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NOS Zenith updraft carburetor replacements for Marvel


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If you ever thought about swapping out your much beloved Marvel for something less challenging, this is your chance.  This guy has a bunch of different NOS Zenith updrafts for sale. I bought one of these.  It was for a GMC '41 6 cyl 248.  I think it will be a pretty good match for my '30 6cyl 257. They are just as they appear in the pictures.

 

http://www.ebay.com/itm/262116173741?_trksid=p2060778.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT

Edited by Dwight Romberger (see edit history)
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Hi Dwight, I have a 1925 Standard six with a Marvel which seems to have a "sunk" float. It has been suggested to me that I should replace with a more reliable carb. Could the Zenith you mention here be suitable for my car? Thanks for the info, Frank

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Hi Frank,

 

I am not an expert. I am barely a novice at this..

 

Carbking is the expert, and hopefully, he will chime in. He has recommended Zenith + Stromberg updrafts as replacements for Marvels.  He also recommends getting one that was designed for as close an engine to yours (cu. inch) as possible.

 

Although mine was designed for a 248 and my engine is a 257, it is pretty close.  Plus, a slight variation of this carb (venture size?) was made for a 41, 42, 43 GMC Truck with a 257.

 

You will have to make or buy an adapter, since the Marvel flange is offset 45 degrees.

Edited by Dwight Romberger (see edit history)
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Thanks Mark,

 

Here is a good test article for the carbs Mark has posted

Carbking also sells them.

 

http://dmacweb.com/documentation/tech%20docs/Zenith-updated.pdf

 

 

http://www.thecarburetorshop.com/Aftermarketupdraftcarburetors.htm

Edited by Dwight Romberger (see edit history)
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Dwight - I followed the link on ebay, but was unable to read the tag number.

 

What follows is OPINION (mine) and others may/will have differing opinions.

 

Virtually any Zenith is superior to virtually any Marvel, period.

 

Having said that, some Zeniths are much better than others for a number of reasons.

 

Many (not all) of the modern Zeniths (current production) have no power circuit (power valve) to enrich the mixture under wide-open throttle application. This is normally not an issue for "parade" vehicles, or vehicles normally driven in moderately flat terrain. Those that tour will want the better Zeniths with the power circuit. 

 

Should you need parts, we make rebuilding kits for virtually any Zenith, clear back into the early 'teens; but for those carbs made prior to WWII, other parts may/may not be available, and the kits are hand-made, thus expensive. The two series before WWII for which most parts are available are the 63 series and 263 series. ALWAYS check the identification (tag) number to find the series.

 

If the carb is a universal (designed for aftermarket, not original equipment), jetting is somewhat more forgiving than for O.E. carbs.

 

If the carb is an O.E. carb, we have found a good rule of thumb is the "donor" engine should be within +- (plus/minus) 3 percent of the "donee" engine.

Example: if one has a 250 CID engine, 3 percent of 250 is 7 1/2. So one could reasonably expect good results using a carburetor from an engine within the range of 242 1/2 to 257 1/2 CID.

 

Not saying a carb outside the range won't work, but it might require more tuning.

 

If you acquire a new-old-stock Zenith with an accelerator pump:

 

Zenith used brass pumps (not leather) in most updraft applications. AT LEAST 90 PERCENT OF THE NEW OLD STOCK CARBS OF THIS TYPE THAT WE HAVE DISASSEMBLED HAVE A STUCK PUMP!!! EXPECT IT!

 

Not a problem if you have patience. Once the pump is unstuck (assuming you don't damage the pump freeing it), it will work fine. However, if you damage the pump in freeing it, chances are a new pump is constructed from either unavailablium or verypricium! If you have access to an ultrasonic cleaner, place the entire carb in the cleaner for about 30 minutes (plain water) BEFORE you attempt to disassemble to free up the pump. Run the heaters at about 165 degrees F. So far, knock on wood, has worked for us every time.

 

And if you tear out the gears in the rear end from all the extra power you now have, don't blame me ;)

 

Jon.

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  • 4 years later...

Hi Jon, do you think this new Zenith updraft carburetor could be suitable, besides parade rides, for my 1926 Studebaker Big Six, EP ( 354 cu in L-head engine)? 
Thanks, JRA

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2 hours ago, JRA said:

Hi Jon, do you think this new Zenith updraft carburetor could be suitable, besides parade rides, for my 1926 Studebaker Big Six, EP ( 354 cu in L-head engine)? 
Thanks, JRA

WHICH new Zenith carburetor?

 

Identification number???

 

Jon.

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19 hours ago, raydurr said:

A brand new carburetor would ruin all the running bad, popping back and flooding. A Buick without a Marvel would be boring. LOL

Ray - I like your post, but JRA has a Studebaker, which probably has, or had, a Penberthy.

 

Jon.

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