Marine diesel air filters, or the lack thereof.

[Chris Patterson]

Here's just a general question that has been bugging me for quite some time. My Westerbeke has no air filter. It does have an apparatus that's called a breather box, or some other goofy name, that the only use for it seems to be sound dampening of the intake air. But zero filtering capability. Now I'm aware of the fact that these boats don't run up and down dirt roads, (unless you're snoozing at the helm), but still, air still does contain particulate matter, albeit not much at sea.
I realize that I tend to be a little O.C.D. about diesels, very badly, and unrepentant as well. But wouldn't the addition of SOME type of filtering element be a plus? The rule of thumb is, for every one part fuel, it uses a hundred parts air. And clean fuel and air,(and oil of course), is the operative term with diesels.
Any comments on this? I am thinking about a K&N retrofit, just so I will quit obsessing over this.
Or tell me to shut up and get some sleep, and I'll understand..

 

[centerline]

all marine engines usually have either a screen, such as a flash arrester/supressor on a gas engine, a screen as a filter to keep a something like a loose rag or whatever out of it, or in the case of outboards, nothing at all other than the motor shroud/cover.
hopefully you will never encounter any severe dust, clouds of bugs, or flying debris such as you would get from following a hay truck or chip truck down the highway.... or in the event of a knock down or rollover, flying rags and nuts and bolts in the engine compartment... you should be fine.

 

[Jalepeno]

I’ve been wondering the same thing. My 1979 vintage Yanmar YSM12 doesn’t have one and it always starts within a couple seconds, doesn’t burn oil doesn’t smoke and runs well. Maybe her long life is attributed to healthy living?

 

[Maine Sail]

With sailboats the big concern is belt dust which can get pretty darn nasty... I install a quite a few K&N filters on small diesels.

 

[RichH]

Small marine diesels dont have 'air cleaners', what you see is a silencer that attenuates the noise of the opening and closing intake valves.

Even far out at sea, airborne particulate are and remain in the range of 30,000 particles per cu. ft. @ 0,1µM ... even outside of the 'dust belt' ... although the accepted most damaging particle in a diesel engine is 20µM ... a bit too big to be 'airborne'.
Those ultra-brilliant sunrises you occasionally see along the SE USA coast and the caribbean islands is due to dust blowing in from the Sahara desert ... and is that 'yellow stuff' you occasionally see on deck - all being transported by the easterly 'trade winds'.

That withstanding, a DRY K&N or other type of DRY actual filter will be of some benefit .... just be sure to well 'oversize' it based on the cubic ft intake per unit time of your engine. You dont want a 'suction' or vacuum to develop on the intake side of a diesel engine; therefore, if you elect to apply an intake air filter, the 'bigger' (surface area) the better.

 

[Chris Patterson]

Hmm. Vewy interesting. And sort of what I suspected. I'm relatively certain that these particles are small, but I'm shooting for zero tolerances. That's kind of cool information about the sands causing the light refractions, another bit of information that I can inflict on my friends, so I can dazzle them with my brilliance.(Note to self, develop some friends). But that was a generality of what I was assuming. AND the natural contaminants of the engine itself, ie: Maine's belt slow disintegration. Wee tid bits of insulation, etc. Even in the sun rays through a port light, I can SEE particulate matter, probably from the cushions, clothes, whatever. And while these small pieces of cotton are probably not very abrasive to a liner wall, I still don't want them in there, (I say this while I light a cigar).
I have the engine compartment naturally aspirated to an outside vent, due to an earlier discussion about how it would take a tremendously sized blower to have forced air induction, but that really doesn't eliminate much.
So any ideas on where a man might locate said filters? NAPA already turns out the lights when they see my truck pull up.

Incidentally, I try and keep the boat as clean as possible to try and keep the dust down, but picky woman says it could be better..

 

[Stretch]

Looks like your wife had a ''Hen Party'' last night Chris.

There is a trailor park joke around somewhere....need mor coffee...

 

[SamLust]

The manufacturers leave the air filter off so the engine can suck up the fiberglass dust after the finishers forget to do it on factory final inspection.

I stuck a nice big K&N on the end of the snorkel of my 3GM 30. Couldn't hurt.

 

[Bob 04 H260]

My 3GM Yanmar has a factory foam airfilter. Hunter installed a 3" hose from the end of the airfilter intake assembly right out to the transom of the boat to allow fresh air to the engine I suppose, no worry about belt dust anyways. I do wonder about the hose causing restriction on the air coming in. Would it make sense to put a vacuum gauge in there to see if there is too much of a restriction ? or is there a better way to determine if it is restricting air flow to the engine ?
Bob

 

[Nom De Guerre]

I would retrofit a filter if it were my engine.

The 2GM Yanmar in my boat has a factory air filter/silencer assembly, with replaceable filter/silencer.

 

[Tribu336]

I have always wondered where the engine was getting its air from? I suspect it is coming through leaks around the engine compartment inspection doors, under the companion way stairs, cockpit compartments covers, etc. Am I correct or is there a specially made air path that I don't know about?

 

[Maine Sail]

This is a good example of what can be captured in these engine rooms..

New:

6 months later and it is black from belt dust:

 

[Chris Patterson]

Yecch! That is sort of what I expected. It seems as if the intake air is an afterthought on some of these engines, if it's even a thought at ALL. I've had this on my mind for some while, as I've already direct ducted air to the engine from a scoop vent aft. I just used the 4" hose kind of like a house dryer would use, with the thought that there is no way this little 30B with a roughly 1 1/2" intake hole could swallow. But it's still unfiltered air nonetheless. This issue particularly started "haunting" me when I got drafted into a twin 1050 Caterpillar installation. You can IMAGINE how much air these puppies need.
But, even with it ducted from outside, eliminating the air being drawn out of the cabin, you KNOW that the crap being thrown off of the belt is being "consumed".

By the way, those pics that I threw in for the entertainment value is from a recent boat I looked at by invitation. A real fixer-upper.

This is mine.

A clean engine is of the Lord..

 

[sailaway78]

K&N

I replaced the foam filter on my Yanmar with a K & N. Fits right into the existing air box/silencer/filter. I can't prove that it does a better job than the cheapo foam Yanmar element, but it makes me feel better.

 

[gettinthere]

I read some comments here about ducting air intake from the outside...sucking in salt air? Is that such a good idea? Mine draws from inside the boat so the salt content of the air is much lower. Much ado?

 

[Ken Cross]

Yamar SB12 in a 1977 boat. No air cleaner no adding oil between changes. No idea how many hours are on it. I put on around 100 per year but only had it and installed the working hour meter last year.

I guess I'll leave it alone, but I keep noticing people saying "Silencer" Is there really such a thing for this old monster?

 

[Gudenuph]

Out there it's all 'salt air'.

 

[Chris Patterson]

Salted air. Interesting. And a thought that I haven't considered. I have no idea of how much cleaner, salt wise, that there would be if it were aspirated inside, or outside of the boat. I just figured that it would be cleaner outside, given all the dust, etc, that seems to be generated inside, what with my onboard meth-lab and the such. I guess salt crystals could be abrasive, but durn it, now I've got to over think THIS one to death. I do know that on average, in one square mile, in a month, 21 tons of dust settles. Wow. Now at sea, that equation is mute. But for a coastal sailor, in the winter when the prevailings are blowing from land to sea....hmm...
More insane thoughts...I have LONG considered K & N's filtering claim, about more mileage, less fuel, etc. But unless the factory filters are too restrictive, OR...K & N is way less so, it's the only thing that can account for this. Venturi's, and ram flow technologies only go so far. And you can not force induct air at 7 knots. It makes no sense in that respect.
So, the logical approach, (which of course is not actually logical at all), would be the oil-bath breather. I know that there are some other old farts out there who remember these things. Little could pass through THAT quagmire. But, you would have to gimbal it. Oh the problems..
I would digress, but some things just bother me. Like the Croc shoe, etc.

But yes, that crazy thing on my crusty ol' Westerbeke is a "silencer" of some degree, that keeps the racket down from the dried out old valves rattling in there, and the inrush of the polluted atmosphere as well. It looks suitable to filter out pets, and small children is about all. Which is another argument for removing it altogether. Maybe I could duct it in from behind the head. It would solve several problems at once, with the added benefit of methane gas induction.

I think I'm on to something..

 

[RichH]

Here's some news for ya'. If that boat dust isnt salt crystals, its probably exfoliated dead human skin cells ... and Ill let you be the one to 'taste' them with your tongue to find out which variety. Hint: the skin cells aren't 'salty'.

 

[gettinthere]

I love the idea of inducting air from the holding tank! Altho I'd be concerned with motoring in a tailwind!