[C320-list] exhaust elbow question
Stanley Rogacevicz
SROGACEV at holycross.edu
Fri Oct 6 07:17:16 PDT 2006
Jon,
I wonder if Mack's statement was taken a bit out of context or if it
was a quick answer 'shot from the hip' to a question in the class ?
Maybe he meant periodically or something ? I know ... big mouth that I
am .... I would have had to raise my hand to say something like - That
goes against everything I have ever heard about internal combustion
engines over the last 40 years - Explain Please. My assumption would be
that the best time to blow out the carbon dust is while its cold and not
so sticky, but that seems to be a very extreme measure. I know I have
read articles that basically said that the first 10 seconds of an
engines day is when all the Wear/Damage occurs.... the rest of the day
is just a well lubricated coast in comparison. While Jeff's comment
about the difference between Gas and Diesel not washing the lubrication
off the cylinder walls is fine that's just a small portion of the engine
parts that need pressurized lubrication to stay alive. The thought of a
relatively dry rod bearing starting at full throttle gives me shivers.
Stan
formerly "Christy Leigh"
c320 #656
Wickford/Narragansett Bay RI
>>> <jonvez at comcast.net> 10/6/2006 9:32 AM >>>
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
> > > >
> > > >
> > > >
> > > >
> >
> >
>
>
>
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