Odd Carburetor

[Ethan1]

 I have a Rochester DualJet 2MC #17056156 carb. Can anyone tell me how the secondary system works? Or is there even a secondary system? The secondary flaps in the air horn are non-existent, but still has the secondary flaps in the throttle body. It looks like a Quadrajet, except for the air horn assembly w/ no secondary flaps. Carb kind of confuses me. Thanks!

[Ethan1]

I have a Rochester DualJet 2MC #17056156 carb. Can anyone tell me how the secondary system works? Or is there even a secondary system? The secondary flaps in the air horn are non-existent, but still has the secondary flaps in the throttle body. It looks like a Quadrajet, except for the air horn assembly w/ no secondary flaps. Carb kind of confuses me. Thanks!

 Here is what mine looks like:

 

[Shark Racer]

Fascinating. Without the air valves, I can't imagine that it really has secondaries, but it still requires a 4 barrel intake to run. Maybe something they did to try to simplify costs? (1 intake for all cars?)

Have you taken it apart to see if there's any passages? Would love to see photos of a detailed teardown.

[Ethan1]

Fascinating. Without the air valves, I can't imagine that it really has secondaries, but it still requires a 4 barrel intake to run. Maybe something they did to try to simplify costs? (1 intake for all cars?)

Have you taken it apart to see if there's any passages? Would love to see photos of a detailed teardown.

 Haven't taken it apart yet, Steve. Will do a detailed teardown of this carb though.

[Shark Racer]

Looking forward to it. Thanks Ethan!

[omaha]

yeah its just the front half of a Q-jet but with the casting still in place. they also made them without the rear so it looks like an actual 2  barrel. I guess if you were real careful you could make it into a 4 barrel. don't know if the passages ae there though.

[Ethan1]

 Mine is a DualJet 165.

 Have way down the page it shows the model DualJet 165.

 http://www.hotrodders.com/forum/would-stock-holley-good-mpg-189464.html

[Shark Racer]

Great info, thanks Ethan.

[Schurkey]

There may be a functioning Q-Jet throttle body, but the carb is just a two-barrel.  Just making a guess:  If you've got throttle plates for the secondaries, someone replaced the throttle body with one from a Q-Jet.  I would not expect GM to have paid for the throttle plates, throttle shaft, and machining/assembly to put non-usable secondary throttle plates into a carb that isn't going to have functioning secondaries.

DualJet 165


DualJet 200




DualJet 210

[Ethan1]

There may be a functioning Q-Jet throttle body, but the carb is just a two-barrel.  Just making a guess:  If you've got throttle plates for the secondaries, someone replaced the throttle body with one from a Q-Jet.  I would not expect GM to have paid for the throttle plates, throttle shaft, and machining/assembly to put non-usable secondary throttle plates into a carb that isn't going to have functioning secondaries.

DualJet 165


DualJet 200




DualJet 210

 You are correct, Schurkey. Thought it had secondary throttle plates. I must of had a brain fart. Here are some pictures of it.

 

 

 

[PMD1969]

Could have been a cheap way of trying to save on fuel.  Instead of changing manifolds, linkage, vac lines and everything else on the car/motor this carb would step it down to a two barrel.

[Shark Racer]

I'm thinking it was to ease up production. One manifold for everything. I'd love to own one, neat carb.

[Ethan1]

I'm thinking it was to ease up production. One manifold for everything. I'd love to own one, neat carb.

 It is a neat carb. Unusual, but neat.