Oil Bath Or Regular Air Filter Element?

I gave up on the oil bath when my Jeep choked out and died one day on the side of Mount Bross in central Colorado... at about 13,000 feet elevation. They simply don't flow as much air as a paper air filter.

 

My guess from an ability to filter out the finest particulate and ease of cleaning/replacement.
1st: paper element
2nd: multi stage oiled cotton/gauze
3rd: oil bath
Dead Last: typical replacement K&N

In desert racing, commercial equipment filters are widely used. Check out Unique Metal Products or "UMP". typically ran with a filter from Donaldson or one of the other commercial filter MFGs. I do believe they list the specifications for particulate down to the micron, capacity and airflow. All we would need is similar specs from an oil bath assembly to compare and I'm not finding any. I was born after oil bath assemblies were shelved, so my understanding of how they work is limited. But i believe the system essentially relies on velocity of the air and debri/particulate. Using velocity, the majority of the particulate is slung into the oil. The rest being captured and moved out of the air flow by the oil covered mesh/paper element. The question is, what size particulate can the oil bath system remove reliably?

 

I agree.

 

But is long engine life their primary concern?

I remember the old saying that the perfect race vehicle would burn out as it crossed the finish line… But I'd like to get more than 500 miles from my f-head.

 

Gentlemen this has been an interesting discussion. I have never run a vehicle with an oil bath but I think we all agree that an oil bath serves the jeep well. From 30 years of Dirt biking, I can say that the modern elements can stop a ton of dirt also. I do not know which would be proven better in controlled tests. So it comes down to preference to me. The oil bath looks right at home under the hood. It is easier to change out an element than to get a dirty oil bath serviceable. Since these engine are relatively low HP they can get pretty worn as still run fairly well and the oil bath gets all the credit. In my opinion, these engines have inhaled some dirty air over the years--mainly from neglect of maintenance BACK IN THE DAY--not you guys. We share the same goal--no dirty air in our carbs. I have come up with an interesting solution for me (if it works). I will post pics and we will all get a laugh I am sure.

Many thanks to all that took the time to post a thought. Mike

 

It's all just urinating on a fire hydrant without test data or mfg specifications.
As far as desert racing, engine life is paramount. I would presume that a Jeep with an oil bath over the carb would suffer the same issues as a desert racer with an oil bath. Off camber, you're burning oil and previously captured debris (home brew lapping compound?). If the oil bath gets low on oil, you're allowing particulate down the intake because oil isn't being wicked into the element. Everything I've read says oil bath is a finicky technology. Oil level has to be proper. Oil weight has to be addressed for outside air temp. Extreme changes in angle make them less efficient.... so on.

The one major correlation I can make is that service life of engines has gone up immensly from the days that oil bath was an automotive industry standard. Solely because of filter change? Obviously not, but without clean air, power over the engine service life drops off quickly.

 

Just wrap an old sock around the carburetor neck and zip tie it in place. When in dusty conditions, pour some oil on it for extra filtering. When in really dusty conditions, wrap your wife's nylons around it and pour oil on the whole shebang.


Just kidding of course. I run a paper type in my 225 air cleaner, all our tractors and farm only jeeps are oil bath. So I have added nothing to this thread.

 

Check out Donaldson and other manufacturers specs. Donaldson is working on capturing SUB-micron particulates they claim at a 99%+ efficiency. Looking at Commercial oil bath MFGs stats, they list as being up to 95% to 98% efficient and no discussion on the size of particulate.
https://www.donaldson.com/content/d...1-ENG/Donaldson-Blue-Air-Filters-Off-road.pdf
Oil Bath Air Cleaners

I am not doubting your experience, oil bath got us through almost 3/4 of a century of work. I do agree with paper potentially being troublesome, mainly caused by weird shapes and absolutely junk air box assemblies. The late 7.3L Ford is a prime example of a junk airbox, a sealing issue and chewed up turbos, among other things.

Its not really an argument. I was trying to use it as an example. Engines that have tighter tolerances and lighter weight components need cleaner air. As you know, they turn to junk exceptionally fast exposed to dirty air, fuel, etc. Add in the plethora of sensors now located in the intake tract, turbos, etc.
I'm pretty sure Hit-N-Miss engines can digest small pebbles with no ill side affects.

I wont argue with you on that.

 

Tim E on this forum converted one of the later (late '67 - '69) type V6 oil bath air cleaners to accept a paper element - here's a link to his thread:

V6 Oil Bath To Paper Element Conversion

Here's a later thread I started showing my conversion of one of the earlier type (through early '67) V6 oil bath air cleaners:

( Early Type ) V6 Oil Bath To Paper Element Air Cleaner Conversion

 

Just to add a little bit on the heavy equipment air cleaners, they are often multi-stage. The first stage is usually a cyclonic devise that spins up the incoming air causing larger dust and particles to fall into a cup chamber that is easy to service. The air leaving this cyclonic device then goes into a large paper element or oil bath for final filtering.
My VW Vanagon syncro came with a cyclonic pre-chamber with a clear plastic collection bowl that trapped a lot of dirt. I was shocked how frequently the bowl needed to be cleaned of sand and dust, at least on a monthly basis. There was a conventional pleated paper panel filter before the mass flow sensor.
I used to drive an old VW baja bug as a daily driver. I used an old Donaldson oil bath from a Jeep that I mounted inside behind the back seat. I had a hard line run through the bulkhead to a rubber hose attached to the carb top. It kept nearly all the sand out of the air cleaner, and the engine. It was a little loud insde at high revs, but tolerable.
-Donny

 

Hmmm living in the Sonoran desert in Arizona I'm kinda wondering if I should think about an oil bath set up vs the civilian snout with a paper filter or k&n
As I'll be more trailriding and rock climbing hard to find a water crossing

 

The American Army still uses oil bath, and so dose a lot of construction equipment, Just Saying, Good Luck

 

Bringing back an old thread, I'm in the market for an air cleaner for my dauntless. I'm intrigued by the donaldson type S oil-bath units, and am thinking that would be a pretty neat setup. Does anyone know the CFM requirements of a 225 dauntless? I'm starting from scratch, and don't know if I need a 6", 10" 14" paper element, or an oil-bath.

I do seem to recall that the stock 225 oil-bath filter pukes if you lean it too far; I'd like to avoid that, lol.

 

Gold star for the day Howard! Now tell me where I can find the perfect air cleaner for my needs, and while you're at it, can you define my needs too?

(Note: for those of you wondering what my needs are.... ice cream runs, tight bumpy fire roads, minor water crossings possible).