Fuel pump for fuel polishing system - Continuous duty pump necessary?

[Capn Jimbo]

Forgive me, but is the premise - that "an hour+" will filter all the diesel twice - is that correct? Now if you were transferring the fuel to an empty tank, and back again, well that would surely be true. But unless the filtered fuel returned to the tank mysteriously isolates itself from the remainder of the unfiltered fuel - twice - the premise would seem to fail, and while some percentage of the fuel is indeed being filtered multiple times, some may not be filtered at all.

If so, the premise fails and so does the plan. Comments?

[Larry Florida]

Thought about this also. A possible option is put in a second pump identical to your existing pump. This will provide additional backup if you need to use it as your primary pump in an emergency.

My fuel tank is only 15 gallons. Thinking to T off the existing fuel pump running thru a simple fuel filter and back to the tank. Even a 0.5 gmp pump will turn over the tank in 30 minutes. Valve in valve out as needed.

[Maka]

Here is what I do
I have a Perkins 4-108 with a 5 micron filter.

I have two large ( 160 GPH ) Racor filters. The 1st one has a 10 micron filter and the second a 5 micron filter. So theoretically the engine filter never gets particles in it.
Way more fuel gets returned to the tank than is used by Perkins engines. So normal running is also polishing fuel with the set up I have.
I have 4 25 gallon tanks so I can get to the point where I know one or more tanks have only polished fuel in them.
With the size of my filters 160 GPH ea vs the engine @ 1 GPH, a clogged fuel filters is not a problem.
Further more I can by pass either filter while running the engine.... so I can change filters while under way if need be.
I don't think you need a separate fuel polishing set up...with the right filters you will be constantly polishing whenever you run the engine.

I would consider adding another fuel tank to your boat though.

I hope this was helpful.

[noelex 77]

Originally Posted by Maka

I don't think you need a separate fuel polishing set up...with the right filters you will be constantly polishing whenever you run the engine.

This is probably of some help especially if you have an engine that returns a lot of fuel, but a permanent polishing system is very different, filtering vastly higher quantities of fuel. The principal of polishing is that the fuel has multiple passes through the filter.

It is also drawing the fuel from a lower point where the water and muck will collect.

[Kalimniosjohn]

I just installed a fuel polishing system in my boat. I wanted to do a set of the racor 900s but didn’t have the clearance for them so I used two racor 500ma filters. One 10 micron and one 2 micron They are rated at 60 gph and I used a fuel pump rated at 50-58gph that is installed on the suction side of the filters. I have three tanks at 30 gal each so I just assume an hour for one cycle per tank.

I also installed a 20 gallon Day tank and a fuel manifold. Now I can choose which tank I want to draw from to filter, and can either return the fuel to that tank, or send it to the day tank. Once to the day tank the fuel goes through another racor and a regular fuel filter before getting to the engine.

Edit..……...don’t know why it changed the orientation of the pics or how to fix it.

[Capn Jimbo]

It seems that the notion of DIY polishing "systems" seem to have a following, but may be a bit of an unproved concept. Commercial polishers remove all the fuel from your tank, filter it completely, then return it to the tank, often under pressure to blast and clean all the surfaces, rinse and repeat. The biggies even test/analyse the fuel before and after.

Compare to these McGuyver'd DIY setups. A flow of fuel is drawn from the bottom of the tank (on the mistaken premise that that is where the "gunk" collects), passed through a filter and then returned and refouled with the unfiltered fuel in the tank. Multiple passes may reduce the the percentage of contamination but without complete removal, isolation and return the fuel can never be completely clean.

The poster who noted that an existing Racor already does this kind of recirculating is exactly right. The great majority of fuel - under high pressure - is then returned to the tank, 80% would not be an unfair estimate. Our existing Racors already "polish" the fuel. Running dual Racors, esp. equipped with a valve system to switch Racors is a fine idea and just as effective as these DIY, unproven contraptions.-

To me, good maintenance and a good and regular replacement of filters, along with an annual commercial blast and clean will do as well, maybe better.

But hey, whatever floats yer boat. If we want to believe that a DIY "polishing" system does better than our existing, in line single or dual Racors, then have at it hoss. Recirulate your clean polished fuel back into your dirty tank and dirty fuel.

[skipgundlach]

Awesome manifold!!

[davil]

Originally Posted by Capn Jimbo

It seems that the notion of DIY polishing "systems" seem to have a following, but may be a bit of an unproved concept. Commercial polishers remove all the fuel from your tank, filter it completely, then return it to the tank, often under pressure to blast and clean all the surfaces, rinse and repeat. The biggies even test/analyse the fuel before and after.

Compare to these McGuyver'd DIY setups. A flow of fuel is drawn from the bottom of the tank (on the mistaken premise that that is where the "gunk" collects), passed through a filter and then returned and refouled with the unfiltered fuel in the tank. Multiple passes may reduce the the percentage of contamination but without complete removal, isolation and return the fuel can never be completely clean.

The poster who noted that an existing Racor already does this kind of recirculating is exactly right. The great majority of fuel - under high pressure - is then returned to the tank, 80% would not be an unfair estimate. Our existing Racors already "polish" the fuel. Running dual Racors, esp. equipped with a valve system to switch Racors is a fine idea and just as effective as these DIY, unproven contraptions.-

To me, good maintenance and a good and regular replacement of filters, along with an annual commercial blast and clean will do as well, maybe better.

But hey, whatever floats yer boat. If we want to believe that a DIY "polishing" system does better than our existing, in line single or dual Racors, then have at it hoss. Recirulate your clean polished fuel back into your dirty tank and dirty fuel.

=======================================
Nigel has a comment on this subject on his latest book

[Kalimniosjohn]

Oops after replying I realized that my response didn’t have anything to do with the OPs question. The pump I used is the “Autobest HP4005 High Performance Externally Mounted Universal Electric Fuel Pump” .

I don’t know what duty it is, however the racor filters are rated at 60gph and 15psi. It is considerably more difficult to find a pump that meets these specifications then I expected. But this pump is rated at 50-58gph and 12-17psi. It’s the closest I could find. I know I could have installed a pump with less gph and psi but why not get the most out of the system? So far I’ve let it run for 2-3 hours non stop several times without it ever even feeling warm. Hope this helps.

[noelex 77]

Originally Posted by Capn Jimbo

The poster who noted that an existing Racor already does this kind of recirculating is exactly right. The great majority of fuel - under high pressure - is then returned to the tank, 80% would not be an unfair estimate. Our existing Racors already "polish" the fuel. Running dual Racors, esp. equipped with a valve system to switch Racors is a fine idea and just as effective as these DIY, unproven contraptions.-

So if these numbers are correct, if you use 200 litres of fuel a year four times this amount or 800 litres is filtered and returned to the tank each year.

To put this into perspective, my polishing system, which is not a high volume pump, has already filtered more fuel today than the engine system will filter in a year.

[skipgundlach]

Originally Posted by Capn Jimbo

The poster who noted that an existing Racor already does this kind of recirculating is exactly right. The great majority of fuel - under high pressure - is then returned to the tank, 80% would not be an unfair estimate. Our existing Racors already "polish" the fuel. Running dual Racors, esp. equipped with a valve system to switch Racors is a fine idea and just as effective as these DIY, unproven contraptions.-
.

Eh???

A change in the yard immediately following our wreck pulled out a pile of grunge.

Another change after a rock-and-roll return for rehab, under staysail alone (Marathon to St. Pete), more, but significantly less than the first, grunge.

Good deal on the wreck and the fuel, as I expect it cleaned out the tank pretty well.

Two more changes, both pre-emptive, as the vac didn't show it clogged, with minor grunge.

NO Racor changes since we started 11 years and 3000 hours ago.

Unproven? I don't know how you measure, but it seems effective.

As to lots of volume, a Perkins doesn't put the same amount of fuel through as does, say, a Yammie. But I'd rather, in any case, be changing out less expensive polisher refills than Racors.

YMMV, and I'm biased, but if you're merely going to series-mount Racors, IN THE SUPPLY LINE, when it (if) clogs, you're stuck...

[TCL]

Thanks to everyone for all of the responses. Sorry for the delay in following up; I'd been away from the internet for a couple of days.

The pics, specs, and recs for pumps will be very helpful.

Just to clarify one point in my original post (in response to, among other replies, No. 16 by Capn Jimbo):

The statement in my original post that referenced "an hour+ to cycle through the tank twice" was simply to note that the pump would have to run for several hours, not to suggest that I believed that cycling through twice would be sufficient. That's why I said "[i]deally, I'd like to be able to run the polisher for several hours using successively smaller filters."

As far as debate over whether a polishing system is necessary, I've enough anecdotal evidence to believe that the polisher will help. I scrubbed my tank clean in late fall, fuel sat in the refilled tank while the boat was on the hard over the Winter, and during a trip this Spring, with about half a tank, a night at anchor in some heavy seas apparently stirred up enough gunk to overcome the existing filtration.

Thanks again to everyone.

[Maka]

As Captain Jimbo pointed out..a commercial fuel polishing outfit will completely empty your tank and then refill it with polished fuel.
So to polish your own fuel properly you need a separate tank to do the polishing in as well as the polishing system.



If your fuel supplier is providing filthy fuel and If you have room in your engine compartment for an extra fuel pump and filters, supply and return lines then by all means go to the expense of installing a dedicated fuel polishing system on your boat.
You might be better off building a separate system ( like the pros use )you can operate from the dock next to your slip.


To my way of thinking, the reason to polish your fuel is so you don't have engine failure due to clogged fuel filters, especially in critical situations, which Murphy's law insures. You can accomplish this goal with an overly aggressive fuel filtering system like the one I have and is why I have it.



I forgot to mention that I can draw fuel from any one of my four fuel tanks and return fuel to any tank I choose via my fuel supply and return baffles.


Here is a quote I found that may help put things in perspective.

"Some in-line pumps models (Bosch P7100) return at least 40/50% of fuel to the tank, and Cummins PT returns over 80%."


Fair winds and clean fuel.

[noelex 77]

Originally Posted by Maka

So to polish your own fuel properly you need a separate tank to do the polishing in as well as the polishing system.

The fuel polishing system usually doubles as a fuel transfer system, so this can easily be done with most polishing systems (providing you are not full with fuel).

I am not sure this would polish the fuel any better, but it is an option if you feel it helps.

[Larry Florida]

Originally Posted by Maka

Way more fuel gets returned to the tank than is used by Perkins engines. So normal running is also polishing fuel with the set up I have.

.

I have a 2 cyl westerbe with this same setup and assume most diesel engines do also. Did you come across any specifications confirming the percent returned to the tank? I recall researching this last year and concluding a very minimal amount of fuel bypasses back to the fuel tank.

Thanks in advance