Diesel Air Filters

[Comodave]

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.

I had 6V53s in a previous boat. They slobbered quite a bit of oil out of the air boxes. The mechanic came up with a solution that worked very well and was cheap to contain the oily air coming out of the air boxes. He took a couple of small hoses and ran them from the air box outlets to a fuel filter canister. He removed the element from the canister and hooked the hoses to the canister head. He left one input to the filter head open for the air to escape. He said the air flowing into the canister would hit the side and the oil would stick to the side and then run down inside the canister. Then the clean air would flow out the open inlet. I would drain the canister about every 24 hours and get about 6 to 8 ounces of dirty oil out of it. Simple to do and no ongoing cost after the initial install. And think about how much oil was not sprayed around the engine room since I got about 6 ounces out every 24 hours run time. Cheap Airsep.

 

[backinblue]

According to my mechanic, oil from the crankcase vent should not be an issue for me unless the oil is over-filled or the engine is very worn and there is excessive blow-by. Any opinions on this? I'm thinking at this point that I will trust Yanmar's design and stick with the foam sock filter and be sure to change it regularly so it doesn't deteriorate.

 

[Kurplunk]

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

My Jonh Deere 6404 has just an air box also with the crankcase ventered into it. Other than custom fitting a piece of foam to fit inside, is there a solution for better air filtering?

 

[backinblue]

My Jonh Deere 6404 has just an air box also with the crankcase ventered into it. Other than custom fitting a piece of foam to fit inside, is there a solution for better air filtering?

Did you look here?
https://www.walkerairsep.com/
You also might be able to fit a generic filter from K&N or S&P depending on what the shape of the airbox/intake is.

 

[C lectric]

My Jonh Deere 6404 has just an air box also with the crankcase ventered into it. Other than custom fitting a piece of foam to fit inside, is there a solution for better air filtering?

You have what I used to have and got rid of. I replaced mine with a bottom plate 1/4" and a top plate 1/8" aluminum and m y K&N sandwiched between.
Get rid of the air box. It is not a filter at all. It is meant to keep out small birds and large insects.

I don't know the configuration of your engine, a 6 cyl. , but adaption should not be too difficult. I was lucky and could use simple sheet aluminum with the top plate Checker or Diamond pattern. Carefull measuring and and a few tools and I did my own.

I would imagine you may need to adapt to the intake flange in a slightly different manner.
My engine is a V8 but the photos should give you some ideas.
I doubt you will need the size I used. I went for the largest I could fit which I realized much later I need not have done.
K & N and other like them, S &B filters offer many different shapes and sizes.

FOr the crankcase venting you could then consider the Racor CCV , or a different arrangement. But first is what you want to do for the actual filter itself.

 

[backinblue]

Nice fabrication job

 

[Kurplunk]

It is not a filter at all. It is meant to keep out small birds and large insects.

Soooo true!
Thank you the effort put into your reply, that gives me a solid starting point.

 

[FF]

Those are known as Sparrow Strainers.

Many boat engines come with only intake silencers as a source of airborne contamination is not expected on the water.

 

[backinblue]

That would mean that everyone's engine room is as perfectly clean and shiny as brand new!

 

[Pete Meisinger]

Foam filters can and will do the job. I can't explain why a F.L. piece of foam costs $25.00 or more though.

The real problem is the crankcase ventilation system or lack of it.Build your own condensing contraption or buy one built for your engine but it will be good for your engine and engine room.

It was discussed at this forum quite a while ago with some really good design suggestions.

pete

 

[SteveK]

Foam filters can and will do the job. I can't explain why a F.L. piece of foam costs $25.00 or more though.

The real problem is the crankcase ventilation system or lack of it.Build your own condensing contraption or buy one built for your engine but it will be good for your engine and engine room.

It was discussed at this forum quite a while ago with some really good design suggestions.

pete

Pete, It is not easy to take a strip of flat foam and hold the ends together until the crazy glue sets. That foam filter woud cost me $60 or more.
In another thread I ordered the square profile O rings for $4.68 US a dozen. So far reasonable. But then shipping and handling said we need $33 US and then my biggest pet peeve, the exchange rate. So $50/12= dam expensive but necessary.
Just finished the order for K&N filters. Only $54 US............ each, $203 CAN$ later.

 

[backinblue]

Foam filters can and will do the job. I can't explain why a F.L. piece of foam costs $25.00 or more though.

The real problem is the crankcase ventilation system or lack of it.Build your own condensing contraption or buy one built for your engine but it will be good for your engine and engine room.

It was discussed at this forum quite a while ago with some really good design suggestions.

pete

I agree with all your points. It's still a head-scratcher to me why these expensive and excellent engines don't include a decent crankcase ventilation design. A hose that lays on the air filter? What am I missing?

 

[Xsbank]

In a low-performance engine like most of what we have, hidden below decks in a pretty clean environment, a really good filter is not needed. The K and N filters are certainly adequate for this purpose as they are not very good.

Every filter comparison I've ever read that includes K&N puts them way behind oem filters for filtering and add no measurable performance gain. What they are really good at is making more induction noise and selling filters.

On your car, over-oil them and destroy your MAF, under-oil and destroy your engine. Is there any way to test that you've got the correct amount of oil?

How do you clean yours? Bucket of gasoline? Brake cleaner? Use the "special" K&N oil?

Whatever filter you use, make sure you can put a bucket or a plastic bag or your rain gear or whatever over it in case of a runaway. If you lose control of your old clamcrusher, cutting off the air is the only way to stop it.

 

[backinblue]

I don't share your opinion of K&N but at the same time I'm not a raving fan either. I have used one on my motorcycle and several cars. Cleaning is very easy using the water-soluble K&N cleaner/degreaser. Oiling with the spray oil is easy and never had a problem from excess oil. There are many online dyno tests that show a few HP gain over OEM. I'm sure there are also plenty of studies that show little to no gain. Either way, a handful at HP at WOT is not going to make a noticeable difference to anyone unless they are a racer looking for an extra 1/100th sec in the 1/4 mile. I used them in the hope that I might gain and extra little performance but also improves mpg and the fact that they last a lifetime. I thought it was a plus to have a K&N that I can clean and re-use regularly. That said, in my latest new car, I will probably stick with the OEM filter and change it ahead of schedule which is 30K miles.

 

[83GB]

A while back I emailed K&N and asked them what filter would fit my 120 Lehman. They e-mailed back they had no model that would fit.... Are others jury rigging some way of replacing the metal basket that has the foam filter over it?

 

[SteveK]

A while back I emailed K&N and asked them what filter would fit my 120 Lehman. They e-mailed back they had no model that would fit.... Are others jury rigging some way of replacing the metal basket that has the foam filter over it?

Another poster said K&N RC-4570 fits, the specs suggest it. I should have mine in a few weeks. The throat of the intake is 2 7/8" or 2.875" True it is not listed as a FL120 filter.

 

[backinblue]

I agree that many of our engines are not going to be specifically listed and you need to find and fit a generic that has the right dimensions.

 

[AIRSEP Tech]

Here's some info on the AIRSEP kit for Ford Lehmans.


https://www.powerandmotoryacht.com/boats/cleaner-and-greener


Kit Part# KWFLN-1 Includes adapter plenum.

 

[AIRSEP Tech]

They are also offering a discount, $ 100 off the AIRSEP kit for Ford Lehman

non-turbocharges engines.



http://walker-airsep-superstore.mys...n-marine-engines-non-turbocharged-kit-kwfln-1

 

[Xsbank]

That review is twaddle; no way a crankcase thing will stop the sheen on the water of a Lehman. Its not oil anyways, its fuel.

Get a nice plastic bottle like "protein" comes in, run the vent hose into it and run another hose to the intake. Drain the oil every decade or so. Or, run your vent outside to the atmosphere, the oil will condense and run back down to the engine. Mine goes up the stack.

 

[catalinajack]

For the Lehman just use a foam filter from a wet-dry vacuum cleaner.

I agree with all your points. It's still a head-scratcher to me why these expensive and excellent engines don't include a decent crankcase ventilation design. A hose that lays on the air filter? What am I missing?

 

[backinblue]

For the Lehman just use a foam filter from a wet-dry vacuum cleaner.

I get it, there are lots of solutions we can come up with but it doesn't address my point, why should we have to? Why doesn't the engine manufacturer?

 

[SteveK]

For the Lehman just use a foam filter from a wet-dry vacuum cleaner.

You know, I wondered what happened to my foam filter. Seriously in this disposable world, I have not been able to find a replacement.

 

[catalinajack]

In the case of the Lehman, the manufacturer does have a solution. It's a foam filter. With a clean engine room, no dust to speak of, foam is good enough for my Lehmans as recommended by the manufacturer. How many times do we see comments to follow the manufacturer's recommendations?

I get it, there are lots of solutions we can come up with but it doesn't address my point, why should we have to? Why doesn't the engine manufacturer?

 

[backinblue]

In the case of the Lehman, the manufacturer does have a solution. It's a foam filter. With a clean engine room, no dust to speak of, foam is good enough for my Lehmans as recommended by the manufacturer. How many times do we see comments to follow the manufacturer's recommendations?

What I was really referring to was the crankcase ventilation, which in my case is simply a hose the sits on the face of the foam air filter. Yes I guess it works, but these are not cheap engines. Is it just me that thinks there could have been something a little better than that?

Yes, boats don't drive down dusty roads, but as others have pointed out, even if the water is relatively clean doesn't mean the engine room is. Dust from belts wearing for instance. Again, a screen may be sufficient most of the time, but I can't help thinking a proper filter can't hurt. If your engine room is completely sterile, you will never need to change it.

 

[FF]

"but it doesn't address my point, why should we have to? Why doesn't the engine manufacturer?"


The eng mfg realizes its not needed , although an intake silencer can be very nice.

 

[SteveK]

Update. In an unscientific study I replaced the original foam filters with the K&N. Took the boat on a trip and found that it was well worth the effort.
Whereas before 1650 RPM was needed to achieve 7.5 to 8 KN, now it only needs 1500 RPM. Morale is if you have a filter installed consider changing it for a new one as they do get clogged, perhaps with the aid of crankcase vent assist.

 

[smitty477]

Update. In an unscientific study I replaced the original foam filters with the K&N. Took the boat on a trip and found that it was well worth the effort.
Whereas before 1650 RPM was needed to achieve 7.5 to 8 KN, now it only needs 1500 RPM. Morale is if you have a filter installed consider changing it for a new one as they do get clogged, perhaps with the aid of crankcase vent assist.

"Whereas before 1650 RPM was needed to achieve 7.5 to 8 KN, now it only needs 1500 RPM."
FWIW...
If your boat speed changed while at the same rpm then it was not related to the air filter.
If your boat speed went up at the same rpm it was not related to the air filter.
And if your boat speed went down at the same rpm it was not related to the air filter.

 

[SteveK]

"Whereas before 1650 RPM was needed to achieve 7.5 to 8 KN, now it only needs 1500 RPM."
FWIW...
If your boat speed changed while at the same rpm then it was not related to the air filter.
If your boat speed went up at the same rpm it was not related to the air filter.
And if your boat speed went down at the same rpm it was not related to the air filter.

Thanks for the worthless reply.

 

[backinblue]

Update. In an unscientific study I replaced the original foam filters with the K&N. Took the boat on a trip and found that it was well worth the effort.
Whereas before 1650 RPM was needed to achieve 7.5 to 8 KN, now it only needs 1500 RPM. Morale is if you have a filter installed consider changing it for a new one as they do get clogged, perhaps with the aid of crankcase vent assist.

Did anything else change? That sounds "fishy" to me. lol. Not disputing what you experienced, but here's my take. A better filter may allow you to gain more HP, but your props are spinning at a speed in proportion to your engine RPM. Your boat speed should depend on how fast your props are spinning, not how much horsepower it takes. So whether it takes 400 HP or 500 HP to spin your props at a given RPM, your props don't know the difference and your boat speed should be directly related to your prop speed and engine RPM. Sounds like something else was in play like wind or current or cleaner bottom or less weight on board (fuel and water etc).

Where an air filter would make a difference, if WOT got you to 3000 RPM and now gets you to 3100, that could mean you are now making more HP and able to spin the props faster. Similarly, if your GPH went down for the same RPM, your engines are now more efficient than before (i.e. using less fuel to create the same RPM because there is less air resistance from your filter allowing your engine to spin more freely)

I'm sure there are others who will tell me I'm all wet (pun intended again), so I'll look forward to feedback.