Hot air pipe

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Model T Ford Forum: Forum 2012: Hot air pipe
Top of pagePrevious messageNext messageBottom of page Link to this message  By William L Vanderburg on Friday, April 13, 2012 - 10:53 pm:

I have one of these but had never put it on. So today, I decided to do so, for the hell of it.

I have found that the repro hot air pipe isn't made to really fit right, and I had to "cut" the pipe in several areas to get it to fit properly.

And technically, it STILL doesn't fit right.

Oh, well, obviously another part "reverse engineered". I don't remember who I got it from, although I could probably find out. I have EVERY receipt for any item I've ever bought for the car.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Steve Jelf, Parkerfield KS on Friday, April 13, 2012 - 11:34 pm:

You should have been at today's auction. You could have had an original pretty cheap.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Hal Schedler, Sacramento on Friday, April 13, 2012 - 11:43 pm:

What are the pros and cons of the hot air pipe? I currently am not running one,,,should I?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Craig Anderson, central Wisconsin on Saturday, April 14, 2012 - 12:13 am:

In Sacramento you apparently don't experience carburetor icing......if you did you'd know it.


Top of pagePrevious messageNext messageBottom of page Link to this message  By David Dare - Victoria Australia on Saturday, April 14, 2012 - 12:17 am:

G'day Hal, l have heard both arguements for and against the hot air pipe, me l use them and have at times not used them, l guess ( my opinion ) your driving location will probably have a lot to do with it, but having said that, l'm down under, predominantly warm to hot, l still use it, its a personal choice l think....
I am personally not convinced that hotter climates dont need them, l have heard that the engine "will" run hotter if you do, l have seen that, but then l also believe that the radiator if working properly will overcome that heat problem.day Hal, l have heard both arguements for and against the hot air pipe, me l use them and have at times not used them, l guess ( my opinion ) your driving location will probably have a lot to do with it, but having said that, l


Top of pagePrevious messageNext messageBottom of page Link to this message  By David Dare - Victoria Australia on Saturday, April 14, 2012 - 12:18 am:

what is that ?? its all jumbled up, thats not how l wrote it .


Top of pagePrevious messageNext messageBottom of page Link to this message  By Craig Anderson, central Wisconsin on Saturday, April 14, 2012 - 12:44 am:

It depends on the humidity.
There is a terrific venturi action in the carb which removes heat so fast it can lead to icing.
I had a 1936 Oliver Hart Parr 70 tractor with a 6 banger engine and the carb would turn white with frost in no time flat. It would stay that way until the engine warmed up but I never experienced actual carburetor icing up the jets the carb.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Dallas TX on Saturday, April 14, 2012 - 12:54 am:

I think it depends on the quality of the gas. If you have 1925 quality gasoline you need to use a hot air pipe. If not you don't.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Doug - Braidwood (glow in the dark), IL on Sunday, April 15, 2012 - 09:53 pm:

Here is IL I have had the carb ice up while driving. Temp didn't affect it much, but humidity did. I currently run without because I am looking for a usable original. With my 26, I need the tab to be in the back not the front. I think the plugs don't soot and the carb doesn't ice if I run it.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Scott Conger on Monday, April 16, 2012 - 06:18 am:

*If you have 1925 quality gasoline you need to use a hot air pipe. If not you don't.*

Bold statement, but still an opinion.

In Florida, my '13's carb will ice and require a very rich mixture which will foul the plugs in 10 miles. The addition of a hot air pipe solved that problem. I was able to immediately lean out the mixture by 1/2 turn and I haven't changed a plug in 4 years (about 5 thousand miles for this car). Fuel mileage went from 12 MPG to 20 MPG.

My '19 doesn't need the hot air pipe to run, but it runs better with it. Several cars in our club run well without them, however all have very cold, sweaty carbs and intakes, and I would not be surprised if those owners are having to run a bit rich. The fact that many get poor gas mileage seems to support this.

Relative humidity in FL is perpetually high and definitely contributes to the problem.

So there's empirical evidence of the need for a hot air pipe, in some instances, with 2012 gas.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Dallas TX on Monday, April 16, 2012 - 06:50 am:

I've tried them. The cars go slower with hot air pipes installed regardless of temperature. In the past ten years I have lived in Kentucky, Arizona, Virginia and Texas, driving year round in all four places. Never had a bit of carb icing from below zero temps near sea level to 115 degrees at 4500 feet in Arizona. No effect on spark plugs or anything else.

The intakke manifold will be cooler than any other part of the engine due to Bernoulli's (spelling questionable) law.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Scott Conger on Monday, April 16, 2012 - 07:33 am:

Our car lived in VA for two years and did not require a hot air pipe there either, but it sure does in FL.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bob Jablonski on Monday, April 16, 2012 - 07:59 am:

All has to do with humidity, not temperature

Talk to a fly guy & he'll confirm


Bob J.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Hal Davis-SE Georgia on Monday, April 16, 2012 - 09:11 am:

I run a hot pipe and have still experienced carburetor ice. I'd hate to see it without one. Bound to be worse. In a dryer climate, I can easily see how one could do without one, but for South Georgia, I'm keeping mine.


Top of pagePrevious messageNext messageBottom of page Link to this message  By John Manuel, Lafayette, La. on Monday, April 16, 2012 - 10:37 am:

Humidity in south La. is extreme. I'm going to put my hot air pipe back on to see if it helps with my plug fouling issues. I had left it off when I pulled the manifold when I first got the car a couple years ago---couldn't see the point in it.


Top of pagePrevious messageNext messageBottom of page Link to this message  By David Stroud on Monday, April 16, 2012 - 05:48 pm:

Here in N.W. MO. the carb will ice up without a hot air pipe, depending on conditions. I have seen it happen. Dave


Top of pagePrevious messageNext messageBottom of page Link to this message  By James A. Golden on Monday, April 16, 2012 - 09:37 pm:

What they used to say in the Navy works with the hot air pipe.

Cut to specs, pound to fit and paint to match.

You really need that unit, so force it into position.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Dallas TX on Tuesday, April 17, 2012 - 06:55 am:

Just to clarify, carb icing occurs in the venturi of a carburetor. When it happens the engine quits because fuel can no longer be pulled into the venturi. If you can see it happening you must be Superman. You would have to have X-Ray vision.

I've driven my Ts in rainstorms all day on tour in temperatures from 28 - 80 degrees. Never a hint of carb icing without a heat tube. I say put one under the seat and if you ever meet someone who imagines he has carb icing give it to them.

I think perhaps you are mistaking normal water condensation on the outside of the carburetor for carb icing.

This is my dog Rocky after riding all afternoon in the '13 touring with no side curtains at about 55 degrees while on tour in Indiana. He's a good boy!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Doug - Braidwood (glow in the dark), IL on Tuesday, April 17, 2012 - 07:14 am:

Royce I have had the carb ice up to the point that the car would stop running. I see frost all of the time on the outside. That is of no consequence to me.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Patrick on Tuesday, April 17, 2012 - 08:51 am:

I have an original hot air pipe on the Holley NH of my '26 coupe and have found it necessary to bend it in so the choke rod will clear it so I can twist it when adjusting the carb and operate the choke wire when I pull it out to choke the carb when starting from the inside. Anyone else had to do this with their hot air pipe? Jim Patrick


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan Treace, North FL on Tuesday, April 17, 2012 - 09:24 am:

Jim
Are you sure your T has the correct hot air pipe?

The 4582 came in style for the model years.

Here is the 4582B (factory #T-686C)...used for '25-'27 with HolleyNH using the univ joint choke/carb adjuster.


Note how the flat space is given for the rod, and how the manifold clamp ear is formed one piece the backside of the hot air pipe for mounting. This is '25'-'27.

Here is the typical 4582 for '24 to about '22



And here are two of the earlier styles,

Note how the mounting 'ears' for the clamp stud are fastened to the earlier hot air pipes.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Patrick on Tuesday, April 17, 2012 - 12:19 pm:

Dan, Mine is the upper picture in your post with the one piece securement hole. It was on my all original coupe when I bought it in 1970. Jim Patrick


Top of pagePrevious messageNext messageBottom of page Link to this message  By clayton swanson on Tuesday, April 17, 2012 - 01:35 pm:

small aircraft people say you loose 10 horsepower when you turn on the carb heat.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Dallas TX on Tuesday, April 17, 2012 - 02:01 pm:

Exactly. The cooler the intake air, the more power you can make because there is more oxygen per any given volume as inlet air temperature decreases. Not only do you get better power, you get better fuel economy. That's why aircraft pilots turn off carb heat any time they can.

By the way, take off the choke stove any time you have a few free minutes. It is unnecessary.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Cecil Paoletti -- Rrnton WA on Tuesday, April 17, 2012 - 02:24 pm:

Royce, could you be more specific? What do you mean by "choke stove." Does a Model T have a "choke stove?"


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Patrick on Tuesday, April 17, 2012 - 02:27 pm:

I'm always reluctant to remove a part that Ford engineers deemed necessary, but it won't be the first time that experts on this forum have convinced me that some parts are just not needed.

Why did Ford design the intake air pre-heater if it is not really needed? Is it only meant for the initial first few minutes of running on a cold Michigan morning and after that, is a detriment to the the subsequent engine performance? If so, it certainly is not needed here in Florida. Do you think that, in my case, in warmer climates, that, removing the pre-heater will result in a smoother, more efficient running engine? Jim Patrick


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan Treace, North FL on Tuesday, April 17, 2012 - 03:30 pm:

Jim

I'm in No. FL and the hot air pipe is needed. Always one on my T's....every Henry stock part, including the engine pans too.

Without it you will see frost on the lower bend of the intake, esp with the alum intake. The cool gasoline particles hit that spot first, and you will get a cold pipe, cold to touch..try it without and you see for yourself.





This is the set up that frosted. The red intake is an alum ex-size type. When first mounted the intake frosted.

So I added a repro hot air pipe, but was still winching that the hot air would lower performance, so I cut away a part of the upper pipe. Now don't know what the cutaway opening does to help, but by adding the hot air pipe shown, the frost went away.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Dallas TX on Tuesday, April 17, 2012 - 05:36 pm:

The heater or choke stove was needed because gasoline vapor pressure was very different in 1909 - 1927 than it is today. We no longer need to heat the carburetor to vaporize the fuel, even at low temperatures. The engineering of gasoline has eliminated the problem the heat tube was installed to fix.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Walker, NW AR on Tuesday, April 17, 2012 - 07:26 pm:

Royce -- The frost that many of us have seen on our intakes and carbs formed there while using modern gas, not 1927 gas. Please read the above thread. Are you saying that everyone is wrong but you?

I'm reminded of the two mothers watching the marching band in a parade, and one says to the other: "Oh look, everyone is out of step except my Little Johnny." :-)


Top of pagePrevious messageNext messageBottom of page Link to this message  By Tom Carnegie on Tuesday, April 17, 2012 - 07:54 pm:

At least one of the Ford instruction books says to remove the stove in the summer. I pretty much agree with Royce on this from my experience. I don't use a stove, and in my climate, I have never had my T carb freeze up, and I drive most every day in all kinds of weather. Now, my definition of freezing up is not frost on the outside of the manifold. Frost on the outside causes no problem. Freezing up means having the throat ice to the point that the engine will not run.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Peter Borland. Bathurst. NSW. Australia. on Tuesday, April 17, 2012 - 08:18 pm:

G'day,

I fly, and when in flight you are using cold air for power and economy. If you notice a drop in performance from the engine you pull the carby heater on and use heated air to melt the ice that is forming in the carby,once cleared you return to cold air for regained performance and economy. The only other time you engage heated air on the intake is when you are landing to ensure that you do not get an unexpected icing when you need everything to be working perfectly. On our cars we can have the same problems, if you live in high humidity, cold or high altitude areas you may find that you require the heater pipe fitted all the time, other areas where you have warmer air you will probably not require one. So many variables make the need for, or not a decision made through experience. For Ford to fit them to all cars solves all of his reliability problems as the cars are used in all conditions, and does not allow for a bad reputation to be made because of a problem that may or may not occur. Cold air, more dense air equals more power, hot air, less dense reduced power. Not super critical on a "T" though, If you can do without it because you do not have a icing problem, use a filter instead, icing a problem use the heater pipe. The choice is yours to make.
Have fun and play nice.

Peter


Top of pagePrevious messageNext messageBottom of page Link to this message  By Donald Conklin on Tuesday, April 17, 2012 - 09:59 pm:

I was wondering how the aluminum and iron manifolds compared in this issue. Dan has indicated the condition is worse with the aluminum manifold. I was thinking the better conductivity of the aluminum would have helped to reduce icing.
Both of my T drivers have aluminum intakes with shields over the front portion of the intake and exhaust manifolds, in my minds eye this helps. I also use air cleaners that may make some difference.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Patrick on Tuesday, April 17, 2012 - 10:22 pm:

I'm going to give Royce's suggestion a try and remove my intake pre-heater and see what happens. Rarely, if ever, has he steered me wrong in the advice he has given. Anyway, the intake heater has always gotten in the way of the choke connector which sometimes binds the choke rod and prevents me from being able to adjust the carb. Hopefully, I will be pleasantly surprised... that my T will run smoother and find the "stove" is not necessary here in Florida. Who knows. This may become the new argument in place of whether or not a water pump is needed. We need a new controversy. LOL! Thanks Royce. Jim Patrick


Top of pagePrevious messageNext messageBottom of page Link to this message  By David Stroud on Tuesday, April 17, 2012 - 11:34 pm:

Right on Mike!
Royce, when I refer to "carburator icing", I am referring to ice on the carb. I didn't stick my finger in it to see if there was ice-frost on the inside, but I'd bet there was. I know I'm not as smart as you, but believe it or not, I CAN tell the difference between ice and condensation. There is just no middle ground with you is there? It's Royce's way or no way. JMHO Dave


Top of pagePrevious messageNext messageBottom of page Link to this message  By Ted Dumas on Tuesday, April 17, 2012 - 11:38 pm:

If your car runs fine without the pre-heater, then you might develop a little more power without it. The tradeoff in my view is that the pre-heater gives you somewhat better carburetion at the expense of less dense (warmer) air in the cylinder. The more air mass in the cylinder, the more power you can develop, assuming that all other factors are constant. The supercharger utilizes this principle. A trial with and without should tell you which is best on your car.


Top of pagePrevious messageNext messageBottom of page Link to this message  By J Berch on Wednesday, April 18, 2012 - 01:43 am:

I was out cruising with my friends in our T's. I thought I'd take a walk on the wild side and remove my heat stove. They all had water pumps with Evans NPG+C coolant in the radiators, Watts clutches, E timers and high viscosity oil in their crank cases. Suddenly my truck began to slobber. Try as I might, the RPM just kept dropping. I finally pulled off to the side of the road. There I sat surrounded by an angry mob of Model T people grumbling about being late to the ice cream shop. I apologized profusely and explained that I didn't need a heat stove. luckily one of the guys had a jug of 1925 gasoline. I pulled my heat stove from the toolbox installed it, and away we went.

All joking aside, in my opinion, Peter Borland nailed it. Do what works for you in your climate and conditions.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Thode Chehalis Washington on Wednesday, April 18, 2012 - 01:57 am:

This chart kind of tells the whole story.

Mid temperatures at high humidity can lead to icing. Very cold temps are not a problem, nor are very high temps. Low power is more likely to ice up then high power. You may pull up a mountain with no problem but ice up coming back down under exactly the same weather conditions.

In an ideal world a Model T would be like an aircraft, have a manual carb heat control. Of course icing up is not as much of a problem if you don't have thousands of feet to fall out of the sky.



Jim


Top of pagePrevious messageNext messageBottom of page Link to this message  By J Berch on Wednesday, April 18, 2012 - 02:03 am:

Thanks for posting that Jim. I think something similar was posted on the last annual discussion on this topic.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Scott Conger on Wednesday, April 18, 2012 - 06:42 am:

I need to amend my original post. I stated that my carb on my '13 would ice. I was sloppy in my description, and in fact is not always true. The carb and intake in fact become extraordinarily cold and in only the coldest weather we have in Fl will it form ice.

However, the exact description of what happens is irrelevant to my original, accurate, description of always having to run so rich to overcome the effect of a chilled carb and intake manifold that the plugs would foul as a result of that over-rich mixture. The stove cured this.

The actual driving requirements of several members contributing to this thread are that their cars will NOT run well or at all without the stove. Coincidentally many of those folks live in high humidity climates. Some folks find that they do not need it at all.

The fact as spelled out in the thread is that SOME cars absolutely need them (and it appears that early cars with aluminum intakes appear somewhat more vulnerable to this).

The opinion of some, is that all of those folks who find that their cars run much better with the stove are completely wrong in their assessment. I personally find that to be astounding and redefines the definition of "stubborn".

Does your car need it or run better with it? Who knows? Try it and see.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Dallas TX on Wednesday, April 18, 2012 - 07:47 am:

Ice forming on the outside of the carburetor is not carb icing. Again, try it you will like it. I've had a carb heat tube under the back seat of my 15 for many years. Never needed it yet.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Larry Smith on Wednesday, April 18, 2012 - 11:10 am:

Hey Dan, are those original 1912 valve cover wing nuts? I've never been able to find any. Also those hot air pipes probably keep the bugs out some too!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Patrick on Wednesday, April 18, 2012 - 11:20 am:

Years ago, I purchased a foam air filter from Snyders (T-6205) which I will be clamping onto the intake of my NH when I remove the intake pre-heater. That'll keep the bugs and dust out. Jim Patrick


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bernard from San Buenaventura, Calif on Wednesday, April 18, 2012 - 12:39 pm:

Highjack -- highjack -- highjack -- alert!

The one clear advantage I see on the hot air pipe is that it's less likely that the carburetor will swallow any unfavorable objects. So what is the general opinion on using an air cleaner?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Wednesday, April 18, 2012 - 12:54 pm:

Oregon fall or spring don't remember which. Granted this was just at idle.


Top of pagePrevious messageNext messageBottom of page Link to this message  By James A. Golden on Wednesday, April 18, 2012 - 12:58 pm:

Jim, your T will run better with bugs and dust than it will with that air cleaner and no pre-heated air.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Patrick on Wednesday, April 18, 2012 - 01:21 pm:

James, I'm not sure what you mean. Are you saying it would run better:

A. With the intake pre-heater?
B. Without the intake pre-heater, but with the foam intake filter
C. Without the intake pre-heater, but without the foam intake filter.

If B, why would running a foam air filter be detrimental to performance? The open celled foam is very porous and barely impedes the flow of air at all.

Keep in mind I'm down here in Florida where it's warm pretty much year round. Jim Patrick


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan Knoll on Monday, September 03, 2012 - 03:51 am:

I think I may be experiencing Carburetor icing.
The weather this evening :

Temperature: 54°
Wind: Calm
Dew point: 52°
Pressure: 29.96 in.
Humidity: 94%
Visibility: 1.2 miles

My car seems to run like crap but only at night : I noticed the carb was really iced as was the aluminum intake manifold . My Model A wire mesh air cleaner is down low under the side apron. Tomorrow it is coming off and the new heat pipe is going on. I will really be interested to see if it helps. I checked my points and cleaned the plugs this evening also. The new Champion X plugs were pretty fouled already , #1 being the worse. I have a brand new radiator and am running a 50/50 mix of antifreeze, and notice the lower steel pipe never gets very hot ...I may actually be running to cold ..I also have just the half hood so It never really gets hot under the hood. we will see what happens...


Top of pagePrevious messageNext messageBottom of page Link to this message  By David Stroud on Monday, September 03, 2012 - 03:59 am:

Dan, no that can't happen. Just ask Royce. Dave


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dan Knoll on Monday, September 03, 2012 - 04:05 am:

LOL Dave.... I assume that was a "tongue in cheek"
comment ? Unless I have some hidden problem I don't know about , it's sure the only explanation I can come up with .

The chart sure says at that humidity , temperature and dew point it is probable...


Top of pagePrevious messageNext messageBottom of page Link to this message  By Fred Dimock, Newfields NH, USA on Monday, September 03, 2012 - 04:23 am:

Jim and Bernard -
When a T has a hot air pipe the bugs will be well done by the time they get to the carburetor! :-)


As for me in New England, I tried the hot air pipe on a 19 with a NH carb and found no difference so I took it off because I knew that colder intake air gets more gas into the combustion chamber and better performance


Top of pagePrevious messageNext messageBottom of page Link to this message  By David Stroud on Monday, September 03, 2012 - 05:15 am:

Dan, yup. Dave


Top of pagePrevious messageNext messageBottom of page Link to this message  By Bob Coiro on Tuesday, September 04, 2012 - 01:07 am:

My uneducated, newbie position would be that the original pre-heater was designed not so much to prevent carburetor ice as to help vaporize the low-quality fuel that was available at the time. In modern context, I see it as a neat gadget for raising the air intake up out of the grit-injestion zone. My car didn't come with one, so I use a cheapie foam air-cleaner soaked in oil. Not that I have anything with which to compare, I probably enjoy better performance because a pre-heater does rob power. On the other hand, there's something good to be said for originality.


Top of pagePrevious messageNext messageBottom of page Link to this message  By William Rowles on Tuesday, September 04, 2012 - 02:18 am:

The first after-market accessory I bought for my '20 runabout was the foam air filter, which replaced the heat pipe. She ran fine with the cooler and cleaner air until one day when the air temp. and humidity were such that it iced up and quit running. I have removed the air filter and re-installed the heat pipe since I don't drive in dusty conditions and don't like the engine to quit running while driving. Decided Henry put the intake manifold/carburetor heat on the V-8 before he added the air filter to the engine!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Nevin Gough on Tuesday, September 04, 2012 - 03:21 am:

I took my T for a drive one summer evening. After a mile, the motor died and I came to a stop. Fortunately, I had my Model T guru with me, and he immediately saw ice on the manifold. After letting it sit for a while, it started first pull, and I drove it home.

I bought a stove for it, and after 7 years of use, have never had that problem again.

Maybe I was mistaken, and so was my friend....but I'm leaving my stove on.


Top of pagePrevious messageNext messageBottom of page Link to this message  By David Stroud on Tuesday, September 04, 2012 - 04:45 am:

Nevin, you must be mistaken. As I posted above, just ask Royce. He is never wrong. Dave


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Dallas TX on Tuesday, September 04, 2012 - 06:16 am:

If you say so Dave. Thanks!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dave Huson, Berthoud, Co. on Tuesday, September 04, 2012 - 08:06 am:

There must be someone in Colorado that uses hot air pipes but I have never seen one in use. Some one above mentioned that you might need one in high elevations but I think my Ts are driven at higher elevations than any one in this forum and I have never had a problem. I drive my Ts to the highest peaks and passes that I can find at least every other week. I also drive my Ts in to town EVERY DAY and don't use one. Maybe you need hot air pipes in Florida but I don't think you need one around here.
Its your T, put a hot air pipe on if you want, I sure would not criticize your choice.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Terry Woods, Katy, Texas on Tuesday, September 04, 2012 - 09:38 am:

Even aftermarket carbs like Stromberg used a preheating system, but note that henry didn't when he changed to the vaporizer. Probably that was because the air/fuel mixture was being heated another way.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Tuesday, September 04, 2012 - 11:42 am:

Manufactures later added a "hot spot" to the intake manifold, look at the Model A intake. The stove pulls hot air off the exhaust manifold to help vaporize the fuel. The best illustration shows the fuel forming droplets on the inside of the intake because of not being atomized/vaporized, now I have to remember which book I saw it. On dry low humidity days I can run without it but that time of years is passing and it will get put back on. I have never really noticed any change in speed with it on. Even the 20's Chevrolet 4's had a pre-heat setup, pulling the heat off the exhaust pipe and running it in a flex tube to the intake.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Doug Money - Braidwood, IL on Tuesday, September 04, 2012 - 12:35 pm:

I know through the seventies, there was a pre heater connected to the air cleaner. There was also manifold heat applied to the intake that was an exhaust chamber that ran through the intake from side to side on a V8.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Bender Tulsa Oklahoma on Tuesday, September 04, 2012 - 12:40 pm:

I think and this is my opinion that the fuel back in the day of the T Model was just plain poor and needed the hot air pipe to assist in vaporizing it enough to get a good air/fuel mixture. As noted other carburetor manufactures follow suite but not all. So it maybe the design required the addition of the hot air pipe also.

I have a number of Model T's none have the hot air pipe on them, I found they seem to hurt the engine performance and that was then just a seat of the paints opinion formed years ago.

I drive long distance tours, not like Dean Yoder but close.

Having driven from flat lands, Rockie Mountains, high plain deserts, Gulf coast into Florida, East coast, mid west and fixing to head to the North east in a few weeks , I have never had a problem with icing. Yes it sweats, and I have seen frost form on the out side of the carburetor, but never had one quit or cause any issues.

The attached is facts from our Dyno testing. Using a hot air pipe robs power. If you feel you need it run it.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Peter Claverie on Tuesday, September 04, 2012 - 12:46 pm:

This may or may not be a hijack, but as I read all the above posts and ruminated on modern gasoline vs: 1920's gas, it occurred to me that there are two variables these days that MIGHT have an effect on the need for a pre-heat stove.

One, as was discussed yesterday, is the presence or absence of Ethanol in the fuel, which must, I assume, change its volatility somewhat - I don't know in which direction.

The other is the use of Sta-Bil or Sea Foam. Or not. Again, I don't know what these products actually do, in terms of changing the volatility of the gasoline.

And, if either of these "additives" changes the volatility of the fuel, what effect might that have on its tendency to ice up in a carb?

Just asking.......


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mark Gregush Portland Oregon on Tuesday, September 04, 2012 - 12:59 pm:

Was the engine tested in above chart a stock engine or modified? 3 horse is a good increase.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Mike Bender Tulsa Oklahoma on Tuesday, September 04, 2012 - 01:20 pm:

Stock Ford High head, steel intake, NH carb sway back, .030 pistons, old Ford cam, worn but not to bad, valve lash set by piston position, used a dizzy for spark.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Dallas TX on Tuesday, September 04, 2012 - 05:34 pm:

Carb icing would be caused by humidity in the air versus the pressure drop = temperature conditions very low, moisture very high. It would not matter what kind of fuel you are running.

I say carry your hot air pipe under the seat. If you find that your car dies and the throttle won't move due to ice accumulations you might need it. I carried mine around for a decade and then retired it to a place of honor on the garage shelf because it was never needed.

As Mike has proven, and anyone with a 9/16" wrench can easily prove for themselves, the hot air pipe cuts power dramatically.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Thode Chehalis Washington on Tuesday, September 04, 2012 - 11:38 pm:

Just to keep things balanced here we need to list the advantages of a hot air pipe.

1. Better fuel economy.
2. Lower horse power resulting in less load on the motor, transmission/drive train and longer life of all components.
3. No carburetor icing.
4. Slower top speed resulting in a safer car.
5. And many have reported less spark plug fouling.

The advantage of no hot air pipe:
1. More Horse Power (If you consider that an advantage)
2. ?? Anymore ???

I think if a person really wanted a car with more horse power, a Model T would not be my first choice.

I'm glad everyone is free to make their own choice.

Jim


Top of pagePrevious messageNext messageBottom of page Link to this message  By Nevin Gough on Wednesday, September 05, 2012 - 02:52 am:

I think Royce is saying that your economy improves without the hot air pipe.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Dallas TX on Wednesday, September 05, 2012 - 06:36 am:

I said there are no drawbacks to removing the hot air pipe. Economy is improved by cooler intake air. I disagree with any statement that carb icing results from anything you can do to or with your T.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Scott Conger on Wednesday, September 05, 2012 - 07:58 am:

Royce, in FL, and without a hot air pipe, our '13 will develop frost on the aluminum intake and requires a very rich mixture to remain running. This leads to fouled plugs and poor mileage (about 14MPG). Eventually, I can no longer get the car to start until I clean the plugs (in about 20 miles).

With a hot air pipe, I do not get a frosty intake, and I can lean my carb to the point of about 20 MPG. I haven't had to remove a plug in 5 years and the car typically starts on one or two pulls.

Should I believe you or my lying eyes?


Top of pagePrevious messageNext messageBottom of page Link to this message  By Erik Johnson on Wednesday, September 05, 2012 - 10:01 am:

From the Ford manual (1917 edition):

What is the purpose of the Hot Air Pipe? Answer No. 50
  
It takes cold air from around the exhaust pipe and conducts it to the carburetor---where the heat facilitates the vaporizing of the gasoline. It is usually and advisable to remove this pipe in the hot season---but it is an absolutely necessary feature during cold weather.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Dave Huson, Berthoud, Co. on Wednesday, September 05, 2012 - 11:46 am:

Eric Johnson:

Berthoud has a very mild climate in the winter, but it can get down to 10% above. I can start all my Ts with no problem including hand crank Ts and I have never run a hot air tube. My Ts are not garage queens, I drive one of Ts every day. While it rarely snows in Berthoud, If it does I put chains on my 24 coupe or Center Door and drive them to town with no hot air pipe and no problem with icing. I also dive my Coupe or Center Door in hard rain, with no problem.
I have also driven various Ts that I own in Northern Calif, Oregon and Washington. These areas have a bit of humidity and I never had a problem.
I watched the CARBURETORS in the Montana 500 being inspected every year with a go no go and then sealed with a wire. I have never seen a hot air pipe. These are some of the best T mechanics there are. If Hot air pipes help why do none of them use them ????

Again if you believe that you need a hot air pipe use them !!!


Top of pagePrevious messageNext messageBottom of page Link to this message  By Erich Bruckner, Vancouver, WA on Wednesday, September 05, 2012 - 12:18 pm:

I'm just glad this wasn't about any one of us personally.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Scott Conger on Wednesday, September 05, 2012 - 12:19 pm:

Read any internet search on carburetor icing and you will see that icing is not a cold weather problem, it is a heat/humidity problem. Hot humid climates hold considerably more moisture in the air than cold/low humidity climates. My car's intake will NOT frost up in FL winter. It WILL frost up in summer. Small aircraft pilots all have been versed in this phenomena and are taught how to cope with it.

Ford's original purpose is exactly what is being supported with the majority here...it was for vaporizing crappy gas, and we in the enlightened modern age do not have to suffer with the fuel as was used in the '20's. However, and particularly with an aluminum intake, there are thermodynamic facts from which we cannot escape. I along with others have experienced it and know how to eliminate it. In hot/humid weather my car will foul plugs to the point of quitting, without the hot air pipe. In my case isn't an opinion or belief, it's a proven fact. My other two Ts with iron intakes will not do this and do not require hot air pipes.

Folks in CO, WY, MT and the west in general, do not experience 90F days with 85% humidity very often. In FL, we do, (and brother, it ain't a little bit of humidity...it feels like it would melt granite), and any small amount of time reviewing an icing chart available in a multitude of places on the internet will show you that FL summer conditions are ripe for frosting up an intake (particularly Aluminum), while western climates' temp/humidity are not.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Dallas TX on Wednesday, September 05, 2012 - 02:35 pm:

Scott,

Sounds like your float level is too high, or you have a vacuum leak.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Jim Thode Chehalis Washington on Wednesday, September 05, 2012 - 07:44 pm:

Dave,
You asked, "I watched the CARBURETORS in the Montana 500 being inspected every year with a go no go and then sealed with a wire. I have never seen a hot air pipe. These are some of the best T mechanics there are. If Hot air pipes help why do none of them use them ????"

The short answer is because it is a race, the fastest car wins the race. Montana is usually pretty dry and carb icing is not likely. The other thing to consider is that if you look at the icing chart you sill see the the more load the engine is under, the less chance of icing. I wonder how many carry one if the conditions are ripe for icing? It is an allowed equipment item.

Now if the event was to go the 500 miles and use the least amount of gas and be the most trouble free without regard to how long it took, then a hot air pipe would make more sense.

Drivers need to decide for themselves; What are the weather conditions? Are they in a race? Or are they putting down the road just enjoying the trip.
Jim


Top of pagePrevious messageNext messageBottom of page Link to this message  By Scott Conger on Thursday, September 06, 2012 - 06:18 am:

Royce, you know full well that frost on an intake and the carb is not caused by a vacuum leak, unless you believe that air going past the butterfly at high rate due to high vacuum in the intake is a vacuum leak. I call that a carburetor. Myself, Jim Thode and others have explained this phenomena from every angle possible, including charts which show under which conditions this can occur. Good God Man, even Stan Howe posted about seeing this condition, with certain types of carbs being more prone to it than others, back in 2009.

By Stan Howe on Saturday, January 03, 2009 - 12:21 pm:
I've had a dozen or so Stromberg OF's on my test engine in the last year or two and every one of them runs better with the Ford heat tube on the intake that without it. I don't have one of the original Stromberg "Hot Spot" setups but I'd sure like to try them. The manifold will get so cold without the intake heater that it will form frost on the outside of the manifold. I've never really paid that much attention to how much a standard NH or other Ford carb cools down the manifold but the OF's have a fairly small venturi and that must be what makes them frost up.

I know from other posts that on any subject, you're right and everyone else is ill informed, but in this case, you're just plain wrong.


Top of pagePrevious messageNext messageBottom of page Link to this message  By Royce in Dallas TX on Thursday, September 06, 2012 - 06:51 am:

Scott,

You are complaining of an excessively rich mixture, poor mileage, and fouled plugs. Not normal symptoms of carb icing. Sounds like a vacuum leak, with you compensating by opening the mixture, and then you get fouled plugs. If it runs better with the hot air pipe then something is really wrong with your car.

Possibly your aluminum intake has a porosity problem, I have had to weld a couple of the new reproductions and some original ones to fix this exact problem.


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