dons56

oil bath air cleaner modification

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Has anyone out there modified an oil bath air cleaner to take a paper filter and still look like the original oil bath?  My son (SpecialEducation) and I have talked about this for years but were afraid to pull the trigger until we had a second one on hand in case we foul it up royally.  What are your thoughts?  Good idea?  Bad idea?  

 

I have a 1956 Buick Special Riviera.

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Why would you want to change it.  Most of the literature that I have seen says when properly serviced the oil bath air cleaner removes  more and smaller particles while not restricting air flow.  One other nice thing about the oil bath cleaner is that oil is always available.  Sometimes a specific paper filter is not when you need it.

Go back to forums home page and do a search "paper filter oil bath", you will find this has been discussed 92 times.

It is your vehicle and of course you can and should do as you please.  Read up on topic (even do a search on Google or whatever is your search engine) and then operate your car as you see fit.

Happy hobbying.

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If you put oil on a chain link fence, things will still get through. 

 

If you can't find an air cleaner lid that's the same size as the original filter, the only thing you can do is cut the top off the filter and use a suitable paper element under it. 14"x3" is the ideal filter for little to no restriction according to Edelbrock. Take it with a grain of salt, but when sizing a suitable replacement, find something that had close to the same surface area. The 4 barrel cleaners are easier to adapt. You can hide another lid in there or use a filter that fills the entire housing. 

 

Measure the top of your current cleaner and see what fits. The aftermarket is limited to 14 and 10, but you could have something made. For what it's worth, people have told me a paper filter is more restrictive than the oil bath but I actually gained vacuum with the paper filter, which tells me the paper breathed better. Again, it's all about surface area.

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I've found lots of anecdotal discussions on this forum and others, but no hard research showing the filtration level difference. 

 

From my days as a propulsion systems engineer, I know that typically debris is responsible for more cylinder wear than the metal/metal contact. 

 

We are not looking to win speed or efficiency contests, so preserving the engine is the #1 priority here. 

 

Lower manifold pressure = less power, so if Beemon has observed more vacuum, that would be consistent with restricted flow, but there are other factors to consider:

 

It is very dusty in Kansas, particularly this time of year.  Oil bath maintenance is messy.  Good quality paper filters can be blown out and reinstalled in minutes for free...

Edited by SpecialEducation (see edit history)

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6 hours ago, Beemon said:

but I actually gained vacuum with the paper filter,

 

42 minutes ago, SpecialEducation said:

Lower manifold pressure = less power, so if Beemon has observed more vacuum, that would be consistent with restricted flow,

If you want to see high vacuum close the choke on a running engine and observe the vacuum reading before it stalls.:D

 

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I have been running 22 years with this oil bath and the car is actually running better than when I bought it.  The other side of that is that I may not know the damage until the engine quits and we rebuild but since I don't know what the wear was when I bought it I still won't know...  Maybe I just feel better thinking I am doing something important when i change a paper filter...

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It was always my understanding that it wasn't the oil on the mesh that did the real filtering it was the sharp turn that the air had to make.  The air went around and the particles, even microscopic ones couldn't make the turn and were flung into the oil, thus leaving clean air for the engine.

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The sharp turn is inertial separation. It does better to catch particles with more mass. Less mass = less inertia = easier to change direction and be ingested.

1956 also started out with an open screen in the hood ornament that would allow air & debris to enter the engine compartment. Buick decided mid-year to replace the screen with a solid plate painted to look like a screen to reduce the debris being ingested.

Edited by SpecialEducation (see edit history)
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6 hours ago, old-tank said:

 

If you want to see high vacuum close the choke on a running engine and observe the vacuum reading before it stalls.:D

 

When taking vacuum readings, with no cleaner its generally higher than with the oil bath cleaner. My basis of documentation was comparing to manifold vacuum with no cleaner, with oil bath and with paper. The paper decreases manifold vacuum, but not as much as the oil bath, which to me tells me it is less restrictive and filters more efficiently. I was always told the oil bath will flow more and be less restrictive, but my empirical evidence says otherwise. 

 

Also on the topic of oil bath cleaners, since it usually pops up in these discussions, but big rig construction machinery have special oil baths with multiple layers of filtration, with the last usually a pleated paper filter. Or as a pre-filter, at least.

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Edited by Beemon (see edit history)

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If heavy equipment uses oil bath it tells suggests to me that it is less costly than paper filters.  I would imagine in the dusty conditions such as road building or strip mining that paper would fill up quickly where oil bath can have quite a reservoir of oil and thus go for long periods between servicing.  Paper will restrict more and more until no air can pass through.  Oil bath should not care now dirty the oil is... to a point.

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The oil bath part is like a pre-filter, kind of like ours, where there's a second filter medium above it. The difference between our filters and heavy equipment filters, though is that the air is pulled through the oil on the heavy equipment filters vs our filters where the air goes across the top of the oil. If the oil level rises in our filters, it can potentially be sucked into the intake, carrying all the particles with it. Heavy machinery, to my knowledge, uses pleated paper with the oil bath as a pre-filter to get all the dust out and then using the paper filter to filter out the rest of the air.

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2 hours ago, Tinindian said:

It was always my understanding that it wasn't the oil on the mesh that did the real filtering it was the sharp turn that the air had to make.  The air went around and the particles, even microscopic ones couldn't make the turn and were flung into the oil, thus leaving clean air for the engine.

Exactly

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1 hour ago, Beemon said:

our filters where the air goes across the top of the oil

It does both dropping heavy particles in the oil  as air makes the bend and some oil is drawn up into the mesh to catch more dirt and that is drains back into the reservoir.  And your mesh never looks dirty unless it was used without oil.

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We've been through this discussion a few times over the past few years.  I can see how the oil bath filter works on cars and many industrial engine applications.  AND why many of the "hd fleet" engines used oil bath rather than dry paper.

 

One thought I just had was that as the air passes over (or through the oil reservoir in Beemon's example), the resultant "air" will have some oiliness to it, as a result.  This might also serve as "upper cylinder lube" or "valve lube" in some cases.  A dry paper filter would not be that way, thereby to gain the same affect, would need some of the "upper cylinder lube" fuel additive . . . of that time.

 

As for the industrial filter where the air goes through the oil, as it makes its directional change?  That oil must be very bubbly, which would decrease the filtering capability, relying upon the directional change to "trap" the heavier particles in the air.  In those industrial applications, "working time" is much desired over "down time", so the longer service life the air filter elements might have between scheduled maintenance, the better.

 

There are some companies which clean and recycle paper filter elements for fleet users.  But these are more on-road fleets of trucks than off-road construction machinery.  And, of course, it's not very easy to leave out the filter in an oil bath filter, but it CAN happen with a dry element filter.  Even if somebody might forget to service the oil, there can be a certain amount of filtering happening.

 

It used to be that oil could be disposed of anywhere, or at least not near trees, shrubs, or grass.  Now, things have to be done in a more environmentally friendly manner.  Different times.  Different vehicle design orientations.  Different maintenance issues.  As with automatic transmission fluid, power steering fluid, or brake fluid in power convertible top mechanisms, it was best for the customer for the car companies to use "common fluids" which almost any service facility (especially non-dealership) might have.  This has changed over the years as different needs were met.  Using a specific power steering fluid rather than automatic trans fluid in power steering systems, for example.

 

I know some have modified their oil bath housings to accept dry filter elements.  Each to their own.  I know that I'd rather change or shake-out a paper filter element than have to put on a pair of nitrile gloves to do what we normally did "bare-handed" in prior times.  Be that as it may.

 

One other thing, at least on cars, is that those older engines didn't have quite the air flow demands as later and larger engines might.  Carbs didn't flow as much either.  Nor was anything over about 3000rpm usually attained by most engines in their daily life.

 

Several different things to consider.

 

NTX5467

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Did it on my 55 Cadillac and worked out fine.  Just removed the wire mesh filter, replaced with a paper element and added some open cell foam rubber to fit between the top of the filter and the underside of the top of the housing.

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Take you air cleaner off and take a picture of it apart......I think Dave is correct, you can remove the inner mesh part and replace it with a paper filter of the same size....you would also remove oil and clean out all the oil residue.

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One of the obstacles to this project is that with no specific information like what size filter will fit etc., I don't want to take the chance I will destroy my oil bath filter.  I had a line on a second filter to experiment on but by the time I payed for the part and shipping the cost was just too rich for my blood.  The oil bath seems to work so I guess for now I will continue with it...

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I wish I had my info handy--but I believe a good tight fit on my '56 Century was found using a filter designed for a mid-80's Chevy S-10.  Seals without needing additional gasketing.

 

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… your oil bath filter was not only designed to fully and efficiently filter particulates bound by incoming air mass flow, It was also designed to cushion and quiet sonic noise from the open ingestion of incoming air through the air horn of the carb … replacing with a paper filter will not improve upon either of these key design features … which leaves only the idea of by using a paper filter one supposedly would minimize having to eventually change the oil in the oil bath which is more time consuming than just switching out a paper filter … even though the paper has a higher percentage and reasons for inferior lasting filtrations but then again most of us do not run our classics delivering pizzas or commuting to work racking up mileage so where is the technically  positive point and hassles of drinking the cool aid and changing to a paper filter as the oil in the bath could actually go for a couple years before you would need to give it any attention … and when needed just flow it through a high micron automotive spray paint filter and put it back in the bath for another two years ….  

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'Tis true that newer is not always better; especially in this case.  The oil bath does a far better job than the paper filter.  Paper filters were intro'd as matter of convenience in eliminating the mess when performing the necessary maintenance.

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