Re: T&T: Running higher HP engines at low speeds.
A number of "experts" told me that the fact that your temperature gauge
reads 180-degrees doesn't mean that the INTERNAL temperature of the engine
is high enough to burn efficiently. My gauge will go up to 180 at high idle
after a while. The thermostats are obviously clicking in. When I run at
3200 RPM or so, the gauge definitely goes up a bit. (NOTE: Low tech
analogue gauge.) IF this is true, some folks may THINK they're running
their engine(s) up to temperature, but they're really not????
Allen Ames
SESAME, Liberty Park anchorage, New Jersey
blog: http://camano130.blogspot.com/ http://camano130.blogspot.com/
photos: http://community.webshots.com/user/allen_ames/
http://community.webshots.com/user/allen_ames/
From: "Allen Ames" sesame@snet.net
To: trawlers-and-trawlering@lists.samurai.com
Subject: Re: T&T: Running higher HP engines at low speeds.
Date: Fri, 21 Sep 2007 07:50:42 -0400
<"experts" told me that the fact that your temperature gauge
reads 180-degrees doesn't mean that the INTERNAL temperature of the
engine
is high enough to burn efficiently.
Allen et al,
What a great discussion - the reason this list is so valuable!
Following on Allen's comments and question - talking about a Perkins
6-354 - if the engine temp. is indicating normal range (175F), does
it matter what RPM is used - can damage (glazing etc.) occur during
long stretches of 1000 rpm usuage under load (underway) with engine
temp. at 175F?
Jim on Jazz
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I know that this topic has probably been beat to death and should be allowed
to die out gracefully, but I noticed that the same topic showed up today on
boatdiesel and my hero, Tony Athens opined on it. Well more than opined.
Tony quoted his extensive real world experience and the experience of his
bros boat with twin Yanmar 370s, which incidently now has 2500 hours on
them. Here is his post:
Robert,
I have been dealing with high hour annual use marine diesels for over 25 yrs
with 100,000's hours of operation, and I have yet to see a marine diesel
engine suffer from low speed operation..
But, I see the exact opposite every month and make lots of $$ because of
it..
A very recent example of low speed use is an 18 day charter my Bro's boat
just completed ( this week) , tagging about 150 Thresher Sharks for the CFG
here in S. Calif.. 18 days, 240 hrs on a pair of 370 Yanmars, 360 hours on a
Cummins 45 Kw gen set, and 853 gallons of total fuel burn between all
engines..
You figure out the duty cycle.. But that's low speed running to the max, and
I would not expect to see not less than 25000 hrs on the gen before anything
shows up, and 10,000+ hrs on the mains .. In the last 24 months , he has
logged about 2500 hrs on the mains and about 3500 hrs on the gen set.
Low speed running = high hour long term hassle free use and much $$ saved in
my book..
Just remember that coolant temps need to stay at thermostat opening temps,
and a 2-10 minute , medium to high speed cruise "clean out" needs to be done
every once in a while ( maybe every 20 hrs or so) if pyro temps after the
turbo are below 650F when low speed running.......
Tony