Fuel Filter Micron level?

Frank: I hear your points and I understand your logic..... but, just to continue with the discussion ........Let's say I have a set of dual 900MA filters.......which in my case, a single 900MA alone would offer tons of fuel flow margin to begin with.......and I run one in standby.

I regularly inspect my bilge, and part of my inspection includes noting the vacuum guage on my filters.

I fill up with a new load of fuel and go on a planned 3 hour cruise....hmmmm....where did I hear that before....Anyway....1 hour into the cruise....rut roh....things ain't going so well. I pull back the throttles and head down into the bilge. I notice my filter vacuum guages indicate that my active filter is in the early stages of clogging. So.....I switch to the standby filter. I note it took ~1 hour to get to this point on the active filter, so I can make a realtively confident assumption that I've got probably another hour before my standby filter starts to act up. Important to note is.....I now know that I've got an issue. At that point, I can throttle back and assess the situation....I can call for help, swap out the active filter....or make a B-line for the nearsest safe port.....which may mean just turn around and go home. If, my calculation is wrong, and the second filter starts to exhibit the same issue....I still have the option to put them both online again and limp home....but...the difference is....I had options.

Now....I've never had a filter clog on me. I generally get my fuel from a realiable source. So, I am only guessing on what will happen in a situation where my filter clogs.
 
I guess we can argue the capacity now or later question forever. I'm in the deep south and we are prone to fuel quality issues. I treat my fuel and manage it appropriately, but in 15 years, I've had one occurrence where a Racor got clogged. We had purchased fuel at a small marina on the way home from a trip and got a dose of sludge. Two hours out, my rpms wavered a little, so I throttled back to 2200rpm and we came on home. By the time we got to the channel near our marina, I couldn't turn more then 2250 rpm. We got back in the slip and I never left the helm chair. Had I used your approach, I would have had to crawl over a hot engine to access the fuel valve to get to the other filter online. I guess my point is that dual 900MA's give you roughly 4X the capacity you need and to clog up both filters to the point of sucking air would mean the fuel would probably have the consistency of mud.

The one point I need to make here is that your approach may seem conservative to you, but what is not conservative is the marginal size of the standard configuration of a single 500MA filter for Cat 3100 series engines. Your engines "process", i.e. either burn or return to the tank via the return lines, roughly 2X the fuel burn rate. At 23 gph, you are processing 45-50 gph thru your Racors. You have no margin as it is so, capacity now or capacity later is a moot point.
 
I ran in really bad fuel issues in the Bahamas and in KW. Filters clogged with dead organisms (black crap I'm told is dead stuff, reddish crud is alive and kicking) in just a few hours on fuel I picked up at Green Turtle. Having those dual filters really saved my butt in the Abacos, and once in Key West.

I did a fuel plan on my return where I cam back to Lauder close to vapors and then shocked my tanks with BioBor, and added just 50 gal in each tank and ran it out on a run to Miami Beach and back, then shocked again and then filled up. I cut open one racor for a internal peak and it was really compacted.



I like the dual set up and I have had my buitt saved twice over time with it being there, vs having replace filters over hot engines in a running sea way.
 
I am by no means a marine diesel engine expert, and would defer to Frank and Dom in matters concerning "oil burners". But recognizing that someday (hopefully!) I will get to a point in my life when a boat large enough to justify diesels is secured in my slip, I do try to read and digest as much information as possible concerning diesel issues. As such, I would like to refer the readers here to a resource I found informative and useful:

http://sbmar.com/main/articles/marine_fuel_filtration_-_the_seaboard_way/

This is one of several informative and clearly written articles presented on this site, and I hope the information there is an aid to everyone reading this thread. If not, I can skulk back to my gas burner restoration... It does address several issues like common rail vs. conventional diesel applications, fuel burn rate vs. fuel processing rate, etc.

Dale
 
Great article Dale. I have been thinking about redundant filters as It seems the Racors that I have are pretty small (500MA's) but have wondered if dual Racors is the best option. As a matter of fact I had to clean out my port side Racor today as I saw sludge build-up in the bowl. I love the idea of the vacuum gauges like Dom has installed. I would love to see pictures of this setup since we have the same boat. One of these media filters ahead of the Racor may just be the way to go.
 
11496_RAC_75-1000MAX_PPM
 
Why? Dual Racors do the same thing the article recommends except for 2 things.........Racor elements are about $7 ea; Fleetguard elements are about 3X that, and while Tony Athens is a well respected diesel engine guy on the west coast, he is a Cummins Fleetguard dealer, hence the recommendation to use Fleetguard spin-on prefilters.

Also, the photo of the vacuum gauge on the Racors that Mark posted is the set up for a dual filter installation. With a single Racor assembly, the vacuum gauge usually replaces the T handle at the top of the filter.
 
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Well then maybe I will rethink things. From what I read in your posts you would rather have twin 500MA's than switch to a single 900MA. Would it make any sense to have anything more than (2) 500MA's per side?
 
Asureyez said:
I ran in really bad fuel issues in the Bahamas and in KW. Filters clogged with dead organisms (black crap I'm told is dead stuff, reddish crud is alive and kicking) in just a few hours on fuel I picked up at Green Turtle. Having those dual filters really saved my butt in the Abacos, and once in Key West.

I did a fuel plan on my return where I cam back to Lauder close to vapors and then shocked my tanks with BioBor, and added just 50 gal in each tank and ran it out on a run to Miami Beach and back, then shocked again and then filled up. I cut open one racor for a internal peak and it was really compacted.



I like the dual set up and I have had my buitt saved twice over time with it being there, vs having replace filters over hot engines in a running sea way.
Click to expand...

Chad

Do you run normally with both filters providing flow to the engine, or do you run through one filter and keep the other for reserve in case of a problem?

Graham
 
HUMPH said:
....As a matter of fact I had to clean out my port side Racor today as I saw sludge build-up in the bowl. I love the idea of the vacuum gauges like Dom has installed. I would love to see pictures of this setup since we have the same boat. One of these media filters ahead of the Racor may just be the way to go.
Click to expand...

Here's a pic. Oil filled Vacuum guages with resetable tell tale needle that holds the highest level read. That way you don't have to be in the bilge while the motors are running at high RPM to see how high the level is at cruise RPM. I usually check the needles on my pre-flight. Also, note the petcock valves on the bottom to easily drain the bowl without any mess.

racorwithdrainandguage.jpg
 
Ken,

It is all about flow capacity. A single 500MA flows 60 GPH, so a dual 500MA set up would double that to 120 GPH. The 900MA flows 90 GPH; dual 900MA's flow 180GPH. So dual 500MA's flow 1/3 more than a single 900MA flows.

Even though a single 3126 burns about 20 GP at WOT; about 12 GPH at 2400 RPM, the Racor must process roughly ± 3X that due to the return system on the engine. That means that the single 500MA is just barely covering your need and you have no excess capacity in case of a clog. Adding another 500MA would help, but dual 900MA's would be much better.

Be careful shopping online prices for the additional Racor. If you add a single 500MA to your present set up, you will also have to buy and install the fuel manifold, valve and vacuum gage separately, so the cost will be more than just the cost of the filter canister. I suspect, but am not sure, that there is a ready market for a used 5000MA. Around here, every Bubba seems to think he cannot travel unless it is in a 3/4 or 1-ton diesel pick-up with as more doors than a Kroger store. They spend a ton of money on tuning chips, supplemental fuel filters, wheels, tires and chrome. I would look at buying the dual 900MA set up and sell the single 500MA's you have now.
 
I looked into all of this a year or so ago, and I don't have the exact info with me. But, from memory, on the 410DA, the fuel lines installed at the factory are too small of a diameter to take advantage of the flow capacity of running dual 900MA filters opened in parallel. Your easiest, and least expensive upgrade option is to switch out to a single 900MA Racor. You will still need to use an adapter to reduce the inlet/outlet sides of the filter to accept the current smaller size fuel lines.
 
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