Fuel filters question

smitty: is this the required reading? https://www.sbmar.com/articles/marine-fuel-filtration-the-seaboard-way/
Fleetguard/Cummins centric, but can't tell the author. And, its definately pro progressive filter.

SoWhat: also, pump wear, not just nozzle diameter. But yes, understanding always helps.

I monitor the 2 Racor filters but not the on engine filters.
The boat came with the dual Racor, I added the large Racor.
30 to 10 to 7 micron.

diver dave said:

smitty: is this the required reading? https://www.sbmar.com/articles/marine-fuel-filtration-the-seaboard-way/
Fleetguard/Cummins centric, but can't tell the author. And, its definately pro progressive filter.

SoWhat: also, pump wear, not just nozzle diameter. But yes, understanding always helps.

Click to expand...

Yes - that is one of the best overview articles around, there are others.

I am getting the feeling that most people believe a 2 mic filter is like screen door and that it filters anything below 2 mics - that is not close to what happens with all of these filters as they 'pass' much larger debris than their rating.
Since I never thought I could learn as much as all these folks that spend their life doing these things I always sought out the filters manufacturers recommendation as well as engine manufacturers best practices.
Over time I was able to confirm how correct all of them were with my first hand experiences with our used boats as well as my short experiences 'filtering' large industrial fuel tanks (2 million gals +).
I know that I cannot do better than what they have perfected so I am always curious why folks will 'believe' a post on various forums rather than the people that work full time and do this for a living.

I work with people currently that have a 30 year trail of engineering debris behind them. Yeah, a little jaded.

I just read the Parker story on micron rating. https://www.parker.com/literature/Racor/Mobile_The_Micron_Rating.pdf

So, I read the 3 pages and know enough to be dangerous.

As suspected, there is no "sure thing" when it comes to filters. You quickly learn that this technology is a statistic matter, meaning, you deal with percentages.

Nominal Micron Rating
Absolute Micron Rating and
MultiPass Micron Rating.

Back to the math. Racor talks of 98, 95, and 90% efficiencies for their stated 2, 10, and 30 micron filters. OK, so if I only have a single 2 mic filter, I should expect 2% of 2 mic particles to pass that filter. Makes sense. If I put two in series, I might then expect 98 plus 98% of 2 = 99.96% of the particles to be captured. Can I assume this test is done at the filter flow rating? Further, can I assume that if one reduces the flow rate, a better efficiency can be obtained? And, at least as far as boat fuel goes, we are talking single pass? Granted there is diesel bypass which rather complicates the argument. But, one could also make the case that the FIRST pass fuel needs to be clean, also.

Am I still on the tracks? I don't want to go down the wrong rail, as I have a thought to explore further.

FF said:

"Hello??? —There is no better option."

The good option is a genuine fuel tank, instead of a box to hold fuel.

Almost all of the water and grunge will settle in a sump where it can easily be removed.

A second option is a centrifugal fuel filter which can remove far finer gunk than a filter bank. .

Click to expand...

The 3rd option is better still

Genuine fuel tank plus centrifugal x 2 (quick flick if one gets clogged) and secondary filters with water trap on engine.

2 years on same filters, zero crud evident in tank, zero pressure on gauges.
Not sure why I just bought 12 new filters, at that change rate it'll be a lifetime supply.

Add: currently running 10 mic in the racor

YEs maybe. But lets see if we can figure out a system with no moving parts first. [emoji847]

Some of us have the equivalent of Briggs and Sttatton lawnmower engines, and some have the little brothers of Airline GE turbines....

Yet one size filtration method fits all....

"YEs maybe. But lets see if we can figure out a system with no moving parts first."

A built in sump that can be hand bailed (USN style) does require some effort , but there are no replacement parts required , except perhaps the person doing the bailing.

For a distance cruiser that refueled from drums , or from a questionable source , a sump would be the viable solution , even if the "fuel" were 25% water.

diver dave said:

I work with people currently that have a 30 year trail of engineering debris behind them. Yeah, a little jaded.

I just read the Parker story on micron rating. https://www.parker.com/literature/Racor/Mobile_The_Micron_Rating.pdf

So, I read the 3 pages and know enough to be dangerous.

As suspected, there is no "sure thing" when it comes to filters. You quickly learn that this technology is a statistic matter, meaning, you deal with percentages.

Nominal Micron Rating
Absolute Micron Rating and
MultiPass Micron Rating.

Back to the math. Racor talks of 98, 95, and 90% efficiencies for their stated 2, 10, and 30 micron filters. OK, so if I only have a single 2 mic filter, I should expect 2% of 2 mic particles to pass that filter. Makes sense. If I put two in series, I might then expect 98 plus 98% of 2 = 99.96% of the particles to be captured. Can I assume this test is done at the filter flow rating? Further, can I assume that if one reduces the flow rate, a better efficiency can be obtained? And, at least as far as boat fuel goes, we are talking single pass? Granted there is diesel bypass which rather complicates the argument. But, one could also make the case that the FIRST pass fuel needs to be clean, also.

Am I still on the tracks? I don't want to go down the wrong rail, as I have a thought to explore further.

Click to expand...

In my past we had full access to Scanning electron microscopes as well as may other lab pieces - the SEM is not suitable for reviewing injector tips but a high resolution light microscope is good for that. After 'playing' with a bunch of these thoughts when we were in research engineering we figured out that we were really far behind the curve in the subjects.

Single pass filtration - The specs for fuel are typically over engineered so that an engine spec of 2 mics could get along well with a 10 mic last filter. The newer fuel rail engines are not nearly as forgiving so their specs are tighter.
Diver Dave - a question , which engine(s) do you have? If single pass filtration were that important would your engines lube system have a full pass filter?
I do not believe the math is accurate for the serial filters but I doubt that exact results are important anyway. Predicting filter life is not linear when you open the system multiple times.
I have read that filter efficiencies are 'best' at the intermediate load stages when they are neither completely new or loaded with contaminants.

Two experiences that showed me that the function of filter size and filter life are not linear but exponential...
1. A larger twin diesel boat I bought that had sat for quite some time and had fuel which was much worse than I had expected – had to move it from Haverstraw to Northport NY so I could easily get it back into shape , about 60 nmiles by water. It had on engine filters, water seps, and Racor 500’s with 2 mic filters as it was splashed for the season. I had already ‘sucked’ the bottom of the tanks as best I could before it left the hard. Doing a quick check out cruise a well before the trip home we went about 2 miles before the ‘new’ 2 mic filter port side began to fail. After replacing that one the stb failed and before we got back to the dock we had both fail again. 4 filter changes in less than a few miles. Returning the next week I had changed the Racors to 10 mic filters and placed bulk spin-ons ahead of the Racor’s. On the next day we were able to proceed home for the 60 mile trip with no issues to a home port where we could more easily deal with the existing fuel issues.
2. When I worked for a company that ‘cleaned’ muti-million gallon fuel tanks as part of their services we were working our way through a tank farm in northern NJ. Typically the tank is lowered to about 1 foot of fuel depth where the lowest 2-3 inches will be left as a mixture of fuel and ‘mudded’ contaminants. We clean the fuel by cycling it to another adjacent tank thru 6” lines driven by truck mounted vacuum pumps. The pumps flow the fuel through very large ‘bag’ style filters of varying porosity. We would make muti passed with varying filter sizes (staged filtration) starting with the courser filter and ending up with the fine filter required for a tank pass grade. It was common for a first pass course filter to last at least an hour or more before the flow rate made it necessary for it to be flushed and cleaned. On more than one occasion one of the techs made an error and loaded tie 3rd grade filter (finest) into the system before we finished the first pass. It was always impressive to see that this filter would not last ½ the time, not 1.4 the time either but that it was sounding a pressure problem in much less than a minute.

Lessons I learned – functions of filter pore size do not result in linear degradation but in steep logarithmic fashion. Filters of the same physical size but of a 2:1 porosity rating show a massive difference in overall contaminant holding capacity (again logarithmic). Filters of a larger porosity can hold many times the contaminants as the same filter of a lower porosity but may pass too large contaminants for the end use. Utilizing staged filtration takes advantage of the best performance characteristics of each filter media.

Consider reading all the pdf’s made available by places like Racor, Cummins, Baldwin, CAT, or any of the major diesel supply manufacturers.
Alternately you can just follow their lead rather than experiment with improving on their previous work.

FF said:

"YEs maybe. But lets see if we can figure out a system with no moving parts first."

A built in sump that can be hand bailed (USN style) does require some effort , but there are no replacement parts required , except perhaps the person doing the bailing.

For a distance cruiser that refueled from drums , or from a questionable source , a sump would be the viable solution , even if the "fuel" were 25% water.

Click to expand...

I agree that an improved fuel system would be a great goal - but in most every case there would be large amounts of time and money to implement the changes.
In this post most all of these fuel filtering choices are very simple and quite cheap to employ.

psneeld said:

Some of us have the equivalent of Briggs and Sttatton lawnmower engines, and some have the little brothers of Airline GE turbines....

Yet one size filtration method fits all....

Click to expand...

I have enjoyed the stock staged filtration in many diesels that I have owned or have been responsible for including but not limited to:
- Perkins
- Lister Petter
- Cummins
- Hino
- CAT
- Yanmar
- Navistar
- GM

many of them were built quite a long time ago aa they were in boats/trucks older than 1990 or in facilities that were built earlier on. (some earlier than 80's)

Not really my point... it is simple but you are locked on a concept that has its merits..... even if overkill for some.

A lot of us have run many different and types of diesels.

psneeld said:

Not really my point... it is simple but you are locked on a concept that has its merits..... even if overkill for some.

A lot of us have run many different and types of diesels.

Click to expand...

I do not think I locked in on anything - in each case it was the manufacturer or the filter provider that did the work and provided the solution.
I have never gotten the impression that any of these manufacturers or parts providers were aiming for overkill. Overall ease of use, safety, and length of service while considering costs is the aim - IMO - my summation of reading the articles.

I'll elaborate on my theory that progressive filtering is counterproductive.

First; It does a sub-optimum job due to media. To set a baseline, let's suppose you need to design a system that needs to trap to the 2 micron level. You have a HPCR diesel. Per test results, a 2 micron filter is on the order of 98% efficient, first pass. So, you need a second 2 micron filter to follow. Page 96 of: https://etd.lib.metu.edu.tr/upload/12611586/index.pdf. So, now you have a two filter efficiency of .98 + .98*2 = 99.96%. A 30, then a 10 micron filter in front doesn't help the 2 micron trapping at a significant level.

Second; The idea of a "final filter" on-engine to work with a single off-engine filter is flawed. On engine filters are subject to vibration, especially on diesels. Page 116 of the above doc. This hurts efficiency especially on these single micron sizes. So, you don't get full benefit of a multiple filter pass at small micron sizes. Some of that last 2% is being shook out of that last filter, going into the engine.

Third; You don't know with certainty, what size particulates are in the fuel. The forwarded benefit of progressive filtering is primarily related to spreading the particles out among several filters, thereby prolonging the service life. This may work great with a continuous spread of particle sizes, each being trapped in the various media. It will not usually work that way. One filter will clog before the others, and the question is then: which one?? This then, talks of complexity. Many canisters to vacuum monitor. If you have a 30 and 10 off-engine, plus the back up filters, you are at 4 monitors, and still have not accommodated the on-engine filter. If you go 30,10,2 off engine, paired, then you have significant monitor, plumbing, and operational complexity.

Fourth; Each progressive filter needs to satisfy the flow rates. And, larger is better, not just for service life, but for media efficiency. Filters work better with less pressure and less flow. Water separation too, but lets not expand this argument. But, with progressives, you have a multitude of filters to arrange, and is becomes less likely each will be "very large".

So: the alternative.

First filter: a "very large" 2 micron filter. 98% efficient at 2 micron, actually more, since the specific flow rate per unit media is low. The ability to accommodate more 100 micron particles is greater than the progressive, since I now have room for a larger filter.
Second filter; Another, of the exact same filter.

Engine filter: should need changing now once per millennium. Exaggerated, but you get the idea. It doesn't really have much to do. Plus, it shakes too much to trust for the small stuff anyway.

benefits; Stocking only one type of filter at sea. No guesswork required to figure out which filter is clogged. Plus, no excuse not to monitor that lead filter, its' the one. Better filtering; not relying on the on-engine filter. Water sep will be better with the large filter, that's an argument again related to speed of the fluid at the media, and the size of the system, below the media, to hold the water.

diver dave said:

I'll elaborate on my theory that progressive filtering is counterproductive.

First; It does a sub-optimum job due to media. To set a baseline, let's suppose you need to design a system that needs to trap to the 2 micron level. You have a HPCR diesel. Per test results, a 2 micron filter is on the order of 98% efficient, first pass. So, you need a second 2 micron filter to follow. Page 96 of: https://etd.lib.metu.edu.tr/upload/12611586/index.pdf. So, now you have a two filter efficiency of .98 + .98*2 = 99.96%. A 30, then a 10 micron filter in front doesn't help the 2 micron trapping at a significant level.

Second; The idea of a "final filter" on-engine to work with a single off-engine filter is flawed. On engine filters are subject to vibration, especially on diesels. Page 116 of the above doc. This hurts efficiency especially on these single micron sizes. So, you don't get full benefit of a multiple filter pass at small micron sizes. Some of that last 2% is being shook out of that last filter, going into the engine.

Third; You don't know with certainty, what size particulates are in the fuel. The forwarded benefit of progressive filtering is primarily related to spreading the particles out among several filters, thereby prolonging the service life. This may work great with a continuous spread of particle sizes, each being trapped in the various media. It will not usually work that way. One filter will clog before the others, and the question is then: which one?? This then, talks of complexity. Many canisters to vacuum monitor. If you have a 30 and 10 off-engine, plus the back up filters, you are at 4 monitors, and still have not accommodated the on-engine filter. If you go 30,10,2 off engine, paired, then you have significant monitor, plumbing, and operational complexity.

Fourth; Each progressive filter needs to satisfy the flow rates. And, larger is better, not just for service life, but for media efficiency. Filters work better with less pressure and less flow. Water separation too, but lets not expand this argument. But, with progressives, you have a multitude of filters to arrange, and is becomes less likely each will be "very large".

So: the alternative.

First filter: a "very large" 2 micron filter. 98% efficient at 2 micron, actually more, since the specific flow rate per unit media is low. The ability to accommodate more 100 micron particles is greater than the progressive, since I now have room for a larger filter.
Second filter; Another, of the exact same filter.

Engine filter: should need changing now once per millennium. Exaggerated, but you get the idea. It doesn't really have much to do. Plus, it shakes too much to trust for the small stuff anyway.

benefits; Stocking only one type of filter at sea. No guesswork required to figure out which filter is clogged. Plus, no excuse not to monitor that lead filter, its' the one. Better filtering; not relying on the on-engine filter. Water sep will be better with the large filter, that's an argument again related to speed of the fluid at the media, and the size of the system, below the media, to hold the water.

Click to expand...

By all means do whatever you like - I suggest that if your engine(s) are still under warrantee that you follow your manufacturers specs until they expire.
Which engine(s) do you have?

smitty477 said:

I do not think I locked in on anything - in each case it was the manufacturer or the filter provider that did the work and provided the solution.
I have never gotten the impression that any of these manufacturers or parts providers were aiming for overkill. Overall ease of use, safety, and length of service while considering costs is the aim - IMO - my summation of reading the articles.

Click to expand...

Yes you are, I never said those engines under manufacturer recomnendations...and the way they are installed in some boats.

I kept it simple, gave a direct case and why.

I didnt go back, but I think I did say I would have progressive filtration if I routinely refueled from questionable sources or couldnt keep my fuel clean.

Whatever......my comments are not directed at those already doing it but those that might get worried when they are not. Knowing they dont need to be if certain conditions even the provided articles refer to is my point. If they stay wioried, your suggestions are great.

"I agree that an improved fuel system would be a great goal - but in most every case there would be large amounts of time and money to implement the changes.
In this post most all of these fuel filtering choices are very simple and quite cheap to employ."

The question then becomes are you one of the 1 in a few hundred that are going to head out offshore , where Sea Tow can't come with a rope?

In my dreams even inshore boat first purchasers would refuse a boat with out a real fuel tank.

Even the inshore folks would enjoy the time and cash ,NOT spent in attempting to have clean fuel 100% of the time.

"Even the inshore folks would enjoy the time and cash ,NOT spent in attempting to have clean fuel 100% of the time."

- twin engines with twin tanks
- do not travel off shore
- time and costs for staged filtration is minimal
- have completed about 30,000 nmiles so far without an issue

"The question then becomes are you one of the 1 in a few hundred that are going to head out offshore , where Sea Tow can't come with a rope?"

Around here the stats on who really heads 'off shore' is maybe 1 in 10,000 I am not sure about other locations.

diver dave said:

I'll elaborate on my theory that progressive filtering is counterproductive.

So: the alternative.

First filter: a "very large" 2 micron filter. 98% efficient at 2 micron, actually more, since the specific flow rate per unit media is low. The ability to accommodate more 100 micron particles is greater than the progressive, since I now have room for a larger filter.
Second filter; Another, of the exact same filter.

Engine filter: should need changing now once per millennium. Exaggerated, but you get the idea. It doesn't really have much to do. Plus, it shakes too much to trust for the small stuff anyway.

benefits; Stocking only one type of filter at sea. No guesswork required to figure out which filter is clogged. Plus, no excuse not to monitor that lead filter, its' the one. Better filtering; not relying on the on-engine filter. Water sep will be better with the large filter, that's an argument again related to speed of the fluid at the media, and the size of the system, below the media, to hold the water.

Click to expand...

Sounds like just another form of progressive filtering...

-Chris

ranger42c said:

Sounds like just another form of progressive filtering...

-Chris

Click to expand...

The conclusions here are a result of reading one grad students 2010 research paper from India. The summary conclusions that are listed suggest mounting the filter off of the engine to avoid vibration. These were a result of particular counts and had no relationship to actual engine performance or filter life.

The suggestion above is for serial filtration and to avoid staged filtration.
Suggest the thoughts presented and their sources be compared to the sources and thoughts of the rest of the diesel user community.

ranger42c said:

Sounds like just another form of progressive filtering...

-Chris

Click to expand...

Well, still clearly "multiple" filters. My notion of "progressive" is the design where you are targeting filter media to trap, in sequence, large, medium, then small particles. To make my position clear, I see benefit in multiple filters of the correct sizing, but see no benefit in a cascade of ever decreasing sieve sizes in our use cases.

Now, this is not the case for every motor, fuel pump, etc. In the case of a car, with an in-tank pump, you may need to protect it with a coarse filter, and then a finer filter after the pump to protect the injectors. You don't want a fine filter in-tank, due to access issues. But, in the case of a series string of filters mounted in a ER bulkhead, I see no need for this madness.

Obviously, you don't NEED to, and it can work either way. After all, even a plow anchor works sometimes.

smitty477 said:

The conclusions here are a result of reading one grad students 2010 research paper from India. The summary conclusions that are listed suggest mounting the filter off of the engine to avoid vibration. These were a result of particular counts and had no relationship to actual engine performance or filter life.

The suggestion above is for serial filtration and to avoid staged filtration.
Suggest the thoughts presented and their sources be compared to the sources and thoughts of the rest of the diesel user community.

Click to expand...

I will say it is curious that you need to go to a student to get real data. But, then, Racor is not anxious to publish data that indicates filter weakness. And, I suspect the big players are perfectly happy with their customer base buying lots of different size filters, and changing them frequently due to poor engineering filtering design. That's "filtering" design, not "filter" design. I am not targeting issues with the actual filters.

diver dave said:

I will say it is curious that you need to go to a student to get real data. But, then, Racor is not anxious to publish data that indicates filter weakness. And, I suspect the big players are perfectly happy with their customer base buying lots of different size filters, and changing them frequently due to poor engineering filtering design. That's "filtering" design, not "filter" design. I am not targeting issues with the actual filters.

Click to expand...

Please tell us which engine(s) you are contemplating this application for? There are likely specific sites of folks that deal withy these exact applications. Are they 'secret' engines?

Perhaps do what most of the big player articles say which is not this - "And, I suspect the big players are perfectly happy with their customer base buying lots of different size filters, and changing them frequently due to poor engineering filtering design"

- Use your existing on engine filter at the specified mic rating, usually common and mostly economical (no $$ added)
- Use your existing secondary filter ate the specified rating usually common and mostly economical (no $$ added)
- If you want to increase capacity and safety add a third bulk filter inline , usually cheaper than the existing filters and will increases life and holding capacity by 10X or more easily.
- If you want to know how each filter is really doing add a vacuum gage at each filter for about $20-25 each. This will add life, safety and a diagnosis element for likely less than $100.

"But, then, Racor is not anxious to publish data that indicates filter
weakness"
I am not a personal fan of Racors but if you run any filters the way you are planning you will be using many more filters than is needed - just what you say you want to avoid.
Buying filters of varying mic ratings do not add expense- changing filters less often saves time money and is mush safer.