Failed Experiment

[nkaminar]

If you never make mistakes you are not trying anything new.

One of the neat things that the engineers did at Ford was to design the intake and exhaust manifolds to be bolted together to transfer heat to the intake charge. This helps atomize the gasoline which was more important in 1928 than it is today.

The Weber carburetor on my engine has an aluminum manifold and is kind of cold blooded. It takes a while to warm up and operate correctly. So, I thought, why not insert a 1/4 inch copper plate between the exhaust manifold and the aluminum intake manifole. I filed the back side of the aluminum manifold to get about 0.005 inch clearance between the intake manifold and copper plate and used counter sunk screws to attach the copper to the exhaust manifold, see photo below.

Well. it worked too well. With my IR temperature gun, I measured 375 F on the outside of the intake manifold while the normal temperature, when warmed up is about 150. So off came the copper. I now just let the engine warm up a little longer before driving off.

[alexiskai]

Seems like in theory you could remove progressively more copper by drilling holes in the spacer until you got the conductivity you wanted. Would be a lot of trial and error though.

[Ranchero50]

Originally Posted by nkaminar

If you never make mistakes you are not trying anything new.

One of the neat things that the engineers did at Ford was to design the intake and exhaust manifolds to be bolted together to transfer heat to the intake charge. This helps atomize the gasoline which was more important in 1928 than it is today.

The Weber carburetor on my engine has an aluminum manifold and is kind of cold blooded. It takes a while to warm up and operate correctly. So, I thought, why not insert a 1/4 inch copper plate between the exhaust manifold and the aluminum intake manifole. I filed the back side of the aluminum manifold to get about 0.005 inch clearance between the intake manifold and copper plate and used counter sunk screws to attach the copper to the exhaust manifold, see photo below.

Well. it worked too well. With my IR temperature gun, I measured 375 F on the outside of the intake manifold while the normal temperature, when warmed up is about 150. So off came the copper. I now just let the engine warm up a little longer before driving off.

Sounds more like your timing is retarded and you're pushing too much heat out the exhaust. My 1.5" 18ga header tubes don't get that hot at the exhaust ports while idling.

[700rpm]

Somehow your story brings the tale of The Sorcerer’s Apprentice” to mind.

[Synchro909]

Originally Posted by nkaminar

If you never make mistakes you are not trying anything new.

One of the neat things that the engineers did at Ford was to design the intake and exhaust manifolds to be bolted together to transfer heat to the intake charge. This helps atomize the gasoline which was more important in 1928 than it is today.

The Weber carburetor on my engine has an aluminum manifold and is kind of cold blooded. It takes a while to warm up and operate correctly. So, I thought, why not insert a 1/4 inch copper plate between the exhaust manifold and the aluminum intake manifole. I filed the back side of the aluminum manifold to get about 0.005 inch clearance between the intake manifold and copper plate and used counter sunk screws to attach the copper to the exhaust manifold, see photo below.

Well. it worked too well. With my IR temperature gun, I measured 375 F on the outside of the intake manifold while the normal temperature, when warmed up is about 150. So off came the copper. I now just let the engine warm up a little longer before driving off.

A minor thing but the carburettor atomises the fuel. The heat from the manifold system vaporises it. Only the vapour of fuel will burn and with the horrible mixture if hydrocarbons in fuel today, it is more important to have heat in the manifold now than in 1928 when they used a better mix of hydrocarbons.
A while ago, I was talking with a guy in NZ as we looked at his car and he had welded an aluminium box under the manifold and run hot water from the top hose through it. Not only did the carburettor not ice up but he was able to come down a jet size and got better economy.

[CWPASADENA]

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Originally Posted by Synchro909

A while ago, I was talking with a guy in NZ as we looked at his car and he had welded an aluminium box under the manifold and run hot water from the top hose through it. Not only did the carburettor not ice up but he was able to come down a jet size and got better economy.

Several owners in this area who are running Weber carburetors have done the same thing. It really helps.

Chris W.

[nkaminar]

Rancho, Timing is not retarded. I was running at a fairly fast clip, more than an idle. I am also wondering if there was a closed loop: hotter intake leading to hotter exhaust leading to hotter intake.

Synchro, Thanks for correcting me, vaporizing. I thought there was a lot more heavy components in the gasoline of 1928, or maybe I was thinking 1915. I know Ford had to lower the compression ratio of the Model T because of the quality of the fuel and kept it fairly low for the Model A. Or maybe that was the octane rating.

In my automotive engineering class in college we distilled gasoline which left a heavy brown tar after the lighter parts vaporized. Quite a range of the size of the molecules, each vaporizing at a different temperature. This was in the 1960's so gasoline has probably changed.

The hot coolant from the engine would be a better solution as the temperature is more or less controlled and limited.

[KenBolton]

Mistakes? I’m not familiar with the concept!

[katy]

How about mounting that copper plate w/only one fastener in one corner. Then hook up a pull cable so you could manually pull-push the copper in or out to adjust the amount of heat going to the intake manifold.

[Will N]

Interesting thoughts in this thread. Not to hijack it, but to add to the conversation, for the standard Zenith carb arrangement, do we really need that heat transfer feature of the exhaust/intake manifold nowadays, with the better fuels we have? As nkaminar said, the intent was to heat up the intake manifold so poor, low octane fuels of the late '20s would atomize. But with modern fuels that just love to vapor lock in the hot weather, would it be better to insulate the intake from the exhaust manifold?

[George, Iowa]

Great Post! I will be waiting to see what you do next! One of my favorite quotes below!
“There are no failures – just experiences and your reactions to them.” – Tom Krause

[CHuDWah]

Originally Posted by George, Iowa

Great Post! I will be waiting to see what you do next! One of my favorite quotes below!
“There are no failures – just experiences and your reactions to them.” – Tom Krause

Henry Ford had the same attitude, “Failure is simply the opportunity to begin again, this time more intelligently.”

[alexiskai]

Originally Posted by Will N

Interesting thoughts in this thread. Not to hijack it, but to add to the conversation, for the standard Zenith carb arrangement, do we really need that heat transfer feature of the exhaust/intake manifold nowadays, with the better fuels we have? As nkaminar said, the intent was to heat up the intake manifold so poor, low octane fuels of the late '20s would atomize. But with modern fuels that just love to vapor lock in the hot weather, would it be better to insulate the intake from the exhaust manifold?

It's important to distinguish between insulating the intake and insulating the carburetor. If you have a vapor lock problem, you can buy a phenolic spacer to insulate the carb from the manifold.

[Synchro909]

Originally Posted by Will N

Interesting thoughts in this thread. Not to hijack it, but to add to the conversation, for the standard Zenith carb arrangement, do we really need that heat transfer feature of the exhaust/intake manifold nowadays, with the better fuels we have? As nkaminar said, the intent was to heat up the intake manifold so poor, low octane fuels of the late '20s would atomize. But with modern fuels that just love to vapor lock in the hot weather, would it be better to insulate the intake from the exhaust manifold?

In many ways, the fuels available in the 1920s were better than what we get these days. In those days, there was a much lower demand for fuel so they were able to be more choosey about which group of hydrocarbons they used. As demand rose, fuel chemists had to add to each end of the spectrum to keep up volume. That is, they added more volatile hydrocarbons at one end and less volatile at the other. These hydrocarbons have different boiling temperatures. If you allow a container of fuel to evaporate, there will be an oily residue left that will not evaporate (vaporise) unless heated.
Now, let's establish one thing that many have difficulty understanding. Petrol (gas) does not burn but its vapour does. If you submerge a spark plug in petrol and discharge it, nothing will happen (no oxygen) but do that in the vapour and the result is quite different.
The carburettor atomises the fuel into small droplets which enter the manifold on their way to the cylinder. If the manifold is cold, the droplets do not turn to a vapour and therefore do not burn properly. The more volatile hydrocarbons vaporise quite easily (sometimes too easily, causing vapour lock) while the heavier ones do not. If the inlet manifold is heated, more of the heavy elements will vaporise and if they all do, you have complete combustion. If the inlet is not hot enough and some of the heavier ones do not vaporise, the engine runs lean. There is enough oxygen in there for complete combustion but the un vaporised heavy elements do not burn, meaning the engine is lean. The bind is, if the induction route is hot enough to vaporise the heavy elements, it is likely hot enough to cause trouble with the volatile ones boiling in the carburettor. Modern cars are designed to handle this but our cars were made for a different fuel. Different! - better in some ways, not as good as modern fuel in others. The octane was not as high as modern fuel but octane has nothing to do with any of this.
Contrary to common belief, high octane fuel burns slower than low octane.

[alexiskai]

Good article on the physics of vaporization:
https://www.hemmings.com/stories/art...t-now-you-dont

[shew01]

Originally Posted by alexiskai

Good article on the physics of vaporization:
https://www.hemmings.com/stories/art...t-now-you-dont

I enjoyed that article. Thanks for posting.


Sent from my iPhone using Tapatalk

[Chris Haynes]

Using the choke to keep it running smooth until warmed up is certainly not a new concept. A cooler intake keeps the fuel cooler. Cooler fuel, like any liquid, shrinks when cool and expands with heat. Cooler fuel puts a bigger charge into your cylinder equaling more power. Many racers have their fuel line go through a container of dry ice just before entering the carburetor.

[woofa.express]

I ran radial engines in my aeroplanes for years. The first rebuilt exchange I purchased came without a carburettor gasket so I made one. I later learned they aren’t used because the conduct of heat from the engine to the carb eliminates icing so I removed it. In addition, carburated engines have a control to induce hot air into the carb to stop ice or eliminate what has already formed.
The induced engine heat (because of no carb gasket) was only a problem on one occasion. A day when fire bombing in extreme heat. Whilst on the ground reloading, the fuel in the carby just got too hot. When I’d open the throttle it would cough and blow black unburned fuel from the exhaust until the hot fuel in the carb was refreshed with cool fuel, then normal operation resumed.
I once had a 4-cylinder ute and figured if I could make the intake air cooler I’d get even better economy, so I modified it. Carb ice drove me mad. The engine would run badly until it snuffed out. It did run normally but only if it reached operation temperature. I returned the system to “as designed”. Whilst I haven’t modified a fuel system since I do agree with nkaminar Who says, and I quote If you never make mistakes you are not trying anything new.

[CWPASADENA]

Charles Lindberg almost lost the Spirit of St Louis when flying from San Diego to New York to start his non stop flight to Paris. He was crossing the Rocky Mountains and flying the plane at this high of an altitude for the first time and the carburetor started to ice up. The engine was running rough and he keep loosing altitude, but was finally able to get down low enough without hitting a mountain that the warmer air melted the ice and the engine picked up power. At a stop in St Louis, a system to heat the incoming air to the carburetor was installed before he proceeded on to New York.

Carburetor heat is necessary and most modern production automobiles with carburetors had provisions to either heat the air before it entered the carburetor or heat the actual carburetor itself or both. I do not think Model A's had a big problem with the carburetor actually icing up because the air that entered the carburetor was warmed by the exhaust manifold and muffler head pipe. Heat transferred from the exhaust manifold to the intake manifold helped with fuel vaporization.

Chris W.

[katy]

Originally Posted by CWPASADENA

most modern production automobiles with carburetors had provisions to either heat the air before it entered the carburetor or heat the actual carburetor itself or both. Chris W.

A lot of carburated vehicles used a "heat riser"w/a bi-metallic spring at the exhaust pipe connection to the exhaust manifold. W/a cold engine it deflected exhaust gasses against the intake manifold to heat it.

See: https://www.hemmings.com/stories/article/all-rise