Re: Oil bath air cleaners are ineffective

rrlund · Jan 8, 2010

Musta missed that discussion. Was it anything like the one I posted a year ago saying that I have 2 tractors with oil bath and 2 with dry element,and the 2 with the oil bath get more moisture in the oil than the ones with dry element?

keh · Jan 8, 2010

Back when they were racing stock cars on the beach at Daytona they found the big engines were sucking oil and sand into the engine through the oil bath cleaners, so they went to dry filters. On tractors, my gripe is that a lot of them put the filter, oil or paper, right in front of the radiator. The fan is then sucking dusty air into the air intake as it is drawn through the radiator. Also, the air filter in front of the radiator blocks some of the air flow which is not good.

KEH

Jerry/MT · Jan 8, 2010

The use of classical Boundaty Layer Theory in this discussion is inapropriate, in my opinion. That theory is based on flow over surfaces that are realtively long in the direction of the air flow, (i.e flat plates, air foils, pipes, etc.) and have reltively moderate pressure gradients in the direction of flow.

That"s not the case in steel mesh found in typical oil bath air cleaners. The flow in these devices is a wake flow, is more analogous to a series of flat platse at 90o to the flow. There is hardly any length available to develop a classical boundary layer and the flow is unsteady, highly turbulent and three dimmensional. Italso happens to be a three phase flowfield with gaseous air and liquid oil and solid particles. Nothing short of a full 3-D, time dependent Navier Stokes analysis will define the discrete flow field.
These devices depend on the particle inertia, mesh and housing geometry, and oil viscosity to work. Without some serious test data, I personally don"t understand how the author can claim they are ineffective. I think the biggest problem with oil bath air cleaners is that are such a mess to clean if they are not properly maintained and messy to clean and that"s why they were replaced by paper element filters. It"s analagous to why the canister type oil filters went the way of the dodo bird. they were plain messy to change. Of course not all spin on filters were oriented to not be a mess to change!

Opinions are like belly buttons;everybody"s got one. This is mine on this subject.

JMOR · Jan 8, 2010

(quoted from post at 13:24:51 01/08/10) The use of classical Boundaty Layer Theory in this discussion is inapropriate, in my opinion. That theory is based on flow over surfaces that are realtively long in the direction of the air flow, (i.e flat plates, air foils, pipes, etc.) and have reltively moderate pressure gradients in the direction of flow.

That"s not the case in steel mesh found in typical oil bath air cleaners. The flow in these devices is a wake flow, is more analogous to a series of flat platse at 90o to the flow. There is hardly any length available to develop a classical boundary layer and the flow is unsteady, highly turbulent and three dimmensional. Italso happens to be a three phase flowfield with gaseous air and liquid oil and solid particles. Nothing short of a full 3-D, time dependent Navier Stokes analysis will define the discrete flow field.
These devices depend on the particle inertia, mesh and housing geometry, and oil viscosity to work. Without some serious test data, I personally don"t understand how the author can claim they are ineffective. I think the biggest problem with oil bath air cleaners is that are such a mess to clean if they are not properly maintained and messy to clean and that"s why they were replaced by paper element filters. It"s analagous to why the canister type oil filters went the way of the dodo bird. they were plain messy to change. Of course not all spin on filters were oriented to not be a mess to change!

Opinions are like belly buttons;everybody"s got one. This is mine on this subject.

erry, we have butted heads, but not this time!

ncpapaul · Jan 8, 2010

If they are ineffective how come I have to clean black mud out of the bottom of them everytime? Paul

730d se · Jan 8, 2010

It is an old design that worked great for many years on all types of engines.
A few restrictions, must stay somewhat level, or at least not on extreme hill sides. Must use the proper oil which is typically the same oil used in the engine.
I can see in a race car making high speed turns that the oil would flow over to the outside, leaving an air gap on the other side, thus letting in particles and also allowing oil to get high enough to get in to the engine. Speaking of the oil level, it also must be exactly in the right location.
They are messy and not forgiving and flexible like paper filters, but they are also ORIGINAL.
Just like generators over alternators, if you are truly in to the classic part of these, you will accept the shortcomings. It goes with the "territory".

buickanddeere · Jan 8, 2010

An oil bath aircleaner is much better than nothing.
A quality and correctly sized dry element aircleaner is much better than an oilbath.

Dean Barker · Jan 8, 2010

From filter testing, oil bath air filters are usually around 94% efficient whereas most paper air filters are 99.99% efficient. We used to dust an average of one engine a year on our experimental tractors running in Arizona because of a paper air filter rupturing. After the paper air filters came out with the additional safety element inside the main element, we never lost one engine.

Anonymous-0 · Jan 8, 2010

Not just Barker, buteveryone
Can,t anyone support WAGs, opinions, "theories", speculations with hard, raw, factual data, official reports!? We don,t see much real content here anymore...'Bout like talkin heads on boob tube. Someone must actually KNOW some FACTUAL info!

Re: Oil bath air cleaners are ineffective

rrlund

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keh

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Jerry/MT

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JMOR

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ncpapaul

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730d se

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buickanddeere

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Dean Barker

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Anonymous-0

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