Jump to content

Original literature, mostly carburetor


Recommended Posts

6 minutes ago, hidden_hunter said:

Do you have anything for the Johnson carb in the 1922 Cadillac? 

 

Such a fantastic carb.... 

 

Often in the shop, we debate different types of technology. Fuel and fuel systems are often a topic of discussion. Usually most agree that a Cadillac Johnson carburetor is comparable to running an old shoe with a hole it it for a fuel metering device, and most agree the shoe is much more adjustable for mixture, and gets better mileage. And, the shoe smells better when the under hood fire occurs.......so, it’s really a significant improvement for ANY Cadillac Johnson carb from 1913 to 1932.

 

PS- for authenticity purposes, PLEASE do NOT use a Chinese shoe, if you look hard enough at good will, pre war shoes are readily available in many attractive colors. Just remember, ladies high heels are harder to tune.

Edited by edinmass (see edit history)
Link to post
Share on other sites
11 minutes ago, edinmass said:

 

Often in the shop, we debate different types of technology. Fuel and fuel systems are often a topic of discussion. Usually most agree that a Cadillac Johnson carburetor is comparable to running an old shoe with a hole it it for a fuel metering device, and most agree the shoe is much more adjustable for mixture, and gets better mileage. And, the shoe smells better when the under hood fire occurs.......so, it’s really a significant improvement for ANY Cadillac Johnson carb from 1913 to 1932.

 

Mine runs ok (I can maintain 45-50mph at about 1/2 throttle on the flat) but it likes to leak fuel out the top of the bowl (not sure if it's the needle or the float) mostly after you let off the throttle. Potentially I need to dial the fuel regulator back a bit, could be overwhelming it or the "non standard" spring for the accelerator (mostly because the book doesn't tell you where to attach it and I'm pretty certain it wasn't originally a brake spring wrapped around the oiler for the gen) 

 

The rest of the carb seems to be in good working order and I have the preheat blocked - which surprises me how cold the central body of the carb gets despite the massive amounts of heat the engine is throwing off. 

 

Fuel milage.... lets be honest it was never going to be great (it weighs over 5000lbs when fully fueled) :D Based on my rough calculations it's sub 10mpg - though the carb pouring fuel on the ground might not be helping much 

Edited by hidden_hunter (see edit history)
  • Like 1
Link to post
Share on other sites

The Cadillac Johnson carburetor was also a “rev limiter” as the engine can and will spin much faster than the stock fuel system will allow........and it will come apart. 45 mph for any 20’s Cadillac is the high end of safe and normal. Most cars talk to you when you drive them......if you listen, you find the sweet spot where the car is in the groove and not pushing itself. That is where ALL pre war cars should be driven.

Edited by edinmass (see edit history)
  • Like 2
Link to post
Share on other sites

I have never seen ANY documentation on the Cadillac/Johnson carburetors from Johnson.

 

There is some documentation on repair in the Dykes Encyclopedia, as well as the Radco repair manuals.

 

We do custom make rebuilding kits for these; however to add to Ed's comments:

 

The most expensive component to the rebuilding of the Cadillac/Johnson carburetors is the automatic, underhood halon fire estinguishing system.

 

Remember, these things come from the same company that thought the way to preheat fuel (other companies used water jacketed or exhaust jacketed carburetors) was to run an electrical current to a heater in the carburetor bowls! ;)

 

Jon

  • Like 2
  • Haha 1
Link to post
Share on other sites

Before I bought my 1914 Cadillac, with 7,000 original miles, I thought I had seen every bad idea you could do to a car.Thr float bowl gasoline heater looked like one of those individual tea cup heaters you plug into the wall to boil your cup of tea. It my amazement, it was still hooked up and functioning. The car had its original coil, points, and condensers as well. I immediately disconnected it, and later on Modify the wiring harness to make it look like it was hooked up; but in reality it was not.

  • Like 1
Link to post
Share on other sites
8 hours ago, edinmass said:

The Cadillac Johnson carburetor was also a “rev limiter” as the engine can and will spin much faster than the stock fuel system will allow........and it will come apart. 45 mph for any 20’s Cadillac is the high end of safe and normal. Most cars talk to you when you drive them......if you listen, you find the seat spot where the car is in the groove and not pushing itself. That is where ALL pre war cars should be driven.


Yep, the brakes are also a limiting factor as well! 

Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...