T&T: The case for following manufacturers recommendation: was 2 vs 10 micron filters

[Peter Pisciotta]

> ...almost everyone in the 10 micron camp 
> says the  same thing "this is what the 
> manufacturer recommends". But nobody 
> including the  manufactures can tell 
> them why.

I hate to belabor this - its gone on too long already,
but I really have to summarize the discussion. On the
"2-micron" side, there's logic - and that's about it.
Now, it's pretty good logic from some folks who have
obviously spent some time thinking about this, but
still, logic, and a willingness to accept clogged
filters as long as they are easy to get to and change.

On the other side - the so-called "10-micron" side,
you have major engine manufacturers supporting their
position with warranty dollars and R&D dollars; along
with the filter makers themselves, and even a
smattering of industry experts. All saying to run
2-micron secondary filters on the engine-mounted
filter (you have little choice, though some new
engines come with a 10/2 filter, an outer core of
10-micron filter material and an inner core of
2-micron filter material); and a 10-micron primary
filter (the "Racor" filters).

How big is a "micron?" Well, 10 microns is under
4-10,000ths of an inch, and 2 microns is under a
10,000th of an inch - we're talking microscopic
material that is beyond the ability of all but the
most sophisticated machinery to tolerance. The
'period' at the end of this sentence is over 600
microns. Asphaltines (a common fuel tank crud item"
are incredibly long and bulky substances. Take a
dipper of crystal clear spring water and you may find
giardia, a common bacteria that causes constant
diarreah, and is a whopping 15 microns, absolutely
invisible to the naked eye.

This is microscopic material, not the "pigs and
chickens" floating around your tank (rust,
asphaltines, dirt, etc). Injector tip orifices range
in size from 40-100 microns, barely visible to the
naked eye, but relatively large in the big scheme of
things.

The heart of the 2-micron camp is "if a 2-micron
filter is gonna clog, I want it easy to access." The
experts are saying "why not design a system that
doesn't clog?" More importantly, you won't endanger
your engine and we'll back-up our recommendation with
warranty dollars - and you'll be happier in the long
run.

More logic: stories of clogged 2-micron primaries are
common (Bob Senter's discussion noted a couple on the
Nordhavn Atlantic Rally). But I know of no similar
stories of clogged 2-micron secondary filters that had
a 10-micron primary (or even 30 micron filter for that
matter). 

I don't expect any of the hardcore 2-micron folks to
change their thinking. They have their logic and are
gonna stick to it, regardless of their experience with
microscopic-level particles. But for those who are
undecided, consider the advice of experts: staged
filtration (10 micron primary filter,
engine-manufacturer recommended secondary filter), and
maintain your filtration system - change the filters
regularly. Learn how to change and bleed your
secondary filter (its fast and easy after you've done
it once or twice). You'll be rewarded with a system
that is trouble-free, and worry free.

Peter
www.SeaSkills.com