News:

Due to a technical issue, some recently uploaded pictures have been lost. We are investigating why this happened but the issue has been resolved so that future uploads should be safe.  You can also Modify your post (MORE...) and re-upload the pictures in your post.

Main Menu

Carburetor Discussion

Started by Ty, March 19, 2009, 02:53:00 PM

Previous topic - Next topic

0 Members and 1 Guest are viewing this topic.

Ty

Hello,
I would like to be convinced that new Zenith replacement carburetors ($1,100) to fit my 1937 Cadillac V12 engine are the way to go. The following information was provided to me by a very reliable and trusted vendor and I am told these are new, very efficient, universal updraft replacement units. They can be used on a wide range of different engines, as they have fully adjustable high speed circuits, unlike conventional carburetors with fixed circuits. I understand this particular carb has been used by several different Cadillac V12/V16 owners with great success and I would like to hear your comments regarding your experience with them.

My Cadillac V12 has separate throttle linkage hookup to the (2) carburetors and I can use this same setup on the new Zenith carbs by adjusting the throttle arms on the carbs. The major change will be the bolt-up to the manifold, as the flange on the Zeniths is smaller than the Cadillac manifold. This requires the fabrication of a small flat adapter plate to mount the new carbs. But, any machine shop can easily make these plates. I understand that fuel mileage is subjective, and depends upon the engines overall condition, carburetor adjustment, altitude, drivers foot habits, and many other factors and that anything at 10-13 mpg would be excellent for the original V12 Cadillac, using modern regular unleaded fuel. So, my original Detroit carbs would not be replaced for better gas mileage.

But, this new carb setup would be very simple for tuning. Once the carburetors are installed, I could simply set the idle mixture adjustments, as with any other carburetor; then bring the engine up to approx 1500-1600 RPM. Fix the throttle at this RPM so it cannot vary; then adjust the external high speed main jets, and tune to the highest RPM gain. I would then have effectively set the high speed main jet circuits to the current needs of the V12 engine, without worrying about being to rich or to lean.

If faced, during a run like the Great American Race, with high altitude, it is a simple matter to stop the vehicle, and with the engine running, again at 1500-1600 RPM, re-adjust the main jets to the new altitude. When coming back down to normal altitudes, say under 3000 ft, stop and again re-adjust the main jets. Normally sea-level up to around 3000 ft is normal; at 3000-6000 ft, an adjustment is needed, and again at 6000-9000 ft another adjustment would be necessary.  

At least with these new carbs I could do this, and keep on going. With the current original Detroit carbs, and all standard factory carbs, I would have to take the carbs apart and change jets, and re-install. So, the Universal Zeniths prevent a lot of guessing and labor, involving correct fuel mixtures for altitude compensation.

So, I'm interested in the #267 Zineth updraft carbs for my '37 Cad V12. I plan to restore my V12 for the Great Race to California from Maryland. My current Detroit carbs should deliver, by design, 10 miles per gallon and I am told that they are hard to tune.

I’d like to know your experience with them and if you have found them to be more dependable on such a trip and adjusted for elevation change performance.

Many thanks,
Ty Stinson
CLC22330

Stinson

I guess there are not many people having V12's and V16's using these new carbs after all?
Many thanks,
Ty Stinson
CLC#22330
Ty Stinson
'37 Cad 8519 Touring Sedan V12
CLC22330

Walter Youshock

Hopefully it will get more attention in this forum.
CLC #11959 (Life)
1957 Coupe deVille
1991 Brougham

Don Rundgren

Ty,
I do not have the experience you are looking for but I am interested in any feedback you may get. I have a 32 V-12 with the dual Detroit Lubricator carbs and am experiencing driveability problems, although I only recently acquired the car and am just starting to sort it out. I have also read a number of negative comments about these carbs and their apparent bad reaction to current gasoline with 10% ethanol blend but I intend to do as much as I can to get around that and am hoping they can be retained. I will follow your posts with interest.
Don
McKinney, Texas

Stinson

Thank you Walter and Don. I really hope someone can talk about their experience with these Zenith replacement carbs. They sound great, and can be used without changing anything permanently to the car. This is very important for when someone else would like to purchase the car in the future and reinstall the original carbs.
Ty Stinson
CLC#22330
Ty Stinson
'37 Cad 8519 Touring Sedan V12
CLC22330