Primary Fuel Filters

Hello everyone and thanks for the thesaurus of information you share.
I'm replacing the old DAHL 201 filters with new RACOR turbine filters.
Motors: DD 671Natural - 310HP each.
Question:
I can't find the Dahl 201 specs.
Do I want Racor 1000MA (180Gph), 900MA (90Gph) OR 500MA (60Gph)?

Not sure exactly how much the DDs pump per hour but it is a lot. I had 6V53s (216 hp) in a previous boat and had the 1000 Racors in it. Keep in mind that DDs pump way more gph than they burn.

My last boat had 671’s with Racor 1000’s. I don’t believe the 900 series are sufficient.

m/v ATHENA said:

Hello everyone and thanks for the thesaurus of information you share.
I'm replacing the old DAHL 201 filters with new RACOR turbine filters.
Motors: DD 671Natural - 310HP each.
Question:
I can't find the Dahl 201 specs.
Do I want Racor 1000MA (180Gph), 900MA (90Gph) OR 500MA (60Gph)?

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What you need are your engine's fuel flow specs. Volume at RPM. Not fuel burned but fuel burned plus return. This will tell you which Racors to use. I suspect contacting Racor will be a good way to go if you can't find the engine specs.

With old skool engines I like the dual system. The setup with the 1,2,both,off valve. I run on a single element and if I am caught by surprise with a fuel problem RPMs will drop. If I react to the problem quickly enough I can pull it back to idle and switch to the other never missing a beat. Then as soon as I can I change the plugged filter. All of this can be done without ever having to shut down. I keep a jug of clean fuel handy in case I have to top up the housing before putting the lid back on. No need to fill it to the brim, Racors are designed to deal with a bit of air at the top. And generally the older engines can swallow a bit of air and keep on running.

Each engine should pump about 35 gph depending on plumbing bends, restrictions, etc. I use 900s on my DDs. I have 2 Racors with 1 online and 1 ready to go. Generators also go thru the Racor. And each engine has it's own secondary filter.

Comodave said:

Keep in mind that DDs pump way more gph than they burn.

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In fact some say it's a fuel polishing machine with a prop attached.

Thank you all for the replies. I just read an article on the subject by Steve D'Antonio who's opinion is "the bigger the filter, the better". So, Racor 1000MA it is. Thanks again!

Agree that bigger is better. The filter element on the 900 is only slightly bigger than the 500. The 1000 element is huge in comparison. But they are large format containers. Filter housing is 22-inches tall and requires 10-inches clearance above to swap elements. If I had space, I'd use for polishing.

Athena
Suggest you read Tony Athens' articles on fuel filtration. Sure, big Racors work but spin on filters carefully arranged provide superior filtering with much easier changes. And a much smaller footprint.

900's would be fine for 671N. Nothing wrong with going with the 1000 as it can hold like twice the dirt before needing a filter change.

sunchaser said:

Athena
Suggest you read Tony Athens' articles on fuel filtration. Sure, big Racors work but spin on filters carefully arranged provide superior filtering with much easier changes. And a much smaller footprint.

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absolutely +1 - and vacuum gauges eliminate surprises along the way.

Not sure where I read it, and a quick web search came up empty, but I remember a caution about oversizing the Racor filter may reduce the turbine action which helps to remove the water from the fuel. The theory is that if the filter is designed for 180gph and you are pumping 30gph, you may have insufficient rotational velocity to get the centrifuge effect to cause the water to drop out into the bowl. The filter element is treated to block water, but may foul sooner because it is doing more of the water removal. Might be worth looking into further. Sorry to cloud the issue without links to support.

If flow rate is too low to get good rotational speed in the bottom, then flow rate is also slow enough that simple gravity will separate out the water. I have used over sized Racors in many apps and have had no problem with them separating out water.

Good point Ski.

Before the Raycore the water was taken out with a very fine mesh cotton sock in a 1 quart glass jar.

Think lawnmower filter but in a GIANT size.

These worked well, and after emptying were as good as new, the usual on engine filter took care of any remaining particles.

The turbine affect of Racors does not work on Lehmans and perhaps Perkins, not enough volume. A Lehman returns virtually no fuel and demands no more than 2.5 gallons per hour. My twins consume just 3.5 gallons per hour. In my opinion, a Tony Athens setup using sequential filtering with vacuum gauges is far superior for a Lehman, or any engine, for filter changes, even underway, quite simple. If one feels the need to check the bowls daily, just open a bottom drain and check. The clear bowl of a Racor is difficult to discern any crud or water anyway.

I do not have an Athens setup but if I were retrofitting, that is what I would install.

Tonic1 said:

Not sure where I read it, and a quick web search came up empty, but I remember a caution about oversizing the Racor filter may reduce the turbine action which helps to remove the water from the fuel. The theory is that if the filter is designed for 180gph and you are pumping 30gph, you may have insufficient rotational velocity to get the centrifuge effect to cause the water to drop out into the bowl. The filter element is treated to block water, but may foul sooner because it is doing more of the water removal. Might be worth looking into further. Sorry to cloud the issue without links to support.

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catalinajack said:

The turbine affect of Racors does not work on Lehmans and perhaps Perkins, not enough volume. A Lehman returns virtually no fuel and demands no more than 2.5 gallons per hour. My twins consume just 3.5 gallons per hour. In my opinion, a Tony Athens setup using sequential filtering with vacuum gauges is far superior for a Lehman, or any engine, for filter changes, even underway, quite simple. If one feels the need to check the bowls daily, just open a bottom drain and check. The clear bowl of a Racor is difficult to discern any crud or water anyway.

I do not have an Athens setup but if I were retrofitting, that is what I would install.

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See Ski's post #13.

catalinajack said:

The turbine affect of Racors does not work on Lehmans and perhaps Perkins, not enough volume. A Lehman returns virtually no fuel and demands no more than 2.5 gallons per hour. My twins consume just 3.5 gallons per hour. In my opinion, a Tony Athens setup using sequential filtering with vacuum gauges is far superior for a Lehman, or any engine, for filter changes, even underway, quite simple. If one feels the need to check the bowls daily, just open a bottom drain and check. The clear bowl of a Racor is difficult to discern any crud or water anyway.

I do not have an Athens setup but if I were retrofitting, that is what I would install.

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I didn't realise - that the Lehman's and Perkins don't have much return. I assumed the return for them was the same as others. Our Perkins M135 consumes 28L/hr at WOT 2600RPM (ignoring propping!), and I assumed that at 1500RPM or about 6L/hr, the return would be 10+ L/hr as I've heard number of 3-10x the consumption at lower RPMs.

I didn't say that a Perkins engine returns a small amount, I said perhaps. I did say that a Lehman does not. Bob Smith from American Diesel used to do engine instruction classes. He would bring an operating Lehman on a pallet. He would not even bother to rig a collection device for the return line so little fuel would be returned. Does anyyone else know whether a Perkins also does not return much fuel? I suspect not but I do not know.

mcarthur said:

I didn't realise - that the Lehman's and Perkins don't have much return. I assumed the return for them was the same as others. Our Perkins M135 consumes 28L/hr at WOT 2600RPM (ignoring propping!), and I assumed that at 1500RPM or about 6L/hr, the return would be 10+ L/hr as I've heard number of 3-10x the consumption at lower RPMs.

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I know my Lehman 120 doesn't return much.... I remember more than one 135 owner saying it returned a lot more... how much I have no idea but different than 120s (I also believe fuel pump differences were mentioned)...


Out of the TT archives....


"When I ask Bob about doing this he warned not to. He said that the reputation of minute fuel return was earned by the 120's, but that the newer generation engines like the 135's had a significantly larger fuel return than the 120's. I assume, and didn't ask, that it was because of the different type of injector pump. He told me that if I did the "T thing" on my 135's that it "might" induce too much air and / or turbulance in the incoming fuel and cause me problems."

Lehmans return little to none. My 900's seem to do a good job.As I understand it the "turbo" or "spin" effect of the raycors is for water removal mostly. But the big canisters, almost 2 qt. seem to act as a big sediment bowl and they do trap water effectively. I sometimes get a little when I empty the canisters.

pete

Anyone have any idea how much return to expect from a 40 year old Perkins 4-236? I too have been planing to change to the dual Racor.

I have dual Racor 1000s (from the previous engine) on my 135 HP John Deere. Maximum fuel flow is 35 GPH. Normal cruising flow is around 20 GPH. Ski is correct that everything that would settle to the bottom of your fuel tank, falls to the bottom of the bowl in the Racor. Only the lightest particles travel up to the filter element.

Ski in NC said:

If flow rate is too low to get good rotational speed in the bottom, then flow rate is also slow enough that simple gravity will separate out the water. I have used over sized Racors in many apps and have had no problem with them separating out water.

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Ted

Wouldn't this be the same with an all-metal filter with a bottom drain? Open the drain before each cruise to check for water or crud? Seeing crud or modest amounts of water in a Racor bowl can be difficult anyway, especially with those equipped with a metal shield which obscures the bottom half of the clear bowl where for what one is looking resides.

O C Diver said:

I have dual Racor 1000s (from the previous engine) on my 135 HP John Deere. Maximum fuel flow is 35 GPH. Normal cruising flow is around 20 GPH. Ski is correct that everything that would settle to the bottom of your fuel tank, falls to the bottom of the bowl in the Racor. Only the lightest particles travel up to the filter element.



Ted

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catalinajack said:

Wouldn't this be the same with an all-metal filter with a bottom drain? Open the drain before each cruise to check for water or crud? Seeing crud or modest amounts of water in a Racor bowl can be difficult anyway, especially with those equipped with a metal shield which obscures the bottom half of the clear bowl where for what one is looking resides.

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The bottom metal shield obscures less than an ounce of the bottom of the Racor bowl. A small light shining from the opposite side makes it easy to see the contents near the very bottom. If there is significant water in the bowl, it's easily spotted by the color difference, especially with dyed fuel.

If doing an engine room check while underway, doing a visual inspection through a transparent bowl makes far more sense than opening a drain on an operating engine in seas.

While I have no statistical evidence to back it up, I would guess that a higher percentage of people doing an engine room check before getting underway, are much more likely to visually inspect the Racor bowl than those who would have to draw a filter sample, analyze it, and dispose of it.

Ted

Do any TF members see water in their Racors? If so, where did it come from? Then what was the fix?

I had a small amount of water and crud (most probably asphaltene) appear in the Racor bowl of the fuel polishing system when transferring fuel from the storage tank to the day tank in January. I assume it was from one of three fuel docks I purchased from between October and January. I think I know which one, but won't say without proof. Some facilities don't utilize a filter where the supply hose attaches to the pump.

As all my fuel goes through the polishing system before going into the day tank, I'm not worried about an engine related problem. As the fuel fill gets a new oring every year and is protected from weather and seas along with the tank vents, I'm confident it was a fuel retailer problem (crud in their storage tank). The tank is angled to completely drain through the transfer plumbing so no loose contaminants should remain in the tank. I will continue to monitor fuel coming out of the tank, but feel the system has resolved the problem.

Ted

I mounted a small LED light behind the Racor bowl so I can see what is in the bowl more easily. They come on with the other LED lights in the engine room.

Comodave said:

I mounted a small LED light behind the Racor bowl so I can see what is in the bowl more easily. They come on with the other LED lights in the engine room.

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That's a damn good idea. Thanks!

jleonard said:

That's a damn good idea. Thanks!

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Ditto!