DIY Diesel Polishing

[goboatingnow]

Originally Posted by darylat8750

"I'm not sure what you are really achieving here, the volume transported and the lack of any tank agitation, will mean your just polishing the good fuel, not the crap in the bottom."

Drive into a short period 2 meter head sea for a couple of hours with half full tanks. That will give you plenty of agitation. There is a reason most people have filter issues when it is less than mill pond smooth.
I'm trying to work up a system that can work as a pre-filter while underway as well as a polishing system when not running the engines.

yes but that head sea agitation will block your engines filters, running your fuel polishing system will in harbour or clam seas, will just send the good stuff around and around

dave

[Rustic Charm]

Originally Posted by goboatingnow

yes but that head sea agitation will block your engines filters, running your fuel polishing system will in harbour or clam seas, will just send the good stuff around and around

dave

I think the idea is that once you have it clean, the fuel polishing system will then keep it clean. So that during the rougher seas, you don't have the problem I had. At least that's what I'm planning.

[NRosenthal]

Sorry for the drift, I have a tank related question.
I have 2-50 gallon alum. tanks on board. One has an inspection port. The second is an upright tank under the cockpit, there is only about 3"-4" of clearance above the tank, and I would like/should have an inspection port on this on as well. I know I could cut an opening in the cockpit sole bla bla....Opinions on placing one high up on the side of the tank, I realize it would have to have a perfect seal don't want fuel leaking. I just hate to put holes in any exterior surfaces of the boat. If it can be done, lets talk about the port.
Neal

[model 10]

Originally Posted by NRosenthal

Sorry for the drift, I have a tank related question.
I have 2-50 gallon alum. tanks on board. One has an inspection port. The second is an upright tank under the cockpit, there is only about 3"-4" of clearance above the tank, and I would like/should have an inspection port on this on as well. I know I could cut an opening in the cockpit sole bla bla....Opinions on placing one high up on the side of the tank, I realize it would have to have a perfect seal don't want fuel leaking. I just hate to put holes in any exterior surfaces of the boat. If it can be done, lets talk about the port.
Neal

You could put a port on the bottom if you used good sealant. I would not trust a gasket. A two part poly sulfide sealant will do the trick.

[Island_Moose]

I can see the potential, but I reasoned that if I start a regular polishing routine as soon as I fill the tank, the good fuel will be the only thing in there.

My system will allow me to polish the main tank while motoring (or sailing)on the day tank, through two completely separate systems.

John

Originally Posted by darylat8750

"I'm not sure what you are really achieving here, the volume transported and the lack of any tank agitation, will mean your just polishing the good fuel, not the crap in the bottom."

Drive into a short period 2 meter head sea for a couple of hours with half full tanks. That will give you plenty of agitation. There is a reason most people have filter issues when it is less than mill pond smooth.
I'm trying to work up a system that can work as a pre-filter while underway as well as a polishing system when not running the engines.

[noelex 77]

Originally Posted by goboatingnow

Im not sure what you are really achieving here, the volume transported and the lack of any tank agitation, will mean your just polishing the good fuel, not the crap in the bottom.

The professional fuel polishing systems use a large pump which agitates the tank. The permanently installed system like this (and mine) don't have a powerful enough pump to stir up the tank, but sailing especially in rough water stirs up the tank better than any pump.

I have mine on all the time I am sailing. Even a small pump like mine is still filtering 50 L an hour so it's not hard to filter the equivalent of the total fuel tank each time you sail.

I also leave mine on at anchor whenever we have excess solar power. Without agitation the polishing is less effective at removing debris (although the pickup for the polishing is at the very bottom of the tank where debris will tend to settle). Still conditions are probably better at filtering water out of the fuel. As well as being very bad for the injectors water is one of the major factors in developing the dreaded diesel bug.

Anyway its usually on for several hours a day and the combination of filtering with and without agitation covers all bases. It has made a noticeable difference to tank cleanliness.

[colemj]

Originally Posted by noelex 77

The professional fuel polishing systems use a large pump which agitates the tank. The permanently installed system like this (and mine) don't have a powerful enough pump to stir up the tank, but sailing especially in rough water stirs up the tank better than any pump.

That is because these smaller lift pumps are a very poor choice for a fuel polishing system. Our gear pump pumps 360gph through our polishing filter. The return is plumbed down to the bottom of the tank on the opposite side of the pickup. It does a great job of stirring the fuel while running.

Mark

[noelex 77]

Originally Posted by colemj

That is because these smaller lift pumps are a very poor choice for a fuel polishing system. Our gear pump pumps 360gph through our polishing filter. The return is plumbed down to the bottom of the tank on the opposite side of the pickup. It does a great job of stirring the fuel while running.

Mark

I think no pump comes close to the agitation and stirring that you get when sailing.

[colemj]

I don't know about that in general - a catamaran doesn't heel, and our tank is only 11" high with 3 sets of baffles in it. I don't think the bouncing we do while sailing stirs it up much at all. If so, only when we are below 1/2 tank full and only when we are beating into high chop or beam onto large seas.

And as GBN points out, there is no purpose in sitting at anchor polishing clean fuel. Going sailing to hope for some agitation and filling of the tank with sediment seems pointless and fraught with potential problems to me.

A proper fuel polishing system will stir the tank while it is running. Using the small, low flow lift pumps and a small filter for fuel polishing is a waste of effort. For another $100, you can have a real system that works as it should.

Mark

[goboatingnow]

personally I have used ( though not a permeant installation) a Racor 500, and a jabsco, nitrile based impeller pump. I noticed little agitation of the tank ( it was semi transparent plastic ).

So they key would be ( a) a low placed pickup, and high placed return, and (b) clean tanks to start off with .


Dave

[Cheechako]

"I think no pump comes close to the agitation and stirring that you get when sailing."
I think there are two approaches; small pump and long term polishing, large aggressive pumping and short term polishing. Either should work.
Old diesel is not just dirty on the bottom of the tank, look at it in a glass jar and it's full of suspended growth. Polishing this either way will yield nice clear fuel.
With a small pump go out sailing for the day and your tank will be as stirred up as any other method you are going to get I think. Do this a few times and you ought to have some pretty good fuel. Even the commercial fuel polishers cant do your whole tank (unless you have an unusually open tank access.) Both boats I had done had one opening in the tank and one side of the baffle could not be reached with the pressure hose. Going sailing would have stirred this up just as well.

[DeepFrz]

So they key would be ( a) a low placed pickup, and high placed return, and (b) clean tanks to start off with .

Niet! (Except for the clean tanks to start off with.)
Both pickup and return should be near the bottom of the tank. A short return tube will only aerate the fuel if it is above the level of the fuel line.

For what its worth, I believe that Mark has it right. Most boats, even cruising boats will spend more time at anchor or at a berth than they will spend sailing. It would be nice to have clean fuel when setting out as well as when returning.

[model 10]

Aerating the fuel? You are going to far with that.

[Rustic Charm]

Originally Posted by colemj

For another $100, you can have a real system that works as it should. Mark

What professional fuel polishing system can you get for adding $100? I've priced professional systems and the cheapest is $900 and most are over $1000. Mine being made will cost me nothing other than a few clamps as I'm using what's already there apart from buying a new Racor 500. But that won't be on the fuel polishing side.

[Cheechako]

Originally Posted by tedsherrin

What professional fuel polishing system can you get for adding $100? I've priced professional systems and the cheapest is $900 and most are over $1000. Mine being made will cost me nothing other than a few clamps as I'm using what's already there apart from buying a new Racor 500. But that won't be on the fuel polishing side.

The return fuel location is of no consequence... the flow is very low with a small pump setup.
If you get your fuel/tank clean once, you're good to go with a small setup. If your fuel is getting grungy and stale after that you are either not motoring enough or have too much fuel on board!