Dickerson Fuel polishing system (and other small ramblings/projects)

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    Been awhile.  Hope your spring comes soon, was 75 here in MA the other day.

    I wanted to share my fuel polishing system that I came up with for Siena.  It has been running for a year now and works brilliantly.

    I borrowed heavily from this webpage:  http://www.cruisingonstrider.us/FOpolishing.htm

    The main components are (2) Shelco stainless steel filter bodies (FOSBN-786), a Carter fuel pump (P4070)

    The rest is just fittings, fuel line, hose clamps, a DPDT rocker switch, a 12v relay etc.

    This is the schematic I used:


    I custom made 2 parts  which aren't really available, 1 is a bracket to hold the filters and the other is an aluminum tank bung.

    Here's what it looks like installed.  The aluminum bracket holds the Shelco filter housings.  I bought these because they are US made, very high quality SS housings, I paid $16 each on eBay, that accept industry standard filter cartridges.  I buy filters from McMaster Carr for about $5/each in any micron you could want.  I use 10 micron filters and a pair easily filtered 100 hours x 72 GPH or 7200 gals of fuel with no apparent reduction in filtering capacity.


    In words this is how it works:

    I made a new tank bung that that I use for a fuel pickup.  You can't use the engine pickup because it will starve the engine for fuel as I found out.  I made the bung from aluminum.  The in tank portion I tapped for a pipe thread.  I used a NPT compression fitting to attach some flexible 3/8″ soft copper.  I test fit the dip tube until I had found the very bottom forward part of the tank.  Once it was bent perfectly and the right length (lots of trial and cutting with pipe cutter) I secured it by tapping the tank for some small SS allen cap screws and black RTV sealant.




    I drilled a hole in the tank using a hole saw.  At first I was worried about the small amount of chips in the tank but let me tell you, the polisher works well!!  Hoovered up the chips and they were all found in the first filter housing.

    So the fuel pickup leads into engine compartment and into the first filter housing (1).  The fuel line then exits the first filter (2) and goes to a Carter P4070 fuel pump (3).  This a 72 GPH pump.  It works really well.  At anchor the noise would be annoying but I only run when the engine is running so it's a non issue.  After it leaves the pump, it now pushes fuel through the second filter (4).  From this point I would typically return the fuel to the tank.  I have a sight glass I found in my parts bin to check fuel (5).

    The other bit of functionality I built into the system is the polisher can act as a backup to the main engine lift pump.  By opening (6), closing (7) you've now shut off the racor and are supplying 10 micron fuel to the engine.  I tried this out underway and it works great.  Can change out the stock Racor element, under power, and prime the Racor back up with fresh clean fuel and then put the Racor back online and go back to polishing fuel.

    To power the setup, I run it off a DPDT rocker switch mounted on the port external side of the engine compartment (quarterberth area).  In the down position it runs the pump off the 12V system, so it's ON any time the main battery switch is on.  In the UP position, it runs when the engine is running,  I tapped power from the Balmar smart regulator, fed this to a fused 12v relay.  This is how I run it 99% of the time.  So when the engine is running I'm polishing the contents of the tank 2x an hour.  For spring commissioning I run it for a few hours and make sure I've gotten all the junk at the bottom of the tank.

    If I were to do it again I think only one filter is necessary.  These filter elements are pretty large.  I ran the same pair all season long with maybe 100 hours of engine time.  When I took them apart the first filter housing had all the aluminum chips and black sludge.  The second filter was spotless.  I would normally change a Racor mid season but when I checked it it looked new too.  I assume this is because the polisher runs through far more fuel in an hour and caught all the junk before the Racor had a chance too.  The turbine bowl also was free of almost any sediment compared to the year before.  I ran the 2 filters because I bought 2 on ebay for $16.00/ea and I like overdoing things.  If you were to run a single filter you'd want the filter before the pump to protect it, thus “pulling” fuel through.

    I also made a few custom parts for Siena last year.

    First was a new engine kill plunger.  The stock one fell apart.  We make brass steam traps here so I had lots of brass laying around.


    Here's what it looked like.  I put in a silicone o ring so no water can get past the plunger rod


    I also made a new Racor vac gauge.  The original malfunctioned and was cloudy.  One of my distributors makes these gauges for the military and he kindly sent me one.  Little bit of machine work and I have a nicely made brass T handle.


    That's it, hope you enjoyed.  Working on adding in a bobstay for a stainless fitting I'm making for the sprit.  Want to run an asymmetrical spinnaker.  Will post pics when done.

    Fleet Captain

    Well done Peter,

    A very tidy design, fabrication and installation.  “Crew Rest” has just a simple manifold with double (and selectable) Racor FG500 filters.  I rely on the high percentage return of unused fuel during running operations for the polishing.  D41 “CAVU” has a very sophisticated fuel plumbing scheme that allows concurrent running, polishing, and redistribution of fuel between her two tanks.  Complicated enough to carry a checklist to position about 9 valves to move what to where.

    Thanks very much for the post.



    I appreciate clean diesel fuel like I appreciate clean underwear.  Just makes the world right.


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