I bought a 1986 Catalina30 last fall. One of the things on my winter punch is is to figure out what to do with the air cleaner. The standard air cleaner is there but is missing the foam filter. The simple thing to do is to just replace the filter, but I am thinking of converting to a paper element. I am just find it hard to believe that lack of a decent high efficiency filter appears to be standard practice. Am I over thinking this? Should I just replace the cheapo foam element? If it should be upgraded any ideas?
Air cleaner - or not?
- Thread starter seaduct
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a controversy.. but speaking about the smaller, low cfm engines
there might be some advantage of installing an air filter on a small marine engine but it should in no way replace the flash suppressor screen that should be there.
(the flash supressor is the screen that prevents the flames from shooting back into the engine compartment in the event of a backfire... and possibly causing an explosion. an air filter shouldnt be depended on to do this)
I personally have not seen any advantage of an air filter, but I have seen the disadvantage when a paper element becomes damp, swells and then causes restriction in the airflow.
I have been around boats and on the water all my life and I know of a couple boats with original engines that are approaching 70 years old that have never had an air filter on them and they still run in top shape... and many more that are at least 50 years old and still in top running shape..... all original and without air filters. both inboard and outboard engines. (but then, there may be other areas of the country with dirtier marine air than we have here in the west)
I have also seen big fancy boats and runabouts that are less than 15 years old that have air cleaners installed and some of the owners have had to rebuild their engines and others have trouble with keeping their engines running....
it all has nothing to do with whether an air cleaner was installed, but has everything to do with how they are maintained. I dont care who ya are, I will argue that there isnt much dust floating around the marine environment of the type that is critically harmful to an engine, so in my opinion there is not much point in adding an unnecessary bit of equipment to keep out what isnt there to begin with. But there are others that will disagree. if timely oil changes and proper maintenance can get you 70+ years of good steady use and lack of it causes premature failure, then someone if going to have to prove to me the benefit of an air filter on a boat engine before I will tell anyone its a good idea to install one. but im not telling you that you shouldnt either.....
so it comes down to whether you want one on your engine or not...
there might be some advantage of installing an air filter on a small marine engine but it should in no way replace the flash suppressor screen that should be there.
(the flash supressor is the screen that prevents the flames from shooting back into the engine compartment in the event of a backfire... and possibly causing an explosion. an air filter shouldnt be depended on to do this)
I personally have not seen any advantage of an air filter, but I have seen the disadvantage when a paper element becomes damp, swells and then causes restriction in the airflow.
I have been around boats and on the water all my life and I know of a couple boats with original engines that are approaching 70 years old that have never had an air filter on them and they still run in top shape... and many more that are at least 50 years old and still in top running shape..... all original and without air filters. both inboard and outboard engines. (but then, there may be other areas of the country with dirtier marine air than we have here in the west)
I have also seen big fancy boats and runabouts that are less than 15 years old that have air cleaners installed and some of the owners have had to rebuild their engines and others have trouble with keeping their engines running....
it all has nothing to do with whether an air cleaner was installed, but has everything to do with how they are maintained. I dont care who ya are, I will argue that there isnt much dust floating around the marine environment of the type that is critically harmful to an engine, so in my opinion there is not much point in adding an unnecessary bit of equipment to keep out what isnt there to begin with. But there are others that will disagree. if timely oil changes and proper maintenance can get you 70+ years of good steady use and lack of it causes premature failure, then someone if going to have to prove to me the benefit of an air filter on a boat engine before I will tell anyone its a good idea to install one. but im not telling you that you shouldnt either.....
so it comes down to whether you want one on your engine or not...
In a discussion about this on another forum, concerning a Westerbeke 30, little consensus occurred. As usual. However, IF you are so inclined to go with the filter route, (and I did, I'm very obsessive), K&N makes a neat little filter that is a bolt on.
There are 4 Cat 30's in our dock, none have anything in the air cleaners. One person was worried about it and put in a foam element. It was sucked down the first time he throttled up. DOH!
If it's not broke, dont fix it!
If it's not broke, dont fix it!
Two words......... BELT DUST !!!!!!
Here's a 1 season old K&N installed on a Universal M-25. The reason it is black is due to the load on the alt and the belt dust created by it.. The loads on today's alternators with their undersized belts are quite tremendous. Even when properly aligned, pulleys cleaned and the belt properly tightened, they can shed quite a bit of dust in bulk charging..
New:
One season later:
After cleaning up some of the belt dust...
The manufacturer installed that foam element for a reason. Our Westerbeke has a paper element filter identical to a car, it gets dusty.
But of course there's no dust in a marine engine bay..... Like none here either...
And this engine bay is also dust free...
On a ski boat where the batteries are rarely if every discharged then the engine space will be quite clean. On a sailboat with deeply cycled batteries belt dust can be pretty darn messy..
Here's a 1 season old K&N installed on a Universal M-25. The reason it is black is due to the load on the alt and the belt dust created by it.. The loads on today's alternators with their undersized belts are quite tremendous. Even when properly aligned, pulleys cleaned and the belt properly tightened, they can shed quite a bit of dust in bulk charging..
New:
One season later:
After cleaning up some of the belt dust...
The manufacturer installed that foam element for a reason. Our Westerbeke has a paper element filter identical to a car, it gets dusty.
But of course there's no dust in a marine engine bay..... Like none here either...
And this engine bay is also dust free...
On a ski boat where the batteries are rarely if every discharged then the engine space will be quite clean. On a sailboat with deeply cycled batteries belt dust can be pretty darn messy..
You can go the K&N route, and it's a good one. The foam filter can be purchased for next to nothing at NAPA:
7-02278
Pre-filter
replaces Briggs & Stratton
270782, 271794
Pre-filter
for 7-02210
7-02278
Pre-filter
replaces Briggs & Stratton
270782, 271794
Pre-filter
for 7-02210
I have been using a filter from one of the auto stores that with little modifacation fits in the old metal air filter for my m25 xpb... It gets really dusty if i dont have a newer good fitting belt... I will be looking for K&N and see what they got.... are they in the florida area?
I don't know where they are located company wise, but K&N is everywhere, and a respected filter manufacturer. I put them in every vehicle I own. On their website, a small one will need you to identify what the O.D. of your intake is, so you can clamp it around it. A K&N will last you a long, long time with periodic servicing.
My argument has always been, on average, for every one part fuel that an engine uses, it uses 100 parts air. It should be clean air.
My argument has always been, on average, for every one part fuel that an engine uses, it uses 100 parts air. It should be clean air.
Poke around here, might even have a part # (if not I'll keep looking, I know he posted it on an Ericson message board topic)
http://www.pbase.com/mainecruising/m25_air_filter__pcv_valve
Thanks Stu & Chris looks like a simple fix and i will no longer have to waste time modifying a filter to fit....
The only thing that gets my engine & compartment dirty is the stupid opening that Universal makes on top of the valve cover. Originally I beleive that it has a small hose that runs back to the air cleaner box, which also has a hole in the side of it to accomodate this hose. Before I replaced the misssing hose I wuld get a bit of oil working its way out of the top of the cover that would spit back over the engine. Not as bad once I hooked up this hose. But I would worry that if I installed a paper element, that this blow by hose would soak the paper element of an air filter in motor oil & ruin it.
You could also route fresh air to the air filter/air intake, might have to build an air box. You dont have to let it draw dirty engine compartment air. Plus, cooler fresh air would help economy.
As long as the engine doesn't have excessive blowby, routing the crankcase vent to the air intake should be a problem. You could also extend the breather tube into the intake a short way to keep any oil from fouling the filter. However, with fresh air to the engine, it really shouldnt need more than a protective screen, at least on a diesel. Gas engines need a spark arrester.
As long as the engine doesn't have excessive blowby, routing the crankcase vent to the air intake should be a problem. You could also extend the breather tube into the intake a short way to keep any oil from fouling the filter. However, with fresh air to the engine, it really shouldnt need more than a protective screen, at least on a diesel. Gas engines need a spark arrester.
The hose is just upper crankcase ventilation. Same principal as the P.C.V. valve on yer truck. It serves a couple of purposes, and should be intact. Running to the intake, it is sucking air back into the chambers, and through that hose creating negative pressure. Unless you have a bad/leaky valve, it should never blow oil back out the filter.
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