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Fri Jan 21, 2011 5:19 pm

I have pair of Weber 46 IDA2 carbs (made in Italy) that has markings OJ in where should be serial number, does anyone knows what these markings stands for? How old are these?

Fri Jan 21, 2011 6:24 pm

You have a very rare set of carbs that were used for a racing porsche motor.Google search for info.

Fri Jan 21, 2011 6:30 pm

Porsche was the primary user, the 46IDA carbs first showed up in the late fifties, also the 904 CarreraGTS and 911R used them. And yes they are rare, especially if you have a right & left. Sorry, have no idea what the OJ stands for.

Fri Jan 21, 2011 8:29 pm

busman78 wrote: and 911R used them.
The 911 was a 6 cylinder and used (2) 3 barrel carbs. One of them bing the Weber 46IDA3C.

Fri Jan 21, 2011 10:11 pm

Yes, the 911R used the 901/22 engine, same engine the 906 Carrera had and was available with either Bosch Mech FI or a pair of 46IDA's.

Sun Jan 23, 2011 1:22 am

busman78 wrote: Yes, the 911R used the 901/22 engine, same engine the 906 Carrera had and was available with either Bosch Mech FI or a pair of 46IDA's.
While the 911R's Webers were called 46IDAs, they are more correctly called a 46IDA3C. The 3C stands for triple choke. The 46IDA3C is nothing like the 2bbl version. In fact, it's more like an IDF.

Here is the IDA3C:

Sun Jan 23, 2011 1:26 am

busman78 wrote: Porsche was the primary user, the 46IDA carbs first showed up in the late fifties, also the 904 CarreraGTS and 911R used them. And yes they are rare, especially if you have a right & left.
The IDA (both 46 and 48) didn't exist until 1964. Prior to that the Weber used on early 904s and in Can-Am racing (63 AC Cobras too) were IDMs

Here's the difference, IDM left, IDA right:

Sun Jan 23, 2011 10:06 am

Bruce, curiousity, is that carb on the right a 46IDA two barrel? The Weber books I have make little reference to a 46IDA two barrel except that it was a short lived production and everthing after that is the three barrel version if it is 46mm. Unfortunately the IDA section of the book does not give specific dates, although it does have a blurb about a 1959 race in which the Italians won using Weber carbs, it did not specify IDA, IDM or what Weber carb was used.

Mon Jan 24, 2011 2:23 am

No, the carb on the right is a common (but very early) 48 IDA.

Other than the bore size at the bottom, and the various jets, there is one part on a 46 IDA that is unique to that size. There is a small brass collar that goes around the accelerator pushrod to limit it's travel. In some early diagrams this part is shown in a separate box.

Wed Aug 19, 2020 12:01 pm

The Weber IDA series carburetors were a replacement for the IDM series carburetors which were manufactured from 1955 to 1964. During 1963 Weber transitioned from the sand casting manufacturing process to the die-casting manufacturing process, some say with Ford’s help. The IDM series was employed on several original manufacturers cars including, Porsche, Maserati and Ford (GT40 or just GT). The IDM series was typically regarded as a high performance carburetor and were used primarily for racing applications by these manufacturers as well as sports racers of the period. Ford, Shelby American and Chaparral also used the 48 IDM series carburetors on their race cars, Ford and Shelby American eventually changed over to the IDA series carburetors in mid to late 1964. Chaparral used 48 IDM carburetors all the way into the 1968 Can Am season and never switched over to the 48 IDA series carburetors. The IDM series carburetors were offered in various model sizes, 45 IDM were used by Maserati and Porsche, 46 IDM on Porsche Carrera engines (4 Cam), 48 IDM on American V8 engines. These IDM carburetors all utilized the same carburetor body casting but differed in the throttle plate sizes. The 46 IDA (2 choke) carburetors were intended as replacement carburetors for Porsche Carrera (4 cylinder, 4 cam) racing engines that were originally equipped with 46 IDM carburetors and were never a factory installed carburetor. There were some performance upgrades made to the IDA series carburetors that were not found in the IDM series carburetors. After Weber switched over to the IDA series carburetor design the IDM series was made obsolete and both IDM carburetors and tuning parts disappeared causing many owners of cars equipped with IDM series carburetors to retrofit their cars with IDA series replacement carburetors, making the IDM series carburetors very valuable to owners that have cars that were originally equipped with them.

Wed Aug 19, 2020 12:06 pm

I would contact Pierce manifolds for info on those.

https://www.piercemanifolds.com/default.asp

eQ

Wed Aug 19, 2020 12:23 pm

Weber 46 IDA 2 carburetors are no longer in production. The early production 48 IDA in Bruce’s post above is actually a second design late 48 IDA1 or possibly a 48 IDA4.

Wed Aug 19, 2020 8:12 pm

The well known rally Super Beetles (1302) built by Porsche Salzburg in Austria had their 1600 cc engine fed by the 46 IDA 243 carburetors. ~ 120 hp! Per 2/72 article in the German "Gute Fahrt" magazine.

Thu Aug 20, 2020 11:54 am

It is interesting to note that the footprints are the same for, 45IDM, 46IDM, 48IDM, 46IDA AND 48IDA carburetors. This makes manifold selection to any number of manufacturers engines very easy.

Thu Aug 20, 2020 12:42 pm

Good luck finding any but one of those carbs easily :shock:

Wed Aug 26, 2020 5:55 am

RACEWHERE wrote: The early production 48 IDA in Bruce’s post above is actually a second design late 48 IDA1 or possibly a 48 IDA4.
The carb in the pic I posted is just a 48 IDA. No number after the IDA. My guess is mid to late 60s production.

Mon Aug 31, 2020 11:30 am

not sure how true/accurate it is...but I saw someone post on a FB group that someone is making IDMs again...of different sizes too.

but then again...it is Facebook...

BJ

Fri Jun 11, 2021 3:38 pm

any info on the 50IDA webers?

Mon Jun 14, 2021 2:50 am

well, that's quite a find! It looks like they were used on the Group 4 Maserati Boras
http://www.gtc-collection-cars.com/car-for-sale/1973-maserati/bora-gr4-42.html

Wed Jun 16, 2021 12:18 pm

pretty strange parts! what about the difference between the 48IDA1 and 48IDA4? they look the same, what can i check on them?