MA 450S Carter Carb

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Re: MA 450S Carter Carb

Post by Scoutpilot » Wed Jul 05, 2017 10:57 am

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Re: MA 450S Carter Carb

Post by Chuck Lutz » Wed Jul 05, 2017 12:45 pm

OK...so the "SA" indicates a Carter factory rebuild and as Olaf has stated, not all original parts were put back together as in his example of a 450.

So...while the Carter spec sheet dated 1939/1953 shows a pic of a smooth air horn, it indicates this is for the "440" engine and the MA and covers the 450S and the 450SA.
That means we should not take for granted that the photo of the smooth air horn is correct because by 1953 none of the Carters had that ribbed feature!

Looking at the 12/39 "440" for the 1940 Willys spec sheet; it indicates it is for serial numbered 17000 and higher. It has a pic of a SMOOTH air horn. It is a 450S.

Looking at the 12/40 "441" for the 1941 Willys AND the 1941 MA; it indicates it is for the 50001 and higher and the air horn is RIBBED!

With that I mind if you are building a factory MA then you want a Carter 450S which would have had a RIBBED air horn on it. If you were building a MA that went through a rebuild program after the 1953 date then you might have a 450S or a 450SA and you might have a smooth air horn.

However, those who have the Carter spec books can probably look up each of those dated circulars and see if they include a blow-up that lists the part numbers. I would be willing to bet that the RIBBED and the SMOOTH air horns have different part numbers!

Just a theory of course...
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Re: MA 450S Carter Carb

Post by rjbeamer » Wed Jul 05, 2017 1:12 pm

Postby Chuck Lutz » Wed Jul 05, 2017 12:45 pm

OK...so the "SA" indicates a Carter factory rebuild and as Olaf has stated, not all original parts were put back together as in his example of a 450.

Chuck what about this post below.
Roger


Postby Scoutpilot » Tue Jul 04, 2017 2:15 pm

Carter carbs went through many, many design changes. “S” is the original “System” designator. “A’”, “B”, “C”, “D” indicate a design change not always obvious to the casual observer. e.g., The change from a 636S to a 636SA involved a design change to the main nozzle.

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MA 450S Carter Carb

Post by wo2jeeper » Wed Jul 05, 2017 1:47 pm

Chuck Lutz wrote:OK...so the "SA" indicates a Carter factory rebuild and as Olaf has stated, not all original parts were put back together as in his example of a 450.

So...while the Carter spec sheet dated 1939/1953 shows a pic of a smooth air horn, it indicates this is for the "440" engine and the MA and covers the 450S and the 450SA.
That means we should not take for granted that the photo of the smooth air horn is correct because by 1953 none of the Carters had that ribbed feature!

Looking at the 12/39 "440" for the 1940 Willys spec sheet; it indicates it is for serial numbered 17000 and higher. It has a pic of a SMOOTH air horn. It is a 450S.

Looking at the 12/40 "441" for the 1941 Willys AND the 1941 MA; it indicates it is for the 50001 and higher and the air horn is RIBBED!

With that I mind if you are building a factory MA then you want a Carter 450S which would have had a RIBBED air horn on it. If you were building a MA that went through a rebuild program after the 1953 date then you might have a 450S or a 450SA and you might have a smooth air horn.

However, those who have the Carter spec books can probably look up each of those dated circulars and see if they include a blow-up that lists the part numbers. I would be willing to bet that the RIBBED and the SMOOTH air horns have different part numbers!

Just a theory of course...
ok, something for the theory. The ribbed airhorn was ment to keep a small round airfilter on civilian vehicles. The ribs prevent them to slip of easy. On MB/GP/GPW jeeps we have the smooth airhorn and those were also on the MA. Now some speculation, possible is that first MA were build with avaible parts (ribbed horns) and got later a horn of better/other/universal,etc specs. Thats something I could follow.

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Re: MA 450S Carter Carb

Post by damar2yxr » Wed Jul 05, 2017 2:24 pm

The education here is priceless.
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Re: MA 450S Carter Carb

Post by Chuck Lutz » Wed Jul 05, 2017 3:33 pm

Roger...I considered that as well...that the most likely scenario was an "A" indicated the model in question had been modified in some manner. Then I remembered that the FIRST of the MB carbs were 539S but had a K1 date coded tag on them and had linkage that was different from the standard 539S we associate with the GPW and the MBs after the first 4,000 used that earlier style linkage....

If the "A" indicated a change in the basic model at the Carter factory, we might assume that the earlier 539S with one kind of linkage would have been replaced by a "539SA" after the first 4,000 carbs, would we not?

As I stated, and I think Scoutpilot hinted at and now Olaf has mentioned....changes did occur with the 440, the 441 and the MA carb production at Carter which we don't have enough info on to confirm at this time without part numbers for the smooth and ribbed air horns taken from the spec sheets themselves.

So....depending on when your MA was made, it might have had a ribbed or a smooth air horn....I think the jury is still out on that one!

I wonder what Lloyd's books have to say on the matter?
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Re: MA 450S Carter Carb

Post by Fred Coldwell » Thu Jul 06, 2017 10:08 pm

Chuck Lutz wrote: . . . I wonder what Lloyd's books have to say on the matter?
Nothing, because Lloyd's 5 volume set of books cover only "The Evolution of the Willys-Overland MB Jeep" as stated in the title. Lloyd has not written a book on the MA Jeep. However, the MA Parts List does cover the MA jeep. And here is a full page illustration of and close up from page 26 of the Willys MA Parts List (TM-10-1102) effective June 2nd, 1941:

Image Image

Notice the ribs on the top of the carburetor air horn? There are no changes to the carburetor in TM-10-1102 Change No. 1 dated June 25, 1941 or in TM-10-1102 Change No. 2 dated December 1, 1941. The Denver jury finds this factory evidence persuasive that the Carter 450S carburetor used on the MA jeep came from the factory ribbed for pleasure.
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Re: MA 450S Carter Carb

Post by chasendeer » Thu Jul 06, 2017 10:35 pm

Fred Coldwell wrote:MA jeep came from the factory ribbed for pleasure.
Love it!!!

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Re: MA 450S Carter Carb

Post by Fred Coldwell » Fri Jul 07, 2017 4:44 am

wo2jeeper wrote:Please do your homework better. The ribbed top is never used on a MA. That is a civilian top. The 440 does have the ribbed top ans also the civillian 450s. The 450S was not exclusively for the MA. The non ribbed top with hole is for the MA's 450s. This one has not . . .
I disagree with wo2jeeper's (Olaf's) above statement for the reasons given below.
Chuck Lutz wrote: . . . So...while the Carter spec sheet dated 1939/1953 shows a pic of a smooth air horn, it indicates this is for the "440" engine and the MA and covers the 450S and the 450SA.
That means we should not take for granted that the photo of the smooth air horn is correct because by 1953 none of the Carters had that ribbed feature!
I agree with this statement from Chuck. The Willys MA Parts List effective June 2, 1941, contemporary to when the MA was in production and not 12 years thereafter, lists only the 450S carburetor for the MA. It does not list the 450SA, which is incorrect for the MA but which is covered by Olaf's 1953 revised spec sheet for Carter Carbs models 450S and 450SA. Like Chuck, I do not trust the picture of the smooth rimmed air horn in Olaf's 1953 spec sheet for the 450SA carburetor because it was revised 12 years after MA production ceased.
Chuck Lutz wrote:Looking at the 12/39 "440" for the 1940 Willys spec sheet; it indicates it is for serial numbered 17000 and higher. It has a pic of a SMOOTH air horn. It is a 450S. Looking at the 12/40 "441" for the 1941 Willys AND the 1941 MA; it indicates it is for the 50001 and higher and the air horn is RIBBED!
I have not yet seen images of these two spec sheets that Chuck mentions, so I cannot confirm his observations. But his belief that the MA 450S carb had the ribbed air horn is consistent with my independent research discussed below.
Chuck Lutz wrote:With that I mind if you are building a factory MA then you want a Carter 450S which would have had a RIBBED air horn on it. If you were building a MA that went through a rebuild program after the 1953 date then you might have a 450S or a 450SA and you might have a smooth air horn.
I agree with the observation in Chuck's first sentence. As an aside, I doubt Olaf's belief (repeated above by Chuck) that "SA" identifies a carburetor was rebuilt at the Carter factory, for the simple fact that Carter supplied thousands of "SA" suffixed carburetors to automobile manufacturers who were building brand new cars. I doubt those automobile manufacturers would accept thousands of rebuild carburetors for installation on their brand new cars. Instead, I lean toward Scoutpilot's suggestion that "SA" was a standardized revision to the original "S" carburetor having the same model number.
Chuck Lutz wrote:However, those who have the Carter spec books can probably look up each of those dated circulars and see if they include a blow-up that lists the part numbers. I would be willing to bet that the RIBBED and the SMOOTH air horns have different part numbers! Just a theory of course...
I agree with Chuck's theory and will answer half of this question for Chuck. I hope Olaf answers the other half. The Willys MA Parts List effective June 2, 1941, contemporary to MA production, on page 24 specifies for the 450S carburetor an air horn assembly having Willys part number 116156 and Carter part No. 6-345S for use on the MA. An illustration of Carter air horn assembly No. 6-345S is found in the October 1940 [revised February 1953] Carter spec sheet for its model 407S and 407SA carburetors used on the Willys Americar model "441" during 1941 and 1942, when the MA was in production. Here is an excerpt showing some illustrated parts from that spec sheet:

Image

Note that Carter air horn assembly 6-345S, the one specified in the 1941 Willys MA Parts List, is shown in a Carter document as having a ribbed top. I find this to be conclusive contemporary factory and vendor evidence that the Carter model 450S carburetor as installed at the Willys factory during MA production had the ribbed air horn.
Chuck Lutz wrote:What is the difference between a 450S and a 450SA? Please show a 1939-1941 Carter spec sheet, not one from 1953 or anytime AFTER the end of MA production. I am curious if the ribs/smooth air horn feature were a part of the differences. [i/] Just askin'.....

wo2jeeper: What is the Carter part number for the smooth top air horn assembly pictured in your 1953-revised 450S and 450SA spec sheet? It might be pictured and identified on the back side of the page you posted much earlier in this thread. Thank you in advance for scanning and providing that smooth top air horn image with its Carter part number immediately below it, similar to my above illustrated excerpt.
Happy Jeep Trails,

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Re: MA 450S Carter Carb

Post by George Hollins » Fri Jul 07, 2017 10:07 am

Fred
I think you are onto something here as you usually are.

May I propose a new theory. I believe there is evidence that the 450S smooth air horn was the EARLY design from 1939, NOT the late design, and the smooth design was superseded and changed to the ribbed design in 1940.

Below are the spec sheets for both the 450S and 507S carbs.

450S sheet released 1939 (reprinted 1946)
smooth air horn 6-315S was superseded by the ribbed air horn 6-354S
Drawing showing the smooth air horn was not updated to show the ribbed air horn.

507S sheet released 1940 (reprinted 1942)
ribbed air horn 6-354S
Drawing shows ribbed air horn.

Based on the Carter spec sheets, the ribbed air horn released in 1940 superseded the old smooth air horn from 1939. Therefore, I believe both the 1941 Americar and the MA had ribbed air horns.

If a 450S is found with a smooth air horn, I believe it was from the original 1939-1940 production.

This would explain why the MA manuals show the carb drawing with a smooth air horn. The drawing was probably from 1939 and never updated.

George
Attachments
Carter 450S parts 1939-01 text.JPG
Carter 450S parts 1939-01 text.JPG (248.64 KiB) Viewed 221 times
Carter 507S 1940-01 text.JPG
Carter 507S 1940-01 text.JPG (198 KiB) Viewed 221 times
Willys MA carb manuals.jpg
Willys MA carb manuals.jpg (146.12 KiB) Viewed 221 times

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Re: MA 450S Carter Carb

Post by Fred Coldwell » Fri Jul 07, 2017 12:39 pm

George:

Thank you so much for answering and illustrating the second half of Chuck's question by showing that the smooth top air horn on the early 450S carburetor had a different and lower Carter part number -- 6-315S -- than the later ribbed top air horn -- 6-354S -- used on the MA version of the 450S carburetor. Your nice 1940's dated Carter spec sheets establish, without a doubt, that the smooth top air horn was the early one and the higher numbered ribbed air horn used on the MA version of the 450S was the later one. This proves that the progressive's collective approach is occasionally the best approach: "It takes a motor pool to identify a carburetor." :wink: Thank you for your excellent post with its clarifying illustrations. I believe it is now established beyond argument that the ribbed top air horn on Dave's 450S carburetor is the correct air horn for a 450S carburetor installed on a MA jeep.
Happy Jeep Trails,

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Re: MA 450S Carter Carb

Post by Chuck Lutz » Fri Jul 07, 2017 2:31 pm

Thank you gentlemen for running down the documentation I did not have to illustrate the changes from smooth to ribbed and back to smooth for carburetors through the civilian, MA, MB era. To add a little fuel to the fire....not only do the spec sheets from Carter tell the tale in real time, the ones used with REVISIONS from years later probably suffer from not being updated with drawings or photos even while the part numbers did change...much like we have come to understand with other MVs manuals or parts illustrations.

Now...let me ask the $64,000 Question here......WHY did Willys require a ribbed air horn for some vehicles and not for others?
An experiment?
Something Willys requested for the "441" that the MA inherited?

Can it be as simple as something to do with how the crossover air horn fitted onto the carb air horn that changed during production? I don't know anything about how the 440 or 441 or MA was fed with air from the air cleaner so maybe there is something to that.

I have no dog in this fight myself...I did run across a flange stamped "200" on the bottom and that is what set me to looking into the MA carb stuff when this thread surfaced with differing opinions on what the MA used. Good to see that the collective "gee" can piece together information from sources to give us a better picture of something like this...
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Re: MA 450S Carter Carb

Post by damar2yxr » Fri Jul 07, 2017 4:26 pm

:arrow:
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Re: MA 450S Carter Carb

Post by Darcy Miller » Fri Jul 07, 2017 4:43 pm

If you look carefully at the 1939 drawing at the sectioned Air Horn you will see on the right hand side the hole that is sometimes mentioned. So it seems the progress is from a hole to ribbed to smooth.

Darcy

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Re: MA 450S Carter Carb

Post by wo2jeeper » Sat Jul 08, 2017 5:05 am

Fred Coldwell wrote:George:

Thank you so much for answering and illustrating the second half of Chuck's question by showing that the smooth top air horn on the early 450S carburetor had a different and lower Carter part number -- 6-315S -- than the later ribbed top air horn -- 6-354S -- used on the MA version of the 450S carburetor. Your nice 1940's dated Carter spec sheets establish, without a doubt, that the smooth top air horn was the early one and the higher numbered ribbed air horn used on the MA version of the 450S was the later one. This proves that the progressive's collective approach is occasionally the best approach: "It takes a motor pool to identify a carburetor." :wink: Thank you for your excellent post with its clarifying illustrations. I believe it is now established beyond argument that the ribbed top air horn on Dave's 450S carburetor is the correct air horn for a 450S carburetor installed on a MA jeep.
but why is the 37-38-39 carb build with ribbed airhorn then ? And why are there so many of them around ? While the smooth top with hole is unfindable. I'll would go for that one.

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