Oil bath air filter

[tdi-rick]

My farmall manual says to clean the oil bath daily. I suppose they anticipate the old days running over plowed ground and excessive dust.
Back in my childhood days my Dad had a Farmall B with a belly mower which mowed at least 1 or more lawns for about 25+ years. Through those years it run about 75% of the augers during harvest and later when unloading for market,talking farming mostly corn at roughly avg 100bu per acre farming 400 acres in the mid 70's and 2000+ in 2000. I drove that tractor like a car for transportation before I got my license. Found out how to override the govener and get near twice the speed out of it. Had pulling contest with my neighbors cub cadet ,hardly ever cleaned the oil bath and I donot ever remember it getting overhauled. The only thing I remember fixing from my use was the draw bar which became a wheelie bar and got bent. Its still being used about half as much on smaller augars and I had been using it to mow woods roads until I bought my own farmall c last year. I remember a few repairs but no motor. I wouldn't be surprised if it had been overhauled once when I was gone for an extended time but either way the engine has held up incredibly considering the hours put on it.

I still haven't changed my Fiat 550's air cleaner for a paper type yet, and it's mainly used for harrowing a bloody dusty dressage arena and slashing paddocks.
Come to think of it, I haven't cleaned it out for a while either :monkey:

 

[robertjinnes]

Everyone is partially correct---

Oil bath filters are the best for shear volume of dirt they will collect without plugging up. they are the poorest for the percentage of dirt that they stop.

Reasoning for volume is that the oil wetted horse hair or equivalent is continually having oil bubbled up onto it, replenishing a clean oil srfuace while washing the dust/dirt into the oil reservoir where the dirt settles out. Unfortunately, some air gets thru the horse hair without effectively being scrubbed of its dirt and the dirt ends up in the cylinders and ultimately in the engine oil. As long as filter oil level is maintained and dirt level doesn't close off air flow it will filter indefinately at approximately the same efficiency. The pleated paper elements filter down to micron level but they only have a small fraction of dirt capacity in comparison.

If you have an oil bath filter on a chipper, most airborn "dirt" is wood dust and fine chips. Not the worst material for an engine to inhale. The same engine on a stump grinder or farm tractor will ingest real dirt causing real damage.

This is not an advertisement but the best filters today for both dirt volume and micron level filtering are DONALDSON and similar Cyclone with outer foam filter and inner paper filter. Not cheap but quality never is.

 

[chowdozer]

Lessons learned from Mount St Helens, May 18, 1980

State of Montana Natural Hazards Mitigation Plan November 2001

Page 5

Transportation
The silica-rich glass shards of ash are harder than steel, thus excessive wear of machinery can be expected. The best mitigation for this problem is to use oil bath or foam air filters where possible, rather than paper filters (Schuster, 1981). Air, oil, and gas filters should be changed frequently, as should engine oil. Brake drums will also abrade rapidly, and should be cleaned as often as possible.

I have yet to see dust as abrasive and fine as volcanic ash.

 

[tdi-rick]

Lessons learned from Mount St Helens, May 18, 1980

State of Montana Natural Hazards Mitigation Plan November 2001

Page 5


I have yet to see dust as abrasive and fine as volcanic ash.

And if you talk to anyone that is involved in filtration they will tell you that a cellulose fibre (paper) filter has a level of efficiency far greater than an oil bath filter or oiled foam.

BTW, air filtration efficiency increases as the filter loads, the only reason you change a filter is that the loading decreases air flow and ultimately performance.

One of our members is a filtration research engineer, I can direct him this way if anyone wants real expert opinion and fact.

 

[chowdozer]

And if you talk to anyone that is involved in filtration they will tell you that a cellulose fibre (paper) filter has a level of efficiency far greater than an oil bath filter or oiled foam.

BTW, air filtration efficiency increases as the filter loads, the only reason you change a filter is that the loading decreases air flow and ultimately performance.

One of our members is a filtration research engineer, I can direct him this way if anyone wants real expert opinion and fact.

And if you talk to anyone that was in the blast zone of St Helens operating equipment, they will tell you they scrapped out more equipment with paper filters than those with oil bath filters. Hence Montana's Natural Hazards Mitigation Plan suggesting oil bath air filters.

You being big on the VW's must know that the oil bath on the bug was one of the best air filters ever made. Here's a thread for you from the baja guys: TheSamba.com :: View topic - Oil Bath Air Filters For Off Road

And of course you can still buy oil bath air filters. If they are ineffective, don't you wonder why they put them on $250K+ equipment?
http://www.mann-hummel.com.sg/EN/industrialfilters/doc/HBZJIL6b4Jk.pdf Page 57.
Typical installation for a heavy dust environment would use a paper element pre-cleaner. I can guarantee under this configuration you will find the oil in the oil bath gets dirty from dust getting through the paper element.
Honda still sells engines with oil bath filters too:
http://engines.honda.com/pdf/manuals/31ZE0601.pdf
Why would they go to the trouble if paper filters are superior and the housing is cheaper to manufacture? An aha moment!

Of course an oil bath filter is only as good as it's maintenance.
Real world experience trumps filtration research engineers. If you don't think so, have your filtration research engineer contact Mann or Honda. I'm sure they can supply him with expert facts and opinion.

 

[tdi-rick]

[snip]
Of course an oil bath filter is only as good as it's maintenance.
Real world experience trumps filtration research engineers. If you don't think so, have your filtration research engineer contact Mann or Honda. I'm sure they can supply him with expert facts and opinion.

I've never had anything to do with VW's, there are other Tdi's in the world

As for Mann, he's currently doing consulting work for them, and has done for Cummins/Fleetguard and Donaldson, probably the holy trinity when it comes to engine filtration.

Fact remains that oil bath filters are poor when it comes to efficiency, there are much better alternatives, but anecdote and myth trumps reality on the internet
The toughest environment for filtration are off road equipment, eg. mining, and they all use massive paper style elements, (with some sort of pre-cleaner) although nano fibre filters are coming on-stream from the majors.

Most issues with paper style filters usually relate to poor sealing, I've seen a number elements that don't seal well, with terrible consequences.

 

[tdi-rick]

BTW, thanks for that Mann catalogue, I don't have that one.

 

[chowdozer]

I've never had anything to do with VW's, there are other Tdi's in the world

As for Mann, he's currently doing consulting work for them, and has done for Cummins/Fleetguard and Donaldson, probably the holy trinity when it comes to engine filtration.

Fact remains that oil bath filters are poor when it comes to efficiency, there are much better alternatives, but anecdote and myth trumps reality on the internet
The toughest environment for filtration are off road equipment, eg. mining, and they all use massive paper style elements, (with some sort of pre-cleaner) although nano fibre filters are coming on-stream from the majors.

Most issues with paper style filters usually relate to poor sealing, I've seen a number elements that don't seal well, with terrible consequences.

yeah, so far you have only offered your opinion. Sounds like you haven't ever used an oil bath air filter either. What is your expertise? You talked to someone who works for a filter company and they told you their filters are the best? haha

 

[tdi-rick]

Missed this, sorry.

Yes, I have an oil bath air cleaner on an old tractor. [edit] re-read post # 14

No, Ben doesn't work for a filtration company, he does independent research, works out of one of our universities ATM (has worked in Europe and the US) and contracts to the big filtration companies.
He's also a member on here so I can ask him over if you'd like someone that really does know what he's talking about, the rest of us are just keyboard jockeys arguing on the internet.

If you are interested here's a thread on oil baths with stated efficiencies Oil Bath Air filter, The Advantages. - Page 2 - Australian Land Rover Owners
The big advantage of an oil bath is it's holding capacity, but efficiencies are below paper and appear on par with oiled cotton gauze (K&N).

Commercial Oil-Bath:

Laboratory tests with various types of dust show efficiencies ranging from 95.4% to 98.6%.

paper or polymer

» Donaldson Air Filters in Donaldson Air Cleaner housings have a 99.95+% minimum overall efficiency.

» The efficiency of the filter actually improves as dust loads up on the surface of the filter; so an air filter gets better as is gets used.

and FWIW here's a thread on testing paper vs K&N's Air Filter Tests (Finally) - Australian Land Rover Owners I supplied the filters.

 

[chowdozer]

Missed this, sorry.

Yes, I have an oil bath air cleaner on an old tractor. [edit] re-read post # 14

No, Ben doesn't work for a filtration company, he does independent research, works out of one of our universities ATM (has worked in Europe and the US) and contracts to the big filtration companies.
He's also a member on here so I can ask him over if you'd like someone that really does know what he's talking about, the rest of us are just keyboard jockeys arguing on the internet.

If you are interested here's a thread on oil baths with stated efficiencies Oil Bath Air filter, The Advantages. - Page 2 - Australian Land Rover Owners
The big advantage of an oil bath is it's holding capacity, but efficiencies are below paper and appear on par with oiled cotton gauze (K&N).

Commercial Oil-Bath:


paper or polymer


and FWIW here's a thread on testing paper vs K&N's Air Filter Tests (Finally) - Australian Land Rover Owners I supplied the filters.

Quoting another forum, lol. There's a real verifiable source that will hold up to scrutiny. Of course you could also read the other posts in the same thread you linked. Many other posts disagree with you.

and FWIW, K&N's stated goal is to build a high flow filter with 98% efficiency. They meet their goal. Do you have a problem with K&N filters that meet their stated goal? If you do, then you are trying to use their filter outside the usage they intended.

 

[tdi-rick]

I give up.

There are two spec sheets in those links, one for an oil bath and one for a paper style element, and FWIW isuzurover on that forum is the filtration engineer I've been speaking of, but if you don't wish to believe it that's ok,
I'm just trying to prevent some other poor sucker from being trapped by the 'an oil bath is better than' a paper filter' crap.

 

[chowdozer]

I give up.

There are two spec sheets in those links, one for an oil bath and one for a paper style element, and FWIW isuzurover on that forum is the filtration engineer I've been speaking of, but if you don't wish to believe it that's ok,
I'm just trying to prevent some other poor sucker from being trapped by the 'an oil bath is better than' a paper filter' crap.

The first link you posted didn't work. I would assume that means you never clicked it. The mistake you make is thinking that all oil bath filters are the same. They are not. Oil bath filters rely on the momentum of the particulates in the air stream and their inability to chage directions quickly. The design has a whole lot to do with how well the filter will perform and each filter is specifically designed for it's application. It is a mistake for you to cite the spec on one oil bath and think that is concrete evidence all oil bath filters are the same and inferior to a paper filter. As I have already posted, of the equipment used in the blast zone after St Helens, the equipment using paper filters suffered a higher engine failure rate than those using oil bath filters. I know you don't believe that, but the reality is real world experience wins over lab tests every time.

I'm still interested to know, do you have a problem with K&N filters that meet their stated goal?

And FWIW, you could go tell the baja guys their real world experiences are just wrong. Tell them they are imagining things because lab tests with the guys wearing clean white coats and control all the variables in a clean room are really the final say. lol
TheSamba.com :: View topic - Oil Bath Air Filters For Off Road

 

[isuzurover]

Hi Rick - thought my ears were burning...

Chowdozer:

Oil bath filters rely on the momentum of the particulates in the air stream and their inability to chage directions quickly.

This quote is correct. Oil bath air cleaners use particle inertia to collect particles.

Filters on the other hand use a range of mechanisms, in addition to inertia. these include diffusion, interception, sieving (in rare cases) and electrostatic effects (in some cases - usually HVAC filters and cabin air filters).

So the only way an oil bath air cleaner can work as well as a fibrous filter is to increase the velocity so the inertia of even small particles is high enough to be captured.

Also, if you look at how filters work, you will find that collection efficiency is (in general) inversely proportional to fibre diameter. That is why many companies like donaldson use filters which include nano-sized fibres. Filters such as K&N which use large diameter cotton fibres can never hope to compete with a properly engineered filter using (much) finer fibres.

As a small anecdote, one of the companies I work with had an F1 team offering them vast sums of money to develop a filter for their F1 engines. They had previously been running an oiled cotton filter of a well known brand. However both their race cars had engine failure during a race in Bahrain... It was found that even sand grains were getting through the filter at WOT filtration velocities.

If you don't believe me on how filters work, feel free to have a read of Aerosol Technology (1999) by Hinds... That is the bext (air) filtration textbook.

 

[chowdozer]

Hi Rick - thought my ears were burning...

Chowdozer:


This quote is correct. Oil bath air cleaners use particle inertia to collect particles.

Filters on the other hand use a range of mechanisms, in addition to inertia. these include diffusion, interception, sieving (in rare cases) and electrostatic effects (in some cases - usually HVAC filters and cabin air filters).

So the only way an oil bath air cleaner can work as well as a fibrous filter is to increase the velocity so the inertia of even small particles is high enough to be captured.

Also, if you look at how filters work, you will find that collection efficiency is (in general) inversely proportional to fibre diameter. That is why many companies like donaldson use filters which include nano-sized fibres. Filters such as K&N which use large diameter cotton fibres can never hope to compete with a properly engineered filter using (much) finer fibres.

As a small anecdote, one of the companies I work with had an F1 team offering them vast sums of money to develop a filter for their F1 engines. They had previously been running an oiled cotton filter of a well known brand. However both their race cars had engine failure during a race in Bahrain... It was found that even sand grains were getting through the filter at WOT filtration velocities.

If you don't believe me on how filters work, feel free to have a read of Aerosol Technology (1999) by Hinds... That is the bext (air) filtration textbook.

I do not consider it truthful when people comment on K&N filters without reading K&N's stated goal in manufacturing filters.

K&N Air Filter Facts You Should Know end of 2nd paragraph

Our goal is to design our air filters to achieve maximum airflow while targeting overall filtration efficiency at 98%.

So I'll ask you the same question I asked Rick. Do you have a problem with K&N meeting their stated goal?

Comparing a K&N with a filter which targets a higher efficiency is apples and oranges.

BTW, I never questioned how filters work. I thought it's intuitive.

 

[isuzurover]

I do not consider it truthful when people comment on K&N filters without reading K&N's stated goal in manufacturing filters.

K&N Air Filter Facts You Should Know end of 2nd paragraph


So I'll ask you the same question I asked Rick. Do you have a problem with K&N meeting their stated goal?

Comparing a K&N with a filter which targets a higher efficiency is apples and oranges.

BTW, I never questioned how filters work. I thought it's intuitive.

Yes I have a problem with their stated goal. It means nothing. 98% measured how, by number or mass? And for what aerosol size distribution? And what test method?

If you use a proper fibrous filter material with sufficiently fine fibres then you could get >>98% (mass-based) particle capture efficiency, and much lower pressure drop (i.e. higher airflow) than a K&N.

98% mass based efficiency is insufficient to protect an engine that is used in dusty conditions and expected to last more than a few races.

The filters I mentioned on the F1 cars did not reach 98% (mass based) efficiency at WOT. In fact the efficiency plateaued at about 80%, as the sand grains were just bouncing their way through the filter.

I would bet that most K&N filters would struggle to achieve 98% mass-based efficiency in real world applications, and they wouldn't come anywhere near 98% number-based efficiency.

BTW - may be intuitive to you, but most people think that filters work like sieves.

 

[chowdozer]

Yes I have a problem with their stated goal. It means nothing. 98% measured how, by number or mass? And for what aerosol size distribution? And what test method?

If you use a proper fibrous filter material with sufficiently fine fibres then you could get >>98% (mass-based) particle capture efficiency, and much lower pressure drop (i.e. higher airflow) than a K&N.

98% mass based efficiency is insufficient to protect an engine that is used in dusty conditions and expected to last more than a few races.

The filters I mentioned on the F1 cars did not reach 98% (mass based) efficiency at WOT. In fact the efficiency plateaued at about 80%, as the sand grains were just bouncing their way through the filter.

BTW - may be intuitive to you, but most people think that filters work like sieves.

What standard do you test filters too? I would assume ISO 5011? Are you familiar with ISO 5011?

 

[isuzurover]

What standard do you test filters too? I would assume ISO 5011? Are you familiar with ISO 5011?

I am certainly familiar with ISO5011. However as K&N state on their website, there are a range of options under 5011 (e.g. ISO coarse of ISO fine test dust, etc...). I cannot see where they state the parameters they test to.

However they do state:

Our actual air filters when tested generally demonstrate a cumulative filtration efficiency of between 96% and 99%.

So - overall (presumably mass-based) efficiency between 96 and 99% (probably for ISO coarse...?).

Which means that a number of K&N filters often do reach their stated goal!

Btw - re your first question. I rarely use ISO 5011 testing (or any ISO tests) as they are fairly crude methods, and I am usually involved in primary R&D, so interested in much more accurate data.

 

[chowdozer]

Let's address the 3 problems you have stated you have with K&N filters.

I am certainly familiar with ISO5011.

Excellent! Then you also know that K&N uses the ISO 5011 standard based on what they have written on their website, the link I already gave you.

The testing procedure used in the past was the SAE J726 air filter test procedure established by the Society of Automotive Engineers, however this procedure was recently superseded by testing procedure ISO 5011.

1.

Yes I have a problem with their stated goal. It means nothing. 98% measured how, by number or mass?

Since you are 'certainly' familiar with ISO 5011, then you know that Section 6 of ISO 5011 covers dry type air cleaners for automotive applications. Further, you also know that Section 6.4 covers the efficiency test. At 6.4.3.3, you weigh the filter and record it's mass. 6.4.3.13 you record the mass of the AUT (article under test) after the test. By subtracting 6.4.3.13 from 6.4.3.3, you get the total mass of dust accumulated on the AUT. 6.4.3.16, you calculate the material balance, ie: the total mass of the dust caught by the absolute filter + the increase in mass of the AUT, divided by the total mass of the dust introduced into the system. From there it is a simple matter to calculate %. From my above rough outline of the efficiency test, I presume you get the idea the efficiency test is based on mass? (of course you could also use the direct weighing method described in Section 6.4.4, that would be mass based also). Those are the only two options ISO 5011 gives for an efficiency test. This answers your 'problem' 1 from above. You should know this if you are at all familiar with ISO 5011.
2.

And for what aerosol size distribution?

Your second 'problem' is even easier to resolve. K&N states the answer right on their website, (the link I already posted).

We subject a sample of our filter designs to this test procedure using Coarse Test Dust, which includes particles ranging in size from less than 5.5 microns to 176 microns.

Since you are familiar with ISO 5011, you also know Section 5 covers test materials and conditions. 5.1.1 outlines the two different ISO grades of test dust that can be used, subject to agreement between test organization and customer obviously. And from K&N's website once again, you know that K&N chose ISO 12130-A4 dust, which not surprisingly is the standard coarse dust. This answers your 'problem' 2 from your previous post.
3.

And what test method?

Your 'problem' 3 is the easiest. ISO 5011 IS the method. The complete test is outlined for you in ISO 5011. The materials, the equipment, airflow requirements, pressure drops, the calibration of the equipment, drawings of the test setup. Everything. Heck, they even include worksheets to record your results.This answers your 'problem' 3 from above. You should know this if you are at all familiar with ISO 5011. I have my doubts.

There you are. All your concerns about K&N filters addressed. I find it disappointing you could not address them yourself, you being in the industry and all.

Btw - re your first question. I rarely use ISO 5011 testing (or any ISO tests) as they are fairly crude methods, and I am usually involved in primary R&D, so interested in much more accurate data.

ummm, ISO 5011 IS the industry standard. Industry standards are used so that any test can be duplicated anywhere in the world at any time and filtration results obtained at different times and/or locations can be directly compared. Every major manufacturer in the US tests to ISO 5011. Not even a point to argue.

 

[isuzurover]

I noticed you missed the quote that K&N state their filters test at 96-99% So they admit that they do not meet their own stated goal of 98% (which has been your main counter argument supporting K&N from the start).

Thanks for the line that mentioned ISO coarse. I missed that. However as I stated I suspected as much.

And if you fail to see the imitations of the ISO test method then I have nothing more to add to this thread.

 

[chowdozer]

I noticed you missed the quote that K&N state their filters test at 96-99% So they admit that they do not meet their own stated goal of 98% (which has been your main counter argument supporting K&N from the start).

Yeah, I was wrong. I admit that. I don't take it personally.

Thanks for the line that mentioned ISO coarse. I missed that. However as I stated I suspected as much.

And if you fail to see the imitations of the ISO test method then I have nothing more to add to this thread.

First, it's good that you now understand ISO 5011 is a test method. A couple posts ago you didn't know that. You're learning. Hopefully, you have also learned ISO 5011 uses mass to measure filter efficiency. I wanted to mention this again, because you ignored my previous post. All the supposed problems you named you had with K&N filters don't exist. Maybe you should start a "B" list because your "A" list failed.

Second, ISO 5011 doesn't have any imitations.