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markpj23 · 09-05-2007, 13:06

At the risk of sounding like a complete idiot....

Checking engine basics today - turbocharged Yanmar 4JH2-DTE. Undid the catches on the air filter housing at the turbo inlet, was going to see if the filter needed cleaning / replacement.

This is all I found - no paper or foam filter element at all. Is it missing or just the way it should be? Manual is very non-specific...

delmarrey · 09-05-2007, 13:12

Well, that would keep the bugs out. Maybe they figured you wouldn't need a filter out on the water. Not much dirt out there!

Pura Vida · 09-05-2007, 13:24

The air filter on my yanmar is not much more than that either. Oddly enough they call it a silencer in the books which makes me wonder if they intend it to filter the air. Delmarrey must be right.

senormechanico · 09-05-2007, 13:29

At least you've got screen on that thing. All my Volvo 2020 has is the perforated sheet metal part.

My previous boat had a Yanmar 3HM35 which had foam over a screen.

Steve B.

Rick · 09-05-2007, 17:08

Mine is the non-turbo version and it also came with no element. Because of that I was reticent to add a paper element that might significantly restrict the intake flow. One quick solution was to cut some wire mesh (about 1/4" mesh squares) to form a cone that would fit inside and form a keeper for heater/air-conditioner filter material. You buy the good kind of material (looks greenish with some kind of resin over the very loose fibers...more expensive again than the paper filters but much better), cut out a piece to make a cone over the form and install it in the cage.

That type of filter does not present much restriction yet is very effective at stopping dust (has everything to do with that resin coating). You can see it visually through the cage without even taking it off when it gets dirty. OBVIOUSLY that dirt is NOT getting into the engine which WOULD cause at least SOME unnecessary wear on the innards.

I monitor closely the mpg that I get overall and detected no decrease with that filter material but do not let it get too dirty. One heater/ac filter can be cut up to make many changes for your engine and will last for a few years at least.

Hope this helps!
Rick

coot · 09-05-2007, 21:14

Quote:

Originally Posted by markpj23

This is all I found - no paper or foam filter element at all. Is it missing or just the way it should be? Manual is very non-specific...

According to the dealer I bought my boat from, it is supposed to look like that. That's why you can't find "air filter element" on the list of replacement parts.

It seems a little weird to me, but I don't feel any particular need to second-guess the engineers who designed the engine.

**Alan Wheeler** · 09-05-2007, 22:36

It is because in our damp environments, paper filters can get too damp and cause major restrictions. The metal screen is there to protect from major obsticles getting sucked in, but as a marine environment is supposed to be dust free, the need for a filter is not as essentila as a road going vehicle.
Personly, I prefer the foam type filters like uni-filter or finafilter. I still feel there is some dust in the air. I was taught that ove time, enough dust to wear and engine would amount to only 1/4 of a cup in total.

NoTies · 09-05-2007, 23:13

On a turbocharged engine I would not mess about by changing the factory filters. Any finer restriction you add can increase the negative pressure between the filter and turbo compressor and possibly result in sucking oil past the turbo oil seal. If you do feel the need to add finer filtration due to operating in a dusty area go BIG in filter area and service OFTEN. The best aftermarket air filter systems I have seen are called airsep (made in the USA) that seperate the oil from the fumes in the crankcase ventilation, put the crankcase under negative pressure (reducing oil leaks) and are cleanable. Expensive but help keep the engine bay nice & clean. Where's nevermonday? He's the man for these questions.

markpj23 · 12-05-2007, 20:24

Thanks for the replies.. I feel much better now. Was feeling pretty stupid having to ask the question... so now I feel much better.

Or... oops .... maybe I'm just part of a large gathering of folks as dumb as I am...??? I'm so confused.....

**Alan Wheeler** · 12-05-2007, 22:03

Or even scarier, you maybe the only smart one here. ;-)

**GordMay** · 13-05-2007, 02:01

By definition, 50% of the public has below-average intelligence. 70% of the (American) public now has regular access to the Internet.
Makes for interesting arithmatic, don’t it.

44'cruisingcat · 13-05-2007, 04:06

The marine environment is dust free? Why do I have to keep vacuuming the boat then? I would go with an oiled-foam type filter such as unifilter as wheels suggested.

Jentine · 13-05-2007, 05:01

There you go again, fixing what isn't broken. Marine diesels run 5000 or more hours without filtration and you feel the need to fix it! Wow, the engineers at a multitude of marine engine manufacturers for the past 100 years must not be too bright.

never monday · 13-05-2007, 06:42

It's just the way Yanmar designed it.
In therory there is minimal need for filtration on a boat. Yanmar does call them silencers and mostly they are for quieting the intake noise of the engine.
Walker AirSep filter as metioned earlier are the "cat's meow" in air filtration; do we need them, I doub't it.