M25XP Air Intake woes

Today I discovered a problem with the air cleaner on my Universal M25XP, 1988 model.
We have been trouble-shooting a problem with the engine stumbling and shuddering at about 1300 rpm. Since it's been a while since the valves were adjusted, that was done -- they were indeed out quite a ways.
Then we removed the air cleaner with it's hose clamp that holds the base on.
I should note that the top part has been vibrating with engine shakes for many years, and I just took it as "normal" that the top part would freely rotate round n round the part where it was swaged onto the base where the clamp is.
Our mechanic said to fix this (!) -- Turns out that another boat in the moorage had some valve and piston damage from many years and hours of that same part vibrating (same engine model), and that this wore the metal to the point where some bits of the inner swaged part broke off and were ingested by the engine.

I had previously removed the whole round 'can' many years ago and washed it in thinner, and, getting little dirt out, left it alone.

Today I opened it up by removing the two long screws that hold the top on. My oh My. :0
Inside was a thick "donut" or ball of aluminum filter material. On the bottom was a fine metal screen to catch…. um…. bits of the aluminum filter media that had broken off and stuck in the mesh. Some could have worked their way through.

I cleaned up all the parts and picked every piece of aluminum shavings (which is what the stuff resembles) out of the screen.

Our mechanic sez this inner donut-shaped filter should not be there to threaten the cylinders with loose bits that work their way through it. This may or may not be a stock part for this engine. It's hard to know for sure at this point.

So now it's all clean. i peened down the inner little flange on the base so that it grips the filter-can floor tightly and no longer will turn.

The "mesh" donut is staying out. The fine screen stays in.

I have cleaned up the outside foam sound-reduction "filter" and will put it back later.

Anyhow, amazing what you can find where you never before thought to look!

Cheers,
Loren

Loren, You might want to update that "thing"! Maybe try the local tractor dealer. The only thing that has going for it is it is fireproof. It will not filter the air well at all and it is well past its prime.

Looks Original

Loren,

I have the same engine. I have been opening that filter, cleaning it with soap and water, oiling it with filter oil and reinstalling in annually. I do not recall seeing and small pieces of aluminum in the screen. I know that some folks have gone to a replaceable paper filter, but a marine environment isn't very dusty. (My dad's A-4 had no filter at all, just a spark arrestor. It ran for many years and may still be in service.)

Your filter appears to be original to me.

May I ask what it cost to adjust your valves? I've been thinking about having mine done.

Paul

newpbs said:

Loren,

PHP:

Our mechanic sez this inner donut-shaped filter should not be there to 
threaten the cylinders with loose bits that work their way through it. 
This may or may not be a stock part for this engine. It's hard to know 
for sure at this point.

I have the same engine. I have been opening that filter, cleaning it with soap and water, oiling it with filter oil and reinstalling in annually. I do not recall seeing and small pieces of aluminum in the screen. I know that some folks have gone to a replaceable paper filter, but a marine environment isn't very dusty. (My dad's A-4 had no filter at all, just a spark arrestor. It ran for many years and may still be in service.)
Your filter appears to be original to me.

May I ask what it cost to adjust your valves? I've been thinking about having mine done.
Paul

Click to expand...

Thanks for the input. In the short term, we will clamp the filter housing back on with no more aluminum shredded stuff inside. Further out, I forsee a conversion to that nice-looking K&N setup that Mainesail has written an article about.

The valve adjustment took about an hour, so multiply that by your local labor rate.

Loren

My first thought was a K&N... My second thought was that the oil required to make a K&N actually work is water soluble So that is why I suggested something from the tractor world. Those filters are designed for rough environments and are very effective.

Why would the water-soluble oil for the K&N be a problem? How "rough" is the environment in the engine compartment?

I replaced the original metal-housed filter on my M-18 with a K&N over a year ago (maybe two by now.) Haven't had a problem yet. I did have to install the inlet fitting for the breather hose myself:



My original filter specifies a thin foam ring that fits outside an expanded metal mesh ring. When I opened the filter the foam had long since disintegrated...

That's the way old air intake "filter." The new version has a foam around it. Other choice, of course, is the K&N. My new-style (1998) filter doesn't "lock" onto the intake either,m it just rattles around, too, even with a hose clamp on it.

http://shop.torresen.com/marine_diesel_direct/Universal/index.php?p=details&mfc=Universal&sku=302181

http://shop.torresen.com/marine_diesel_direct/Universal/index.php?p=details&mfc=Universal&sku=301049

Go to the K&N website and look around in their universal filter specs. I can guarantee that you will find something that will work in your application. I put a K&N on my engine, tossed out the ridiculous Universal "air horn" and never looked back. Simple to press fit a barbed fitting in the back of the K&N rubber housing and run the breather hose to it. No more metal bits in your engine. RT

Don't get me wrong, K&N makes a great filter. It is however susceptible to loosing its effectiveness when it becomes wet. My engine is deep in my bilge it does get wet especially if the engine is run with the bilge holding a fair amount of water, also in the winter the boat can get damp enough that there is standing and dripping water on my engine. Therefore I believe that it is only fair to warn that there is a potential problem. Also the comment that tractor air filters are made for rough environments is not meant to infer that the marine environment is particularly rough ( except for requiring a trouble free, extended life in a salty, wet confined area with poor ventilation in a remote location) but to say that the tractor engineers had spent a considerable amount of time and effort to make the best filters technology allows (and insistently most marine engines started life as a tractor engines) and I believe their quality and solutions are probably far superior fit for a marine application than those offered by say the local auto parts store or industrial air filtration supplier. If you have a K&N filter and keep it dry and oiled you have an extremely effective filter, If it is wet or otherwise un-oiled you have nothing!

Consider this, my 5432 was equipped by Universal with an "air horn". This is simply an empty housing with a metal grate on the end with 1/8" holes drilled in it. The second 5432 I have had the same thing. This device would stop only the largest bits from being sucked in. There was no air filter in the usual sense. In a marine environment there is very little dust and no real need for a filter capable of stopping the fine dust that wheeled terrestrial vehicles are so good at producing. A K&N, wet, dry, oiled, whatever, is overkill in every way. K&N's are not actually very good filters, in fact, they pass more dirt than a pleated paper filter every time. But that is not relevant in our application. RT

M25 air filter?

The can in the photo below is clamped to the mouth of the air intake manifold on my Universal M-25. Inside the can is a metallic looking mesh, and there is a flimsy-looking "filter" element (this one) placed around the can, on the outside.

Hard to imagine that the "filter" element is actually any good at doing its job ... alas, is this contraption (in particular the metallic mesh inside the can) intended to be dismounted and washed? Or is it better to simply replace the whole thing with a standard K&N filter?

TIA, Zoran

Zoran, I added your new thread to the older air filter thread.
You might want to get rid of that mesh stuff.
Little bits can get into the engine and score the cylinder walls according to my mechanic.
Check out the photos from whenI had our filter apart.


Loren

Loren, thank you - good thread, I feel silly I did not find it before posting my own stuff. So, what did you decide in the end? Did you go with a K&N or other tractor filter? (I figure if it's good enough for MaineSail it'll likely work for me too :nerd

Best, Zoran

Mainely, a good idea!

Akavishon said:

Loren, thank you - good thread, I feel silly I did not find it before posting my own stuff. So, what did you decide in the end? Did you go with a K&N or other tractor filter? (I figure if it's good enough for MaineSail it'll likely work for me too :nerd
Best, Zoran

Click to expand...

I am still using the (now empty) can with the foam piece around it. Someday I would like to change to the K&N, just 'cause it looks so cool.

Here you go: http://www.knfilters.com/universal/universal.htm Measure the intake O.D. find a filter with the correct I.D. and outside dimensions that fit your space, order from K&N directly or order the part number from any local K&N dealer (auto or speed parts shops). Install K&N filter and never worry about it again.
RT

For those who still have that after thought of a factory filter GET RID OF IT.... They don't stop belt dust, they rattle, get loose and basically suck.. The K&N filters are a far better filter and allow the high capacity air flow that a diesel needs.

The automotive, dirt bike, rally car, dune buggy, race car etc. markets are far more abusive to an air filter than a marine engine. Marine engines treat filters quite easy...

M-25

Maine,
Any reason you didn't go with a taller filter? I always see more sq/in of filter media as a benefit. Something like this http://www.knfilters.com/search/product.aspx?Prod=RU-0360 Looks in the pic like you have some headroom to allow for it. Just curious. RT

Do you guys oil the K&N filter? Does it matter?
TIA, Zoran

It's the oil that makes them pink, they are white when cleaned.

Glenn

K&N's come pre-oiled and they only need cleaning when dirty or every 50,000 miles. That pretty much means "lifetime" in our application. RT