Salt water diesel cooling
Ralph F. Mudge
I am looking at a 1981 boat that has salt water cooling....no
intercooler. I guess it is also called raw water cooling.
How much of a problem is this to engine longevity?
Sean Holland
The problem with Raw water cooling, is twofold. While much of the
corrosion may be eliminated with proper changing of the internal zincs,
the engine cannot run at a sufficient temperture for efficient operation,
as salt water thermostats are significantly cooler than for fresh. I
converted my Yanmar, and found it runs hotter, has more power, and
certainly makes better hot water for showers. I prefer to cool with a
heat exchanger rather than use raw water, but would imagine your life
expectancy would not be seriously degraded if the engine is properly
maintained. (That is the life expectancy of the engine!)
Good Sailing,
Sean
--
Sean Holland
NP2AU
S/V Spindrift
yac...@sailing.lover.org
In article <32F380...@frontiernet.net>,
"Ralph F. Mudge" <sai...@frontiernet.net> wrote:
>
> I am looking at a 1981 boat that has salt water cooling....no
> intercooler. I guess it is also called raw water cooling.
> How much of a problem is this to engine longevity?
I took a diesel class a few years ago from one of the better-regarded
mechanics here in Annapolis. He expressed the opinion that the *only*
significant difference between raw- and fresh-water cooled engines is the
operating temperature of the engine itself. The FWC engine operates at
around 180F and the RWC at about
108F.
This affects the temperature of the water in your hot water tank. HTH.
Bryan Genez
"Capella" Valiant 40 #158
-------------------==== Posted via Deja News ====-----------------------
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Jere Lull
Ralph F. Mudge wrote:
>
> I am looking at a 1981 boat that has salt water cooling....no
> intercooler. I guess it is also called raw water cooling.
> How much of a problem is this to engine longevity?
Properly maintained, should last essentially forever, but salt causes
corrosion and can salt deposits can build up, creating excess heat,
creating other problems. Hardly anyone maintains them properly any more.
--
Jere Lull
Xan-a-Deux
'73 Tanzer 28 #4
out of Georgetown, MD
See how Xan-a-Deux looks at http://www.castle.net/~jerelull/X-Main.html
Bruce P. Barden
In article <8548318...@dejanews.com>, yac...@Sailing.lover.org wrote:
>In article <32F380...@frontiernet.net>,
>>
>> I am looking at a 1981 boat that has salt water cooling....no
>> intercooler. I guess it is also called raw water cooling.
>> How much of a problem is this to engine longevity?
>
>mechanics here in Annapolis. He expressed the opinion that the *only*
>significant difference between raw- and fresh-water cooled engines is the
>operating temperature of the engine itself. The FWC engine operates at
>around 180F and the RWC at about
>108F.
>
>This affects the temperature of the water in your hot water tank. HTH.
>
>Bryan Genez
>"Capella" Valiant 40 #158
It is a little more compex then this. Salt water forms a scale (for
want of a better word) coating inside the cooling passages of the
engine. This scale formation is influenced, to a great extent, by the
temperature of the cooling water. Since an internal combustion engine
is effectively a device for converting heat to mechanical energy the
hotter the engine runs the more energy is produced (within the limits of
the materials used in the engine, of course).
If a sea water cooled engine is run at the same temperature as a fresh
water cooled engine, to develop the same power power, it will develop
scale in the cooling passages which inhibit the transfer of heat making
the coolant less effective and on and on until the cooling passages clog
and you "burn up" your engine.
The solution used by fishing boats in Australia, and perhaps in other
places, is to use direct sea water cooling but to flush the engine with
a dilute solution of acid every season, or two, when the engine begins
to run hot.
A cruising Yachtie friend taught me the trick (which he had learned from
the trawler crews in Australia). In fact the acid solution he had was
purchased in Australia from a ship chandelier that catered to the fishing
industry. I believe that it was sulfuric acid, water and detergent
(used as a wetting agent).
You disconnect the water inlet and outlet hoses and stick the inlet into
a bucket of this stuff -- start the engine and ran it at low speed
until you get a good flow from the outlet hose. Plug the hoses and shut
down the engine -- wait an hour or so and reconnect the hoses and start
the engine. Run it for 20 minutes or so to flush everything out and
you've got a clean engine for another few years.
As far as longevity goes, the Yachtie friend has been using the same
Yanmar 3 cylinder for the past 15 years.
--
---------------------------------------------
Bruce P. Barden
bru...@pacific.net.sg
Singapore
---------------------------------------------
Bryon Kass
Jere Lull wrote:
>
> Ralph F. Mudge wrote:
> >
> > I am looking at a 1981 boat that has salt water cooling....no
> > intercooler. I guess it is also called raw water cooling.
> > How much of a problem is this to engine longevity?
>
> corrosion and can salt deposits can build up, creating excess heat,
> creating other problems. Hardly anyone maintains them properly any more.
>
> --
> Jere Lull
> Xan-a-Deux
> '73 Tanzer 28 #4
> out of Georgetown, MD
> See how Xan-a-Deux looks at http://www.castle.net/~jerelull/X-Main.html
engines come close this. Volvo MD1 and 2 (B) are still around with
some help from the 60's and Yanmar QM and YS and S series engines
from the early mid seventies. The only ones I have seen from the
recent engines that rot through are the Universal (Kubota) 2-11
or 5411 engines that were from the early 80s. The newer fwc version
of course are fine. The Yanmar 1-3GM raw water seem OK as I have one
from 81 and have seen the loacal factory rebuild them which is a good
sign. There are zinc anodes in most of the engines that should be
inspected and changed. A boat with electrical leakage can kill any
seawater engine quickly.
Bryon Kass
webmaster and
Custom Design
150 Mechanic St.
Foxboro, MA 02035
508-543-9068 or fax 508-543-5127
in THE ENGINE ROOM http://www.ici.net/customers/cusdn
Steve Weingart
In article <dY68yMfU...@pacific.net.sg>, bru...@pacific.net.sg (Bruce P. Barden) wrote:
>
>If a sea water cooled engine is run at the same temperature as a fresh
>water cooled engine, to develop the same power power, it will develop
>scale in the cooling passages which inhibit the transfer of heat making
>the coolant less effective and on and on until the cooling passages clog
>and you "burn up" your engine.
Too true...
>
>The solution used by fishing boats in Australia, and perhaps in other
>places, is to use direct sea water cooling but to flush the engine with
>a dilute solution of acid every season, or two, when the engine begins
>to run hot.
This works. You can also add a tap to fill the engine with dockside fresh
water after use, many Atomic 4 owners do this and the frest water will disolve
the deposits slowly over the week when the boat is not used.
>
>A cruising Yachtie friend taught me the trick (which he had learned from
>the trawler crews in Australia). In fact the acid solution he had was
>purchased in Australia from a ship chandelier that catered to the fishing
>industry. I believe that it was sulfuric acid, water and detergent
>(used as a wetting agent).
It's simpler than that, just use plain white vinegar and leave it in the
engine for about 24 hrs. I don't follow my above advice and I've had some
salt-up in my engine, the vinegar works fine (but the addition of a little
soap as a wetting agent is a great idea).
>
>You disconnect the water inlet and outlet hoses and stick the inlet into
>a bucket of this stuff -- start the engine and ran it at low speed
>until you get a good flow from the outlet hose. Plug the hoses and shut
>down the engine -- wait an hour or so and reconnect the hoses and start
>the engine. Run it for 20 minutes or so to flush everything out and
>you've got a clean engine for another few years.
Same thing, but you really don't have to plug anything, there will be no real
flow once the engine stops (the raw water inpeller prevents any flow, or just
shut the seacock). So, you can use the harsh stuff for 20 min, vinegar for 24
hrs, or fresh water whenever the engine is not being used, they all work.
To make it easy, you can install a T in your water inlet line with a second
ball valve to an aux hose for filling the engine (this is also consider by
some as a possible emergency bilge pump as well, but I don't like it because
you can end up with a water leak *and* a plugged cooling system at a very bad
moment :-)
>
>As far as longevity goes, the Yachtie friend has been using the same
>Yanmar 3 cylinder for the past 15 years.
>
The Atomic 4 in Wyvern is 30 YO and still going strong...
Steve
Skyler Stone
There was a mention of electrical leakage increasing corrosion on raw water
cooled motors. I own a 1975 Farymann R/30, raw water cooled. I am in the
middle of top end over haul and would like to (A) check electrical leakage out of
the boat, and (B) possibly add anoids to the motor. When I bought the Cal 34 that
the motor is installed in I found no thermostats in the engine. I am thinking
about tapping anoids into the thermostat housing. Is there any reason why I
should not perform this operation? and what is the best way to check electrical
leakage out of the boat?
Bob Fifer
The procedure is explained quite nicely in Nigel Calder's book. "Marine
Mechanical and Electrical Manual". One uses a volt/ohm meter to measure
current flow in various points on the boat where bonded throughulls are
installed. The book is well worth the $30 price, and is available at West
Marine or through Boat U.S.
I have a Farymann 18W that has a thermostat rated for >140 deg. F. Above
this temperature scale will precipitate out of seawater. My earlier
Farymann, (k34M) had the thermostat removed by the previous owner. I
recommend that you install a new one of the proper temperature range
(opening at less than 140 deg), otherwise your engine will be running too
cold. This will cause poor combustion and possible dilution of lubricating
oil with unburned diesel.
Farymann does not recommend installation of zinc anodes, but I don't see
why they wouldn't aid in preventing corrosion of the Cylinder sleeves and
head.
PRP in New Jersy is current supplier of parts, but I don't know how much
tech info you can get from them.
I wish that I could talk to a Farymann engineer regarding this very
question about zinc anodes.
Good luck,
Bob Fifer
R...@brown.edu
Tom Heacock
"FM<>I am looking at a 1981 boat that has salt water cooling....no
"FM<>intercooler. I guess it is also called raw water cooling.
"FM<>How much of a problem is this to engine longevity?
I had an O'day 28, 1983 with a salt water cooled 11 HP diesel. I had no
trouble due to salt build up. I kept it in the lower Chesapeake which
is relatively high salinity. I am freinds with the guy who bought it
from me (Isn't that strange?) and I know he still has had no
salt-related failures or problems.
---
* SLMR 2.1a * Perseverance O'Days Forever
---------------------------------------------
* Ship To Shore...For Sailors (703)525-1458 *
---------------------------------------------
Bryon Kass
quite a long time raw water cooled. Some engines like the Kubota
based Universal 2 cyl do not.
JKline6766
A salt water cooled engine, used regularly, is not a problem. When they
sit for long periods of time, passages tend to block and no amount of acid
will unblock them. I have had to remove heads and physically rod out the
passages to get the cooling flow back.
The real problem is temperature. If two idenical engines are placed in
equal service, one being salt water cooled, and the other heat exchanger
cooled, the heat exchanger cooled one will have less wear on it. The
reason is simple. The parts were sized to run at between 180-195 degrees
opperating temp of the engine. If you have a thermostat that opens at a
lower temperature, the engine is always running cold and there is more
clearance between the piston and cyl. The higher the temp, the more
efficient the combustion and less oil contamination.
However, in actual practice, with moderate, non- comercial use, a salt
water cooled engine will have enough longivity to keep its owners happy
for many years.
JIm
RHitchc615
I have a C&C 34 with a Yanmar 20 and raw water cooling. My engine zincs
need replacing about every two years, and I understand that if they aren't
replaced when needed, the ionization will start to dissolve your engine.
Bruce P. Barden
In article <19970223215...@ladder02.news.aol.com>,
Exactly. The zincs (sometimes know as sacrificial anodes)
erode away rather then the engine block itself. I've got the
same engine and with new anodes installed 12 months ago I'd
say that they have lost about 25% of their area in a year.
--
Bruce P. Barden
bar...@ibm.net
Bangkok, Thailand
after 24 Feb I may be contacted at:
bru...@pacific.net.sg
-------------------------------------------