect on the electric heating element.