Diesel Air Filters

Came across this article and wanted to share and get some feedback. This is something I never knew about and wonder what everyone thinks.

https://www.practical-sailor.com/systems-propulsion/in-search-of-better-filters

My Yanmar has a simple foam filter, which I do replace/clean but never gave it another thought. I have used K&N filters on a few vehicles and motorcycle, not just for alleged performance gain but also for their lifetime usability. I'm thinking maybe something like this makes sense for my boat. Is anyone using one of these or something similar?

https://www.walkerairsep.com/product_marine.asp

I had a S&B (similar to k&n but built stronger) on my 6bta when I had the old Mainship. Also had one on a Dosge/Cummins pickup.
I put the one on the boat in case I had a “water event” and the filter got wet. A paper filter would be ruined but the s&b could be dried out.
The one on the truck let it breathe

The stock air filter on my Universal M25 sailboat engine was a course foam ring 1/4" thick that you could see through. Not really a filter, the parts book calls it a silencer. I replaced it with a lawn mower filter similar to a K&N. The intakes on my Perkins T6.354's look like a big funnel with a screen across, holes in the screen are about 1/8". No filters at all. Not happy about that, but it doesn't look like you can retro a real filter in there. Granted a boat engine doesn't see the dust a lawn mower does, but there is some.

Double checking the intake size 3.5" and then getting K&N RC-4570 air cleaners for the FL120

Soo-Valley said:

Double checking the intake size 3.5" and then getting K&N RC-4570 air cleaners for the FL120

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Thanks I may look into a K&N or S&B universal filter also. Couple questions.

Do you have any concerns about whether the filter you choose allows sufficient air volume without restriction for your engine?

Do you have a crankcase vent to deal with at your air intake?

Also just found this which looks like a good solution for my engine:

https://walker-airsep-superstore.my...igh-air-performance-air-filter-for-yanmar-6lp

I will be switching from plain foam CAT intake filters to Walker air. When I change the oil this spring.

For my 3208TA it is about $150 each.

I just found this which should work for my engine:

https://walker-airsep-superstore.my...igh-air-performance-air-filter-for-yanmar-6lp

backinblue said:

Thanks I may look into a K&N or S&B universal filter also. Couple questions.

Do you have any concerns about whether the filter you choose allows sufficient air volume without restriction for your engine?

Do you have a crankcase vent to deal with at your air intake?

Also just found this which looks like a good solution for my engine:

https://walker-airsep-superstore.my...igh-air-performance-air-filter-for-yanmar-6lp

Click to expand...

I got the idea from a thread here and that OP routed the oil breather into the filter as it is now. I am considering a catch can. Yes K&N will allow more air than the stock filter. Besides it works well for the car & bike, I have the cleaner and oil.

When I got my boat the PO did not fi any air filter at all. Maybe was he thinking that his engine bay was clean enough to require none.
First thing I did was to fit one. I got a K&N that fit the intake. Not that I am seeking for any performance increase or whatsoever just to avoid a loose plastic bag I could have forgotten to find it way to the engine heart.

L

Lou_tribal said:

When I got my boat the PO did not fi any air filter at all. Maybe was he thinking that his engine bay was clean enough to require none.
First thing I did was to fit one. I got a K&N that fit the intake. Not that I am seeking for any performance increase or whatsoever just to avoid a loose plastic bag I could have forgotten to find it way to the engine heart.

L

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I fully expect to do the 1/4 nautical mile in less than 2 minutes once I put on those high performer filters.

I just installed a Walker Airsep on one of my CAT 3208TAs over the weekend. I did not do it for the air filtering, the OEM solution worked fine for that, I did it for the oil control. The OEM oil control is inadequate and oil gets in the turbo and after cooler. Fingers are crossed that it will do the trick. I'll be putting one on the other engine in a month or so.

My John Deere came with a K&N. Have 2 that I clean and swap. Like the idea of being able to change it quickly if I feel it's necessary. Added a Parker Hannaifin separator to the valve cover vent. Very happy with its performance. Engine room stays nice and clean as a result!

Ted

I've wondered about this a good bit. My DD 4-71s have no filter (looks like they never have). Just an air box.

Has anyone seen air filters for 4-81/6-71s? Not sure how I'd fit one on the intake - it's probably a 12" x 3" rectangle opening.

My concern too. It was no problem putting a good filter on the sailboat engine, it was designed as a tractor engine so intended to have a good filter. But the big turbos on the Perkys, I don't know if adding a filter would cause problems. And this is a really old, somewhat neglected boat so the engine room is not particularly clean. That's another project in itself.

It's kind of mind boggling to me that these very expensive engines don't include a decent air filter and PCV system. Having a hose from the crankcase laying on top of the air filter to suck in whatever oil and fumes that come out of it? Serious Engineering there! Am I missing something?

Soo-Valley said:

I fully expect to do the 1/4 nautical mile in less than 2 minutes once I put on those high performer filters.

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I know you are joking, but you are also missing the main point of this thread.

backinblue said:

I know you are joking, but you are also missing the main point of this thread.

Click to expand...

No joke, I fully intend on doing what I said. I expect to reach 8 knots off the line too.

I think we beat to death that most filters need changing/upgrading.
And it brought me to remember to do mine, thus getting the K&N
What is the point of this thread BTW

Soo-Valley said:

No joke, I fully intend on doing what I said. I expect to reach 8 knots off the line too.

I think we beat to death that most filters need changing/upgrading.
And it brought me to remember to do mine, thus getting the K&N
What is the point of this thread BTW

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The point is, if you read the practical sailor article, that many diesels have no air filter or have a foam rubber "screen" that can deteriorate. Either way, just because the water is basically a dust-free environment doesn't mean your engine doesn't need a decent air filter. Also the crankcase ventilation potentially adding oil to your intake warrants some consideration in my opinion.

I changed my engines silencers only intake protection to a K&N filter many years ago, roughly 30.
I asked about the silencers fitted and was told marine engines don't see enough dirt for it to be a problem.
I did not believe it so I changed to the K&Ns and am glad I did.
In my case I was able to fit a 14" diam. and 4" high unit which only needs cleaning every few years. I also fitted a telltale vacuum guage which is how I know the filter has never plugged. Once tripped it must be physically reset.
It has never tripped.

Regardless every 5 yrs I clean the filters. When I do clean it though it has caught lots of dirt and who knows what that would otherwise have been sucked into the engine.

Yes, there is a noticeable bit more of intake suction noise but it is not objectionable.

backinblue said:

The point is, if you read the practical sailor article, that many diesels have no air filter or have a foam rubber "screen" that can deteriorate. Either way, just because the water is basically a dust-free environment doesn't mean your engine doesn't need a decent air filter. Also the crankcase ventilation potentially adding oil to your intake warrants some consideration in my opinion.

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Good, I did not miss the point of the thread.

C lectric said:

I changed my engines silencers only intake protection to a K&N filter many years ago, roughly 30.
I asked about the silencers fitted and was told marine engines don't see enough dirt for it to be a problem.
I did not believe it so I changed to the K&Ns and am glad I did.
In my case I was able to fit a 14" diam. and 4" high unit which only needs cleaning every few years. I also fitted a telltale vacuum guage which is how I know the filter has never plugged. Once tripped it must be physically reset.
It has never tripped.

Regardless every 5 yrs I clean the filters. When I do clean it though it has caught lots of dirt and who knows what that would otherwise have been sucked into the engine.

Yes, there is a noticeable bit more of intake suction noise but it is not objectionable.

Click to expand...

Thanks, good info. Do you have a crankcase ventilation hose to deal with and if so what did you do with it? Mine currently rest on top of the air filter to suck in fumes and also drips a little bit of oil at times.

Juliet 15 said:

I've wondered about this a good bit. My DD 4-71s have no filter (looks like they never have). Just an air box.

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My generator is set up this way. Came from the factory with no air filter.

My old Izuzu D500 had a perforated sheet steel cover on the air intake with no provisions for another filter. A mechanic called it a "nail screen." 13,000 hours when I sold it, but then that boat didn't kick up much dust.

Mischief Managed said:

I just installed a Walker Airsep on one of my CAT 3208TAs over the weekend. I did not do it for the air filtering, the OEM solution worked fine for that, I did it for the oil control. The OEM oil control is inadequate and oil gets in the turbo and after cooler. Fingers are crossed that it will do the trick. I'll be putting one on the other engine in a month or so.

Click to expand...

My 1988 Volvo Penta TAMD61A's have after-market filters and the oil-sep devices as well. I believe they are Racor/Parker and were added by the previous owner. In chatting with others who have similar setups, it was for the same reason several folks have mentioned - mainly to snag the oil before it gets to the turbo. At the same time, they removed the overly large and weird Volvo filters and added matching air filters. They are pleated but made of some sort of material that can be cleaned easily, which is nice in the event of any water getting on them.

The oil sep stuff works amazingly well. I've changed the filters in those once so far. I had to go read up on them as I'd never seen them when I bought the boat 2.5 years ago.

backinblue said:

Thanks, good info. Do you have a crankcase ventilation hose to deal with and if so what did you do with it? Mine currently rest on top of the air filter to suck in fumes and also drips a little bit of oil at times.

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I modified the crankcase vent setup that was present when I did the filters.

There was the usual road draft type crankcase vent that exited into the engine compartment. THat got changed. When I redid the filters I lead the vent over to the tops of the filter housings so the fumes are lead back to the engine intakes. I used quick disconnect fittings to make the final connections and to make the service work of the filter easily done.

So far there has been enough slope that I have never seen any amount of oil signs inside. It runs back down to the pick up point.
I used 1/2" id hose to each filter so the air suction flow is kept to a minimum so the oil is not carried easily. Of course the fumes will increase as the engine wears and ages.

If need be I will alter it again so it runs to a catch bottle and then back up to the air intakes.

I don't have a turbo so that is of no concern.

It's well proven that the K&N's are not a real good filter (oiled burlap went out as an air filter in the 30's) they have good flow because they are not good filters. Not that dust and dirt are a huge problem on a boat compared to say a tractor. I have always used shop vac filters.

Brooksie said:

It's well proven that the K&N's are not a real good filter (oiled burlap went out as an air filter in the 30's) they have good flow because they are not good filters. Not that dust and dirt are a huge problem on a boat compared to say a tractor. I have always used shop vac filters.

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Where has it been proven that K&N are not a good filter? I haven't seen any tests that prove that. I have used them on cars and motorcycles and they seem to do a good job as far as I can tell. Not really fair to compare them to burlap, and to your point, your boat is not traveling down a dusty road anyway. I haven't used one on a boat (yet) but I'm guessing they would be better than paper if there was any water or mist of any kind in the air.

backinblue said:

The point is, if you read the practical sailor article, that many diesels have no air filter or have a foam rubber "screen" that can deteriorate. Either way, just because the water is basically a dust-free environment doesn't mean your engine doesn't need a decent air filter. Also the crankcase ventilation potentially adding oil to your intake warrants some consideration in my opinion.

Click to expand...

I am always amazed when the conventional wisdom "marine environment has no or little dust." Try this; 1. anchor somewhere. 2. clean an area on your deck. 3 wait a day. 4. reclean the same spot with a white rag. Bet you find some noticeable dirt/dust on your rag.

Volvo TMAD0

Regarding air filtration; my engines have a replaceable, paper, foam edged filters that we change regularly. Also, there is a metal spin on cartridge for crank case breather. These seem adequate to provide good clean air to the motors and I never see oil vapor from the pans. I agree with the other posts that the engine room ambient air is NOT pure in the environment we run our vessels. Some sort of air filtration is a must. My annual oil sample reports do not indicate any water our major quantities of outside dirt.
Heading should say- TMAD 40

Brooksie said:

It's well proven that the K&N's are not a real good filter (oiled burlap went out as an air filter in the 30's) they have good flow because they are not good filters. Not that dust and dirt are a huge problem on a boat compared to say a tractor. I have always used shop vac filters.

Click to expand...

K&N filters are most certainly not oiled burlap. K&N uses cotton. While the focus is high flow, they still filter (and flow) well, even when dirty. The re-usability is a big plus.

BTW, burlap is (usually) made from jute fibers.

I use a standard automotive paper filter on my AD41B, but would probably be happier with K&N (already on some of my other vehicles). Just haven't got around to that.

I think the key point is that filters on a marine engine is a good thing, even if the level of dust is much lower than terrestrial situations.