The Stovebolt Site Forums The Shop Area Engine Shop Wet vs. Dry Air Filter

Hi Folks,

I have a 41 with the original oil bath air filter. Engine is the 216 six. Would it be better to go to a dry air filter?

Thanks,

Jeff

not better, just different - some would say dry's not as good, some don't like the "mess" of the oil bath because they don't want to be bothered to take care of it, but if the oil bath weren't "better" in some way, modern big trucks wouldn't have them

Bill

I'm still running an oil bath cleaner on my '46 with a 216 & Carter W-1 carb.

Yep, I kept the oil bath after I read that those trucks with the oil bath were the only ones that had only a little bother with all the ash when Mt St Helen blew............... paper elements clogged up real quick.

I switched to a dry element because, in my opinion, it filters better. As you can see above there are differing opinions. My reasoning:
1. Dry elements filter particles measuring in microns.
2. The copper mesh in the oil bath filter has pathways large enough to let particles 100 times larger through.
3. While the incoming air gets pulled through the oil before going through the mesh that doesn't necessarily trap the dirt because the air goes through as bubbles. Each bubble could harbor damaging dirt particles that are small enough to pass through the mesh.

Assuming Dusty is correct about trucks affected by the Mt. St. Helens incident. I believe the paper filters did their job by preventing ash from entering the engines. The oil bath trucks obviously let the ash through or they would have plugged too.

didn't let the ash thru cuz the particles stay in the oil, oil bath filters don't plug up until the oil turns to grease

your reasoning Tiny, is the common take on the question, but on a vehicle subject to dusty conditions they\'re best if properly maintained - apparently the SAE agrees

the reason the switch was made is most city vehicle use doesn't warrant the extra expense in manufacturing and the OEM's cut every corner they can

Bill

I'm going to have to disagree Bill. What you hyperlinked are two individual's opinions with nothing to back them up. Their opinions have no more validity than mine. IF particles touch the oil they would indeed stick I agree. However all you have to do is watch a fish aquarium with the air bubbles going to the surface or simply blow through a straw into a glass of any liquid you prefer. Look at the size of the bubbles and imagine the size of particles that could be in that air. Then look at the size of the openings in the mesh. Small indeed but HUGE compared to the openings in quality dry filter media.

Just one little correction here. The air and the particles do NOT go through the oil in an oil bath air cleaner. The air (with any dust) comes from the top of the air cleaner and is traveleing straight down towards the oil. The air and suspended dust hits the surface of the oil, the air makes a 180 degree turn back up, and any dust that was not trapped on the surface of the oil, simply falls into the oil. There is no bubbling through the oil.

The dry air filter is much superior to the oil bath. They filter better & have less restiction when changed when needed. They were developed for Nascar back in the 50,s. Engines lasted much longer after they started using them. All the large trucks I have serviced in the last 40 years have had dry filters with a circulater to get the large particles before they get to the cartridge. The only good thing about oil bath is the nostalgic part.

your welcome to disagree Tiny, but I took "I read an SAE report a few years ago comparing oil bath ... " to be fact, which maybe isn't always safe on the net, but I'd take an SAE opinion over, say someone's who doesn't understand the way they function, and the guy at Yesterdays Tractors was explaining the way they work, not giving an opinion, and as Jeff points out, there's no air bubbles involved - it's certainly a matter of personal choice, but the oil bath does do a good job if it's correctly used and maintained, the same as the paper filters do if "changed when needed", under normal city conditions

so the answer to the original questions is: "not better, just different" take yer choice

Bill

I looked at a diagram a while back that I thought showed the air passing through the oil. It is possible I misread the diagram. If I did I stand corrected on that point however it doesn't alter the fact that smaller holes filter more dirt. A quality dry element filter has smaller holes by several magnitudes than the mesh in an oil bath filter.

Well, thanks all. What an interesting debate. I never guessed it would generate such good opinions/facts. I appreciate the comments and will have to think it over as to what type of filtration I go with.

Jeff

Wow what a discussion,

Can i add a few curve balls too!

I think it is to do with air speed or engine rpm and also piston materials used.

My ford 3000 tractor is about 30 years old, and has an oil bath filter and still starts with out glow plugs. Cast iron pistons, and low rpm/ air speed. Think of all the dust when plowing.
My son has a 2005 model dirt bike with the best filter you can buy. Last month he rode in dusty conditions for 45mins with the air cleaner not fitted correctly and dusted his engine. Now it will only roll start. No compression and time for new piston. Alloy piston/14'000 rpm and a 1/4 inch gap under the oil filled foam filter and engine destroyed in 45mins.
In short, i think newer vehicles rev harder, have greater air intake speed. The engine materials are lighter alloys and not as durable and tolerances are less so a better air filter system is required so 'horses for courses'.
All the best
James

Jeff Nelson: a small correction on your post; a 180 degree turn is actually no turn, it is straight. You meant to say a 360 degree turn, did you not? Think about it.

My opinion is, that either works fine when used correctly, but most manufacturers have gone to dry filters for two reasons: cheaper to put on the vehicles initially, and then they get to sell you lots of disposable filters down the line. So it all boils down to the almighty dollar.

Bri - this back seat driver would tell you a 180 degree angle is a straight line, but if you make a 180 degree turn you'll be heading back the way you came [as in "U" turn], and if you make a 360 degree turn [a "donut"] you'll wind up going the same direction you started you think about it

Bill

Holy angles batman! You are right, Bill! Man I feel like a dope. So Jeff, you are totally correct. No wonder I had such a hard time with my math classes in school.

Now...

I am soOoOOooOOoo turned around, my head is spinning. At mutliple 90 degree angles even!

Hi guys,
I bet every ones head is spinning now! Mine is
All 'Baldbaron' wanted to know was if 'we' thought his '41 with 216 needed a filter upgrade?
My vote is 'no'. Whats yours? 65 years on.
Lets stand up, and give our opinion. 'Yes' or 'No'.

James

Somebody told me to run ATF in my oil bath air cleaner. So I did. Haven't changed the fluid, so I can't say how it worked out.

I'm going to cut open my oil bath and modify it for an element type. Best of both worlds,
Scott

How about using a K&N filter? They may be more
expensive but you can clean them and reuse them.
That's what I did on my dual carbed 235.

My two cent vote is for paper filters.

Wow. I like to scan for posts that have a LOT of replies, or few/none. This certainly had a LOT. I'm personally running an oil bath filter. Since Armagedon is coming - complete with lots of airborne ash - I am for darn sure going to be mobile when the s_ _ _ hits the fan. Don't want no paper filter slowing me down. Those darn volcanoes up here in the Pacific Northwest!

"How about using a K&N filter? They may be more
expensive but you can clean them and reuse them."

You can clean and reuse the stock oil bath filters that these trucks came with. My 58 is still on it's first and hopefully last air filter. Still looks good, especially after a cleaning.

Quite a few years back, I had a Ford truck with an oil bath (I was 14 and driving with a hardship license). Didn't really know squat about vehicles so I didn't check any under-hood stuff out. My dad checked it out, I bought it and about three days later I was giving it hell out in a field when it starting boiling smoke out the pipes. I was sure I screwed it up so I headed back to town and it cleared up almost immediately. I got to my grandparents house to explain how I was 'just driving down the road' when it started smoking. My grandpa opened the hood and showed me the air cleaner and told me it wouldn't have swallowed any oil if I hadn't been 'acting up'!!

That's the only oil-bath I've had. My '39 arrived sans-air cleaner and my '67 has a paper element.

Yeah, Grandpas know stuff.

They're kind of like Santa Claus in that respect.

That's a lot of great info about air cleaners and it brings up a question. I just get a new truck 55.1 series w/235 and there is no air cleaner. While i like he oil bath for the look i really just need to get one and the paper air cleaner will be easier to find. So which one is the best for fitment and availability

I don't think it really will make all that much difference in engine life, unless of course You are driving it 500 hundred miles a week or something Even then it probably would not matter that much if each was serviced occasionally.

I agree, but my '55 had the standard air filter, not the oil bath type. And I needed 2 of them due to the 2 carbs I'm running. So I just got a couple of Mr.Gasket universal housings ansd 2 K&N filters. Looks good and works. Would have used 2 oil baths, but there are hard to find in my area, not many were optioned this way around here.

Longbox55,

I was just referring back to the OP's question of whether to use a dry or oil bath filter. I didn't mean to imply that you shouldn't have used K&N filters in your case, just that a K&N air filter is an oil bath filter so he might as well just stick to his current reusable oil bath filter as get a K&N.

No offence taken, Lumberg. My suggestion was given as an alternative if an oilbath wasn't availible. I've seen where some guys in the car restoration side modifying oilbath housings to accept K&N elements, keeping the stock look with the nawer technology inside. If the oilbath is in good shape and you dont mind doing the maintanance, than by all means use it. I just couldn't find a pair of them when I was building my engine, so I opted for the modern equivelant.