Fuel Filtration Systems

[Dockhead]

Originally Posted by Wotname

All worthwhile points PLUS
Have a day tank (say 12 to 24 hours of fuel) that is gravity feed to the engine and filled from main tanks via normal filters and electric transfer pump. This should ensure engine is only getting clean fuel. Also makes bleeding easy due to gravity feed and decreases problems on minor leaks (fuel leaks out rather than air getting sucked in). If one does has a have a main tank problem, one should have quite a few hours to resolve it before day tank is dry.

I also strongly endorse Dockheads sump drain. I use mine regularly and it is nice to know that there is no water / crud building up in the tank. Takes all of 15 seconds to drain off a sample. Please note that ALL aircraft fuel tanks have drain sumps and these are drained at daily inspections and after every refueling.

I forgot to mention the day tank.

If you want a 100%, sure fire and total solution to fuel problems, a properly installed day tank is it. Much more useful than fuel polishing.

The day tank should have its own sump, preferably glass or with a glass port in it, should have a sight glass, should be very accessible, and should be capable of being opened up in minutes.

As Wotname said, eliminates air leak problems, priming problems, etc. Fill it and drain its little sump every day as part of your startup checklist. In an emergency, you can just dump your emergency jerry tank into it.

This the killer app for fuel management. I can't believe I didn't think to mention it. If I were building a custom yacht from scratch, I would certainly include this -- inside the walk-in engine room, on the bulkhead next to the workbench

[leftbrainstuff]

Originally Posted by gts1544

Gentlemen:

On our Perkins 4-108 powered 41' Beneteau in the British Virgin Islands (read warm and moist), we currently have a 30 micron Racor 500 filter as the Primary and the Perkins #26561117 as our Secondary (Microns unknown). We do use Biocide with every diesel fill, but still have some contamination in the tank, which ultimately clogs the Racor after time. My question is whether I should go to the 10 micron Racor element to better protect the secondary filter or whether I should stay with the 30 micron so as not to have to change it so often? Any advice would be appreciated! gts1544 - George

Anytime you're clogging filters its time to clean the tank. If you're using biocide and still having problems then a tank clean is due.

Once clean the best defence is to use your fuel and refuel from a known high volume source where the fuel is fresh. No easy task when cruising.

Nobody ever got in trouble for polishing their diesel too much.

We run 3 stage filtration. Racor 500s primary with 30 micron, then our elec lift pump is a Racor P series fuel conditioning module with 10 micron. Our tertiary filter is a 2 micron on our Perkins 4-236 and generator.

We polish our fuel weekly and also polish anytime we transfer between tanks.

Each year I inspect the inside of the fuel tanks. I remove any contamination after emptying the tank by transferring fuel to another tank.

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[leftbrainstuff]

Originally Posted by Dockhead

Of doubtful value considering the small volume of air which can "breathe" through the vent. There were calculations made by people posting on this in other threads, showing the vanishingly small volume of condensation possible from tank breathing.

This fact was also used to debunk the myth that full tanks attract less water than empty ones. I believe MaineSail posted some really good factual data on this, IIRC.

Most of the condensation anecdotes relate to truck fuel tanks. Well known problem in the military where tanks experience large temperature changes in hot and humid areas. Vehicles in humid areas not used are the worst case scenario. This is why the military keeps their tanks fuel. Mil Std 810 is the bible here.

I logged temperature on our boat and found less than 2 deg temp diff adjacent the fuel tanks. I haven't done the math but water accumulation through breathing will be 2nd order at best. (aka insignificant and supportive of Mainesail's hypothesis)

Most water would be ingested while filling or from contaminated sources.

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[leftbrainstuff]

Originally Posted by sailorboy1

As a water treater who also deals with the water in fuel tank issue in industrial installations I disagree. The volume of air/water isn't really an issue, the issue is that it exists and happens.

But believe whatever you want.

And what are the temperature deltas in these industrial installations? At least a magnitude difference by my calcs.

Thermal expansion of the tank and contents is what makes them breath. You rarely see that same temp diff in yachts with bilge mounted fuel tanks.

The newly ingested humid air then condenses leading to accumulation of moisture over time. Keeping the tanks full minimises the quantity of humid air ingested at each cycle. See Mil Std 810 for details. I forget the actual Mil Spec for marine diesel which covers this issue. Water ingestion is proportional to humidity and air space volume.

This was also proven independently in motorsport fuel quality analysis by me back in the 80s when we would source our pump fuel based on maximum heat capacity. I dont have the data anymore.

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[leftbrainstuff]

Originally Posted by SailRedemption

I ordered the Fleetguard "Double Double" dual setup from Seaboard Marine

http://www.sbmar.com/smx-fueltration.php

Their filters stop water from passing where from what I read Racor doesn't. They hold more contamination and are dual stage. Also they come with vacuum gauges from Designated Engineer.

Here's my set up before I mounted it in the engine room..

Attachment 102306



- Ronnie...on the geaux

The racors separate water by density. They use centrifugal force the same as a centrifuge but at very low flows.

Note emulsified fuel wont seperate water which can pass through the racors.

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[Wotname]

Re the day tank; I don't even like the name, I prefer to think of it as "just your fuel tank" like it is in a car say. The other tanks on board should be considered "storage tanks" and you refill your fuel tank from your storage tanks (again just like your car).

Set up your storage tanks as such and set up your fuel tank (day tank) accordingly. While they share some similar requirements, they also have different needs to be best practice.

Is there any downside to using a day tank (apart from say space or cost). I have never been able to think of any downside but perhaps others know more than me .

[darylat8750]

A few comments.

My old Lehmans return very little fuel to the tank.

An aux fuel pump ($65) and a refurbished Racor 900 from EBay ($130) and some marine grade fuel line, fittings and some wire and a switch ($80 +-)was all it cost to plumb from the bottom sump of two tanks through the Racor 900. I can draw from either sump.
Then I can send the fuel:
1. To each engine via individual Racor 500s plus the engine mounted filters.
2. To either fuel tank

So I can run one engine from its normal tank feed and run the other tanks fuel through the big filter before the smaller filters. Or run both engines off either tank if I get bad fue in one side. Or pump fuel from a sump and return it to either tank. I keep a case of 30 micron filters and a case of 10 micron filters and several 2 micron filters for the 900 and several 10 and 2 micron elements for the 500s. Maybe overkill if you never buy fuel in third world places..... One bad load of fuel will make you a believer.

One other point. My engines are supposed to be able to deal with any particle smaller than 10 micron. A 10 micron filter will not stop ALL particles larger than 10 microns. They only have to stop a certain percentage (I don't recall exactly but I think it's around 97 percent.). Good reason to filter the fuel more than once.

[dohenyboy]

http://www.sbmar.com/articles/marine..._seaboard_way/

Good article


Why can't things remain where i carelessly left them?

[Nicholson58]

Originally Posted by noelex 77

Do you mean Raycor fuel filters? (Diesel is called diesel oil in some languages which can be a bit confusing)

The larger Raycor fuel filters like the 500, 900 etc have a plastic tab that can be punched out in an emergency to bypass a blocked filter. This cannot happen without a deliberate action. They also have a water check valve that will cut the flow with water in the bowl. As far as I aware there is no internal bypass relief valve.

If I have this wrong, or if it different on the smaller spin on filters it is important for owners to know. Could you elaborate?

These are my Racor filters (Note - not raycor). I disassembled all of these and the spare. There is a bypass ball check. It passes oil (fuel) when the element becomes sufficiently plugged or if the ball check is faulty.

Also note the newly installed Franz bypass filter on the 12 KW generator. (Shiny can above the generator). No hoses yet. This will divert a small stream of crankcase oil from the pressure sender to the filter and return to the crank case pan. The bypass filter is 1 micron. I am also installing one on the main engine and another on the fuel system. This is another maker of bypass filters. Gulf Coast Filters, Inc. Specializing in Bypass Oil filters, Fuel filters, Hydraulic filters and Custom filtering

Some people also install "spinners" for cleaning. This is a compact centrifuge for fuel or oil

[socaldmax]

Originally Posted by Badsanta

Very interesting read, but some thoughts. The Baja filter is great but will not separate water from fuel. If you add any treatment to your fuel that has an emulsifier in it water will not be separated with a filter funnel or your racor. I have the racor 500 on my boat and feel the the water separator is fairly useless with my 3/4 gallon an hour use. Maybe at 40 gallons an hour but not my boat. In my humble opinion I feel that most fuel gets contaminated from sitting sometimes for years or from low use marina fueling stations.

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You use the Baja filter when pumping fuel from a dock or other sources into your boat. I just tested mine in the sink, filled it full of water and not a single drop came through.

If you put an additive in, it will probably be into your tank, not before the Baja filter. I don't use emulsifiers, I wouldn't recommend anyone else use them either. Just a cetane booster with biocide, lubricity and stabilizers.

[noelex 77]

Originally Posted by Nicholson58

There is a bypass ball check. It passes oil (fuel) when the element becomes sufficiently plugged or if the ball check is faulty.

The only bypass ball check I can find in the Racor turbine series is the hollow aluminium check ball. This floats up against the seal when the fuel is stopped, thus preventing fuel bleed-back. As I understand, it also floats up to seal in the presence of water in the bowl.

I think you are misunderstanding the function of this valve. It cannot let fuel pass when the element is blocked.

This diagram makes it a bit clearer:




If you have one of these filters make sure you take a look at Maine Sail's excellent rebuild instructions:

Rebuilding A Racor Turbine Filter Photo Gallery by Compass Marine How To at pbase.com

Nice engine room BTW .

[Nicholson58]

Originally Posted by Dockhead

That looks pretty good. Is that a rubber cap over a screw-in o-ringed cap? So a double cap? If so, then that plus standing well proud of the deck would probably be ok. Downside would be stubbed toes and snagged lines.

I believe you are right to question the deck filler port as a likely water source. I always doubted condensation as serious. It has been 6 years since I cleaned the tank interiors. I just dropped a thief into my primary tank and found no water whatsoever. We have also never found any water in the Racor bowls. We are in Michigan with wild temperature swings. Our Marina, Torresen's, is a known diesel service & rebuild center with many years of operation, several really old guys with more experience than I will ever have. In their spring diesel clinics for boaters, Gordon Torreson has stated emphatically that most water enters you tanks form the deck port due to poorly seated fittings or cracked, dry O-Rings. They used to offer free O-Rings to their regular customers.

There are new above flush fittings as you show that help prevent this source.

[Nicholson58]

Originally Posted by noelex 77

The only bypass ball check I can find in the Racor turbine series is the hollow aluminium check ball. This floats up against the seal when the fuel is stopped, thus preventing fuel bleed-back. As I understand, it also floats up to seal in the presence of water in the bowl.

I think you are misunderstanding the function of this valve. It cannot let fuel pass when the element is blocked.

This diagram makes it a bit clearer:




If you have one of these filters make sure you take a look at Maine Sail's excellent rebuild instructions:

Rebuilding A Racor Turbine Filter Photo Gallery by Compass Marine How To at pbase.com

Nice engine room BTW .

Thanks for the flow diagram. I hope that you are correct. Next Racor cleaning I will study the porting with this in mind. I naturally have my doubts because I build & specify hydraulic servo systems. The bypass check is the standard format for almost all filters in the business. We have to specify non-bypass types to prevent damage to servo valves.

The flow diagram also points out a flaw in the Racor system as we normally use it on a boat. Generally, the flow rate is insufficient for the turbo section of the device to be properly efficient. I am trying to resurrect the link to the article I read as I researched the bypass filter system we are now installing. The bypass loop has a pump that passes 40 to 50 gallons/hour. Typical fuel consumption on a boat is 1-4 GPH. If the polishing bypass loop is added to the Racor circuit then the flow through the Racor will be about 10X. This is enough to make the turbo effective.

The facts for sailboats is that we use small amounts of fuel over a long period of time. Fuel may be in our tanks for months or years. The places we buy fuel may likewise have long turn-over periods and the storage facilities may not get a regular cleaning either. Any fuel tank issues are accentuated due to this. Over the road trucks, commercial trawlers etc. have a very short tank residency & high turn over. The short of it is we probably have the worst possible fuel of any users & utilize the least effective cleaning system.

Read the links & testimonials here & do your own research on these. I found my way onto the Trawler's & trucker's forums where bypass filters are commonplace. If I ever find the detailed article on this showing proposed flow diagrams I will post the link.
Turbo Diesel Registry Magazine

[noelex 77]

Yes, I think it is widely acknowledged that at the rate our yacht engines are pumping fuel, the "turbo" action is not doing anything.

However, the design still works well allowing the water and heavier particles a chance to fall to the bottom before passing through the filter.

A bypass system with a pump would certainly make the swirling action work better. I still like the idea of a completely separate polishing system. That way if there are no extra joints to let in air and the polishing filter gets clogged it does not effect the main engine. (Does this apply to a bypass system? It is not clear)

Importantly the polishing pickup can also be from the very bottom of the tank where the water and crud will collect.

I also wonder at the high flow rates with a bypass system if the water is emulsified into the fuel more?

[Kenomac]

Maybe so. I've been polishing our fuel once per week times a total of two months with a nine month gap until two weeks ago. I've never seen any water at the bottom of the polishing filter bowl. I have yet to change a filter. The system polishes 150 gallons per hour.