Micron size filters

Could I use a 30 Micron Racor filter or should I use a 10. Naturally aspirated 100 HP diesel??

CaptFun said:

Could I use a 30 Micron Racor filter or should I use a 10. Naturally aspirated 100 HP diesel??

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Primary or Secondary? What does your engine manual say?

What engine?

In general, either would be ok. I use 10 unless it clogs too quickly, then may use a 30. The secondary is what defines the cleanliness at the injection system.

Some engines do spec a 30 as a primary.

The Primary. The Secondary is a NAPA 10 Micron.

The usual configuration for boat sized diesels is 30 micron primary and 10 micron secondary. Those sizes keep particles out of the fuel that cause major damage to fuel system components.
But there are advantages to running really clean fuel - longer injector and pump life. I run a 2 micron primary and the filter lasts about 500 hours. But my tanks are clean and I buy clean fuel from dealers that maintain their tanks and filters. Not just any marina.

Whatever the engine manufacturer specifies.

I run 10 micron primaries since the secondaries are a pain to change and bleed.

CaptFun said:

Could I use a 30 Micron Racor filter or should I use a 10. Naturally aspirated 100 HP diesel??

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Ideally, both.
Two stage primary filtration starting with a 30 mic, then a 10mic, followed by a 2 mic secondary.
Read all about it at sbmar.com, they will not lead you wrong.

Fuel Filter - Micron sizing Question

You need to give us a little more information, different mfgrs. have different recommendations, So what Make, Model, age & type of engine ?
Does engine have filters on it & what are they & do you want to have to change your on engine filters regularly, or would you rather change your before engine RACOR's or what ever you have more often.

Different Diesel Engine Makers have different injector systems, also year of manufacturer means different specs.

KAPND is absolutely correct about the recommended way to do it.

But then the question is - do you have even dual series fuel filters ?

I like to run a smaller filter than 10 microns in my RACORS to save how often I must change the factory fuel filters on the engine.

So I run 2 micron filters & that has worked for me for 4 decades.

30 micron first then a 10 (or 2 micron in my case) next, then your factory on engine filters as back up as no filter stops 100% of everything, 100% of the time.

Better safe than sorry I say.

Good Luck.

Alfa Mike

Thank you one and all. I removed my primary filter out of the hell hole. I mounted a water seperator follow by 2 racors (10 micron) in series. I attached the 3 units to starboard and hung it from a pilot house floor stringer. I now remove the stairs and there it is, life is good

You really should do step filtration, as someone else posted Tony Athen's website which he talks a lot about that, also understand ultra fine can put an extra load on fuel pump. As many have stated you should follow the manufacturers recommendations.
Human nature is if 10 micron is good 2 micron is even better, and that's not always the case.... Good luck!

While step filtration is fine and really the preferred method, many of us running 2 gal per hr diesels have run 2 micron primary and secondary filters for decades with great results.

With a vacuum gauge, you can tell if there is a strain on the fuel pump.... and go from there.

kapnd said:

Ideally, both.
Two stage primary filtration starting with a 30 mic, then a 10mic, followed by a 2 mic secondary.
Read all about it at sbmar.com, they will not lead you wrong.

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Exactly how my boat is set up...

I run 10 micron Primary Racor 900s with Cummins spec on engine secondaries....no clue what micron(2 I think) but it is what is specced for the engine.

Remember the rating on the filter is nominal, not absolute , so those 2 filters will still pass 30 chunks at times.


That is why multiple filters in a row work so swell , and are mostly needed on modern electric injection systems.

10 micron Racor as Primary

We have been using a 10 micron primary (Racor 500FG) for the last 22 months (Since we bought Encore), and in the last year, I've had to drain about 1/2" of 'junk' from the filters every few months.

This last week, a trip to Captiva was taken in less than ideal conditions, and we hobby horsed for 3 hours steady. During a routine Engine Room check while underway, I found about 1" of 'junk' at the bottom of one of the Racors (the other was negligible). My manifold allows me to isolate one filter (I use both all the time), which I did, and drained the 'junk'. I filled the filter with fresh diesel, and upon bringing back online, about 1/2 of 'junk' filled the bottom of the clear bowl. During the entire trip home, the engines ran flawlessly at 1700-1800 rpms, but during the 5 hour trip the filter gained almost 1" of (you guessed it) 'junk'. At home, I tested it for water, Negative. I drained the bowl into a clear container and let it settle. Attached is the result.

Alge? Bacteria? Have birds been crapping in my fuel tank?
I replaced the Racor filters with new 10 micron (the old ones had no evidence of green anything in them), but I thought what the heck...Your thoughts?

VJameslanza said:

We have been using a 10 micron primary (Racor 500FG) for the last 22 months (Since we bought Encore), and in the last year, I've had to drain about 1/2" of 'junk' from the filters every few months.

This last week, a trip to Captiva was taken in less than ideal conditions, and we hobby horsed for 3 hours steady. During a routine Engine Room check while underway, I found about 1" of 'junk' at the bottom of one of the Racors (the other was negligible). My manifold allows me to isolate one filter (I use both all the time), which I did, and drained the 'junk'. I filled the filter with fresh diesel, and upon bringing back online, about 1/2 of 'junk' filled the bottom of the clear bowl. During the entire trip home, the engines ran flawlessly at 1700-1800 rpms, but during the 5 hour trip the filter gained almost 1" of (you guessed it) 'junk'. At home, I tested it for water, Negative. I drained the bowl into a clear container and let it settle. Attached is the result.

Alge? Bacteria? Have birds been crapping in my fuel tank?
I replaced the Racor filters with new 10 micron (the old ones had no evidence of green anything in them), but I thought what the heck...Your thoughts?

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That's some nasty looking fuel. From the photo it looks like water, which suggests you have a way for water to get into the tank.

Tested with Gasoila Water Finding Paste, and the results were negative.

If that was coming out of my fuel tanks I'd be pretty concerned. That is not at all normal. I would suggest getting the tanks cleaned.

Ken

VJameslanza said:

Tested with Gasoila Water Finding Paste, and the results were negative.

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Be that as it may, it is a clear liquid, denser than water. Kind of narrows down the possibilities to water, glycerin and sulphuric acid.

Delfin said:

Be that as it may, it is a clear liquid, denser than water. Kind of narrows down the possibilities to water, glycerin and sulphuric acid.

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Good point Delfin. What color is the coolant in the engine system?

Looks kind of like anti freeze.

George, the coolant is yellow, but why would that have anything to do with the fuel from the tanks? The green stuff is kind of lumpy, but liquid-like. You can see it a little better in this photo. The color like Archie mentioned does look like anti-freeze that's been in an engine way too long.

The color of this is through a thin layer of dyed diesel, the color is still quite bilious green, this photo was just to give you some idea of what the 'junk' looks like.

I really do appreciate all the input gang, that's what I love about the TF, lots of knowledge, lots of opinions, lots of ideas as to which way to go.

As I mentioned in my earlier post, I cut open the filters, and there was absolutely nothing in them, no grit, no small pieces of dirt and definitely none of that green stuff. So the coalescer is doing its job spinning the junk out of the diesel.

Where would anti-freeze and diesel fuel find a common location in the engine? The oil, recently changed shows no indication of water or foreign matter. But the closed cooling system and the fuel delivery system (pump, injectors, return) don't seem to 'overlap' at any point.

Please keep the opinions and ideas coming, we might be getting close.
Jim

Can you draw a sample off the bottom of the fuel tank? See if that crap is in the tank. It almost has to be. If so they I would look at getting the tank cleaned. Check the O rings on your furl caps. Check the top of the fuel tank for rusting holes that could let water into the tank from bad caulking around the filler neck.

ComoDave,
I agree, I think the junk has to be from the tank, but I have no way of knowing which tank, and on the Albin 40, the two outboard tanks are nearly inaccessible. The only way to get a sample, I would think is to have the fuel pump run with the fuel going into a bucket, as the pickup is at the top of the tank, with (I assume) a pipe reaching down into the bottom of the tank.

I'm sorry to be taking up so much space and time, but there IS a way for me to determine which of the two tanks it is from by closing the pick up alternately from one tank to the other, and pumping into a bucket.

If you suspect water, replace the o-rings on your deck fills!!

Diesel fuel and coolant might meet in a fuel cooler if you have one. Water in the tanks come from the tank fill cap, water on top of the tank leaking in, the tank vent, or the fuel dock.

Yes, it can be a PITA to get access to tanks. But you do need to find out where your crap is coming from because at some point it will probably overtake your filters and then you will be way worse off. My tanks have a straight shot down the filler neck to the tanks. If needed I could drop a tube down and pump a sample of the fuel. However that still does not tell you how the water is getting into the tank. Do you have an inspection camera that you can work above the tank to see if there is any rusting.