Air Filter Conversion

[mountain goat]

Does anyone have any information or pictures of a air filter conversion from "oil bath" to "dry" filter(s) on a PD-4106. I'm looking to convert mine.

Thanks, Brian

[Barn Owl]

Topic: GM oil bath to paper filter conversion.

My bus was already converted. I still haven't been convinced one is better than the other yet. Paper filters get pricey when you start buying four at a time.

[mountain goat]

Barn Owl, Do you have any information on the conversion you have?   Who make it etc.?

[luvrbus]

Look at the ECO series air fiters you should find one with the right cfm and size they cost around 140 bucks and comes with the housing they are a all in one unit

good luck

[JohnEd]

My money is on the oil bath.  If they still offer it on farm machines that operate in dust clouds as I have been told then it doubly has my vote.  I used the OB on my Beetles for 200K mile plus and they had lots of sand and grit in the bottom and my engines, at tear down, were in great shape as far as not having been dirted.

NOW ABOUT THAT K&N FILTER, and I use that term loosely.

I bought one of those $48 pups for my 440.  You do so many things that you forget what came when or who killed Cock Robin.  One thing I did a while after installing that filter was to adjust my carb(urator for those to young).  Any body remember what the complication was with a carb running too lean?  You have to jack up the idle and then the mix will only go so far and then she dies abruptly.  It is supposed to die off slowly and track the mix adj.  I had that symptom and I rebuilt the carb.  The plot thickens!  As I was on my way out of Eugene, headed for the cool coast, I stopped at the tire store to get aired up.  While waiting for the service rep I pulled the engine compartment cover and fired "the Beast" up.  Ran sloppy and wasn't a happy motor.  Turned her off and opened up the air cleaner so I could tinker with the mix rods in the ThermoQuad...mostly out frustration and boredom.  That and I really like the sound and smell of that gaser  big block.  Well, as I was pulling my head out of the engine the rep knocked and asked about the pressures.  I slapped the cover on the carb before shutting her off and the engine rpm dropped 250RPM.  Say, WHAT?  After the tire pressure thing got settled I hoofed it across the street for a paper filter.  I held that K$N up to the light and I could see a huge number of holes that were not obstructed....would pass dirt just dandily.  The outside of the filter had not a spec of dust or dirt on it and with little wonder.....no air got thru anywhere except the HOLES.  I checked another filter, K$N and it had the same holes.  I then checked that counter test model and IT HAD HOLES THRU IT AS WELL.  K$N!  That dollar sign is not a typographical error.

This isn't hearsay.

Now I used foam filters on my dirt bikes for many years.  greatest things ever.  Stopped dust like a champ.  Collected it on the outside and when the dust coating got to thick the dust crud just dropped off leaving a clean patch of filter.  We loved those things.  They were called the Green Weeny and they were unsurpassed at stopping dust.  Water went thru them like a sieve so the east coast bunch had different ideas but in So Cal who ever heard of water?  Now the point of this is that that "green foam filter material" is still sold in sheets and the oil is readily obtainable....K$N maybe.  Visit your dirt bike store for Mfr and stuff.  You can overwrap the foam over your paper element and the element will last forever. The foam is rinsed in gas and then thoroughly washed and rinsed in Tide and then roiled when completely dry.


Don't say I didn't warn you.  I believed all that hype and I really wish somebody that is going in for a dyno event could install some of these things and get a truly "scientific" eval complete with all the higher order math.

There, now I feel better,

John

[06 Bill]

Brian   Take all the stuff out of your filter canisters, and clean. Go to Wal-Mart and get 4 fram filters about the size of the original
mesh units (can't recall#) cut the disc out of the blank end, install and good to go.   06 Bill

[Barn Owl]

It was late last night and I see the link I posted looks more like a header. Go to my post above and click the "Topic: GM oil bath to paper filter conversion" that is light blue. It is a link on how mine where done.

I would keep the oil bath if I were you. Plan on a set of papers every 8k miles. The air intakes are in the wrong place, in my opinion, on the GMs. I have seen some who ran the intake to the top of the roof.

[TomC]

Number one-do not use K&N filters on big rig Diesels-they do NOT stop all dirt.  Two- do NOT blow out a paper element with an air hose-it creates small holes that dirt can get in.  Just by a new one.  You should have a restriction gauge on the air intake and it will show you plenty of time to buy a new air filter.  Even at nearly $100.00 a pop for an air filter-still really cheap compared to an engine rebuild.  Good Luck, TomC

[gus]

I agree with BO, my oil bath filters are original and will stay that way.

Paper filters are way too expensive four at a time. Paper filters is a very good business to be in!!

They're a little messy to clean and refill, but what isn't with these engines?

Be sure to use clean oil. It is tempting to use old oil but it won't do the job.

[JLL]

I converted to foam filters on my 4106 about 10 years ago I'm very satified with them.
Call PHil Humbert  952-657-2140
12790 58th st.
Mayer MN  55360
it is an easy convertion and easy to maintain. T o clean them you wash with warm soapy water and spray a little filter oil on.
JLL

[gus]

JLL,

Sounds interesting. Some lawn mowers use that system.

How long does the foam last?

What is filter oil and how much does the conversion kit cost?

[JohnEd]

The foam ones we used on our dirt bikes lasted years and that was with cleaning them every other week fo 5 months.

John

[JLL]

Gus
I bought the foam filters at least 10 years ago. I think I paid about $160.00  They have a screen cylinder that goes up inside the cans and the foam slides up and over them.  The oil for them I buy from NAPA
it's just called fillter oil. They had  life time guantee. If you don't damage them.  You have to clean them with soap and water.  Gasline will ruin them.  I learned that the hard way.
It depends  on your driving conditions on  how long between cleaning.  I only drive about 3500 mile a year and clean them only once a year.
Good luck
JLL

[mountain goat]

Lots of good suggestions here. The foam filters sound good to me. My stock elements are deteriorating and I don't want to risk sucking any of the "mesh" into my fresh engine overhaul.

JLL, Does Phil Humbert sell the filter conversion?


I had to remove the ENTIRE Air filter assembly from the bus in order to hone the right side cylinder bores for fitment of new liners. The oil in my filter "bowls" was clean as were the elements, BUT when I pulled the assembly I found 45 years of dirt and grime! It was a wonder the engine was able to get air at all. This "stuff" was caked on so thick it took 1  hour with a putty knife, 4 cans of degreaser, $10 at the local car wash to get it all cleaned up! I'll bet I scraped 15 pounds of "stuff" off of these. So just cleaning the filters and replacing the oil is NOT enough maintenance on these older buses.

[JohnEd]

JLL,

That's the stuff....or it sounds like the stuff.  The difference is that ours were fuel and gas PROOF.  Being used on a ,motorcycle it would have had a short life if gas "ruined" it.  The problem, as I see it, is that that "filter oil" is a high viscous, sticky, substance.  The stuff that we used, back in the day, would have laughed at SOAP.  We used gas cause it took that to get the oil out and with the nearly clean filter STRONG soap did the rest.  In doing this cleaning a lot of dust was transferred from the surface to "all thru the filter medium".  That meant that a really thorough cleaning and, most important, RINSING was needed to get the medium dust free.

The foam is a highly QA'd material with consistant texture.  I made a couple filters from regular foam and they worked, as would any substance with that sticky oil, but they lacked durability.  You have a solid lead to a filter that will work but were it me, I would still look into the mfr of the cycle product only cause cleaning with a solvent pre washmade life so much easier.

Get a filter minder installed on your air cleaner.  Doesn't matter if your filter is clean or dirty if it is restrictive enuf to trigger the "minder".  You then need to clean it or discard it.  If the minder says no flow resistance then you are good to go.  It also lets you see the bad flow coming.  They cost about $25 on EBay and it would be worth that much to avoid an unneeded change or cleaning.....what what?

If your oil saturated foam filter isn't at least dry looking and dirt caked...it isn't in need of cleaning.  When you ride a 250cc, one lung-er, you can tell if only a single pony has come unhitched.   I never cleaned that filter because it had become restrictive....never.  And we tore our engines down at the end of every season back then and replaced the rings and cleaned carbon.....no wear from dirt...ever.  We got rid of the paper filters cause half way thru the first day they started to loose power if conditions were dusty and you weren't the guy that was ALWAYS in the lead.  Great memories and a wealth of experiences.  None of us escaped without serious injury, I might add.

I would still stay with the oil bath filter if I could.  Proper oiled foam is its equal.

Good luck with this and welcome,

John