Curious Newbie question

J

JBohannon

Senior Member
I am just curious as to how not having an aircleaner affects a Model A engine. In todays engines we would not think of not having one. I would think back in the day they went down a lot of dirt roads.
 
I think for many, the hesitation to have an air cleaner has something to do with the gravity fed fuel system. A stuck float will allow gas to drip out the carb and soak an aircleaner. A tour here in Michigan had a car light up in flames from this. Fortunately there were a dozen Model A guys with what should be mandatory fire extinguishers in they're nearby cars. I personally will risk the various particals getting sucked up over the risk of losing it all in minutes. I think engine pans may have a lot to do with keeping out the bad stuff, too. Perhaps years ago, it just wasn't a big deal for a gritty industrial booming country to be concerned with?
 
I drill 2 1/8'' holes in the air filter top beside the wing nut stud to allow any extra gas to drip on the engine pan and down on the ground. This signals me that the float is sticking and prevents raw fuel build-up in the air cleaner
 
The A engine was designed to suck dirt and keep running for 10's of thousands of miles. The thick babbitt is will allow dirt to embed and not hurt the crank. With todays modern roads the dirt is even less of and issue.

Modern engines use inserts. They fail with dirt the babbitt does not care about. So the modern engines or any with inserts need filters.

Running with dirt is allowed in all the A systems. The original fuel filters catch most anything that would give the carb grief. Then the original carb has a single bolt to drop the bottom in case you have a problem with dirt getting through.

Keep in mind the dirt is not going to be the reason your engine fails. The number one failure of the A engine is a mistake during the build phase.
 
I run mine for mainly backfire protection:eek:. Filtered air is just icing on the cake:D:D:D:D

Joe,,,
Damn, they missed that important little bit of info:rolleyes:..
 
While you're right about most roads being dirt, the majority didn't drive many miles back in the day. Somewhere I read that most people never left their county. So as Kevin said, Model A engines being very forgiving on injesting dust, very few miles being driven, and speeds/rpm relatively low, I could see engines lasting quite a few years. It's normal for us to be conditioned by what we do today. Our region/club drives a lot of miles as roads are paved but the downfall is most of it is done with higher rpm's then back in the day. As been said our driving today exposes the A to limited dust. Besides the potential gas-soaked filter most don't use a zero restricted K&N filter element and don't balance their carb so they likely have an over rich gas/air mix.
 
Holy Crap, my old 4 banger was DESIGNED to suck dirt:eek::eek::eek:. Man, I going to build one hell of a vacuum cleaner.:cool::cool:. Where is B. Willaimson when I need him:confused::confused:
 
you should talk to Howard Taylor, excellent on carbs and tuning.. He tells you TAKE IT OFF, was not there in the beginning and does not need it. he also feels that it does effect the quality of the running engine., Had one and took it off, Good Luck
 
The original Air Maze filter element wasn't paper like many are today; it was a wire mesh/fiber design. This allowed dripping gas to leave the filter. It didn't filter as finely as paper does so wouldn't clog up with fine dust that the engine can ingest, which also allowed the atmospheric pressures to stay relatively the same without affecting the tune.
 
For the investment I put in my complete rebuild I'm not inclined to allow my engine to be a "dirt vacuum". Of course this robust little engine will take a lickin' and keep on tickin' but that's not my phylosophy of car-care! Back in the day, no doubt, much less attention was paid to careful use and maintenance. And if the old girl started blowing smoke, scoring journals or abrading valves and stems - no biggie as long as it kept "running."

No doubt some of you have seen the insides of an engines that had been "sucking dirt" for thousands of miles - especially the cylinder walls. Who would intentionally do that to these rare and costly engines?

I run an over-sized, low-resistance paper air filter and inspect regularly for fuel leaks.
And I carry a fire extinguisher. It's a risk trade-off I've been able to manage OK for many years and miles.

To varying degrees, whether you drive dusty dirt roads or clean pavement, there are always dust and microscopic abbrasives in the atmosphere. They take their toll. IMHO all engines should have oil and air filtration. Cheap life insurance when installed and maintained properly.
 
Also if you use an Air-Maze filter with metal screen, and apply an lite coat of oil it will help trap more dirt. You just need to clean and re-oil it often. Air-Maze wire screen filters were sold as after market parts during the entire time A's were made. They are not a "new / modern" created device. Based on this, some orginal owners must have also felt that it was a good idea to provide some sort of air filtering.
 
What other makes did not put air filters on their engines?

When I first got mine, the first thing I bought for it was an air filter because I thought it was missing. I never would have thought that Henry did not put one on it from the factory.
 
Stationary engines didn't have any air filters. Old boat motors didn't have filters. If you use the wire mesh filter, rinse it in gas, blow dry, then oil the mesh to catch the dirt and hold it until the next cleaning. Many older lawn mowers used wire mesh, but most of the newer ones have changes to open cell foam, which is also rinsed in gas and reoiled. Some later cars have an open cell foam filter wrapped around the paper, to prefilter the air and make the paper filter last much longer.
 
Has anyone any experience with this style?
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Earle,
'voice of reason' ! You probably won't get many votes,eh!!
Well, if a good stock engine was designed to ingest/suck dirt, just think of what a good sucker that you've built by spending upward of $10K...and be satisfied that you did good!
 
VWJoe said:
Holy Crap, my old 4 banger was DESIGNED to suck dirt:eek::eek::eek:. Man, I going to build one hell of a vacuum cleaner.:cool::cool:. Where is B. Willaimson when I need him:confused::confused:
Click to expand...
I wasn't gonna' get drug into this, 'til I noticed you misspelled my LAST NAME!:eek:
BALDERDASH! BALDERDASH! BALDERDASH! Why would ANYONE try to justify throwin' DIRT through your carb!!:eek::eek: It ain't smart & it'll EAT YOUR ENGINE ALIVE! Get a highboy filter with a low restriction paper or a K&N element & your engine will say, "THANK YOU, KIND SIR!" (I thought I'd heard everything, 'til I just read, "MODEL A'S WERE DESIGNED TO RUN ON DIRT!!!!!) Bill Williamson
 
im agreeing with you mr.bill. the reason they didnt run air filters is because of ignorance.they just didnt know.im talking about the average owner.after reading this i jumped on the phone to a old friend. he was there.lol he said that they guys back then didnt really understand what was going on. they just knew that if it would start, they were good.they didnt think about all that crap getting sucked in and what it would do.they use to advertise a air filter for the country folk to make them cars last longer .im just relaying what a man almost 90 told me, cause i sure as he-- wasnt there.lol
 
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