[C320-list] exhaust elbow question

[Len]

Checked the tachometer on my 3YM30 with a photo tachometer (put reflective
tape on flywheel, infrared beam reads actual rpms) and at dock in
neutral found boat tach @ 2,500 rpms actually 2,775 rpms, full throttle boat
tach @ 3,450 actually 3,775.  Each tach may vary, but suggest worth
checking.  Plan to recalibrate tach to be closer to reality soon.

Len Krane
Aqua5  #1070
Marina del Rey, CA


On 10/6/06, Allan Field <Allan.Field at comcast.net> wrote:
>
> While at the Annapolis Boat Show today, I talked with the Mack Boring rep
> regarding the Yanmar diesels.  Here is what he said.
>
> Warm-up in neutral at idle speed of 900-1000 rpm.  We should be able to
> hit
> hull speed between 2700 and 3100 rpm and we should be able to reach
> 3500-3600 rpm's.  But he acknowledged that many of us have problems doing
> so
> due to, "screwing around with different prop configurations".  The engine
> is
> designed for continuous operation at three-quarters of maximum rpm's (3600
> x
> .75 = 2700).  He also said that the engine mounted tachometer will read
> about 150 rpm's less than actual.
>
> When shutting down, put it in neutral, let it idle for 3-5 minutes, then
> shut down.  If the engine has been run for a long time at low speeds,
> after
> the 3-5 minute cool down period, rev it up in neutral 2-3 times then shut
> it
> down.
>
> Based on something I was told long ago, I make sure that every time I take
> the boat out, I run at 3000 rpm's for at least 10 minutes.
>
> The rep also gave me a brochure for their 1 day classroom followed by
> 2-day
> hands-on classes.  This has been on my Good Intentions List for sometime
> now...
>
> Hope this helps...
>
> Allan S. Field
> Sea Shadow - #808
> Columbia, MD
>
> -----Original Message-----
> From: c320-list-bounces at catalina320.com
> [mailto:c320-list-bounces at catalina320.com] On Behalf Of jonvez at comcast.net
> Sent: Friday, October 06, 2006 8:32 AM
> To: C320-List
> Subject: Re: [C320-list] exhaust elbow question
>
> Bruce,
>
> I agree and will change my SOP. One has to balance logic against all of
> the
> 'experts' out there--another testament to this list as it's great to
> bounce
> these things off everyone and get a sanity check.
>
> Regards,
>
> Jon
>
> -------------- Original message --------------
> From: "Bruce Heyman" <BruceHeyman at cox.net>
>
> > Jeff/Jon,
> > If you only put 50-100 hours on your engine per year then you have at
> least
> > 40 years before you have to worry about it. If however you are blessed
> with
> > year round access to the water but cursed by the typical wind forecast
> of
> > "....light and variable, less than 10 knots...." which translates to 2,3
> or
> > 4 knots at best and almost guaranteed to be on the nose you will put on
> may
> > more hours.
> >
> > The typical 18 wheeler seems to get 1m miles or more before the engine
> is
> > torn down or replaced. I'm guessing that they are only driving on the
> road
>
> > for 2-3000 hours per year but they generally leave the engine idling
> even
> > when they are eating, sleeping, fueling, loading, being weighted.... so
> they
> > probably end up with 5-6000 hours per year. At a million miles that
> means
> > that they rebuild/replace after about 7 years or 42,000 hours.
> >
> > Wouldn't it be great if we could get 42k hours out of your little
> diesels!
>
> > Now that our boats are made out of what Hershoft called "frozen snot"
> the
> > boats last forever, provided they are reasonably maintained and
> upgraded.
> > Which means that boats that are 30-40 years old are very serviceable and
> > very popular and usually are priced in the 20-30k range? Not fun when
> you
> > have to spend 8-15k to re-power, you will never get that money back!
> >
> > While I could be wrong I don't think I agree with it is ok to rev the
> engine
> > when it is cold, even when it is during warm weather. Our engines are
> made
>
> > with all sorts of alloy's which have different temperature coefficients
> of
>
> > expansion. The designers take these into account when they design and
> > manufacture the engines. This means that when the engine is cold you do
> not
> > have the right tolerance in the bearings, gears, rings, valve stems,
> push
> > rods.... This means then when our high compression engines fire all this
> > "slop" results in additional noise, vibration and it would seem to me
> wear.
> >
> > When we start our engine we seem to go through two transitions. The
> first
> > is very quickly after starting, the low oil alarm goes off and the
> really
> > loud pinging becomes just loud pining. I assume this is most of the
> parts,
>
> > lifters, bearings, rings.... are getting a dose of oil. The second
> > transition is after 3 to 10 minutes and seems rather abrupt. I assume
> the
> > combustion chamber is now up to temperature and the fuel is being burnt
> > evenly, the engine just seems to settle down and run smother and
> quieter.
> >
> > I think I'm going to continue to be gentle (no throttle) with the engine
> at
> > start but based on this discussion I am going to rev the engine at the
> end
>
> > of the day before it is put away for the last time. What do people
> > recommend, let it run up to 4000 RPM and then pull the kill or run it up
> to
> > 4000 RPM then throttle back and kill it when it is back to 900?
> >
> > Bruce
> > Somerset 671 SoCal
> >
> > -----Original Message-----
> > From: c320-list-bounces at catalina320.com
> > [mailto:c320-list-bounces at catalina320.com] On Behalf Of
> jonvez at comcast.net
>
> > Sent: Wednesday, October 04, 2006 9:58 AM
> > To: catalina at thehares.com; C320-List
> > Subject: Re: [C320-list] exhaust elbow question
> >
> > Jeff,
> >
> > I think you have the right perspective...The same mechanic/trainer also
> > said, anything you do to these engines may be a matter of whether you
> > rebuild it after 4000 hours or 10,000 hours-- at 50-100 hours a year,
> either
> > way, it's a loooong time and a lot of abuse.....
> >
> > Regards,
> >
> > Jon Vez
> >
> > -------------- Original message --------------
> > From: "Jeffrey Hare"
> >
> > > Hi Guys,
> > >
> > > Don't sweat the warmup/revving thing. Most agree you shouldn't load it
> > > until it's warmed up, but reving a diesel after starting it in the
> summer
> > is
> > > simply a non-issue. In the middle of winter is a different story
> because
>
> > > the oil doesn't flow well.
> > >
> > > Revving a *Gas* engine that hasn't warmed up for a couple minutes in
> cool
> > or
> > > cold weather is a different story. Gasoline washes the oil off the
> > cylinder
> > > walls, while diesel doesn't really suffer from that phenomenon given
> that
> > > Diesel fuel *is* oil.
> > >
> > > Clean oil, clean air, and clean fuel, running it hard/fast it'll
> outlive
>
> > > many of us.
> > >
> > > -JeffH
> > >
> > >
> > >
> > > -----Original Message-----
> > > From: jonvez at comcast.net [mailto:jonvez at comcast.net]
> > > Sent: Wednesday, October 04, 2006 10:52 AM
> > > To: John Van Vessem; C320-List
> > > Subject: Re: [C320-list] exhaust elbow question
> > >
> > > John,
> > >
> > > I am certainly not an expert on this, but the info. I received was
> from
> a
> > > two day diesel class I took that was put on by Mack Boring....I guess
> I'm
> > > back to being confused??
> > >
> > > Regards,
> > >
> > > Jon Vez
> > >
> > > -------------- Original message --------------
> > > From: John Van Vessem
> > >
> > > > Running a cold engine up to full RPM is probably the worse thing you
> can
> >
> > > do to
> > > > any engine. The Yanmar manual says that you should run the engine up
> to
> > > full
> > > > throtle prior to shutting down, when the exhaust is hot and all
> bearings
> >
> > > are at
> > > > their disign tolerance.
> > > >
> > > > John Van Vessem
> > > > Sojourn 645
> > > > Vallejo Yacht Club
> > > >
> > > >
> > > >
> > > > ----- Original Message ----
> > > > From: jonvez at comcast.net
> > > > To: Allan.Field at comcast.net; C320-List
> > > > Sent: Wednesday, October 4, 2006 5:02:18 AM
> > > > Subject: Re: [C320-list] exhaust elbow question
> > > >
> > > >
> > > > Koen,
> > > >
> > > > I posted several questions related to the exhaust elbow as I was
> > > interested in
> > > > proactively replacing mine (my boat is in it's 8th season in salt
> > water).
> > > >
> > > > My confusion was whether the elbow was custom made by Catalina like
> the
> > > muffler,
> > > > or whether I could get it from a Yanmar dealer--than answer is BOTH.
> > Some
> > > hulls
> > > > (with the Yanmar) had a custom elbow made by Catalina...even though
> I
> > > suspected
> > > > this was the case on mine, I couldn't confirm until I went to a
> local
> > > Yanmar
> > > > distributor myself. Even Catalina couldn't answer this
> question....The
>
> > > good news
> > > > is that if you do have a custom elbow from Catalina, you can indeed
> > > replace with
> > > > a stock Yanmar elbow...The bad news is, you need to buy 3 pieces
> (for
> > > about $360
> > > > vs about $160 for just the elbow). The Catalina elbow is a one piece
> > > elbow,
> > > > whereas the stock parts have a manifold, an adjusting screw
> connector
> > and
> > > the
> > > > elbow. Once you have replaced with the stock parts, you will only
> have
>
> > to
> > > > replace the elbow (top part) going forward....
> > > >
> > > > As for time, Mr. Douglas had suggested 5-8 seasons is a good time to
> > > replace.
> > > > One suggestion on keeping the buildup under control from Mack Boring
> is
> > to
> > > start
> > > > the engine at full throttle and bring it back to idle as soon as the
> > > engine
> > > > starts...This will blow a lot of the build up out and presumably
> delay
>
> > the
> > >
> > > > inevitable...
> > > >
> > > > Regards,
> > > >
> > > > Jon Vez
> > > >
> > > > -------------- Original message --------------
> > > > From: "Allan Field"
> > > >
> > > > > Koen - There are 2 concerns with the exhaust elbow. The first is
> that
> > it
> > >
> > > > > clogs over time and will impact engine performance. The second is
> that
> >
> > > it
> > > > > eventually gets pinhole leaks. Both happened on my previous boat.
> > Trust
> > > me
> > > > > when I say that you don't even want to think about the mess you
> will
>
> > > have if
> > > > > the elbow gets a pinhole leak. The engine compartment fills with
> black
> >
> > > soot
> > > > > that never completely goes away no matter how much you clean,
> clean,
>
> > > clean,
> > > > > and clean some more.
> > > > >
> > > > > I intend to replace my elbow prophylactically over the winter at
> about
> >
> > > 500
> > > > > hours, change the hose to the aqua lift muffler, add a hump hose
> at
> > the
> > > > > muffler, and pull the muffler, send it back to Catalina, and have
> a
> > > > > duplicate muffler made to sit on a shelf until when I need it.
> Again,
> > > you
> > > > > don't even want to think about the mess if these parts fail.
> > > > >
> > > > > Allan S. Field
> > > > > Sea Shadow - #808
> > > > > Columbia, MD
> > > > >
> > > > > -----Original Message-----
> > > > > From: c320-list-bounces at catalina320.com
> > > > > [mailto:c320-list-bounces at catalina320.com] On Behalf Of Koen
> > Bennebroek
> > > > > Sent: Tuesday, October 03, 2006 9:05 PM
> > > > > To: c320-list at catalina320.com
> > > > > Subject: [C320-list] exhaust elbow question
> > > > >
> > > > > I seem to remember someone mentioning that the exhaust elbows on
> > C320's
> > > get
> > > > > clogged and are recommended to be replaced every so often..
> > > > > My local mechanic, who will do the very first service on our boat
> soon
> >
> > > (so
> > > > > we do not have experience either with him or with the engine
> > > > > service in general), recommends we order the elbow and gasket from
> > > Perkins
> > > > > (I believe tadiesel sells them?) in advance to save time.
> > > > >
> > > > > Is this a good suggestion? We have purchased the boat used 2
> seasons
>
> > > ago, so
> > > > > I have no idea what the history of this part is.
> > > > >
> > > > > Thanks for any suggestions,
> > > > >
> > > > > -Koen
> > > > >
> > > > >
> > > > >
> > > > >
> > >
> > >
> >
> >
> >
>
>
>
>