Fuel Filtration 101 & Racor fuel filter numbers

[Ron Hill]

Hawk : Look at my post above. 
If the bleed valve is closed no fuel is returning to the fuel tank.  With the bleed valve cracked open you have a self bleeding system. 

[Hawk]

Ron,
Its gone below 0 degrees celcius here so everything slows down, including my brain.
I re-read the posts. My bleed valve is closed and all works well. So where is the fuel gone that is supposed to go back to the tank if I keep the valve open 1/4?

Thanks,
Hawk

[prh77]

Hawk

            Think of it like this.....with that valve closed, all of the fuel [ a small amount ]  is pumped to the injection pump, and then is used to run the engine. When the valve is open....1/8,1/4 turn or whatever.....part of the fuel pumped through is still being used to run the engine, and the rest [a greater amount ] is being bypassed back to the the fuel tank, only to be pumped through the system again.

[Hawk]

OK got it.  Newly "polished" fuel is going back into the tank making for a better tank of fuel over time.

Thanks

[Stewartn]

If it helps, here are the numbers I use. I am sure the book calls for a 30 Micron primary and a 10 Micron secondary (engine). Why use a 2 Micron? Sounds like overkill, if Universal says 10 is OK.
Hope it helps.

Universal     M35 B      SN WW 2556 D904               

Fuel Filter, Engine         Universal # 298854       NAPA 3390 or WIX 33390
                                                   10 Micron
      
Oil Filter                      Universal # 300209    NAPA 1334 or WIX 51334

Primary Fuel Filter         Racor #    R 15 P 30 Micron (Red Top)            
Raw Water Impeller      Universal # 302875     or   Sherwood #  0900K

Alternator Belt         Gates 11A1015 Notches         

[Ron Hill]

Stewart : Thanks for the Info. 
The belt # you are using is a metric number and depends on whether you have the OEM alternator or not ??   What may change the length from the belt is a differant alternator!
I have a Balmar Hi out-put alternator and use a 11A1030 meteric size or 7405 Gates belt size SAE.

Hawk & Guys : What you need to do is to is disconnect the small fuel return line (last injector) on any Universal engine that has a closed bleed valve and turn on the electric fuel pump.  You'll be surprised to find that NO fuel flows.  However, open the bleed valve and you'll have a gusher coming out trying to go back to the fuel tank!! 
Don't try this with a M25XPB or M35 engine as the electric fuel pump will not engage until the glow plugs are activated and neither have a bleed valve!!   A few thoughts

[Hawk]

Ron,
I thought mine was a M35 as there is no B on the engine ID plate on my 1990. Does that sound right.

Hawk

[sail4dale]

Boy  here is is again ..... Filtration 101   For the simple record:  The first filter after the tank is the 15 micron and the final filter at the engine is the 2 micron. 

I makes no sense to filter initially at 2 micron and then down-stream put in a coarse filter that passes larger particles that you have already filtered out.

I worked for Parker and sold hydraulic and pneumatic filtration for 33 years.

[Ken Juul]

From the scientific point of view you are entirely correct.  Now ask yourself.  If I had to change a fuel filter on a hot engine in a bouncy seaway which one would you rather change?  I'll go with the racor every time.  Yes the second filter is not doing what it was designed to do, but in case of a bypass it wil protect the engine.  It also doesn't need to be changed that often which helps off set the higher cost of the racor elements.

[sail4dale]

If you use a 2 micron filter as the primary then you will NEVER  have to change the spin-on.  You will also
find yourself changing the primary Racor a lot more often. 

But, as a stockholder in Parker Hannifin I encourage you to keep buying a lot of Racor filter elements.

I would however flunk the class attendee that gave that plan on a test in a class that I taught.

Te each his own 

[Mike and Joanne Stimmler]

I only change my 2 micron racor filter once a year, that's not all too often.
If you have to change it more often than that, then you know you have a problem that has to be addressed.

[Hawk]

I know my primary is the Racor 24T which is the 10 micron. Never a problem, but I keep my fuel treated and "biocided".

[DaveM]

I read somewhere, I thought on the Racor site, that the water separator on the 500fg primary filter doesn't work well with a filter size less than 30 microns.  That has me with a 30 micron on the primary and a 2 micron on the engine.  Sail4dale or anyone else who may know does this make since or am I dreaming it.  I am getting old.

Goodwinds
DaveM

[sail4dale]

The Racor literature says that water separation is effective in all the micron sizes and the Aquabloc®II filter element takes care of the water.  They are currently touting the 10 Micron filter element as the standard. 

As for me wen I next but a replacement element I will  get a 10 micron but certainly not a 2 micron.  The fuel we buy is so dirty with particles below 40 microns that I feel the clogging of the 2 micron isn't worth it along with the corresponding pressure drop. 
It is important to keep in mind that a liquid that looks clean is not necessarily so.  The human eye can only detect particles above 40 micron without a scope. 

[Mike and Joanne Stimmler]

DaveM, are you sure that you have a 2 micron filter at the engine? Is it a spin on type because I wasn't aware that they were available in the spin on type.Do you have the part number because I would consider using one.

sail4dale,I haven't had any problems with dirty fuel in California, are you sure your tank isn't contanimated?
As I said, my 2 micron Racor lasts me all year with no problems, also no water ever in the bowl. I must be doing something right.