Fuel Filtering System

Discussion in 'Diesel Engines' started by SeaJay, Nov 22, 2010.

  1. sabahcat
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    sabahcat Senior Member

  2. Stumble
    Joined: Oct 2008
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    Stumble Senior Member

    A few more things...

    1) When referring to Racor filters I used the term in a generic sense. Personally I have a filter set up from a commercial filter supply company that cost me pennies on the dollar compared to a name brand system.

    2) The Algae-X and its ilk really are nothing more than advertising gizmos. They don't do anything, and while most of them also don't hurt anything, relying on something like that is asking for trouble.

    3) A proper fuel polishing system should do three things: 1) move enough volume of fluid to agitate the fuel tank while operating. There is no hard and fast rule on this, but roughly it should be able to cycle the entire tank in no more than an hour (for a pleasure boat). 2) Filter out solid contaminates from whatever source. These filters do not need to be as fine as an engine filter. Personally I use 30 micron filters for this, but smaller will never hurt (so long as the pump can still move enough volume). 3) They need to remove water from the tank.
     
  3. FAST FRED
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    FAST FRED Senior Member

    Many fuel problems would be solved with a genuine vessel fuel tank, instead of a box of fuel.

    A proper drainable water sump in the tank would go a long way to fewer engine stoppages.

    FF
     
  4. mark775

    mark775 Guest

    "A proper drainable water sump in the tank would go a long way to fewer engine stoppages." - Hear, Hear! (Though I, on my boat, would just put the pick-up in the sump and water would never accumulate)
     
  5. SeaJay
    Joined: Jun 2007
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    SeaJay Senior Member

    Mark,

    Thanks for the link to the PS article.

    Sabahcat,

    Now we're talkin! I saw the Griffin's on the web but wasn't sure that how closely they matched the Racors. The duplex set up saves about $250 over the Racors although that's for the non-marine models.

    Fred, et al

    You bring up an interesting point about a sump in a fuel tank. I've wondered myself why this isn't a standard feature. Which brings me to another couple of questions I'd like to ask.

    I wasn't paying close attention when I ordered the Moeller 52 gal. wing tanks, and when I received them I noted that they had 1-1/2" FPT inserts on one side of the tank, close to the bottom. I wasn't excited about having a hole in the bottom of my tank, but they were designed that way and it was my mistake for overlooking the fact in the first place...so now I've got to live with it.

    As these are OEM tanks I guess someone had a reason for requesting the inserts but I'm wondering if they couldn't be used to assist in cleaning the tanks? Any ideas?

    Also, Moeller has recommeded using a plug with Slick-Tite sealant to close the inserts. Does anybody have any experience with Slick-Tite or have other sealants / remedies they would recommend?
     
  6. mark775

    mark775 Guest

    I have installed rectangular tanks with an ever-so-slight fall towards the pick-up with the boat at rest. It's not as good as a sump but better than having a fall in another direction.
    I have used every manner of stuff on pipe threads, even stuff said to be used on nuclear submarines. Nothing I have ever used works as well as this: http://www.simyamaha.com/Leak_Lock_Pipe_Thread_Sealant_p/10004.htm and they just happen to have a great price at the first place I looked for a link to show you!
     
  7. SeaJay
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    SeaJay Senior Member

    Mark,

    I checked out Lock Leak and your opinion seems to be shared by a lot of other guys with experience in a number of different fields...good enough for me, so I ordered up a can. Thanks for the tip!
     
  8. kapnD
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    kapnD Senior Member

    Sea Jay,
    There is some really relevant reading on the subject of fuel filtration on boatdiesel.com. It costs $25 to read there, but if you are designing your own systems, it is well worth it.
    I have installed the same Fleetguard dual filtration system Mark showed us. It is far superior to my old racor 900's, as evidenced by zero fuel problems in the 4 years I have run it. I always cut open my used filters for inspection, and my final on engine filter has been immaculate.
    Consider yourself fortunate to have the 1 1/2" fittings on the bottom of your tank, and create some access to them. At some point down the road you will want to drain/flush
    the tanks. You shouldnt worry about leaks, as long as you use proper sealant. l (I like Rector Seal) There is no pressure in the tank to force the fuel out, and common pipe fittings are designed to hold at least 150 psi.
    Your fuel polishing system strikes me as a bit of overkill on such a small capacity, but certainly wont hurt anything besides your wallet.
     
  9. michael pierzga
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    michael pierzga Senior Member

    You would think that the poor Boys fuel polisher on a diesel would be a day tank that is partially topped off by the engines return line. You would have to make sure that the return fuel in the day tank did not get too hot... Return fuel is very clean, when you dump this clean return fuel back into the main tank, it becomes contaminated again and then you must filter it twice.

    Ive often asked..but the engineers say No No No... return fuel is too hot...I say,cool it...but they never listen. Oh well...pass the box of racors.
     
  10. SeaJay
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    SeaJay Senior Member

    kapnD - You are right about the fuel polisher being a bit of overkill for this engine, but it was a surplus unit from a builder of large yachts that they didn't want to take when they move their facility next year. I got it for about half price and as it has a good gear pump, I'll also use it as my fuel transfer pump as well. It is a 24v system which was the tipping point for me to jump to 24v for the house bank which I think is going to work out well.

    I like what you said about the 1-1/2" inserts, I'm starting to feel the same, but haven't quite figured out how to put them into use. As stated earlier, they are on the sides of the tank with the center of the insert about 3 inches above the bottom of the tank. (here is the actual tank)

    http://www.moellermarine.com/sites/moellermarine/files/FT5219S-R2.pdf

    As you can see, the bottom of the tank slopes sharply downward towards the level of the insert so I guess it is really forming a natural sump. I'd like to plumb in some sort of pick-up tube and valve so that I can seal everything up tight and not have to disturb it later and so it is ready to go when I need it. However, I'm not sure what I actually need. The regular pick up tube goes down to about the same level, so in order to gain some advantage, it seems to me that I need some sort of collection pipe that reaches right to the very bottom. One thought I had was to use the inserts to connect the two wing tanks with an 1-1/2" pipe so to that I can fill both wing tanks from either side of the boat. I haven't quite figured out how to fit that pipe into the engine compartment but I suppose it could be done. I'm VERY open to suggestions!

    Michael - The comments you've received about returning hot fuel from the engine to the day tank suprised me. Gerr specifically recommends returning the fuel to the day tank and says nothing about it being too hot. (He also cites a "rule" about always returning to fuel to the source tank.) If you didn't return to the day tank, you really don't have a day tank, you've got about a 2 hour tank;) However, cooling the fuel is a good idea and with the location of my day tank, some sort of fin cooler could be added without too much trouble. I'll look into this, thanks.
     
  11. michael pierzga
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    michael pierzga Senior Member

    I guess the idea is to be aware that return fuel is HOT. many times shipyard engineers are afraid to approve anything that has not been examined by the guys " upstairs ".
     
  12. mydauphin
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    mydauphin Senior Member

    I have seen fuel coolers/warmers on lines going into engines installed after the filters. Not really sure if the main reason was cooling or warning it up, I guess it could go either way.
     
  13. mark775

    mark775 Guest

    I think they were for cooling.
    Seajay, pardon me but I'm not getting a couple things here...
    What are the little black squares on the side of the tank, the center of each pair being 2" and 8", also at 2.25" and 6.25" on the other side of the tank, at 1.25" ? The drawing says "2 Typ" (Typical?) but that is no clue to me.
    And, what is the "doghouse" for ?
     
  14. SeaJay
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    SeaJay Senior Member

    The little black squares are inserts for mounting brackets. Kinda lame as far as I'm concerned. I'm planning to use a more conventional strap hold-down device.

    I have no idea why the fill neck enters through the "doghouse" or what purpose it serves. However, since that's where I spend a considerable amount of my time, I guess it's a good idea to have a couple on the boat:D

    These tanks are OEM units and I have no idea what boat they were originally designed for. They were one of the first items I nailed down, and to a large extent, worked the design around them. If anybody ever needs to replace them, they can be removed without the use of a chainsaw. It won't be a painless task, but no fiberglass will fly.
     

  15. sabahcat
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    sabahcat Senior Member

    We must have done something wrong with ours

    At the rate that fuel flowed through them, it would have taken hours to filter a 44 gallon drum of diesel

    We checked the first 5 litres to ensure it was clean and then let her rip and let the racors sort out the rest
     
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