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Ditched the "Air Maze"... During my recent head gasket investigation, I noted that the spark plugs were seriously carboned up. Black black black. The engine wasn't running properly...like it was running rich (smelled like it too).
I still think the (Tillotson) carb is a problem...but I'm going thru all the easy things on the checklist (and I still need to finish refurb on the Marvel Schebler). After sorting out the head gasket issues, I decided to pull the Air Maze and clean it. With it off, I took her for a drive...big difference in how she ran! Not stumbling, smooth idle at 480, no smell of raw gas from the exhaust. Hmmmm... Not an easy decision, I've never run an engine without an air cleaner. Yah, I know, I know. The car and carb were never designed to run with an air cleaner (not that the Air Maze does any "cleaning")...but I'm going to run without it. She certainly seems happier...now I have to see if I can straighten out the dent in the carb throat left by the screw that holds the Air Maze on. :( I swapped out the plugs (from Autolite to Champion, gapped at 0.035") and I'll drive them for a while before rechecking. |
Re: Ditched the "Air Maze"... I pulled the maze off mine for the same reason. Never could get it to run or idle properly.
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Re: Ditched the "Air Maze"... Two thumbs up !!
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Re: Ditched the "Air Maze"... I pull them all off. junk.............
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Re: Ditched the "Air Maze"... The problem is not the filter but the design of the carburetor. The float bowl is open to the atmosphere. The fuel flow is determined by the difference in pressure between the jet and the float bowl. When a filter is installed the pressure in the venturi decreases causing more fuel to flow.
The carburetors can be modified by running a passage between the inlet to the carburetor, just before the choke, to the float bowl, and blocking off the opening to atmosphere. That way the pressure inside the float bowl is the pressure at the inlet to the carburetor. There have been a couple schemes on how to do this published here on the Barn. |
Re: Ditched the "Air Maze"... I agree with nkamoinar on this one. air balancing the carburettor would have fixed the issues some of you have had.
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Re: Ditched the "Air Maze"... i do believe in something to prevent crap from going into the engine via the intake, i use a wire screen air maze that stops the big chunks, it runs fine.
on the other side of the coin, i ran my model b (99% of pavement) for 40 years with no air cleaner and never had an issue. if i was driving all the time down gravel roads i would for sure put a proper air cleaner on. i guess it depends on the conditions you use the car in. |
Re: Ditched the "Air Maze"... 1 Attachment(s)
I have wonder if most people know that all of these carburetors Ford released for the model A & B were NOT designed for air cleaner use ?
It's NOT about opinions.... Zenith released this document in 1937 warning people about this, but people act like Zenith must be stupid and want us to ruin our engines. I guarantee that people are not smarter today than they were back then. It is 100% true that an air cleaner will make your engine last longer, but that's only if the carburetor internally was designed for it, if the carburetor is not designed for it, then the opposite happens. If air flow into the carburetor is restricted even a smallest amount then vacuum from the engine pulls air through the float bowl vent. This inrush of air pushes extra fuel through the jets. Then the raw fuel going through the engine washes oil off the cylinder walls, causing scoring and accelerated engine wear far worse than any dust would ever do in a lifetime. You cannot compensate for this by adjusting the carburetor or changing the jetting. The reason why people say that they put an air cleaner on there and they take it off and they don't notice any difference is because this is not something that happens overnight just like a dirty filter, it gets worse with time. There is no warning or symptom that tells you this is happening. It's a slow death, but worse than dust would cause. It's the design of the float bowl vent circuit that makes adding ANY potential restriction to the carburetor cause a problem. All carburetors released for use on the model A have the float bowl externally vented. Every carburetor that has an air cleaner has the float bowl vent inside the carburetor near the choke plate so that all the air entering the carburetor must pass through the air cleaner. When people talk about a pressure balancing circuit basically they're talking about relocating the float bowl vent from externally to internally. It's a relatively simple job. If anybody is interested, I'd be glad to share the procedure for all Zenith, Marvel and Tillotson Ford released carburetors. So here's where a little bit of speculation comes in.... so why didn't Ford put an air cleaner on this car? I believe it's because you have a gravity supply fuel system, and a needle and seat fuel shut off assembly that can stick open with dirt and when this happens, you will fill any kind of air cleaner or contraption full of fuel, and when you do that combined with poorly adjusted spark advanced lever, you will create a fire that you cannot put out. People will say well Fire won't go through the screen on an air maze that might be true, but that does not prevent a backfire from blowing the whole canister right off the carburetor spreading the fire everywhere. Ford knew all this that's why they didn't add the pressure balancing vent relocating circuit, why would they design a circuit into a carburetor that would never be needed. At the time Zenith had plenty of carburetors designed for air cleaner use. That wasn't the issue, they knew full well what air cleaners did and how to make them work on carburetors. I believe that Ford's idea was to let accidental extra fuel just run on the ground where it would be no problem and that the fresh air coming through the radiator would pressurize the area under the hood, and the engine pans would funnel clean air into the carburetor. In 1932 Ford released two items that attached to the carburetor. The first was called an air silencer, which was a noise baffle, it had a very course piece of screen on the bottom, which was unrestrictive. Then they had a firewall mounted oil bath air cleaner, which traps dust by passing it by a pan of oil, and these will not cause a restriction to the incoming air. This is carburetor design 101 not opinion. |
Re: Ditched the "Air Maze"... I soaked my 'air maze' in acetone...blowing it out and soaking several times again for a few days before trying it out again. I saw a major improvement! Decades of built up oily residue and crud came out. It still seems to be too restrictive of intake airflow but high quality after-market options simply look far too modern.
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Re: Ditched the "Air Maze"... For over 50 years I have run Zenith carburetors without any filter or air maze gizmo. I have not yet had any chunks of debris or notice accumulation of crud in my carburetors. Here is another shocker. The Zenith carburetors on both of my Model A's have not been taken apart or had any adjustment for many many many years. I do not use any additives in the 87 Octane 10% Ethanol gasoline I run. Most every engine stoppage I have experienced was due to ignition failures (coils, points, condensers, plastic body parts). I think the carburetor is the most maligned & falsely accused part on the Model A.
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Re: Ditched the "Air Maze"... "It's a relatively simple job. If anybody is interested, I'd be glad to share the procedure for all Zenith, Marvel and Tillotson Ford released carburetors."
Yes, please do share. Thanks for your insight. :) |
Re: Ditched the "Air Maze"... Mine had one, and took me all of 5 minutes to rip it off and find the trash can.
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Re: Ditched the "Air Maze"... Quote:
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Re: Ditched the "Air Maze"... Engine pans keep the crude from going into the carburetor. Engine pans also are used for cooling. Most all cars had them since cars were first built.
They were often thrown out because they were a pain in a$$ to reinstall them or they rusted out, but they were there for two reasons. |
Re: Ditched the "Air Maze"... I agree with Bob Bidonde, the Zenith model A carburetor is nearly bulletproof if it is properly set up and fed a constant clean diet.
If a person takes the time to understand how it is designed to utilizes atmospheric pressure and air velocities to regulate fuel mixtures over various operating conditions it will be evident why you don’t want an air cleaner unless you air balance the bowl. The Zenith is quite a fascinating piece of work, like just about everything else on the car, simple and effective. I suspect more to blame for carburetor issues should be dirty rusty fuel tanks. People don’t want to go to the trouble to remove tank and properly clean and seal them. |
Re: Ditched the "Air Maze"... Quote:
They did also offer a filter for BB trucks in dusty conditions, using the oil bath style. Air filters are quickly becoming the "what's the best oil to use" topic of the 2020's! :D |
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This comment makes me think that you didn't read my entire post, it seems like I've heard all this before.... I'm sure that you're aware by now that the "what oil do I use" question is engagement farming or Click baiting.... it's done intentionally... the people know when they ask that question what they're doing and it's to get people to follow, like, subscribe, comment and click, which makes them money through monetization. |
Re: Ditched the "Air Maze"... Renner, I like your post. I too had an air maze for 15 years on my "A" with the steel screen, but kept thinking over and over, hey, the "A" never came with one, why add something just because everyone else has it and there was a sale from the suppliers ... besides I'm not driving on dirt roads or trailing behind a dust cloud, no reason to have it if the carburetor and all the other motor parts are working in synchronization.
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Re: Ditched the "Air Maze"... 2 Attachment(s)
That's how it looks. And then the engine runs perfectly with filtered air.
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Re: Ditched the "Air Maze"... It has nothing to do with the carb. Except getting dirtier by the mile.
Dust & dirt, and other particles are getting into your valve stems, guides, cylinder walls, Rings. Of course Ford never used a filter. Engines didn't go that long anyways back then. But now, they are and need the protection. What's the big deal anyways? Just run one to be safe. |
Re: Ditched the "Air Maze"... Me too
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Re: Ditched the "Air Maze"... you guys should paint a car without a paint mask and see what happens. same as an engine breathing without a filter.
lets stir it up a bit |
Re: Ditched the "Air Maze"... Adding an oil filter to the engine can do a lot of what an air filter would do.
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Re: Ditched the "Air Maze"... Quote:
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Re: Ditched the "Air Maze"... IGNORANCE IS BLISS......
Happy days to all who celebrate it. |
Re: Ditched the "Air Maze"... Thankfully, we can all make that decision for ourselves.
I figure there's no real filtration with the Air Maze. I have the engine pans mounted and the levels of dust here are minimal. What? Me worry? :D I need to pull the passenger side pan, strip it and repaint (like that when I got her). That Tillotson leaks and the paint is falling off on the inside. Took me about a minute to learn I should close the fuel valve and run the bowl dry every time I shut her down. My problem is that I get out after turning the fuel valve off...and keep forgetting to go back and turn the key off! :o |
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The way Ford compensated for the lack of an oil filter was to use non-detergent oil, change the oil every 500 miles, and include sludge removal on the maintenance list. Airborne contaminants would become entrained in the oil and gradually sink to the bottom of the sump. But if you're using detergent oil, which most people are, you're already pushing that system away from how it was designed, because the detergents will hold contaminants in suspension, sending them through the engine over and over. The use of an oil filter returns this system to balance and improves its efficacy over the original design. |
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i would argue that air cleaners and oil filters were being added to manufactured vehicles and equipment at the same time frame as the model A was being built. manufactures knew that contaminants in the air as well as the oil would harm the engine so they started making filters as part of the vehicle's standard components.. and there were no detergent oils when all this started. Ford was thrifty and stubborn i imagine he saved millions of dollars not putting air cleaners on. |
Re: Ditched the "Air Maze"... Running without an air filter and oil filter is really good for the engine. That is why all modern cars do not have either one. Ha ha.
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Re: Ditched the "Air Maze"... I have many farm tractors that have a gravity fed fuel system, and they all have air cleaners on them, and yes they do leak sometimes. But the air cleaners are higher than the carb, with a pipe and flexible hose connecting them, so they don't fill with gasoline.
They almost all have Marvel Schebler carburetors on them, I have not looked closely at the Marvels to see if they have the pressure balanced system on them, or they may not work the same as the Model A carb. Is the Marvel Schebler carb for the Model A pressure balanced? I would be interested in the pressure balancing to run an air filter. While everyone may so and think that there's minimal dirt, I spent a lot of money on my engine, and I put a lot of miles on it, so I would like it to last. |
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i also work on a 20-35 allis chalmers with an air cleaner, and a carb that looks like a marvel (im guessing the carb is not original), i don't see a separate tube on it. |
Re: Ditched the "Air Maze"... Because it was my former profession, I'd like to share some data regarding air and oil filtration. This isn't meant to lead to further discussion or persuasion, but simply to provide typical —and reliable— figures that everyone can draw their own conclusions from.
The A engine requires, on average, appximately 15 liters of gasoline for every 100 km driven. For each liter of gasoline, around 1:>14 parts by weight of air are needed for combustion, resulting in 180 m³ of intake air per 100 km. Converted to the average dust from paved roads, the amount of dirt drawn in is 1 gram per 1000 km. That's more than 1 spoon. This road dust consists largely of glass-hard silicon and quartz. This is the first component to wear down the honing marks in the cylinder. Approximately 1/4 of this dust also ends up in the engine oil. This furthers abrasion of the soft bearing shells, causing them to wear out more than necessary. Even a simple (mainstream) oil filter cannot completely remove this dust, because the smallest micrometers can pass through the filter pores. However, it still removes more than 80%. When Ford engines were designed at the beginning of the last century, I think this effect of dust and how much it increases wear was probably not yet known. The argument that the dust settles in the sludge at the bottom of the oil pan when using HD-oil (= without depersants, etc.) is misleading. While some of it is bound, as soon as the engine is running and the oil is hot, a large portion of the sludge is stirred up again and enters the entire lubrication system. |
Re: Ditched the "Air Maze"... Quote:
Same experience here with an Air-Maze 'filter' on the '29 Tudor:) It came on the car as we bought it. It fell off on the highway one day as the set screw holding it on a Tillotson carb couldn't 'hold it on' as the air inlet opening had a slight bend from the screw. Vibrations made it fall off. That car never ran so good after that happened. That was in about 1975, and I've never run one since!! |
Re: Ditched the "Air Maze"... NO ONE IN THEIR RIGHT MIND WOULD BE AGAINST USING AN AIR FILTER, THAT WOULD BE RIDICULOUS.
That's not ever the intent when talking about Model A's and air cleaners. The intent is to be educated that there are two distinctly different designs of carburetor, one type that the model A uses that has potential risk of engine damage, and the other one that does not, plain and simple facts. |
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please list them and their potential issues. in the 60 years that i have been working on and driving Model A's i have never personally witnessed a model A carburetor damaging a model A engine. just lucky i quess. |
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I may have discovered and replicated them many years ago here in this forum or in some an other American publication. These instructions also shows the difference between the two factory-modified carburetors. When a filter attachment is installed, the float chamber is/should not vented to the atmosphere, but rather by the (slight diference) vacuum in front of the carburetor's inlet. |
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Is there a specific location for that tube to enter the carb or can it go in anywhere above the fuel level in the bowl? And, is there a specific size for that tube? And, do you think that set up would work with an air maze filter? thank you OU |
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Re: Ditched the "Air Maze"... 1 Attachment(s)
The good, the bad, the ugly – I know, like everyone else, I think?
The tube fits into the original vent channel, which I've marked in blue. The vertical hole at the top must be sealed with a short plug (green). The tube should be as thin as possible; I used 3 mm copper on the outside, it is less than about 1.5 mm on the inside. I glued it in place with your JB-Weld adhesive. The filter type doesn't matter, as the tube compensates the actualy pressure equalization. This is also important because of the increasing dirt buildup, which increases the pressure difference. This modification only applies to the Zenith 2 type. Because I have no experience with other carburetors. I did not change the jets. The engine runs a little bit more ritch. That you can compensate it with the inner turning knob. About +/- 15 degrees. And idle screw. It's midnight in central Europe, have a good night. |
Re: Ditched the "Air Maze"... have you ever seen a Model A flood and soak the filter and when the engine baack fires, you now have a fire that you would not have if not for the air maze filter
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