[C320-list] Engine noise

[Stephane Rousseau]

Hi,


Your are right Kirk,

And Diesel engines need to be run at least at 3/4 of the max. rpm. in
order to burn diesel properly. Running the engine below to often will
build varnish on cylinder ring and with time the engine will do
blowby.


Stephane Rousseau
Wedidit II #544


On 7/18/07, Kirk McCullough <kirk.mccullough at telus.net> wrote:
> Jeff
>
> This makes sense to me. Plus at higher RPM you get there faster and run up
> fewer engine hours.
>
> Kirk McCullough
> Boomerang #124
>
> ----- Original Message -----
> From: "Jeffrey Hare" <Catalina at thehares.com>
> To: "'C320-List'" <c320-list at catalina320.com>
> Sent: Tuesday, July 17, 2007 6:49 AM
> Subject: Re: [C320-list] Engine noise
>
>
> > Hi Brian,
> >
> >  As usual, I summarized in a way that isn't completely accurate.  There
> > are
> > a lot more factors, and many of them I don't yet understand.
> >
> > Specifically, I should have said that motoring to a *specific destination*
> > at 1000RPM will typically take more fuel than motoring to that same
> > destination at 2900RPM.  The exception here might be if you have an
> > autoprop
> > that self-pitches, or a Gori and can motor in overdrive, but the research
> > I
> > was reading didn't address that.
> >
> > I'm still studying this, but from what I understand so far, if you
> > decouple
> > the engine from the prop and just look at fuel consumption over the RPM
> > range, lower RPM burn less fuel than higher RPM as you would expect.  But
> > that doesn't tell the story.
> >
> > When looking at HP transmitted to the water, lower RPM burn more fuel per
> > HP
> > transmitted to the water because (as I interpret it) the propeller curves
> > and engine curves  are only optimal around the engine's "sweet spot".
> > Which
> > is ~2900+ish for the Yanmar 3GM.  As you go outside that sweet spot with
> > lower RPM you're burning more fuel/HP transmitted to the water.
> >
> > So... It seems that you do indeed burn less fuel at lower RPM, but getting
> > to a specific destination may require a little more fuel if you motor
> > there
> > at low RPM.
> >
> > This may account for why some people say the yanmar burns ~.5 gal/hr and
> > others say they use ~.7 gal/hr.  Different props, different RPM used on
> > average, etc...
> >
> > If anyone out there has read the prevailing research and understands it
> > better, chime in.  :)  Typically you find this research when attempting to
> > compare the efficiency of diesel/electric vs. plain diesel drive systems.
> >
> > -Jeff
> >
> >
> >
> > -----Original Message-----
> > From: c320-list-bounces at catalina320.com
> > [mailto:c320-list-bounces at catalina320.com] On Behalf Of Amirault Family
> > Sent: Monday, July 16, 2007 5:51 PM
> > To: c320-list at catalina320.com
> > Subject: [C320-list] Engine noise
> >
> > Jeff:
> >
> > The diesel giving higher consumption at lower revs IS counter intuitive.
> > Could you give a brief overview of the theory? It has me curious and an
> > understanding my lead me to begin using higher revs.
> >
> > Brian Amirault
> > 797 Waltzing Bear, too
> >
> >
> >
> >
> >
> >
> >
> > --
> > No virus found in this incoming message.
> > Checked by AVG Free Edition.
> > Version: 7.5.476 / Virus Database: 269.10.8/906 - Release Date: 7/17/2007
> > 6:30 PM
> >
> >
>
>
>