Oil Bath Vs Dry Filters

[luvrbus]

Here from DD then you make up your mind which is best for you and we can put it to sleep



Air Cleaner Characteristics  

Dry Type                                                                   Oil Bath

99.8 to 99.9 % effective regardless of                     96.to 98.7 effective depending on
engine speed (see Figure 7)                                   engine speed (see figure 7)

Less restriction to air flow                                      Greater restriction to air flow

Performance not affected by                                    Performance may be adversely
temperature                                                          affected by temperature extremes

Compatible for use with turbocharger                        Not recommended for use with
                                                                          turbocharger due to oil mist

May be mounted at any angle                                  Must be mounted vertically


Engine performance will indicate if                            Engine performance will not
if element replacement is overdue                            indicate cleaner is preforming
                                                                          properly

No danger of engine runaway due to                          Possibility of oil pull over
due to oil pull over


Use of restriction indicator is acceptable                  Use of restriction indicator not
                                                                         acceptable

Oil vapor from crankcase ventilator                          Compatible with crankcase
may clog element                                                  ventilator  

This is from Detroit sorry I cannot do the the figure 7 chart Dave can do that when he shows  



 

[Lin]

Sure, when you put it that way it looks like dry filter is a better candidate (sorry, the election is creeping in everywhere), but you can't spill a paper filter.  You just pull out the old one and put in a new one.  Where's the challenge in that?  They are called "oil bath filters" for a reason!  Give me an oil bath, a Spicer, and a huge folding map spread over a 26" steering wheel (none of that new fangled power assist neither. Yeah, and if God meant for you to be cool in the summer, He would have made it more like winter. Air conditioning--Phooey!

[Scott Crosby]

I'm not believing 99.9 as a blanket statement.  There are 25 major brands and styles of paper filters and some must be notably better or worse than others.  Techno's paper filter didn't work out to good.  I'm not saying they aren't better but not all filters are the same. I once saw a study were oil bath excelled vs paper at high rpm.  I can't find it now and don't remember the exact results and even the validity of the study but I wouldn't blanket statement say paper is better.  Type, brand, cfm rating, proper installation and duration of use would all factor into it for me.   

[luvrbus]

I'm not believing 99.9 as a blanket statement.  There are 25 major brands and styles of paper filters and some must be notably better or worse than others.  Techno's paper filter didn't work out to good.  I'm not saying they aren't better but not all filters are the same. I once saw a study were oil bath excelled vs paper at high rpm.  I can't find it now and don't remember the exact results and even the validity of the study but I wouldn't blanket statement say paper is better.  Type, brand, cfm rating, proper installation and duration of use would all factor into it for me.  

Take it up with Detroit not me they used Donaldson or Farr in their manuals and they tell you not to use a paper filter that is over 3 years old in the manual.I don't believe the filter was the cause of Techno's problem either or they could have collected that is why one buys good filters.
I am just passing on the info to the ones that have a question and are thinking about changing to paper what you or I think has no bearing on what people use   

[Scott Crosby]

These aren't in a Bus engine but look at the wide range of results.   I didn't read the whole study so here it is for research.   Most buses I see that have paper it's almost always older than three years    But thd oil baths probably haven't been serviced in three years either on the oil bath ones

http://www.gmtruckcentral.com/articles/air-filter-study.html

[luvrbus]

You are right that is not a bus or truck filter 250 CFM on that test is not much.I have a ? why would you 3 or 4 oil bath filters when 1 dry filter can produce better results.I really thought DD gave the oil baths the benefit of doubt with the 97 to 98 % everyone else says  95% at tops    

[Oonrahnjay]

You are right that is not a bus or truck filter 250 CFM on that test is not much. ... 

    Something I find surprising is that there's a filter that allows more contaminant to pass than K & N!

[Dave5Cs]

I do know from having a family that had lots of fields to plow when I was growing up, My Dad used to clean dump and change the oil in the filters 3 times in a 12 to 14 hour day on a dusty field because he said the oil bath would have so much dust and dirt in it that it actually would come to a point of skimming over and not stopping the dust from going around the center tube and right up into the engine. We had CAT's (Tractors) in those days with 2 oil baths each tractor. Point being if they get cleaned regularly the oil bath would work to a point but if not would pass dirt and dust into engine, where as a paper filter would stop it until it shuts off the air flow unless there was a hole in the filter material.
Dave5Cs

[Scott Crosby]

And I'm not arguing with you Clifford, I'm just having a discussion.  I was just pointing out that To just say paper is better than oil bath is not true.   Specific paper filters under specific conditions can be better than oil bath filters.  And if it costs someone $400-$800 to have a paper canister retro fitted into their bus, the properly maintained oil bath system will work just fine if they can't afford it.  I have paper in my 6v and I get way more dirt out of my oil bath filters.  Yes the paper can have it suspended in the media and the oil adds to the consistency of the dirt in the baths but my eyes see how much dirt I remove even after a 5,000 mile trip from the oil baths and it's a lot that comes out.  That paper filter should be black and not nearly white with the amount of dirt that comes out of just one air bath filter change.  Some oil assperation happens in the intake, but it's clean in the tube not dirty or gritty.  Even my lobes are clean as can be with my oil bath bus.  The EPA complained about the oil assperation and I'm sure the disposal of the contaminated residue too.  There is money to be made in replaceable filters too so motive could come to play on weighing that in.  I also have a sheet from Detroit saying the recommended oil change interval in a 71 series is 100,000 miles.  It don't mean I'm taking that info as the ultimate truth.  Now a lot of this stuff is made in China or some other third world country and would I blindly trust the quality control of it?  What's the failure rate of a paper filter?  How often are they physically examined?  Are they installed correctly?  Could a rat chew a hole in one? Does water damage the paper?  Probably a hundred reasons why they could fail.  For old technology the oil baths can work really good, and in many cases better than paper, but I'll give you that many times paper can be better but not a blanket "better" 

[lostagain]

When I rebuilt the 4-71 in my Courier 96, it had a oil bath filter. Worked pretty good, as long as you service it regularly and keep it clean. When I was researching what to do about turboing that engine, I was asking different mechanics what to do about the oil bath. The young mechs were telling me get rid of it, it will suck oil into the intake. The old mechs were saying keep it, it will work with the turbo, and it won't suck oil. So I kept it just to see. Well it never sucked oil into the intake, and it worked really well. I put 20000 miles on that turboed engine and it did good. I had proved a point, mostly to myself.

I also have a 220 Cummins  for a power unit on a saw mill that is turboed and still running the oil bath filter. It only sucked oil once when I overfilled it once about a 1/2" above the line. It revved up a bit and smoked for a few minutes until the excess oil was burned off. I had my hand ready on the fuel shut off just in case...

Probably the biggest reason they changed to paper filters is ease and speed of servicing, when labor became expensive.

Is paper better than oil bath, I don't know.

JC

[dtcerrato]

In a different respect as in the 2 cycle Jimmys being taken out of production, so too for oil bath air cleaners due to EPA constraints. Read that in a couple articles. I would think a Jimmy would get pretty thirsty without some oil in its intake so I'll just keep letting it sip so it don't get thirsty. You know if politicians took a problem, any problem and talked it like we can well it would be some kind of world, wouldn't it? Probably would be more busses around too! :-)

[luvrbus]

That 100,000 mile oil changed was short lived you should have a bulletin replacing that page I have it 18SE30- release 83.

Engineering bulletin 39 still stands no revisions have been made to it or I would have received it.I really don't care what people use that is their business.

I will say most dry Donaldson filters have a Vaculator valve or tiny holes that shake the dirt and water out of the filter by using the impulse of the engine.

My Vaculator valve keeps my filter fairly clean even living here in the desert that valve is a engineering marvel by Donaldson.

I wish I had Jet Air cleaner like the military uses on Abrams tanks they get a lot of use out of paper filters.
Where did you get the $400 to $800 price ? I can replace those oil baths with a ECO system for $150.00.
I know from years of using a oilbath filter if you don't stay on top of it they will dust a engine ask Brian Evens of Canada  here on the board 
I just posted reference material documented by Detroit the people that made the engine people here can do what they choose to do with it but it here if they need it          

[Iceni John]

A few years ago I modified the intake plenum above my filter to be easily removable so I can now see down inside the filter itself.   My old filter had begun to split internally, probably from old age and maybe also from rain that weakened it, so I made sure I wouldn't have any more surprises in the future.   I also made a rain catch tray inside the plenum to prevent the new filter getting wet.   Anything you can do to make it easy to check the inside of the filter on a regular basis could prevent big problems  -  remember, a split filter won't show any restriction on the Filter Minder.

And just like batteries, look at the production date before you buy.   I had Racor make my ECO-BC to order, so I know it wasn't sitting on a shelf for years getting brittle and weak.

John

[luvrbus]

A oil sample @10,000 miles will show the paper works better than a oil bath I found out years ago

[DoubleEagle]

I toyed with the idea of having both an oil bath and a paper filter on the same engine that was subject to a lot of dust and dirt, but with the air restriction of the oil bath and the oil vapor problem, it would not be practical. We ended up using a Donaldson model that had dual filter elements, one inside the other. That has worked well, but I don't think they have it for larger engines.