Zenith Carburetor and Jet info

[Mitch]

Here are some informative web sites:

http://www.modela.org/

http://modelabasics.com/Carb/ZenithC...l2011-2007.pdf

[BudP]

I myself use one red gasket (they are 0.030) and one grey gasket (0.015) for the float and that seems to work for me.

[DaWizard]

GREAT link. And Yes, this is a great informative web site.

[Mitch]

Renners corner is a great place for carb parts and the best for obtaining flow tested jets. The jet sets sold by the ordinary suppliers cause the zenith to run rich. These flow tested renners jets are on the money and come with a flow spec paper with your purchase. I have rebuilt carburetors on moderns since working as a tech and we always reused the same jets with no issues. Well long story short when i got into Model A's i either reused the jets or bought the suppliers items. Trust me when i tell you putting in the Renners jets makes a world of difference and it will make you a believer also.
Do yourself a favor and also purchase the Renners fuel level gauge when you order the jets. Their gauge is real nice and sturdy, well made compared to the tool all the suppliers sell.....

http://rennerscorner.com/carburetor.html

IMG_7261.JPGIMG_7260.JPG

[BNCHIEF]

Like you said and exactly what to do.

[Mitch]

I find that setting the float level to 15/16th is optimal height (5/16th lower than the 5/8th spec) and this also prevents stalling. This is gone over in the carb rebuilding book by Rex Reheis (BUY THAT BOOK ).

[DaWizard]

Yesterday I put out the word for the club members to donate whatever Zenith carburetor parts they had laying around unused and I would build up a Club spare for whatever.
Well, last night one of our members, Jim in Anaheim on here, said he had some parts or a carb to donate. Well, today he brought it over and I have spent the last few hours cleaning and rebuilding this total carb.

Now, the rant, I have no idea what some folk think they are doing owning a roll of Teflon tape!! Most of my time was spent picking Teflon tape from threads on the idle adjustment screw, the GAV threads, the Main Jet, the Comp jet, just to name a few spots, as well as the inlet threads. DO NOT USE TEFLON TAPE ON FUEL RELATED THREADS!!!

Rant over

I have never seen so much tape used in the assembly of a carburetor. This was way past the point of being ridiculous. Now I need a subject to donate the time on their car to test and tune the carburetor, so I will probably call a few of the members and see who is running the poorest and give them a thrill by running this carb.

Thanks to all for allowing me to let off a little steam, now back to sucking on my bloody fingers from the pick skipping off the tape!!

[Fred K]

Question-what do you use to stop leaks? It seems like on these old carbs the threads need a little help.

[DaWizard]

Fred, if you have the proper tap and parts, there are no leaks.

I am now using a carburetor on my car that had the first threads on the filter hole blown out. Now, this would not seal, so, I ran my ½-20 tap down the throat and took a ½-20 bolt by about 2in long and cut a groove down the side of the bolt from the fuel line hole to the end of the bolt, threaded it in in place of the filter with a single gasket and no leak. Now, it doesn't have a filter, but I figure between the pencil and sediment bowl my gas is strained enough to keep most of the particles from the carburetor. I would show you a picture, but I didn't take any and it isn't leaking so I don't wish to take it apart to show you. I hope you can get a mental picture. If a carburetor has a leak, I fix it, not patch it or goo it.

[Mitch]

Fred read post #13 on this thread. That can help fix leaks if the threads will hold

[Mitch]

I know there are many ways to paint a carb but i use this plastikote lacquer rattle can code # T-3 Hot Rod black
It's fuel resistant..
I have a few carbs that i plan on rebuilding soon and the plan is to powder coat them.

SEE THIS UPDATE
https://www.vintagefordforum.com/for...ack#post224696

[Big hammer]

I've thought power coated would work, I'm not a pc'er let us know how it works

[Mitch]

will do

[dmdeaton]

Powder coat would be cool. This is a topic that really interests me. I printed off the pdf"s you linked above and ordered a couple of the Zenith books. I plan on looking for a couple good cores to rebuild and detail. I got a spare Tillotson with the roadster, wrapped up in a rag and bagged up in the tool box.
Is anyone running the K&N filter on their carbs? Seems like a filter would be a nice thing to have. I read they run rich unless the jets setup for a filter?

[BNCHIEF]

Dmeaton you can run a filter but the carb needs to be pressure balanced if your carb is nasty or needs rebuilding send it to renners and have it pressure balanced then you can run an air filter which I believe in myself.

[DaWizard]

They did not come with filters and all they had back then was dirt roads. I think Henry would have wanted his cars to last and would have had a filter if he thought it was needed.

Any of the carburetors made for back then were made to run unfiltered, so if you decide to use one now, I highly recommend the K&N filter as it will allow more air flow and I think the carburetor would only lean out a bit.

Personally, I do not run any filter on the carburetor since we have paved roads that only pick up tire rubber for dust. I know this because I used to work at a place that was within 100ft of a popular freeway and we had that dust everywhere.

Now, I DO run an oil filter because I don't plan to change oil every 500mi.

My opinion and I'm sticking to it!

[Mitch]

or add a balance tube to the carb

[DaWizard]

Yea, I suppose ya could do that, never tied.

[Greynomad]

Are either of you guys able to post how to balance the carburetor please?

[Big hammer]

My Zenith whistles, starts and runs good, is this normal? Whistles at lower rpm's, it was called to my attention after 200mi first driving this year trip! Yea!

[Mitch]

Mine whistled from to much play in the throttle shaft
Was sucking air through it

[Big hammer]

I'll check that out Thanks

[Mitch]

Carb balancing

An easy way to air balance a carburetor without modifying it's original structure is to get a small piece of metal tube to fit tightly into the float bowl vent. I once used a brass tube about 3/4 to an 1" long. Slide a piece of tubing onto it and place the other end between the air filter and the choke plate, preferably fitting it into the air cleaner housing so you don't need to modify the carb.
If you use a large enough air filter element balancing may not be necessary.

[Greynomad]

OK, Got it. Air passage from somewhere between the air cleaner and the choke plate to the float chamber. Thanks, Mitch

[Dennis]

That should be real easy. I'll have to try that on one of mine.

[dmdeaton]

Mitch, got a pic of this mod?

[Mitch]

No pic saved of it

[Fwilkinson]

There is an excellent article about modifying the Zenith carb for air balance.
It is by Tom Endy in California.

https://www.santaanitaas.org/technical-reference/tom-endys-tech-articles/

Look in the “Fuel” section, click on “Modified Zenith w-air filter”.
There are photos and instructions to guide you.

[Mitch]

If you need to clean up the seats at the sediment bulb or the carb to seal the fuel line connection better purchase this Dremel # 911
from Amazon or such.

[dmdeaton]

I picked up a couple zenith cores to play around with and rebuild. I also ordered a couple rebuild kits from David along with his jets. I am looking forward to building these up. I may try the balance tip Mitch shared. I am thinking of snagging one of the K&N filters.

[BNCHIEF]

Dave is a great guy to deal with and talk to as well.

[Mitch]

Jet sizing information:

http://www.fordgarage.com/pages/jetflowrates.htm

[Cape Codder]

Do the Reener jets have any markings specific to their company on the jets?

[Mitch]

Cape
The Renners jets come with a paper showing the flow specs

[Fred K]

Mitch, I have used the "standard" jets purchased from one of the "good" vendors. You mentioned before that they tend to have the car run rich. Is this why my sparks plugs always look black?

[Mitch]

Fred most likely because they do run rich. What plugs are your running? Try the Renners jets you won’t look back

[Grit Kid]

I don't venture here much, hardly at all because this word scares the shite out of me....:technical".

[Ronald]

Well I have a Maze filter on my Zenith carb in my Tudor and I can cruise at 50 miles per hour with 4 adult passengers with ease. Carb I rebuilt myself for the first time. No mods to carb or filter.

[DaWizard]

Hey Ronald, WELCOME to the VFF!!

[Mitch]

Well I have a Maze filter on my Zenith carb in my Tudor and I can cruise at 50 miles per hour with 4 adult passengers with ease. Carb I rebuilt myself for the first time. No mods to carb or filter.

Welcome Ronald to the VFF!!

Glad to hear that your A is running good. Don’t mess with success

[Mitch]

From Renner's Corner!


ALL of the carburetors released by Ford for use on a Model A or B
had the float bowls EXTERNALLY vented.
So the use of an air cleaner of any type will negatively affect the air to fuel ratios.
These carbs were not designed for air cleaner use.
To allow the use of an air cleaner the bowl vent must be relocated to the INSIDE
of the carburetor near the choke plate area.

This is called pressure balancing.

[Mitch]

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[Mule Driver]

The zenith on my 28 Tudor tends to weep fuel when sitting for a time, even with the fuel shut off closed. I have adjusted the float as close to 5/8 as I can and have even put 2 washers under the float valve but it still tends to weep. Car runs great on the road and idles good. Any ideas??????

[Mitch]

The zenith on my 28 Tudor tends to weep fuel when sitting for a time, even with the fuel shut off closed. I have adjusted the float as close to 5/8 as I can and have even put 2 washers under the float valve but it still tends to weep. Car runs great on the road and idles good. Any ideas??????

Try a viton tipped float valve. 15/16 would be better when you change the valve

Make sure your float is not worn as shown above

[DaWizard]

Mule Driver, take the second gasket out from the float needle. I have found that a second gasket tends to weep between the gaskets.

If you can adjust the float to get that level with the top, you should be good to go.