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LionessRacing

Fuel polishing systems onboard

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Colleague is the sudden owner of a twin diesel trawler after FIL passed. Lehman 135 Engines have 260 hrs on an '80's boat.  Two Large tanks are full, diesel of unknown vintage.

 

 Recommended biocide, and looking into polishing based on personal history with old diesel. 

 

Anyone have experience with on board polishing systems ? 

Current setup is twin large Racors with secondary filters on each engine, boat ran fine from KKMI down to Pillar point about a year back engines run for 10 min since. 

 

 

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Installing an onboard polishing system is dumb.

Plenty of fuel is circulated endlessly when the engines are running. The return lines should be returning nearly all that the pumps move. All this is passing through both the primary and secondary fuel filters and back to the tank.

Paying someone to polish your fuel is even dumber. Shoving a hose down the fuel filler has a high chance of doing nothing and a low chance of doing everything. Your mileage will vary but the cost is stupid given the results, which are random at best.

Instead, if you're really concerned, open the inspection ports and look inside. If you have a problem, you'll know in a few minutes and the solution will become obvious based on what you see.

 

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Ford Lehmans are not GM's Cats, Cummins, very little goes back to the tank from any engine with an inline or DPA pump

pull a return line off and teach yourself

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Given the historic and probable future light use, an in situ system that was timer driven might make most sense. On Lioness, we might go a few seasons on 45 gallons unless cruising.  For a boat that's most likely going to be a marina cottage with occasional trips, the storage of hundreds of gallons is an invitation to fostering crud. 

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Easy enough to buy a Facet 12V fuel pump and a couple of valves, and plumb them into your fuel circuit, bypassing the engine.You can then polish the fuel for as long as you like. The pump draws very little current.

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On 6/18/2017 at 10:53 AM, Moonduster said:

Installing an onboard polishing system is dumb.

Plenty of fuel is circulated endlessly when the engines are running. The return lines should be returning nearly all that the pumps move. All this is passing through both the primary and secondary fuel filters and back to the tank.

Paying someone to polish your fuel is even dumber. Shoving a hose down the fuel filler has a high chance of doing nothing and a low chance of doing everything. Your mileage will vary but the cost is stupid given the results, which are random at best.

Instead, if you're really concerned, open the inspection ports and look inside. If you have a problem, you'll know in a few minutes and the solution will become obvious based on what you see.

 

To use your words, that's dumb.

The idea is to avoid clogging your filters underway.  Off a lee shore or in a tight channel with tide and wind, you don't want to starve an engine.

An onboard polisher makes good sense if you don't use the boat often and if you lack access to scrub the tanks by hand.

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From my experience, fuel polishing can keep clean fuel that way but can't clean a dirty tank, especially one with sludge at the bottom.

If your filter keeps getting clogged, chances are there's crud at the bottom of the tank, which will decide to get stirred up at the worst possible time....

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Polishing fuel is dumb.

Fleetwood has it exactly right. If the problem is dirty tanks, that dirt is not in suspension and no amount of filtering of fuel is going to clean the crap that's accumulated on the walls of the tank. If you're concerned about sloshing fuel knocking this stuff loose and clogging your filters, then you need to polish the walls of the tank, not polish the fuel inside.

And the only way to polish the walls of the tank is to remove the fuel, open the tank and scrub it clean.

Anyone who tells you they can shove a tube down your fuel fill pipe and effectively clean the tank is selling you snake oil.

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13 minutes ago, Moonduster said:

Polishing fuel is dumb.

Fleetwood has it exactly right. If the problem is dirty tanks, that dirt is not in suspension and no amount of filtering of fuel is going to clean the crap that's accumulated on the walls of the tank. If you're concerned about sloshing fuel knocking this stuff loose and clogging your filters, then you need to polish the walls of the tank, not polish the fuel inside.

And the only way to polish the walls of the tank is to remove the fuel, open the tank and scrub it clean.

Anyone who tells you they can shove a tube down your fuel fill pipe and effectively clean the tank is selling you snake oil.

Absolutely correct. Open the tank. Look inside. Clean it out. Polishing is a worthless scam.

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I agree that scrubbing the tank is the best option if you have access to the tank.  That is what I do.

Good professional fuel polishers use high pressure nozzles to knock loose stuff off the tank sides/bottom.  Depending on access and baffle configuration, that can be effective, but only second best.

An onboard polishing system can be run when seas are rough and crap is being suspended in the fuel.  That can remove much of it before the primary and secondary filters clog.  Third best.

Worst:  All the suspended crap shuts off your fuel supply in Seymour Narrows/Wrangle Narrows/Sergius Narrows.

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" Worst:  All the suspended crap shuts off your fuel supply in Seymour Narrows/Wrangle Narrows/Sergius Narrows."

 

Woods Hole was exciting enough... 

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On 6/18/2017 at 0:16 PM, LionessRacing said:

Colleague is the sudden owner of a twin diesel trawler after FIL passed. Lehman 135 Engines have 260 hrs on an '80's boat.  Two Large tanks are full, diesel of unknown vintage.

 

 Recommended biocide, and looking into polishing based on personal history with old diesel. 

 

Anyone have experience with on board polishing systems ? 

Current setup is twin large Racors with secondary filters on each engine, boat ran fine from KKMI down to Pillar point about a year back engines run for 10 min since. 

 

 

Well, sorry to have not checked into this thread sooner. I owned a trawler with a Ford Lehman 135 and cruised in it for over ten years. Fine engine, easy to care for and keep running. 'Sailabout' is correct, they return very little fuel back to the tank so they will not recirculate fuel thru the filters as the engine is running.

Fuel polishing- lot of misconceptions out there. Fuel "polishing" is a bit different from recirculating the fuel thru a filter, which is what most "polishers" do. To "polish" the fuel a very high flow rate is set up across the tank, with a multi-stage seperator & filters. When combined with opening the tank and using a wand to direct fuel into the corners, around baffles, etc etc, it is very effective. Most people who say "fuel polishing sucks" have never seen it done correctly. They are right, a feeble attempt at recirculating fuel and calling it "polishing" is dumb.

Step 1- install the filters in a place where it is easy to change the filter elements correctly. Do not use the screw-on canister type, get the best: Racor 500 Filter/Seperator with the clear bowl & drain & catch basin.

Step 2- get a case of 2 micron filter elements and don't be shy about changing them. Most people act like changing filters is some kind of big deal, it s far easier than rebuilding the injector pump or salvaging the vessel off a lee shore.

Step 3- install a bypass and fuel pump to recirc fuel thru the filter/seperator. It doesn't need to be a big pump but even 10~15 gph will get most of the water and crud out of the tank over the course of time.

If your goal is to have minimum down time, minimum drama and hatred, then this is the way to go. Adding chemical shit to the fuel is bad for the engine. Adding shit to the fuel to save yourself the labor of changing filters is fucking retarded. You can stop at Step 2, I added a recirc/booster pump to our trawler which enabled me to recirc the fuel, transfer it from tank to tank, and use it to 'boost' fuel to the engine or genset or heater when needed, priming suddenly became a total breeze. But we cruised for 6 years without it, it's hardly necessary.

BTW I was a fuel boss in the Navy and have dealt with different kinds of fuel systems on a professional level for decades, most of the advice so far in this thread is in the 'old wives tale' category. Diesel fuel has a precipitate but if it is kept clean and recirced even a little bit, it can last for years. The Navy does not throw fuel away and they have millions of gallons of it laying around for decades, hint hint!

Good luck and if any more questions, don't hesitate.

FB- Doug

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On Blurocket IV we could route fuel from any tank to any other, through all the filters.  3 main tanks plus a gravity-feed day tank, which I'm a big believer in.

All this came in handy a few times, after buying bad fuel in the middle of nowhere.  Otherwise things were clean, because we were careful where we bought fuel.

On my watch, someone (not me!) put a couple hundred gallons of water into the fuel tanks.  The only choice, really, was to call the fuel polishing service, who did it for about the same cost as a fill-up.

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12 hours ago, blurocketsmate said:

On Blurocket IV we could route fuel from any tank to any other, through all the filters.  3 main tanks plus a gravity-feed day tank, which I'm a big believer in.

All this came in handy a few times, after buying bad fuel in the middle of nowhere.  Otherwise things were clean, because we were careful where we bought fuel.

On my watch, someone (not me!) put a couple hundred gallons of water into the fuel tanks.  The only choice, really, was to call the fuel polishing service, who did it for about the same cost as a fill-up.

 

Maybe they were trying to ballast the tanks?

The literature on the seperator/filters says that you need a lot of flow to get the "turbine elements" of the seperator to work. That may be true but I have found that water seperates out in the bowls pretty nicely at low flow rates too. It just doesn't hold much water, so you need to be able to drain it effectively if you have a lot of water in the tanks. BTW I left our 300gal fuel tanks about 1/4 full this past winter, despite all the warnings that this would result in a lots of water condensing into the fuel, I have seen none at all. I changed the filter element before going on a little cruise last week, water can turn the filter elements to mush plus it had been long enough to need checking. A little dirty but could probably have gone another few months/hundred+ gallons flow thru.

+1 on gravity feed from a day tank. Takes up some interior room though.

FB- Doug

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9 hours ago, Steam Flyer said:

 

Maybe they were trying to ballast the tanks?

The literature on the seperator/filters says that you need a lot of flow to get the "turbine elements" of the seperator to work. That may be true but I have found that water seperates out in the bowls pretty nicely at low flow rates too. It just doesn't hold much water, so you need to be able to drain it effectively if you have a lot of water in the tanks. BTW I left our 300gal fuel tanks about 1/4 full this past winter, despite all the warnings that this would result in a lots of water condensing into the fuel, I have seen none at all. I changed the filter element before going on a little cruise last week, water can turn the filter elements to mush plus it had been long enough to need checking. A little dirty but could probably have gone another few months/hundred+ gallons flow thru.

+1 on gravity feed from a day tank. Takes up some interior room though.

FB- Doug

See this about tank condensation:

http://www.pbase.com/mainecruising/fuel_tankt_condensation

 

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Maine Sail knows his shit in most things but this post was flat out wrong. The tank wasn't held at a cooler than ambient air temperature, among other things, so it wasn't a valid experiment.

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He's had the test tank in pretty cold conditions, and simulated in-boat conditions. Agree, its a quick and dirty experiment (went on for a couple of years tho') but no condensation is suggestive. Steam didn't find any water in his tanks, nor have I ever seen much in our tanks (but we live in a warm climate).

Basic physics suggests a similar result. Vapour pressure of water is about 0.02atm, which gives about 0.02ml/l of water at 100%RH. So an empty 100 litre tank will contain about 2ml water (at 100%RH.) Have to be a hell of a lot of very humid air circulation to put an appreciable amount of water in a tank!

Most water in diesel comes already in the fuel.

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10 hours ago, IStream said:

Maine Sail knows his shit in most things but this post was flat out wrong. The tank wasn't held at a cooler than ambient air temperature, among other things, so it wasn't a valid experiment.

? Remember the delta-T of the tank and the surrounding atmosphere is not the same. Sure, the tank will equilibrate to ambient, but anytime temperature changes....... for exxample when the morning is warming up from the sun...... the tank will be colder than ambient. And theory suggests water which condenses in the tank will not evaporate back out. But practice suggests that there is very little, if any. Yet you hear all kinds of very strident advice about condensate in tanks being a yu-uge culprit in diesel engine failures.

This is not to say that water in fuel doesn't suck. It really does. But it's relatively easy to remove and it doesn't come from condensation. At least they don't mix ethanol into diesel.

FB- Doug

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tip from buying a MB car that sat a few years and had a thick bug coat in the tank/intank filter was black with the bug goo

startron bioside  tank cleaner is the same as the fuel conditioner and cheaper in the big bottle

 

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