[Sentoa] Fuel Filter Size???

[Simon Bergen-Henengouwen]

The consensus from 2 trawler owners I met at the dock seems to be 
with you Ron.  Use 2 microns at the primary and larger if need be on 
the secondary. BTW mine is not a common rail or electronic fuel 
injection engine.

Just to add "fuel" to the fire I was reading further that the 
rationale for putting the larger before the smaller is that you need 
a large filter for the pump and after that a small one for the 
injectors.  The argument is that if the fuel pump is run with little 
or no fuel it could overheat and damage the pump.  I thought however 
that on the Cummins both filters are before the pump so this is a 
non-issue. I also read an article where someone had twice tried 
putting a vacuum gage AFTER the secondary filter and had it burst 
both times with resulting dangerous fuel spillage near a hot 
engine.  The reason given was that this was caused from the high 
pressure pulses close to the pump. I believe the vacuum gage needs to 
be BEFORE the secondary filter and AFTER the primary as all of the 
literature I have read seems to suggest.

Can you send me the Issue # of Pasagemaker Jim?  Thanks.

Simon Bergen-Henengouwen
Sinoma
NT32-217 (2002)

At 07:59 AM 10/16/2008, you wrote:
>The QSB 5.9-380 in our 37 uses a 2 micron secondary on-engine 
>(FF5488).  The boat was outfitted with 2 micron elements in the 
>primaries, 10 micron elements factory kitted for replacement.  That 
>is consistent with the Cummins spec and other literature I've 
>read.  BTW, there was a good article in Passagemaker last year on 
>filtering, worth reading.  I'm pretty sure I saved it, will look and 
>forward the issue # if you're interested.
>
>My thought on "reversing" the stages (ie, fine before coarse) is 
>that it's kind of like vacuuming your kid's room - good idea to pick 
>up the pizza crusts before breaking out the Lady Kenmore.  I think 
>it would likely drive up the pressure drop and lead to more frequent 
>element changes. Perhaps even a "clog", which of course is the 
>condition you're trying to avoid.  I also believe there are fuel 
>delivery considerations applicable to the common rail engines (ie, 
>the QSB), that don't come into play for the engines you 
>mentioned.  That may explain some of the differences in the 
>manufacturer recommendations.
>
>But I do agree, that the subject is a favorite for debate, here and 
>elsewhere.  There are plenty of opinions to be had!
>
>Jim Waskowich
>Grand Adventure
>NT37-142
>
>
>--- On Thu, 10/16/08, Seasalt007 at aol.com <Seasalt007 at aol.com> wrote:
>
> > From: Seasalt007 at aol.com <Seasalt007 at aol.com>
> > Subject: Re: [Sentoa] Fuel Filter Size???
> > To: sentoa at lists.samurai.com
> > Date: Thursday, October 16, 2008, 8:14 AM
> > I have never used anything but a 2 micron primary. This
> > includes the tug
> > with a 330 Cummins and my last boat with twin 485 hp
> > Detroits. I change them
> > fairly often because it is cheap insurance and since the
> > secondary is 20
> > microns. When I was cruising full time I changed every 100
> > hours. When the boat
> > sits, I change every 6 months regardless of hours. They can
> > get old and began to
> > deteriorate.  Many would say that I am wasting my
> > money...but alas it is  mine
> > to waste.
> >
> > This subject has been debated many times and there are
> > those who swear by
> > what they do. The engine manufacturers also say not to use
> > a 2 micron...but they
> >  never say why.
> >
> > Ron Carter
> > Sedona 42-19
> > Punta Gorda, FL
>
>
>
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