Rebuilding ThermoQuads: Who has some helpful tips and advice?

[ckessel]

On Carter's, at least later ones, the carb number you're needing for kits/info etc is stamped on the throttle plate. Older ones used a tag held down by one of the screws on the lid. Carter's version of the LIST number for Holley's.

 

[Kern Dog]

I'm hoping that the fix for this one is simple. I have parts from other T-Quads to enable a functioning choke setup.

 

[OKDart]

I think the thing on the front is an altitude compensator.

 

[440 4 speed]

This is the carburetor that inspired the thread for me.

View attachment 1801676
I don’t remember where I got it. I had a guy at a local shop go through it. He did say that I’d need to install and run it in a short time but I got distracted with other things and let it sit.

View attachment 1801677

This one PUKES gas up the throat as the car is running. I figured the needle and seat were stuck so I tapped on the top with a ratchet but it kept pushing gas so I pulled it and swapped on a known good Holley 600.

View attachment 1801678

It essentially has zero miles, it just needs to have this one issue addressed. These are the only numbers I can see at a glance.

View attachment 1801679

With that ugly, bulbous thing at the front I suspect it is from the mid to late 70s.
The carb guy used to rebuild stuff for me in trade for parts he needed for his Dart. I lost some of my rebuilding skills by farming out the work instead of doing it myself.

I am in the Carter Camp. In my youth I saw a few Holly’s back fire and you had flames out the carb.
We have a fairly original 85 350 series classB camper van. 360 4 bbl. It had about 71,000K on it when we bought it in 2009. Now has about 124,000K. It had a Q-jet on it. Went on a trip to Galveston. It was a dog, very little power and was getting a maximum of 9 miles to the Canadian gallon, which is 5 US quarts. Got home and had a local top notch shop that did fuel systems rebuild it.
There is one particular valley south of us that has a real incline. To maintain speed going up I had to use second gear. The trip the next year to AZ wasn’t a lot better.
My friend who was a retired Chrysler mechanic said, let’s make it work well and put one of your TQ’s on it. (There had been an article in the newspaper about his tune up skills) Gordon took one of my 850 carbs put it on, tuned it and it ran so nice. Trip AZ the next year to AZ we got as high 19mpg and could actually gain speed in drive going up the aforementioned hill.
One drawback , the intake didn’t have a pocket for choke, and I haven’t hooked up a manual choke, so it has to warm up a bit.
About 2 years ago Remcharger did some adjustments, and it really performs well. The kick down had not been functioning correctly.

 

[440 4 speed]

SQUARING THERMOQUAD CARB BASES! Or other things.
I get a piece of heavy sheet glass, mine is fron about a 1940’s car vent window.
Get some very fine sandpaper, put on the glass and sand the base down until all is good. Used this method on lots of things since 1970.

 

[Vaanth]

This is the carburetor that inspired the thread for me.




View attachment 1801678

It essentially has zero miles, it just needs to have this one issue addressed. These are the only numbers I can see at a glance.

To identify Thermo-Quads, the model number is stamped on the throttle body lower left rear bolt flange. The model number consists of four digits, usually followed by an ‘S’ or ‘SA’, along with the date code.

The model number is above the date code. Example:

9009SA <-- Model Number
268 4 <-- Date Code

The 6-2363 in the picture is the casting number of the bowl cover, or top, and does not identify the carburetor model.

View attachment 1801679

With that ugly, bulbous thing at the front I suspect it is from the mid to late 70s.
The carb guy used to rebuild stuff for me in trade for parts he needed for his Dart. I lost some of my rebuilding skills by farming out the work instead of doing it myself.

The device on the front of the carburetor is the Altitude Compensator or Alcomp (Alc). Alcomp was introduced in the 1975 model year. This device alters the high speed metering circuit by sensing atmospheric pressure. It mounts to the same area as the IE system at the front of the bowl cover. This system is a driveability enhancement, which also reduces emissions, by allowing the Thermo-Quad to compensate for elevation.

The Idle Enrichment System (IE) is next to the Alcomp. IES is also a driveability enhancement. The IES fitting is the small attachment on the front bowl cover that connects with a vacuum hose and bleed to the Coolant Controlled Idle Enrichment (CCIE) temperature sensor, then to manifold vacuum. It allows a richer mixture during the warm up period to improve driveability. The system supplements the choke function by blocking part of the air bleed to richen it.

For more information about identifying Thermo-Quads and other details, see A Carter Thermo-Quad Guide, Version 3.1.

 

[440 4 speed]

To identify Thermo-Quads, the model number is stamped on the throttle body lower left rear bolt flange. The model number consists of four digits, usually followed by an ‘S’ or ‘SA’, along with the date code.

The model number is above the date code. Example:

9009SA <-- Model Number
268 4 <-- Date Code

The 6-2363 in the picture is the casting number of the bowl cover, or top, and does not identify the carburetor model.



The device on the front of the carburetor is the Altitude Compensator or Alcomp (Alc). Alcomp was introduced in the 1975 model year. This device alters the high speed metering circuit by sensing atmospheric pressure. It mounts to the same area as the IE system at the front of the bowl cover. This system is a driveability enhancement, which also reduces emissions, by allowing the Thermo-Quad to compensate for elevation.

The Idle Enrichment System (IE) is next to the Alcomp. IES is also a driveability enhancement. The IES fitting is the small attachment on the front bowl cover that connects with a vacuum hose and bleed to the Coolant Controlled Idle Enrichment (CCIE) temperature sensor, then to manifold vacuum. It allows a richer mixture during the warm up period to improve driveability. The system supplements the choke function by blocking part of the air bleed to richen it.

For more information about identifying Thermo-Quads and other details, see A Carter Thermo-Quad Guide, Version 3.1.

Thanks, you verified what I thought.

 

[Some Car Guy]

Wow I didn’t know about the altitude thingy. Great carb gets better!