Diesel fuel polisher

[Bumpersbird]

We were on this subject a while back.

I was going to make a fuel polisher as well. After speaking with several marine fuel polishing folks, guys that sell and install this stuff, in my application an additional filter & or a separate system on the coach wasn’t going to change much. Also you’ll never get rid of all of it. The one universal comment made after getting these guys to loosen up and tell me the whole story.

My fuel pump is circulating at least 1 gallon per min through the filter as is and is considered adequate to polish the fuel as is currently installed, My coach also has the Algae-X for whatever good it does..

I would build and use a fuel polishing system if I were to treat my fuel for the first time and filter it before running it through the coach systems, in my case it also feeds the Aquahot and the Generator.

I think this would be more efficient and a lot less dangerous than changing filters on the coach roadside. Pouring this stuff into your tank then going for a drive just doesn't sound like good advise.Once you have cleaned up the fuel, than run the coach, or course taking along a supply of filters just in case.

At present I’ll just run the coach and if the Polishing System ever gets built I’ll treat the fuel when the tank is less than ¼ full and agitate it somehow to break up any accumulations. After a good polish is achieved fill up the tank and polish it again. That should do the trick.

Kurt Horvath
95 Pt 42
10AC

Originally Posted by warbucks13477

Here is what I have come up with so far.

The Racor 900FG obviously worked when it was installed for the size engine etc that BB put in the coach. Just to check I did some quick calculations to see.

ULSD fuel in the US has approx 138,700 BTU per gallon.

A 350 HP diesel engine will use approximately 14,850 BTUs per minute. The Racor 900FG will pass with clean filters approx 1.5 gallons per minute or 208,050 BTUs or approx 14 times as much fuel that is required.

So I have concluded that the Racor 900FG that was originally installed is excellent for its intended purpose IF the fuel is relatively clean. In fact there is enough reserve cleaning surface in the filter to cover normal use for a long time before replacing.

Remember Tom, that your engine isn't 100% efficient. Assuming an efficiency of 35% you need 42000 BTUs per minute of diesel fuel to make 350 HP of mechanical power. This leaves you with a safety factor of 5, not 15, add to this what others are saying relative to fuel consumed versus fuel pumped in a diesel engine.

David Brady
'02 lxI, nc

[warbucks13477]

David 35% efficient? Where did you get that? . Going to add a few things after thinking about this. We have to get over thinking about worse possible cases when attempting to troubleshoot a problem. Quite often it is the simplist things that cause the problems so that is where we should start.

In this case the contaminated fuel is the problem not a misdesign in the fuel delivery system. So it really doesnt have anything to do with the engines thermal efficiency at all. We need to clean up the fuel and the engine should run fine all other things considered.

Sure we can hire a professional fuel polishing service if there is one available. And sure we can use a professional mechanic to work on the engine etc if one is available in our area that is capable of working on the Bluebird. But in my experience there just isnt one in my area and from the horror stories I am hearing on this and other forums over the quality of work that some members are experiencing there are not many qualified shops in other areas either. So I have bought the necessary tools, and gathered all of the technical information I need to work on my coach.

When it comes to cleaning the tank via fuel polishing I will build a tool to do that also. And I hope that others will learn from this and do the same thing.

I spoke with Shane Fedeli today and he wants to polish his fuel also. I volunteered that he could borrow mine when I am done.

[thomase]

I would think a small centrifuge could be used for polishing fuel?
http://www.xyzworks.com/centrifuge.htm
I have built one of these using the dieselcraft centrifuge and a power steering pump off an old junkyard truck. It's great for cleaning up contaminated oils, hydraulic fluids, etc. They claim .1 micron filtering and I can only say that some of the stuff it filtered was so small it had no noticeable texture.

Some semi-truck tractors used centrifuge technology to "polish" the engine oil to extend it's useful life. Mack truck's version is called centri-max or something like that. It would be interesting to have these onboard a bird or truck for fuel, oil, and coolant systems. I built another centrifuge cleaning system around the centri-max product that worked fine but the rotor was part of the filter and became cost prohibitive.

I've got no stake in the company dieselcraft. just a happy customer of their products. www.dieselcraft.com

Thomas Eastham
Houston, TX
83 FC35
currently in Houston, departing for Mexico this weekend

Originally Posted by warbucks13477

David 35% efficient? Where did you get that? .

From here:

http://www.biodiesel.org/resources/r...30_tra-029.pdf

Which gives a BSFC (brake specific fuel consumption)

for the 6v92 of .48 lb/(hp-hr). Converting BSFC to efficiency via

http://en.wikipedia.org/wiki/Brake_s...el_consumption

gives an efficiency of roughly 30%.

Don't mean to derail the topic, just cleaning up the math a bit for the benefit
of future readers. Clearly your stock filter is adequate. But you can see how
given the need to pump more fuel than required, coupled with the efficiency
of the motor, a little crud in the filter can compromise performance. That's
the germane part.

David Brady
'02 LXi, NC

[warbucks13477]

David as so often happens with engineers we can sometimes get lost in the technicalities of the problem and get entirely off the track and waste time. You reference a test done in 1995 on biodiesel fuel to get the 30% efficiency factor that you note which is not relvant to this problem. In fact one does not have to even have to think a lot about the problem of a contaminated Racor filter to know its the contamination that caused the problem NOT the GPH flow rate of the OEM Racor nor the need to change the size of the Racor filter. However to do so is everyones personal choice.

What I attempt to do in my responses is to show the need to look carefully at the problem, gather the necessary technical electrical drawings and mechanical manuals, understand how the system works and then to logically and systematically troubleshoot the problem. The result if you do not do this is wasted time and money resulting from indiscriminately replacing things until the system works. This is one of the reasons that I not only strongly support these forums but also try and get forum members to attend BB rallies where technical sessions are held at every session. Some of us need both things to read and comment on to forumulate and hone our skills but also hands on experience where we can learn even more things.

The bottom line is that on these forums every single post is important even if it is one that is not entirely correct because then it allows all of us to learn and that is what this is all about to me. I learn something new every day as I read these questions and if I dont have the answer, break out my books and find it if I can. If I cant and the answer does come up I write it in my notebook that I always have in my coach when travelling.

thanks David,