need cfm for 4cyl 1924?

[Guest rwolf]

can anyone tell me the cfm for a 1924 4cly Buick? I am considering replacing the Marvel carb with a Zenith. Also , I was wondering what horsepower that engine has?

[carbking]

This is kind of a mathematical exercise just for the purpose of practice, however:

 

The Buick 4 was a 170 cubic inch engine (actually, 169.5 rounded up).

 

CFM (on a 4-cycle engine of 4 or more cylinders) may be defined as:

 

CFM (sub Ve + [(CID x RPM) / 3456] (the CFM is dependent on the RPM desired)

 

I have not found a reference for the maximum RPM of a Buick 4 but would GUESS it to be around 2400.

 

Thus CFM at 100 percent Volumetric Efficiency = [(170 x 2400) / 3456]

 

OR

 

CFM (Sub 100) = 118

 

Now we come to the international fudge factor (IFF ) called Volumetric Efficiency.

 

My GUESS would be the Buick 4 to have a Ve of maybe 60 percent.

 

Plugging in this value:

 

CFM (Sub 60) =  70.8

 

A word on CFM in general: http://www.thecarburetorshop.com/Carbshop_carbsizesandCFM.htm

 

If you are trying to size a Zenith carburetor:

 

Since the design of the Marvel does not allow easy comparisons to more conventional carburetors (venturi size); a BETTER approach would be to determine other engines of similiar type (4 cycle 4 cylinder) of the same period with a conventional carburetor (charts are more readily available for Stromberg and Zenith carbs) and determine a venturi size used in the similiar engine. This would give you an approximate venturi size to find in the Zenith carburetor of the same S.A.E. mounting size (refer back to the article on CFM).

 

There are also additional criteria required.

 

Jon.

[Mark Shaw]

Or go to the Zenith Carb website:

 

http://www.zenithfuelsystems.com/updraft_267.htm

 

Updraft - Model 267

The effect of air cleaner deterioration on this carburetor is minimized by internal bowl venting. the large volume semi-concentric fuel bowl and vent locations combine to permit extreme-angle operation.

Application Dimensions

• Engine Size 100-250 CID
• Throttle Bore 1.181, 1.297, 1.417 inch
• Choke Bore 1.644 inch
• Venturi Diameter
• 18-30 mm range
• Fuel Inlet Fitting
• 1/8-27 inch pipe thread

Standard Features

• Choke Levers: may be specified for positioning on either side of carburetor
• Internal Bowl Venting: minimizes the effects of air cleaner deterioration
• Versatile Fuel Inlet Location: provides flexibility in fuel line location
• Lip Seals: on throttle shaft, minimize air leakage and seal out contamination
• Die Case Construction Throttle Body and Fuel Bowl

OR;

 

Updraft - Model 68

A back suction economized system provides this updraft carburetor with effective part throttle fuel economy. A variation of this design can be specified with components that will handle fuel percolation.

Application Dimensions

• Engine Size 25-170 CID
• Throttle Bore 1.024, 1.181 inch
• Choke Bore 1.376 inch
• Venturi Diameter
• 14-24 mm range
• Fuel Inlet Fitting
• 1/8-27 inch pipe thread

Standard Features

• Choke Levers: may be specified for positioning on either side of carburetor
• Internal Bowl Venting: minimizes the effects of air cleaner deterioration
• Back Suction Economizer: supplied for part throttle fuel economy
• Versatile Fuel Inlet Location: provides flexibility in fuel line location
• Lip Seals: on throttle shaft, minimize air leakage and seal out contamination
• Die Case Construction Throttle Body and Fuel Bowl

 

 

Optional Features

• Compact Fuel Shut-Off Solenoid: prevents dieseling
• Main Jet Adjustment: provides versatility
• Back Suction Economizer: for effective part throttle fuel economy
• Ball Bearings: on throttle shaft for low-friction operation
• Ignition Vacuum Port: provides signal for ignition system
• Power System: optimizes full load performance

Edited September 25, 2015 by Mark Shaw (see edit history)

[Dwight Romberger]

I have been looking at these new Zeniths for a while.

The 267 looks like a winner for the 4 cyl. 

Has anyone tried one?

[dibarlaw]

Apparently there was a market for replacements of the Marvel Carbs early on for Buicks in the 1920s. I can't recall where I found this ad.

[1967 - 1997 Riviera]

This is very interesting (to me at least). I did not think that Zenith carburetors was still around. If it were me, and I was going to go through the trouble of switching to a non-original carburetor for better driving performance, I would try switching to a side draft design. That would make the most sense for achieving the least amount of breathing restriction for the engine on intake. The first Corvette in 1953 used Zenith side draft carbs on the 235 inline six, which is kind of like a little brother to the Buick straight eight.

 

But I would keep the original carb and manifold for whenever the day comes that the car is sold. 

[Dwight Romberger]

It looks like a '30 Buick Larry.

Does the ad say which Stromberg model?

[dibarlaw]

Dwight:

 It does not give a model. But the ad indicates prices for Standard and Master Buicks. So this would be current for 1925-1927 years since afterwards a Series designation was used.

[carbking]

Actually, the 1953 Corvette used three Carter type YH sidedraft carbs rather than Zenith.

 

Stromberg released several different carbs to replace Marvels on the '20's Buicks:

 

4-cylinder 1922~1924 Stromberg J-3321

6-cylinder 1922~1923 Stromberg J- 3253

6-cylinder 1924  Stromberg J-3463

6-cylinder 1926 (standard) Stromberg J-3754

6-cylinder 1926 (master) Stromberg J-3736

6-cylinder 1926~1928 (standard) Stromberg J-3961

6-cylinder 1926~1928 (master) Stromberg A-12602

 

Jon.

[Dwight Romberger]

WOW!

Jon, you are the man!!!!

Is there one for a1930 Standard (or model 47)?

Thanks,

Dwight

[carbking]

Dwight - the factory Stromberg literature that I have shows only the ones I listed above. That listing was from 1932.

 

With research, something probably could be done, but would require an adapter because of the Marvel proprietary flange.

 

Jon.

[Dwight Romberger]

Thanks Jon.

What do the numbers mean behind the "J"? Different ventori sizes?

[carbking]

Dwight - the "J" numbers are what we would refer to today as a "tag" number. Each number is an identification number which identifies a specific type, size, and calibration. Of course, the venturi size is a part of the calibration. The "J" meant that the carburetor was sold only as an aftermarket unit, not as original equipment.

 

"A" numbers were normally (but not always) for original equipment carbs. One has to be careful with this, as Stromberg would assign an "A" number to an aftermarket carburetor sold TO A CAR MANUFACTURER as a factory replacement; so not all "A" numbers are original equipment.

 

Stromberg also had "F" numbers, which were assigned to experimental carburetors. Generally (again, not always) once the experimental carburetor were put into production, either a "J" or "A" number would be assigned. Some production carbs, where the production was quite low, retained the "F" number even though the carb was used as original equipment.

 

We have placed "A" numbers on most of the carburetor listings on our website. Here is an example (Dodge) that has several "A" numbers:

 

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

 

You will also note on the website other numbers on Stromberg applications. In addition to the sales number, Stromberg also assigned a code number to more easily identify the carburetor. You will notice the first Stromberg with an "A" number on the reference also has the number 3-6 (the "A" number is A-11942). Stromberg assigned code numbers for each manufacturer. Dodge was code 3. Other common codes: Ford 2, Studebaker 6, Buick 7, Packard 10, Cadillac 205. The number to the right of the company code was the sequential individual carb sold to that manufacturer. So the 3-6 decodes to the sixth calibration sold to Dodge by Stromberg.

 

Jon.

[Dwight Romberger]

Thanks Jon. I think I understand the aftermarket "J" and the company code.

[Dwight Romberger]

I checked the two brass Strombergs on my shelf:

 

B No. 3

G No. 1

 

Would either work with a 1922 Buick 4 cyl speedster  or a 1930 Buick  6 cyl Master (AKA model 47)?

 

They sure are pretty!

Edited September 29, 2015 by Dwight Romberger (see edit history)

[carbking]

Dwight - definately NOT on the 1930 as they are too small (internally).

 

Depending on the venturi size, either might work on the 1922 4 cylinder if either would physically mount in the available space. Either of the Strombergs is probably physically taller than the Marvel.

 

The B-series Stromberg was the technologically poorest of the Strombergs (although it still is probably superior to the Marvel ). The B-series was pretty much done by 1914, as better Strombergs were available.

 

The G-series Stromberg was excellent for its day, but most parts, other than rebuilding kits, are not readily available.

 

Jon.

[Dwight Romberger]

Thanks Jon for sharing your expertise.

I will try some fitting tommorrow,

As much as I like to keep things original, this is a '22 Buick I am rebodying as a 1914 speedster.

I feel I have a little more leeway for improvements.

I will post some pics.

Thanks,

Dwight