[C320-list] Perkins M30 diesel water temperature sending units

[Mark Seyler]

The filter size for the Racor and the secondary filter generate conflicting
opinions.  I personally think it depends on how much you use your motor, and
how often you are willing to change the filter.

On my boat, I use a 2 micron filter on both my Racor and my secondary
filter. I also usually change the Racor when I do an oil and oil filter
change once a year in the winter, even though I am nowhere close to the
maximum number of engine hours the manufacturer recommends.  Some would
argue what I'm doing is overkill.  But it's a lot cheaper to replace a
filter than to rebuild an injector pump if enough crud gets through the
filter to damage the pump.  And I'd also rather change the filter at the
dock, on a day when there's no wind to sail, instead of while bouncing
around after a clog shut down the motor.

I've seen the argument that the 2 micron filters could starve the engine.
But according to Racor the maximum flow through the filter (when new) is
something like 12gph.  My Perkins only burns about 1/2 - 3/4 gph at cruising
speeds, so I think the filter would have to be pretty thoroughly clogged to
get below that flow rate.  With an annual change of the Racor, and changing
the secondary every 2-3 years, I haven't encountered any problems with
clogging.  But the longer you go between filter changes, the more chance
that the finer filter could get clogged.

You can also find differing opinions about whether the secondary filter
should be the same size as the Racor. Theoretically nothing should be
reaching the secondary filter that is bigger than the screen size of the
Racor filter.  If you use a finer filter on the secondary than the Racor, it
could catch things that got through the Racor, but then you're more likely
to clog the secondary filter.  Some folks argue that using a slightly
coarser filter on the secondary means that it is less likely to clog from
bad fuel, and you'll only have to change the Racor if a clog shuts down the
engine.  But even then I'd want to at least use the coarsest filter size
that would protect the injector pump.  (Maybe a 10 micron?)

For me it's not that hard or that expensive to do the Racor when I change
the oil and oil filter, and I've had no problems with the finer filters on
that schedule.  But if I were using the motor more hours, I might make a
different choice.  I wish you good luck with whatever choice you make.

Mark Seyler
S/V Reality, 
Catalina 320, #232
New Orleans, LA



-----Original Message-----
From: C320-list [mailto:c320-list-bounces at lists.catalina320.com] On Behalf
Of Bob Borelli
Sent: Monday, January 20, 2020 9:19 PM
To: C320-List at Catalina320.com
Subject: Re: [C320-list] Perkins M30 diesel water temperature sending units

Thanks Charlie,  for your response.

My next trip to the boat I will be testing the sender, wiring, connectors,
alarm & horn, and determine the thread size on the water pump sender & see
if I locate a new sender.

I've changed several raw water impellers this season.
First 10-blade lasted 39 hours, 2nd 6-blade 8 hours & current 10-blade 9
hours already has 2 deformed blades.
I grease them before inserting in the pump.  These are Jabsco impellers
18673-0001/0002.

The boat is in a wet slip, winterized diesel.
I will change the fuel filters in April.
Question is which filters.
Currently the primary is a Racor 24S 2 micron & the secondary Perkins
130366020 (4429491) 25 microns.

The marina's diesel guy says the 2 micron primary is starving the diesel &
should change both filters to Racor 24T 10 micron and secondary NAPA 3386 10
microns.

The boat came with the 24S & Perkins, I not sure I want to make a change in
filters.

What fuel filters are you using on on your Perkins M30?

Bob Borelli
C320 #209
Maryland



________________________________
From: C320-list <c320-list-bounces at lists.catalina320.com> on behalf of
Charles Holbrook <charlesholbrook at ymail.com>
Sent: Monday, January 20, 2020 11:38 AM
To: C320-List at Catalina320.com <C320-List at Catalina320.com>
Subject: Re: [C320-list] Perkins M30 diesel water temperature sending units

Thanks for your detailed explanation of your wiring and alarm system.  I too
have a 1995 Cat 320 #192 and I had an engine temp. issue last year but my
audible alarm and red indicator light worked.  Glad to know that as I never
tested it.  Turns out a small fish got sucked up into the intake.  The
strainer stopped anything from getting into the cooling system but I had no
water flow and a couple of pump impellers were damaged.  I just jury rigged
my air compressor hose and gave the main water intake a short blast of air
and it cleared out the system.
Charlie Holbrook, Port Clinton, Ohio"Nautigirl"
    On Wednesday, January 15, 2020, 08:16:45 PM EST, Troy Dunn
<troutwarrior at gmail.com> wrote: