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Old 08-18-2020, 07:45 AM   #1
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Attention those with Fass Fuel systems and filters

One of the big topics on here was going to an Fass or Air Dog fuel pump, especially on the 8.3 cummins with caps injection.

I just finally purchase the pump and noticed that some of those pumps come with an old style filter and others with a new style filter. I wondered why they changed filters?

There are some you tube videos, from Fass, describing the reasons, which brings up some concerns.

First I came across a You Tube video by Truck Master saying how bad the new fass filters are.

The complaint is over the new water separator and the way it works. It absorbs the water in the filter material and will clog up and shut down fuel flow to protect your engine, no matter where you are. Some are claiming it clogs and blows the pump fuse. There is no water drain on the bottom like on the old filters.

So why did they change the filters?

From Fass;

FASS just released their new particulate & water separator filters! However, what does it all mean? The new particulate filter is rated @ 144 microns. The 144-micron particulate filter on the suction side will drastically reduce cavitation, increase flow properties, lower the sound output of the FASS

It seems the majority of these pumps are being put on pickup trucks and they must have had noise complaints. So they made a new pump called the whisper titanium pump. This appears to be a mechanical change in the pump motor connection and the smoothing of the ports to reduce noise.

Then they appear to have gone to a new filter that is really only a 144 micron screen which cuts the noise down further.

For someone owing a diesel pusher we are not that concerned about noise, we are more concerned on getting the best protection possible.

The 144 micron is only to protect the pump. After the pump the next filter does two things. Water and 2 micron fuel filter. It is a rather small canister not like what I have now.

They indicate the filter can handle 4 oz of water before clogging up. I don't know if that is a lot of water for a 100 gallon fuel tank. I assume you are not always going to get water but sooner or later it could happen.

On the you tube site Truck Master he is recommending Cat filters. We don't know the credibility of this person I am only putting this out there to get some feed back and learn from others that have all ready installed the system.

So after all this research and thinking I am wondering about another problem.

This involves the claim of fuel polishing and it's benefit. Maybe someone that has one of these pumps installed can help out with my thinking on this.

I bought the Fass model 100 gallons per hour pump. When you hook it up it is going to circulate the fuel from the tank and through the pump and then back to the tank. If the engine is operating then a certain amount goes to the engine at a regulated pressure. So if I turn on the ignition and the pump starts, is it circulating 100 gallons an hour? The filters that are on the pump are only rated for 25 gph. How can you have a 100 gph pump running through 25 gph filters?

Remember this; The 144-micron particulate filter on the suction side will drastically reduce cavitation, increase flow properties, lower the sound output of the FASS

If we are worried about flow properties why are we putting a 25 gph filter on a 100 gph pump?

I could buy a Racor fuel water separator for marine use that is $169 dollars. But it only handles 45gph. So I would need two of them in parallel for the Fass pump. Obviously if I was just feeding the engine with no return or polishing that would be plenty, but the polishing and built in return from the pump itself should require 100 ghp to handle the pump. Sounds crazy so I must be off base. But where?

The other concern is if you want to aerate a fluid you could pump it from a tank and then spray it into the air above the tank. When you put the hose kit on and feed the output of the pump into the filler neck it seems that you are adding air not removing it. There is just air at the top of the tank and the pump sprays the fuel into this.

Also in polishing the fuel where does this extra air go? I could see if there was some sort of bleed valve on the pump that constantly belched out air that would make sense. But just pumping fuel around and spraying it into air doesn't seem to be a way to reduce air in the fuel.

When we talk about removing air I would expect the excess air to go somewhere.

Or is it that when you apply suction to a fluid and pull it 36 feet you pull entrapped air out of the fluid and the pump has some sort of diverter /diversion thing that sends fuel loaded with air back to the tank and the engine only sees clean fuel. That sounds reasonable but then why do you need to polish it at all. Just run the pump and it takes the air out of only the fuel going to the engine but not out of the whole tank as they claim?

I am getting read to install the system but am hung up now on the filters and placement of the pump.

I am also wondering why this isn't some simple deal of just adding a better pump. The filter change seems to be creating all sorts of doubt about this system. If the water separator clogs you will reduce the flow to your CAP system and damage it. If the filter clogs maybe the pump fuse blows before you damage your Cap pump, but depending on where you are that seems inconvenient.

After writing all this I think the best solution is to put on the Cat filters. These are supposedly the Cat numbers; 1R-0750 for the filter and 175-2949 for separator. That is what some of the you tube commenters are saying, check first. There is another name mentioned and that is Donalson. The Cat equivalent is Donaldson Lube Filter Spin-on Full Flow- P550920, This filter only cost 11 bucks yet it is mentioned often.

Here is a link to the cat filter story.

https://caterpillar.scene7.com/is/co...IaAsTBEALw_wcB

And I don't sell Cat filters or get any money I am just trying to mention that there could be problems with the new Fass water separator and mesh filter setup.

And I have called some of these Fass distributors and also fass itself but they don't seem to have any interest in answering questions.
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Old 08-18-2020, 09:19 PM   #2
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Check out the class 4-8 Airdog diesel fuel/air separator pump with a drain on the water separator filter. The 150GPH model is recommended for the ISC.
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Old 08-18-2020, 09:21 PM   #3
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I dispute that FASS is not made for HD trucks. That's complete nonsense.

To answer the question of where the air goes from the pump - This is why there is a separate return line to the tank - the cavitated fuel and separated air is sent back to the tank, there is no "aeration" of the fuel happening at the tank b/c that would require a spray nozzle of some form. The return line from my 165-gallon-per-hour is threaded right into the top of the tank - I drilled and tapped the tank itself - and the flow is a solid column of fuel right into the tank.

Now I don't know about flow ratings of the filters, but that is what FASS supplied with the pump and it seems to work quite well, the performance of my ISC has been much smoother ever since this install. I DID however skip their first filter and used a larger / longer primary filter that I already had, since I expect that the first filter will suffer fairly quickly from the "polishing" of all the rust / detritus from my tank. It has been installed now for around 300 gallons of fuel used, and so far I'm pretty happy. I don't know anything about the water separator filter, but it doesn't have a drain on it so this thread is the first I've heard about a potential change from something previous. I'm not adverse to "rolling my own" on filters... But this decision needs more information.
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Old 08-19-2020, 02:21 PM   #4
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Okay thanks, you have answered two of my questions. The feed back to the tank is pretty much just a solid column of fuel so there would not be much air picked up in that.

It sounds as though the air is separated at the pump. This is good the engine is getting pure diesel. But the fuel that goes back to the tank still has air in it? So the fuel in the tank will never be air free? And I don't know how much air is really in there to begin with. I have gas cars and they don't need fuel polishing. Maybe there is no air in gasoline.

But I am still wondering why we are pumping the fuel around in a circle unless it is getting rid of contaminants that are taken out by the filter such as rust. But if your tank is clean there is not need to try and remove something that is not there. Or once ten hours goes by all the contaminants should be out and in the filter.

You have told me that you installed a larger or different filter before the pump and that is what I am thinking of doing. I would like a water separator before the pump but didn't want to create too much resistance. I have now thought of installing the pump closer to the tank with a filter as someone else has done on this forum.

I think it was a DAHL filter and they are not cheap. But they look nice. https://agcrazy.com/200-diesel-fuel-...ater-separator

After reading all the posts I have no doubt that the fass or air dog is the way to go to get positive pressure to the CAP pump. And lot's of people report the engine seems to run better. So I am happy to put this pump on just been thinking about the filter situation after seeing that you tube video.
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Old 08-19-2020, 05:48 PM   #5
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What about installing a davco filter before the fass or airdog...
I don't have a fass or airdog, but do use this filter. Been on med/heavy trucks for years. As it get dirty, the fuel level rises, you only change the element when the bowl is full of fuel.
Also has added benefit of a water separator in the bottom. I use a 10 mircon filter, same as the Fleetguard spin on i replaced it with.

[url]https://store.davco.com/category-s/179.htm
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Old 08-19-2020, 06:02 PM   #6
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mackwrench, that filter is interesting. I could not find replacement filters on their website, how much are replacement filters?
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Old 08-19-2020, 06:15 PM   #7
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Quote:
Originally Posted by Ray,IN View Post
mackwrench, that filter is interesting. I could not find replacement filters on their website, how much are replacement filters?
Fleetguard # FS19727 available whenever you get filters...

https://shop.moderngroup.com/fs19727...ter-separator/

It's been the OEM filter on most on-highway engines for many years.

Any air that's pulled from tank/pickup will be trapped in the clear filter housing. You don't change the filter element until the fuel level rises to the black line on element.
I've got about 10k on mine on my 3rd element....the 2nd element I must have gotten some fuel Dukey as it went about 1k miles and filter was at max...the one in my picture has about 2500 miles on it, I changed it in Florida, drove to Austin Texas and back now at that level.
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Old 08-19-2020, 06:24 PM   #8
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Here's a rather interesting read on air bubbles/vapors in fuel:

http://www.davco.com/diagnostics.htm
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Old 08-20-2020, 07:39 AM   #9
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Thanks Mackwrench;

That is the filter I was looking for. I had seen some one else has it on the forum.

I read the article on fuel bubbles and it is informative, although it does nothing to help the claim of polishing fuel. There are two types of bubbles; one caused by an air leak at the suction side, and two; vapor bubbles. You would naturally fix an air leak and they say the vapor bubbles don't effect anything.

So running the pump circulating fuel removes particles but the vapor bubbles apparently will remain or are regenerated by the fuel sloshing around in the tank.

Anyway I am going to order one of the Davco filters. The 382 filter flows 180 gallons per hour compared to the 25 gallon per hour Fass filter they put on the 100 gallon per hour pump fass pump I bought.

It has, or you can get it, with the water electric alarm indicator and it is a clear bowl so you can see what is happening in there.
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Old 08-20-2020, 06:21 PM   #10
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What exactly is fuel polishing? Just continuously pumping fuel though the same filter that is the same filter is filtering fuel before it reaches engine? re-filtered fuel? Can I re-filter my coffee?, Lol

There are specific fuel polishing filtration system that are made to remove, dirty/bad fuel, filter it though a step of different micron filters/separators and put now clean fuel back in tank. These are not the same types of filters for everyday use. They are commomely used in the marine/generator/stationary engine industry, where large amounts of fuel may sit many months or years.

I think the claim of fuel polishing is overrated. Clean fuel shouldn't need polish....but that's my $0.02

Millions of engine's running today w/o any fuel polishing

I'm sure there's advantage to having the aux lift pump. But my thinking is it's a steady push of fuel to the injection pump is all that is gained.

A lift pump that could tolerate to be ran all the time would accomplish the same.... but again, my $0.02
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Old 08-20-2020, 06:29 PM   #11
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Originally Posted by dougw2007 View Post
Thanks Mackwrench;

That is the filter I was looking for. I had seen some one else has it on the forum.

I read the article on fuel bubbles and it is informative, although it does nothing to help the claim of polishing fuel. There are two types of bubbles; one caused by an air leak at the suction side, and two; vapor bubbles. You would naturally fix an air leak and they say the vapor bubbles don't effect anything.

So running the pump circulating fuel removes particles but the vapor bubbles apparently will remain or are regenerated by the fuel sloshing around in the tank.

Anyway I am going to order one of the Davco filters. The 382 filter flows 180 gallons per hour compared to the 25 gallon per hour Fass filter they put on the 100 gallon per hour pump fass pump I bought.

It has, or you can get it, with the water electric alarm indicator and it is a clear bowl so you can see what is happening in there.
Not sure if a new Davco filter comes with it, but you'll need a special spanner wrench to make quick work of replacing the filter element. It's only needed for removal, hand tighten only

I've had one for years, but Davco or Amazon sells them.
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Old 08-21-2020, 07:46 AM   #12
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I found a Davco on ebay new in box for a total of around 300 with tax and shipping. These filters are not cheap and I saw prices as high as 700 for new retail.

They are shipping it today and I now can get on with where to place it.

Thanks for the reminder I will need a wrench and a couple of spare filters for it.
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Old 08-25-2020, 12:16 PM   #13
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Quote:
Originally Posted by dougw2007 View Post
Thanks Mackwrench;

That is the filter I was looking for. I had seen some one else has it on the forum.

I read the article on fuel bubbles and it is informative, although it does nothing to help the claim of polishing fuel. There are two types of bubbles; one caused by an air leak at the suction side, and two; vapor bubbles. You would naturally fix an air leak and they say the vapor bubbles don't effect anything.

So running the pump circulating fuel removes particles but the vapor bubbles apparently will remain or are regenerated by the fuel sloshing around in the tank.

Anyway I am going to order one of the Davco filters. The 382 filter flows 180 gallons per hour compared to the 25 gallon per hour Fass filter they put on the 100 gallon per hour pump fass pump I bought.

It has, or you can get it, with the water electric alarm indicator and it is a clear bowl so you can see what is happening in there.
Fuel Polishing is mainly used for marine fuel tanks. Like a yacht with 700G of diesel fuel contaminated with moisture or sediment.
A fuel problem 300 miles from land is considerably more serious than a stalled engine on land.
Fuel Polishing for land vehicles is more of a side-effect of de-aerating diesel fuel, or excess fuel from the fuel pump.

The reason for a return line to the fuel tank is, the fuel pump output must be more than a fuel-injected engine can demand at full-throttle. At lower RPM there is more fuel than the engine can use, so the excess is returned to the fuel tank.
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Old 08-25-2020, 04:45 PM   #14
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"fuel polishing" is just a term for the continuous recirculation through the filters of the tank fuel. Of course there is a point of diminishing returns, after any grit / debris from the tank has been captured in the filter and less debris remains near the pickup to be carried to the filter.

While driving around, the fuel is moving / sloshing and anything bad in the tank should eventually be captured by the pickup and sent to the filter. My filters (before the FASS) were getting clogged with something rusty and disgusting looking coming from the tank - which suggests that the tank had or has a significant quantity of trash to remove.

Now about the "air" in the fuel. THERE IS AIR IN THE TANK. Of course there is, b/c as you use the fuel, you have to replace it with something. The "air in the fuel" is separated air that is pulled out of the fuel by the pump cavitation and turbulence. If you were watching a clear tubing to the injection pump, you might see bubbles. A suction system also can pull trapped air out of the fuel b/c of the negative pressure, the bubbles will be the air molecules collecting together. The idea with a FASS is that this entrained air is separated and returned to the tank where it just becomes part of the normal air in the tank.

There is always some absorbed air in the fuel, these are hydrocarbon chains with small numbers of air molecules between them. That's why turbulence in a pump can create foaming, and what the FASS separates out
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