Diesel Filters

[ITMaster]

Wow Roger

I've just spent the last two hours reading your link about the fuel systems modifications that you have done, as well as looking at and reading all the other very interesting projects. What a most colorful background you have had. Thanks for the link and all your wealth of knowledge and information

Tom

 

[Bob S]

OK, I'm confused. I was reading in a Catalina 30 Yahoo Group about fuel filters. Lots of great info and history on Universal Diesels. Then I remembered this post and re read it. I was out to my boat today and i have a Racor R24S as a primary filter (2 micron). It is located before the fuel pump then I have a Universal # 298854 as a secondary which I believe is a 10 micron filter after the pump. This is how Catalina sets them up. Is there something wrong in their reasoning? It also recommends changing every 200 hours. On my boat that could be every 4 years, the boat only has 280 hour on her after 13 years. She sat on the hard for 7-8 years. I had no problem starting her this past season!

 

[Richard19068]

spin on filters will include an additional letter suffix of either S, T or P. This signifies the original micron rating of the unit when purchased. The letter S is 2 microns, T is 10 microns and P is 30 microns. If the original filter microns included with the unit is not suitable you can easily interchange filters sizes.

 

[gettinthere]

I just bought a boat with a 60 gallon diesel tank. The tank was just installed this March.
The system has a polishing setup, it is separate from the engine fuel system. The polishing pump draws from the very bottom of the tank, runs through a Racor 500 system and back to the top of the tank. I run this about once a month for at least an hour which will cycle about 50 to 60 gallons.

Anything I should be doing different? I'm using the last of the 30mic filters and will be switching to 10mic when they run out.

 

[Roger Long]

Anything I should be doing different? I'm using the last of the 30mic filters and will be switching to 10mic when they run out.

I would change the Racor to a high capacity depth filter with cheap elements like a Shelco and set it up to just run whenever the engine is on. At the cost of Racor elements, you'll pay for the Shelco filter before long and you can probably Ebay that Racor.

See my link above in the thread for the link to my polishing set up.

 

[gettinthere]

I would change the Racor to a high capacity depth filter with cheap elements like a Shelco and set it up to just run whenever the engine is on. At the cost of Racor elements, you'll pay for the Shelco filter before long and you can probably Ebay that Racor.

See my link above in the thread for the link to my polishing set up.

I scanned your posting, nice work.
Sorry if I missed it, but what do I get by switching, other than cheaper filters?

 

[Fairwind]

The gunked up filter looks like the result of algae growth, then a biocide that killed the algae, then the dead algae plugged up the fuel system.. Marine diesel tanks are prone to this. ANY moisture that collects in the tank is enough to support algae growth which results in pictures like Maine posted.. Changing the plugged filter(s) is just the beginning. Boating can be So much fun...Honey, could you take a look at the head? I pushed the handle up and down but nothing happened..Wait, I forgot to open the valve, ..Oh God! come here quick!

 

[Roger Long]

I scanned your posting, nice work.
Sorry if I missed it, but what do I get by switching, other than cheaper filters?

Retention capacity. The thick fiber element of the Shelco, 1/2" vs thick paper, will hold a lot more crud before starting to restrict fuel flow. Repeated passes of the fuel through the filter will trap and remove even smaller particles than the 10 mu rating of the element.

 

[RichH]

The Shelco has about 75-100 grams of 'capacity', the typical Racor about 35 grams. Capacity is NOT the important consideration but rather 'how much work it takes to filter' so that you dont wind up 'extruding' the already captured soft deformable particles. If you monitor your system fuel filters with a gage, and if you are 'careful' with the recordng of the pressures 'accross the filter' versus some benchmark rpm .... when that 'differential pressure' begins to become lower .... either particles are 'unloading' from the filter or the filter has lost its 'strength' and is no longer capturing.

Most of the particles found in fuel systems are soft and deformable and easily driven THROUGH (extruded) such filters, most of these particles are 'globules' of resins formed by funguses (Cladosporium Resinae, etc.).
The best advice I can offer (especially if you have a tank that historically fouls easily) is to put the LARGEST surface area filter in place .... so that you maintain a low differential pressure across the filter.

The benefit of a recirculation polisher is these extremely small 'globules' are continually removed .... and before they come together with another 'globule', join and form ever larger and larger particles. If there are few or no 'seed' particles, then fouling will be very much minimized. In a recirculation system all the 'work' is done 'off-line' from the main fuel delivery system. With a recirculation system even if the tank does become fouled .... eg. breaking off huge sections of attached resins as during a heavey sea state, the HIGH FLOW CAPACITY (~3 gallons per MINUTE) of the recirculation system will rapidly 'recover' the particle distribution in the tank back to 'normal' very quickly.

 

[Roger Long]

Rich,

I must have misunderstood the conversation we had about a year ago because I thought the difference in retention capacity was more. Still, 3 - 4 times is nothing to sneeze at expecially as fuel goes through the polishing filter at 30 - 40 times the rate of engine consumption. Also, retention unit per dollar is off the charts with filters that cost 1/5 - 1/10 as much.

Please check me on another point so I don't misquote or misadvise.

I think you said that the thick depth filter of the Shelco was less likely to extrude particles downstream when loaded than the thin paper element of the Racor. Is that true?

Field feedback, for anyone who didn't read my whole page:

My guages never showed any change over the approximate 100 gallons burned. The Shelco polishing sediment bowl had an impressive amount of aglomerated black stuff in the bottom. I would guess it was enough to start challenging the Racor but it was in the bowl and the element looked to be quite open. Just a color change.

The Racor sediment bowl looked just a clean as the day I filled the system and the element was only slightly discolored.

 

[RichH]

The Shelco will extrude less deformable particles due to it large physical size (2.5" dia X 10" length). The reason for the previous statement is based on the relatively low fluid velocity through the 2.5"Ø X 10".
I dont remember which Shelco filter cartridge you are using but if its one of their 'graded pore density' (melt blown polypropylene microfiber) then yes, it will have significant dirt holding capacity ... my usual experience is almost 125 grams until plugging.

That sediment in the recirc. bowl bottom is probably a 'coalescence' of the gels and soft/deformable particles you find in such tankage systems. They are probably being retained on the surface, then settling by gravity to the sump of the bowl when the system shuts down - a two-phase, liquid-liquid separation in 'filter-speak'. Everytime these 'softies' gets 'squeezed' through the filter media they (can) come together with 1 + 1 = 2 and thus doubles in size .... and so on until ultimately the ever larger physical size gets retained in the filter media --- that the beauty of a recirculation system - it removes vastly smaller particles than the installed filter rated retention, its much cheaper to operate.

I typically need to change the recirc. filter at every 500-700 gallons, even when assaying the fuel to be 'crystal clear' before taking it onboard. Thats using a 10µM (99%) tapered pore geometry filter.

BTW - I recently fiberglass lined / epoxy coated the internals of my old 100 gallon black iron tank (black iron tanks rot from underneath) . Ive been polishing this tank for the past 7 years without any 'maintenance' other than to empty it during the winter. When I opened it .... looked like the day I finished scrubbing it 7 years ago. This tank was recirc-polished every time I had the engine running (at 3 GPM). My Racor system never saw 'any' challenge, no gage pressure changes, no sediment accumulation, etc. during that whole time ... and I get my Racors for free.

Im glad you seem satisfied with your system.

best regards
RichH

 

[Roger Long]

The Shelco will extrude less deformable particles due to it large physical size (2.5" dia X 10" length). The reason for the previous statement is based on the relatively low fluid velocity through the 2.5"Ø X 10".
I dont remember which Shelco filter cartridge you are using but if its one of their 'graded pore density' (melt blown polypropylene microfiber) then yes, it will have significant dirt holding capacity ... my usual experience is almost 125 grams until plugging.

I actually have the half length 5" filters you thought would be sufficient for my 20 hp engine due to space constraints in the engine space. I assume retention would therefore be half as much. Still, plenty more than the Racor 200. Note to anyone considering such a system: the full length housings are practically the same price. Filters are twice as expensive if you can consider about a penny per hour use "expensive"

I'm not sure what kind of filter elements I have now. I just asked for 10 mu as you suggested and what they sent me looks like white yarn wound on a metal screen. In view of the "filter and drop" function you describe, I think I've got plenty of capacity. Do you think these are the melt blown fiber or should I get different elements?

Here's a picture for others interested in what these elements look like:

 

[RichH]

Roger
Thats a 'string wound' filter. Next time get a tapered pore density melt-blown polypropylene filter - much better, more accurate retention plus will have a lot more 'dirt capacity'

 

[Roger Long]

Roger
Thats a 'string wound' filter. Next time get a tapered pore density melt-blown polypropylene filter - much better, more accurate retention plus will have a lot more 'dirt capacity'

Bummer. I had to buy a case of 60. At current consumption rates, there won't be a next time. My kids will be sorting through the stuff I left behind and saying, "What are all these things?"

I sent John Zotter a copy of the email in which you recommended the filter so I guess there was a mix up on their end. Do you know where I can get these half length filters in less than 60 case lots? I want to put the right ones in. I'll have Barbara knit me a nice thick scarf, or maybe a sweater, out of these.