Double Venturi carb Before/After

[Gary WA]

Double Venturi Bowl half before and after cleaning up! Lots of heat/windex and cold water.Bead blasting.

[Dave in Petaluma]

Gary, where will you find a new venturi for that carb?

[Gary WA]

Originally Posted by Dave in Petaluma

Gary, where will you find a new venturi for that carb?

I have a few and I did that one for someone else who has one. They were available thru the vendors but supply is out.!

[Synchro909]

Does a single venturi fit the housing?

[Gary WA]

Originally Posted by Synchro909

Does a single venturi fit the housing?

yes they will,read where they were changed in late 1928 because mechanics were breaking them when taking apart so changed to single venturi. never tried to run a DV with single not sure on the operation.

[lrf]

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Gary, were there original jets in this double venturi carb and what were they numbered/sized? Didn't Holley/Zenith change them a few times? I ask because I have some jets and don't know for sure what number Zenith (1 or 2) to stick them in. Also, your article on secondary carb wells printed in the national mag was great! Thanks LRF

[johnbuckley]

Originally jets were numbered replacements generally aren't. Flow testing is the only way to ensure accuracy of jets; various articles elsewhere on Fordbarn about that topic!
If going by numbering Idle usually 10 or 11, Main19.5 or 20, Comp 18 or 19, Cap 19, 20, or21 jets are interchangeable on SV and DVs and Zeniths I and 2 and Holleys lookalikes ,

[johnbuckley]

Originally Posted by Synchro909

Does a single venturi fit the housing?

I have run DVs in "single venturi" housings and vice versa and detected no difference in performance or economy. You may need to grind the locating dowel off if fitting a SV to a DV housing.

[nkaminar]

I read somewhere that the double venturi was dropped because of a patent dispute.

[Jim/GA]

Originally Posted by nkaminar

I read somewhere that the double venturi was dropped because of a patent dispute.

Stromberg vs. Zenith April 1928

https://casetext.com/case/stromberg-...nith-detroit-2

[Synchro909]

Good stuff. Thanks guys. I have a KTK carburettor which is DV. I'd like to get it going - just coz. IMO a Japanese carburettor on the Model A would raise a few eyebrows.

[RENNERS CORNER]

Holley / Zenith Double Venturi.... found another core to assemble and run. Here again someone removed the locator / indexing pin. The pin is another item I need to reproduce as many were ground off or tapped out so that a later venturi could be used.

Back when my dad and I used to rebuild carburetors as a service, we would only get maybe 1 or 2 a year.

I wonder how many of these dual venturi upper and lower castings are still out there?

[Joe K]

Originally Posted by Synchro909

Good stuff. Thanks guys. I have a KTK carburettor which is DV. I'd like to get it going - just coz. IMO a Japanese carburettor on the Model A would raise a few eyebrows.

Like a "Mochi" which appeared on the Avatar for one show.


Joe K

[RENNERS CORNER]

Originally Posted by Gary WA

yes they will,read where they were changed in late 1928 because mechanics were breaking them when taking apart so changed to single venturi. never tried to run a DV with single not sure on the operation.

I'm not so sure about that.... I would be interested to know where you read that.

I don't know why that many mechanics would already be working on them in the first 6 months that the car was being built.

What I have read about the DV is that Ford was faced with a potential lawsuit from Stromberg, that is a well documented reason for changing.

I also believe that there would've been Ford service bulletins about this with Ford advising their dealers to replace or be mindful when working on the DV carburetors.

I'm sure at the Benson library there's an Engineering Information sheet that explains this, too bad we can't get back in there....

[rackops]

Originally Posted by RENNERS CORNER

I wonder how many of these dual venturi upper and lower castings are still out there?

I'm sure plenty of them...a guy at Hershey in 2024 had a bucket of double venturi cores. No venturis, but the cores...a lot of them (I picked up a few).

It just all depends on whose collection is being sold off this year...

[alexiskai]

Originally Posted by RENNERS CORNER

I'm not so sure about that.... I would be interested to know where you read that.

That "explanation" appears in Gordon Biggar's book on carbs ("the Rex Reheis way"). He doesn't give any further details, just that one sentence.

[RENNERS CORNER]

Originally Posted by alexiskai

That "explanation" appears in Gordon Biggar's book on carbs ("the Rex Reheis way"). He doesn't give any further details, just that one sentence.

I knew / know both of those guys that worked on that book.

I think like a lot of old timers they always have some bit of folklore / wives tales mixed in with their explanations.

I can't believe that mechanics were breaking that many of them so early on, that's just unbelievable and then to not have any mention of it in service bulletins....

Thanks for the reference though, I'll ask Mr. Biggar about it.

[alexiskai]

Originally Posted by RENNERS CORNER

I knew / know both of those guys that worked on that book.

I think like a lot of old timers they always have some bit of folklore / wives tales mixed in with their explanations.

I can't believe that mechanics were breaking that many of them so early on, that's just unbelievable and then to not have any mention of it in service bulletins....

Thanks for the reference though, I'll ask Mr. Biggar about it.

What he says in the book is that mechanics would twist the halves of the carb to break them apart, which would crack the venturi. Even if this were true, the solution would have been to tell mechanics not to do that, not to redesign the carb at great expense.