Safe and effective air filter options?

[bluesman31]

I really want to filter the air coming into my carb. a reasonable amount

My car came with a spare carb that has a Maze air filter and I bought a paper filter element for it. I have read some posts that say there is a fear of gas draining down into the element and potentially causing a fire hazard with a backfire. I can certainly see the possibility of that. My carburetor could have a sticking float and dump lots of gas at any time I suppose.

Is fire caused by this a real issue or one based on an isolated incident or two?

I really don't want to invest in an expensive highboy element that puts the filter above the carb (the best obvious solution) when I already have an air filter.

I was thinking of possibly drilling some holes to let dripping fuel out while allowing for the filtration of much of the air?

The Metal Maze filter looks safer but almost useless as a filter.

What does everyone else do?

[Tom Wesenberg]

The wire mesh should be oil soaked to grab and hold the dust.

[[email protected]]

I was always heard that the Air Maze filter was only good for keeping out low flying birds from getting into your engine.

I personnally do not use any type of air filters on my Model A's. I believe that there is nothing wrong with running without any air filter on today's modern clean roads with the correct splash pans on your car. Henry did not offer a filter and those original engines ran for many a mile without a problem from dirt ingestion in the engine. If you are planning on racing on a dirt track then maybe another forum could help.

Running air filters could also change your mixture and carb settings by restricting the air flow. Lots of guys have determined that with the amount of air pulled in by a Model A you would need a huge paper element filter or foam element filter like those used on a Caterpiller bulldozer sized engine.

If you are dead set on an Air Maze you can put a large coffee can with a round hole cut in the top to properly fit the Air Maze bottom. The bottom end of the metal coffee can is cut out. This should fit over the mesh or paper filter as a method of preventing a fire caused by a back fire. There should be a sufficient clearance around the metal coffee can to get sufficient air flow for most touring speeds.

I am sure there are lots of the other Model A driver guys that will disagree with running without a filter so I will be watching with interest.

[marc hildebrant]

I would suggest that you do not use an air filter.

With the real changes of backfires and dripping gas, I feel that its much safer to run without the filter. Also, the engine was designed to work without an air filter and the use of one will change the normal operation of the carb.

Marc

[steve s]

Originally Posted by bluesman31

I really want to filter the air coming into my carb. a reasonable amount...

If you don't want to get a carb that's designed for a filter (e.g., Zenith 13922) and spend the money for a correctly configured filter (60$ from Snyders), then a "reasonable amount" is no filter at all.

My Air-Maze and the paper filter I once bought to put in it have long since been tossed. Some folks use filters with no problems; others not. My theory is that carbs set up a bit lean and/or with vacuum leaks and not balanced by venting the float bowl to the air intake probably work about right with an air filter causing it to run a tad richer.

Steve

[B0B]

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I experimented a lot with air filters for my Model A spent a lot of time . The wire mesh screen type filter I started with didn't filter anything but big things like june bugs and grasshoppers we have roads with a lot of sandy dust around here (Lake michigan sand dunes) and I wanted something to keep the abrasive dust out to protect my expensive rebuilt engine . I tried the pleated paper filter they sell and that restricted the air flow causing the fuel mixture to run to rich even with the GAV screwed all the way OFF. those paper type filters they sell are about the same size as on my lawn mower and to small for the Model A engine. I finally bought a K&N replacement filter that was bigger than the paper one I had on the Model A to install it I had to use a longer bolt to fasten it on to the air maze adapter and also drilled a hole for the longer bolt in the rubber end of the K&N filterfor the bolt. I used the air maze end piece under the filter then as a large washer. I wish I could give you the part number of the K&N filter I have no idea what that filter originally was for . I do know it fit right on to the air maze adapter at the top it was longer and a bit larger in diameter than the little paper filter they sell . With the K&N filter on the carb there is NO restriction I can detect at all . The carb adjusts the same with it on or off. This is due to the much larger filter element and better design of the K&N filter. YEP it cost some money all this testing and trying but I now have a filter that works My GAV setting is right at 1/4 turn where Henry said it should be with the filter on or off . Hope this helps ...B0B in Michigan

[columbiA]

With rare exceptionsthere is very little dust encountered on todays roads.In the 50,s I drove a 31 Victoria 75,000 miles in 8 years over mainly gravel & dirt roads and the engine didnt seem to suffer any.The average person today wont live long enough to wear out an A engine thru dirt injestion.Service the car regularly & you will be fine.

[bluesman31]

Bob. When you installed your K&N did you keep the basic configuration of the air maze? Does your barb leak gas sometimes and did you find it was a hazard or would the gas soaked filter work without catching fire in case of a backfire?

coumbiA that is a good story and makes me feel a bit better.

Did these cars come with any air filter from the factory? What did the 32 fords have?

[Benson]

Chris Pelikan did alot of research on Model A carbs ... here are his findings on air filters:

http://www.model-a.org/filtering_air_into_carb.html


Edited:

Here is the "HighBoy" filter that addresses the fire danger:

http://www.snydersantiqueauto.com/5431

The Service Bulletins show an oil bath filter used on AA trucks, I am not sure what year as I do not have a copy of Model A or V8 Service Bulletins handy.

I remember seeing oil bath filters in the SB for both 4 and V8 engines. They are hard to find.

[Jim/GA]

I run an oiled air maze metal mesh filter with a pressure balanced B carb on my S/W Town Sedan (build for long distance touring). I clean the filter element and re-oil it with every engine oil change. You would be amazed at the amount of dirt I see in the solvent I use to clean the mesh element each time I clean it.

Some of our club drives are on gravel roads or country roads, where you would expect some dirt and dist to fly up, but most of my driving is on regular hard top roads. There is a lot of dust and dirt flying around on the SE Texas area roads.

I will admit, I am not running with engine pans between engine and frame right now. (I plan to put them back on soon.) I think the pans help keep a lot of that dust from swirling up under the car as you drive.

Henry was single-minded in his determination to keep the cost and List Price of these cars as low as possible. He left options, like air filters, spare tire locks, etc., to the dealers to sell and to the after-market manufacturers to supply. Just because the car did not come with an air filter when new does not mean it could not benefit from one.

[Peyton]

I wrap an air conditioner vent register filter around the air maze screen. I don't notice any restriction of air flow.

[1932BB]

I run a K&N RC-1890 on a Model B engine. It clamps directly to the carb and is far enough from the exhaust manifold. It looks small but according to plug readings does not run rich at high speeds. The K&N website lists all sizes of filters.

[bluesman31]

I like K&N filters, but I notived they list the material as "cotton gauze" it sounds just as flamable as a paper filter?

Is the fire hazard a real one?

[bluesman31]

Originally Posted by Peyton

I wrap an air conditioner vent register filter around the air maze screen. I don't notice any restriction of air flow.

I like that your filter is not pointing straight down, my cast air maze hangs below the carb where fuel could collect if the float stuck.

[BILL WILLIAMSON]

Those who run NO FILTER, rub your finger, (NO not THAT finger!) inside your carb throat to check for GRIT! Maybe modern roads are not as clean as you thought! (I may "GRIND" on some folks, but that GRIT also "GRINDS" on your rings & cylinder walls!) Bill W.

[BILL WILLIAMSON]

Even the semi-useless wire-maze IS a very good flame arrestor. Bill W.

[bluesman31]

I think I am going to see if I can modify my Maze to point upward or to the side to eliminate the change of fuel pooling and catching fire. If I can do that then the next step is to icrease flow with a larger filter

[Clydes 31 P/U]

bluesman31, I bought the A-9600-ACC filter from Snyders and put a K&N filter on it. It works well for me, I have it mounted on a Marvel carb on a 31 CC P/U.

[Bruce,Upstate NY]

Clyde, is that copper gas line or copper coated steel?

[Clydes 31 P/U]

Its copper line, been on there since the mid 60's, everyone says that it will crack from work hardening but with the coils in there to relieve the stress and vibrations it has lasted almost 50 years.