The Stovebolt Site Forums The Shop Area Engine Shop Oil bath air filter

Does anyone make a modern air filter that inserts into the origional oil bath filter housing on my '40 GMC 228? I would like to do away with the oil bath system.

I don't remember the part number right off hand but when I switched to a dry filter I took the filter housing to the parts house and they were kind enough to sort through their stock until they found one that fit. I don't know if yours is the same size housing as my '38 coupe 216. If it is let me know & I'll go get the part number and post it.

I recall this upgrade being discussed quite awhile back. You might try a search as much info was exchanged.

Yes. I was able to get a 10" S&B cotton gauze reusable top-breather filter to fit perfectly right over the top of the oil bath housing...the part that attaches to the carb. The rest of it I took off.
Works great. Try it.

S&B is a cheaper alternative to the K&N filter, but perhaps K&N makes one too.

I simply removed the brass mesh filter canister and replaced it with a Wix 46036 dry element filter after cleaning the oil out of the housing. It fits perfectly & the filter looks stock to the casual observer.

I had an extra housing. I cut out the center and used a FIL 6184 paper filter. It listed for a 1988 Corsica 2.8 liter engine. It is the right diameter and is 4 inches high.

Why don't you guys stay with the oil bath filter? Just curious.

Joe

I used the same filter as Oldbluetruck to convert it on my 1951 216. I had to remove the guts including the spotwelds that holds them in.

As far as why, no mess and it is a better system. Now I know that will bring a lot of comments but the industry didn't change because they wanted an inferior filter.

Well, you "asked" for comments so ...

Oil bath air filters are still in use in applications where there is potential for a lot of dust. One of the benefits of an oil bath over a paper air filter is constant air flow to the carb. As paper air filters plug up with dust the amount of air getting to the carb will go down. Haven't personally found my oil bath filter to be messy, but that's certainly a personal opinion.

If you really believe that auto manufacturers usually make decisions such as this for reasons having to do with superior technology rather than cost, I have a bridge over the Ohio here in Paducah that I could let you have REAL cheap. :p

Oil bath air filters allow too much debris to pass through the filter media (brass screen). The idea is that any dirt that comes in contact with the oily screen will stick which is true. The problem is that the oily screen has gaps that are much larger than many of the dirt particles. The openings in a dry element are measured in microns. The openings in an old oil bath filter would measure in substantial fractions of an inch relatively speaking. Yes dry element filters plug up in a dirty environment. That is what they are designed to do. The dirt that plugs them up is not going into your engine.

I'm not bad mouthing oiled media filters like K&N. The only commonality between a K&N type filter and an old oil bath filter is the fact they use oil.

Actually, the oil bath filters such as were standard in many of our 'bolts did not depend on the dust being trapped in the mesh. The design is such that the air that comes in (with dust suspended)is headed straight down towards the oil bath and then has to turn back up towards the mesh and then back down towards the carb. The result is that the dust is trapped in the oil bath (before it even reaches the mesh). Actually a very effective design.

I hafta 2nd Jeff's explanation and add that part of the action that happens is the air velocity throws up a fine film of oil onto the mesh which constantly 'washes down' any dirt that makes it that far - read yer shop manuals, there's a wealth of wisdom there!!

the oil bath filters were/are exceptionally effective and were first made 'extreme service' options, then dropped, because it was cheaper to make the dry element filters, and because lazy owners and mechanics decided they were messy and not worth the fuss - they're the absolute best type to have in dusty conditions and at least as good as the dry elements in normal use

Bill

I concur. I like my oil bath and, in a pinch, you have a extra quart of emergency oil (strain it thru a rag) in a dire situation.

I concur with Jeff, Red58, and Laroke. Not sure on all the original oil baths though but mine holds less than a qt. In closing, ya better jump on that bridge deal.

Our 1971 Beetle has an oil bath air cleaner and when you change the engine oil there is just the right amount left over from 3 quarts for the air cleaner. I don't find it to be a problem or inconvenience.

I've never cleaned or changed the oil in the air filter on my truck engine ........but then again it will be a few more months (years?) before it gets on the road

I believe oil is the way to go.

As far as paper element filters, especially the small round ones so many use with the helmet style three inch air cleaners or the small traditional chrome air cleaners, I found that they will actually tend to restrict air flow through the carburetor(s), even when new and clean, to the point to where you are actually driving with with a situation equal to the choke being partially closed. This can effect gas mileage and the ever popular "gray" tailpipe color is never to be seen again. This is why some of our vendors are now showing the use of a larger air cleaner and a larger filter, if a paper element is to be used.

Joe

So a paper filter gets dirty, you spend a couple bucks and replace it. A K&N gets dirty, you clean it, let it dry, and re-oil it. Both will vastly out -flow a restrictive oil bath filter.

There really is a science to the design of air filters. When you require the air to pass through a round slit, make a 180 degree turn, run through a few inches of mesh, make another 180 degree turn and then into the carb, how well is it really going to flow? If oil bath filters suit you, then use them. But they are not superior to modern filters.

And you have the aerodynamic analyses to back that up?

First, we were told that an oil bath filter was messy and inferior. Then we were informed that the large openings in the mesh was what the problem was. And now we're told (without evidence I might say )that the air flow through an oil bath is more restrictive than through a paper filter. Hey, if you want to use a paper filter go for it. It ain't my truck so I really don't care. However, without data, we're all just voicing our opinions and I know mine is always better than someone elses :p

Oh, by the way Hot Rod Dad, this whole thread started with the idea of putting a paper filter inside an oil bath filter. If you are correct in your air flow analysis, then we still have the air flow "problems" of the oil bath cleaner plus the additional restriction of the paper filter. Seems to me we now have the worst of both systems.

Some people just cannot be convinced that the old oil bath filters are probably better than a modern paper filter. Either the advertising guys are really effective or a real prevalent belief is that modern day stuff has just got to be better than stuff from the old days.

Yeah I do. Several articles over the years in Hot Rod and Car Craft magazine to name a few. How many drag racers do you see running oil bath air filters?

And regarding the comment I made about the top breather air filter on an oil bath housing, that was ONLY the housing, with everything else taken off.

Sheese. You guys are real technophobes, know that? You don't think technology has improved in 50+ years? You hang onto oil bath air filters and Rochester 1bbl carbs like they cannot ever be improved upon.

No problem, cherish your opinion, just don't jump down my throat because of mine!!! I was only trying to help. :mad:

Hey, HRD, sorry if you thought I was jumping down your throat, I was trying to keep the discussion light (hence the frequent use of the ). I too was only expressing my opinion (of course, since its my opinion its gotta be right )

OK, now lets kiss and make up. We all know what opinions are like and we all have one. :p :rolleyes:
Ok, now I feel better. :p

Not only am I going to kiss and make up I'm now going to state definitively that we're all right!

I've been doing some more searching and found the following table at several locations on the web. Haven't found the original data, so this may be typical Internet BS. Note that oiled foam (AMSOIL) does the best, so this may be a test that they "sponsored" (nah, I'm not cynical).
Poor gelee, do you think he's still reading this thread that he started or have we scared him off? :p

If oil-bath filters weren't superior at getting rid of dust, they wouldn't have used them in farm tractors.

I had to ask. Thank you all for your opinions.

Well gelee, let us know which direction you decide to go.

Well gelee, let us know which direction you decide to go. Bottom line is its your truck.

I like my oil bath cleaners on my old trucks but I dont know why. I would'nt dare put one on my wifes STS, paper there is fine and I dont have to worry about getting a drop of oil on that super glaze,hand rubbed,clear coat paint.

That may be why GM used oil bath then as opposed to paper now,our trucks were made to work and todays trucks are posers(as in a skateboader that can't skate but they pack a pretty board).

I personally hang on to my oil bath air cleaners and Rochester carbs because I "cut my teeth" on them and they float my boat!!
Hobert

Bruce,

Since all of my truck is being restored as origional (except the rear end gears) I believe I will keep using the oil bath system as long as it doesn't create a mess. I dont have any experience with this system but that hasn't stopped me with the rest of the truck.
Thanks to everyone for their opinions.

Way to go with original resto and oil bath. Not much too it really. We await your next debate starter.

I've got my oil bath air filter and it's in good shape. I removed it when I removed the Rochester. Anyone need it? E-mail me.

And I have a SPARE from a V8 2 bbl setup.

Wow, what a hornet's nest I stirred up! I guess I am the only one that has accidentally kicked over the oil bath container when it is on the floor!

I think there are vacuum cleaner designs that use the same principle as the first stage of the air cleaner.

Through out the '60s most GM cars and trucks were available with optional air cleaner systems. Some of them were called "Desert Pak". They had an oil bath canister sitting off to the side with a hose leading to the paper filter housing. They may have entered the modern era with the paper filter, but they knew it wasn't as good. An oil bath prefilter gave the best of both worlds. In the '70s they offered the oiled foam wrap, but no one cleaned them so they stopped.

They haven't used oil-bath air cleaners for John Deere tractors since 1972. And the engines today are larger and use much more air (turbochargers).

Everyone talks like they used oil bath instead of paper elements in the old days by choice. I didn't think paper filters were invented until the 1960s, so they really was no alternative to oil bath "back in the day".

INTERNET RESEARCH NOTE: Okay, looks like Fram invented paper air filters in about 1950, and the first production car to have one was the 1952 Studebaker.