Air filters?

bobgreco

bobgreco

Senior Member
I was at a local club meeting last night where they were talking about rebuilding carburetors when the carb expert said he never runs with an air filter on his A's. He said Model A's did not come from the factory with air filters and they do not run right with them.

This surprised me a bit, so I thought I would check with you to see if anyone runs without filters or has any other thoughts or comments?

Thank you for your time!

Bob
 
Bob,
I agree with the carb. expert at your lcl. meeting, I think it's a fire hazzard for one thing, And i don't have one on my 31 coupe and never will. JMHO.
 
Bob - I don't use any air filter either. The engine won't run right. However, there is a K&N filter that can be used causing the least amount of problems (I don't remember what number filter that is, maybe someone else does). Also, there is a tube than can be run on the filter and carb to balance the air in the carburetor to compensate for the above mentioned problems (clear as milk, right? again, I can't remember the hook up, but maybe someone on the Fordbarn can).

My memory just ain't what it used to be. Sorry.
 
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The Model A carb has a bowl vent in the top rear of the lower housing near the center. If you connect this hole to a pipe and run it to the inside of the air filter you will balance the carb, so you can use an air filter. Without this balance tube the gas in the float bowl is vented to the atmosphere, but the air filter will cause a restriction, no matter how slight, which will cause a lower pressure through the carb throat. This will make it run richer than it should.

So, if you use an air filter, it's best to use a balance tube.
 
It has also been mentioned that a leaking float valve might cause the gas to be absorbed in a paper filter and become a fire hazard.

I have left my filter in a box following numerous recommendations to not use it.
 
Most of you guys will disagree with me, but someone has to be the "grinch." LOL
In my experience, my car will not run worth squat doodle without the filter, or mesh
screen during the summer in Florida----too much heat going to the carburator. a couple of years ago, the maze fell off and instantly the car started wheezing
to the point that the car would barely run. I was able to make it to a parts house
where I was able to rig up a filter. The filter worked fine until I was able to buy a
new maze and mesh type filter. This happened during Florida's hotttest time of the
year. I agree that some of the paper filters can be a fire hazard, especially the
oversize style. There is no fire hazard, however with the maze system. As I said,
this is just MY opinion and experience.

Jack
 
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I agree with Jack. I have run air filters for many years. I think the trick is to use a oversize filter. Some thing for a big V/8. I don't want all that dust and dirt in my engine from driving down my dirt road, and drive way!

The attached is what I've use for a number of years.

I've run the car with a Tac., with and without the filter and there is no change in RPM's, I.E. idle, pulling the same hill, etc. Fuel mileage down not seem to have changed.

For me I think there is less fire hazard. The back fire flame will be contained with in the filter and filter "plumbing" and will quickly extinguish it's self due the the lack of oxygen, which it has all ready burned.

Just My W.A.G. at the question
JB
 

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Tom Wesenberg said:
The Model A carb has a bowl vent in the top rear of the lower housing near the center. If you connect this hole to a pipe and run it to the inside of the air filter you will balance the carb, so you can use an air filter. Without this balance tube the gas in the float bowl is vented to the atmosphere, but the air filter will cause a restriction, no matter how slight, which will cause a lower pressure through the carb throat. This will make it run richer than it should.

So, if you use an air filter, it's best to use a balance tube.
Click to expand...


Tom do you have a photo of this setup?
 
I have run my 30 coupe without a filter the first few months and then installed an oversized filter just like the one Jerry pictured. I checked the power and gas mileage before and afterward. I found no difference in the way it run or in the mileage. I get about 19 MPG when in country driving. It will do easily 60 mph as I inadvertently allowed my gps to register 60.1 mph monentarily. I personally would not run my car without an air filter. If I am sacrificing something to do this, I certainly have not noted it and the peace of mind knowing my engine remains clean is well worth it.

Steve
 
I have the larger K&N on our model A. Although I don't have the number handy.

I would rather it run a hair rich then constantly sandblast the inside of the engine. I have no desire to vacuum the road with the engine.

We are also around 30 or 50 feet above sealevel, so running the GAV fully closed or near fully closed should compensate for any richness caused by a good flowing filter.


I would have to assume there are modified jets for the zenith that allow you to properly run an air filter?? Does lowering the float level help much or just cause more problems?
 
Running without a filter 'sandblasts' the engine? After 1000's of miles with a paper element on my Air Maze mount, the element has very little dirt on it. That's all its prevented from getting into the motor. Makes me wonder if we really need them, particularly with frequent oil changes.

Who out there that doesn't run a filter can tell us how many miles they've gone before they've needed a rebuild?
 
gilitos, do you run a modern engine without an air filter? If not, why?

I'm not an engineer, but something tells me they started putting air cleaners on pretty much everything from lawn mowers, to cars, to boats in the 1940s for a reason and it wasn't to waste money.

under most conditions, no it doesn't exactly sandblast the engine, but over time the effect is probably the same. And if you go down a dusty road i'm sure the front wheels kick up quite a bit of dust.

Although the conditions are not exactly the same, I know when I go out ATVing with friends on a dry summer day, the amount of coal dust and dirt I wash out of an oiled air cleaner is scary.



Jerry in Shasta : I like that copper tube you have there. Is that home made?
 
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Air filters on an A? A personal preference I would think. My car lasted over 40yrs from new until I got it, driven on dusty shingle country roads & with probable indifferent servicing. No filters used here, near impossible fit with RHD. Rebuilt in early '70's & with coseted low miles done now, no filter too. An A engine should run spot on unfiltered.
Modern autos are designed & fitted new with filters for obvious reasons but how many are replaced/cleaned regularily.
 
FWIW, My 30 Town Sedan has 75K on the odometer. It was run on the dusty roads of Oldwick NJ, a country town in Hunterdon Co, NJ. The engine was never touched, but is worn out. It has standard size pistons and very loose rings. However, The cyl bores are about .036-.040 oversize at the top and about .010-.012 over at the bottom of the cylinder. All this wear in only 75 K. Conversely, my Saabs have twice the miles with less than half the wear. I had a very abused Ford 8N that Cyls were still in spec (though right at the edge) since 1952. I vote for the aircleaner!
Terry
 
Would not the engine pans (if installed) prevented much of the dirt ,dust you are all mentioning from entering the engine compartment> Installed the cheap air maze at the beginning of the season, fell off within two wks and I thought i had snugged it down pretty tight, have not replaced. Only thing I don't like w/out filter is amount of noise generated by the carb (sucking) when opening throttle.
Paul in CT
 
I never could run an air filter on my Zenith, so I didn't use a filter for years. However the carb noise at open throttle was annoying to me, thus I recently installed a high capacity element with the 90 degree elbow from Snyder's and it works great. Engine runs and idles fine and no carb noise at higher speeds.
 
1931 flamingo said:
Would not the engine pans (if installed) prevented much of the dirt, dust you are all mentioning from entering the engine compartment. Installed the cheap air maze at the beginning of the season, fell off within two wks and I thought i had snugged it down pretty tight, have not replaced. Only thing I don't like w/out filter is amount of noise generated by the carb (sucking) when opening throttle.
Paul in CT
Click to expand...

I do believe that engine pans help a lot to keep dust and dirt out of the carb inlet.

If you run without them, you probably need something to filter at least the bigger stuff out.
 
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