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I will elaborate.

You state that carburetor icing will not happen and that I know it. Most interesting that you can tell what I know from miles away.

"Nobody is taking their Packard out to get the family Christmas tree.." you state. "Even if I took it out in the snow.. the underhood temperature.. would keep the carb and pump ...warm." Warm pumps have nothing to do with carb icing.

These statements indicate that you do not understand carburetor icing. I referenced various onloine sources to refresh my thoughts, suggest you google carburetor icing.
It is most common above 32 degrees and can occur up to 75 degrees, moist air is the culprit. When air goes through the carb venturi it cools markedly due to the "venturi effect", the moisture in the damp air condenses and freezes, sometimes closing off the venturi completely. It is a current problem mostly in small piston aircraft but used to be more prevalent in cars before Packard invented the Fuelizer in about 1920. The ideal temperature of an intake manifold used to be 120 degrees, not sure what it is now

I knew this before adn I know it even better now, despite what your beliefs about my knowledge may be.

Your "theory" that you cna't do enough to keep a motor cool to make it last longer is contrary to 100+ years of internal combustion engine research and practice. In short,. it's wrong. New cars have higher temp thermostats and high pressure radiator caps, look at a temp gauge on many new cars whose engines last 200,000 miles any you will see the midpoint number on the gauge is often over 225 degrees.

Why do you think cars have had thermostats to keep the temp UP to 160/180/195 degrees?? Without them they would 140 or so. That's because they run more efficiently (MPG) at higher temps and contaminants including water are "boiled out" of the crankcase oil.

There are many many other incorrect assumptions/facts/conclusions in your last post, suggest you read some books on theory and design. You ask for ideas and help, then you call me a liar?? I know what I am talking about and if I'm wrong I admit it in the forums and correct it. Because that's the way it should be done.

EXPLANATION FROM INLINERS.ORG



The most frequent complaint I have is from members who complain that since they've installed their multiple carbs, the engine hesitates and stumbles at low speed on initial normal acceleration even after warm-up. The most blamed culprit is the darn Rochester Carburetor. Usually it is falsely accused!

Usually when installing dual exhaust manifolds or headers, the production exhaust heat supply to the inlet manifold is eliminated because (except Edmunds and most recently Clifford) there's no provision or instructions to provide heat...Why?? I don't know and could only guess. In any event heat will be required to achieve good driving response and reasonable fuel economy. Here's why:

As liquid fuel enters the manifold from the carburetor, the vacuum vaporizes the fuel and causes a chilling effect on the walls of the manifold much like the chilling effect of spraying an aerosol on your skin. Now you have a cold manifold. If you do not supply a continuous supply of heat the manifold will remain cold and even build frost in some conditions. At this point, if acceleration is attempted, the vacuum will drop, fuel will no longer vaporize, and will condense on the cold manifold walls until they are fully saturated with wet fuel - this takes about three seconds, during which time no fuel is going into the engine ( and thus no power or a "sag") After the walls are fully saturated with fuel the air flow finally picks up and floods some of the cylinders but not all of them because liquid fuel is notoriously bad for equal distribution.

More fuel (bigger jets) will only slightly help this problem and actually worsens the over-rich condition and spark plug fouling and fuel economy.

The solution: Moderate, and continuous heat supply to keep the walls of the inlet manifold warm and fuel in vapor form. Exhaust heat is fast but requires a butterfly valve in one manifold to force the exhaust flow. Water heat is slower but very clean and not corrosive to aluminum manifolds. This method utilizes the water pump to continously supply warm water to a passage underneath the manifold. It is sometimes necessary to weld a tube to the manifold but be sure to obtain intimate contact between the coolant and the manifold wall and floor. Simply tack welding a closed wall pipe to the bottom of the manifold will not result in sufficient heat transfer.


SEEMS LIKE THEY "DON'T KNOW BETTER" EITHER

Quote:

Ok, now what i said:

Quote:

So you basically re-stated what i said, then called me wrong.


You CAN'T do enough to keep the car running cool, in it's correct range. I DON'T want one of the old cars that pukes coolant while idling all over town or that you can't idle into a car show with while the gauge creeps up. If that WAS acceptable then, it's NOT to me now, and i WOULD attempt changes that would prevent that IF they had a chance of working. I don't have that issue now, so i don't believe i need to work on the hot spot.


As for carb icing, i DO understand how it works. You may be confused and think i'm running a packard powered plane and not a 23rd series?

There would, for sure, would be enough heat if the exhaust manifold was still connected metal to metal, and with the intake tied to the 1000lb 200 degree cast iron block. You couldn't avoid it. That's not taking into account that the air intake is at the top of the hood, where the hottest temp air is in an engine bay design that pretty much produces a houshold oven in air temps.

Now, if i was planning on using a separated exhaust manifold like you described above, and the intake wasn't as conductive to block heat with insulators or something, and i removed the hood, i'd be buying that the carb could ice.

The xmas tree comment was meant to convey that, even in the coldest temps, it's just too damn hot under the hood and with all that metal bolted to it for carb icing to be LIKELY or something to worry about.


However, unless we test those theories, we'll not really KNOW, so we'll have to agree to disagree on that point as i don't have the time or desire to test it. Some of your ideas have lead me away from the hotspot as an issue, and i intend to let it go the way it is.

I'm sorry if i've offended you, and i know you do have a vast amount of knowledge or experience. I was merely stating that i didn't think the long shot that was carb icing could be an issue in this setup, even with the metal block off plate in place, and i didn't agree with your conclusion that i was too dumb to work on a simple WGD carb setup.

To Cortcomp

I absolutely did not state or imply in any manner that your problem is or could be carb icing. What I DID say is that if you seal off the heat excahnge between the manifolds you have dangerous likelyhood of that occuring.

You talk of the underhood heat, the 1000lb block etc etc. A 200 degree manifold, not after sitting outside overnight in the winter.

Here are the conditions under which my 23rd series Commercial Chassis hearse experience carb icing until I fixed it. The car was started COLD, there was no heat convection under the hood, there was no reservoir of heat in the block or manifold, everything was ambient temperature, about 45 degrees. It was very moist, very high humidity, thick cold damp air, foggy. The manifold heat riser was stuck open giving little heat to the intake manifold.

I started the car which ran very very well, immediatley I put it in gear and took off. Rear axle ratio probably 4.1+++ so the engine is at relatively high rpm and so is the air velocity in the carb. HIgh velocity = rapid cooling of intake air. Car stalls while going 30 MPH. Will not restart, elapsed time maybe 40 seconds. Pull over, check wiring, fuel etc etc. In a few minutes the ice melts and the "evidence" is gone from inside the carb venturi. The carb/manifold warms and no more problems that day.

Same situation repeats itself several times over the next year. Eventually I suspected carb icing so when it happened
I quickly pulled the air cleaner off and saw the culprit. Next opportunity repaired the exhaust buterfly, problem fixed.

By the way my hearse is not an airplane if I failed to make that clear. And just becase you and you friends never saw this phenomenon does not mean it did not happen. There are many who think that hydroplaning is a bunch of bunk, when it happens to them some become believers real fast, others swear it was black ice on an 80 degree day during a thunderstorm. You just can't fix stupid!