Another question to ponder

[chetbrz]

I recently received an email from a gentleman in Germany who just purchased a 1929 Plymouth touring car.  He has a downdraft carburetor which appears to be sitting on the stock intake manifold which also appears to be installed upside down.   I never thought of doing this but can anyone confirm whether this is possible to do without modification ?  In a prior post Steve talked about a Stromberg Carb and the question came up from Glenn concerning a downdraft to updraft conversion.

If the intake manifold is reversible was this a common practice at the time the industry switched over to downdraft carbs ?

Just curious, Chet...

[imoore]

Hi chet
My Q has a down draft carb. And the manifold was not modified in any way. Just flip it up side down and bolt it on. The only thing that possibly need to be changed, depending on what carb used, is the accelerator and choke linkages.
Theres a photo of my engine in one of the first post i did.
In my opinion these car look much better with an updraft of any sort.
But the down draft makes valve clearances much easier.
Ian

[chetbrz]

Hi Ian,

What a coincidence, you have a touring car and the gentlemen who emailed me also has a touring car and you both have downdraft carbs.
I found the info below on the Chrysler Heritage website, nothing was mentioned about Plymouths of the time but Plymouths were mostly sold out of Dodge dealerships.  Gives one pause to think that maybe a Dodge shop might experiment down the road with a Plymouth conversion.   see link below:

http://chryslergroupllc.extra.chrysler.com/company/Heritage/Pages/Brand-Heritage-1920.aspx

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The Downdraft Carburetor, 1929

The downdraft carburetor, first introduced on the 1929 Chrysler and Dodge models, was one of Chrysler's early "engineering firsts." Before that time, carburetors were usually of updraft design — that is, they were positioned below the engine intake. Fuel tanks located above the intake relied on gravity to fuel the carburetor. Those positioned below the intake used a vacuum tank to feed fuel to the carburetor. Locating the carburetor above the engine intake and relying on gravity to deliver fuel to the cylinders seemed more efficient but required reliable fuel pumps for the system to work. Everitt Shepherd, an engineer with the Holley Carburetor Company, approached Carl Breer with a downdraft design in 1928. Breer was concerned about flooding the engine during cold weather starting, but a float chamber developed by the Stromberg Carburetor Company took care of this problem. The new carburetor design brought increased horsepower and speed from a given engine, while improving starting.

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I checked your first post but the picture of the engine is from the other side.  Did you ever post a picture of the carburetor side ?  The picture that I was sent showed a car that had sat in a garage for the past 40 years.   The setup looked like on carb was sitting on top of another and it looked very old.  I will try to add the picture later

Chet...

[imoore]

Hi chet sorry for the delay,
Mine was converted by one of its previous owners. They only modification they did was to the carby to make the bolt holes line up. i personaly would prefer to convert it back to original. but finding a carby and vac tank is being impossible. I cant say if it has any power/economy gains. but she drives great with it.

Ian

[chetbrz]

Thanks Ian,

Here is a picture of Gordon's setup and his comments:


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I found a similar carburetor as mine on the Plymouth. I think the carburetor on the car is a Carter WO 146-249 from a willis jeep from the second world war. This makes sense. The old carb was bad and after the war are enough parts from the left war vehicles in France available.

I will rebuilt the engine and the carburetor as it is. If the engine is running good with the carburetor I keep it. If not I will look for an original one.

An other problem:  the master brakecylinder. Here it is the same. It is not the original one. But in that case I don't know what it is. Have You a source were I can buy a rebuilt original part?
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Ian,

I think your exhaust manifold may have been changed.  I don't think you can reverse the original manifold and still have the output pointing down, but I am not all that familiar with the 28Q?

Chet...

[aussieQ]

Hy Guys,

looking at both photos and other photos of a Q and U Engines I found on the net it looks like you possibly can flip the inlet manifold on both the Q and U engine keeping the exhaust Manifold as is. it looks like the 2 end of the manifold abd the centre chanber are all built on on the manifolds centreline. the only difference between the two is Ians has the Q exhaust manifold and the other the U (the Q attaches to the exhaust at the rear of the engine and the U attaches to the exhaust at the front.)

Looks like an easy conversion for those who prefer a down draft carby.

Gary S

[imoore]

The inlet manifold can be just spun round. All the intake and exhaust ports are inline.
The exhaust outlet changed due to the re designed engine on the U model.