[C320-list] exhaust elbow question

[domace]

Bruce

After cleaning our the exhaust elbow, my diesel mechanic recommended that I
work my Yanmar engine hard for five or ten minutes at least every fifty
hours or so to blow the carbon out of the exhaust system.  The other advice
was to let it idle for five minutes to let it cool down before turning it
off.

Hope that helps,

Owen
Baloo, #727
Adelaide, Australia

-----Original Message-----
From: c320-list-bounces at catalina320.com
[mailto:c320-list-bounces at catalina320.com]On Behalf Of Bruce Heyman
Sent: Friday, 6 October 2006 9:36 AM
To: 'C320-List'; catalina at thehares.com
Subject: Re: [C320-list] exhaust elbow question


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" <catalina at thehares.com>

> 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
> > >
> > >
> > >
> > >
>
>