Hi everyone,

I need some advice from those of you who have run marine diesels for
several decades. We recently bought a Irwin Citation 38 which came with
a newly rebuilt Yanmar diesel engine. The engine starts and runs very
well as you would expect for an engine that has just been overhauled.
It also has a great paint job and looks pretty much like a new engine
with no rust showing anywhere, however...

In researching this engine--a Yanmar 3HM 27HP--it became apparent that
this series was only produced from 1980 to 1983 when it was replaced by
the 3GM30. In a car engine this would not cause me any angst, because
the block would have been being cooled by antifreeze and/or fresh water,
and the parts would still be readily available. In this case, it is a
23-26 year old marine diesel that was probably produced in limited
quantities, and--since it is raw water cooled--probably had salt water
sitting in the block for much of its life.

My options as I see them a

1) Do nothing and hope for the best. The engine will likely run well
for several years, and I may not need parts for it. Many parts (h20
pump, injector pump, injectors, etc) may be the same as on the 3GM30 and
quite availabe. Of course, that old block is getting thinner all the
time, and may not have nearly as much life left in it as it appears.

2) Convert the 3HM to fresh water cooling. This would stop the block
from deteriorating any further, and could stretch the life of this
engine into a decade or more.

3) Pull the 3HM and sell it. Replace it with either a rebuilt 3GM30, or
a new 3YM30. This is the most costly option both in terms of dollars,
and my time, but should result in the best long term reliability.

What do you think?

Don W.

On Wed, 17 May 2006 16:37:31 GMT, Don W
wrote:

What do you think?

It depends.

How are you going to use the boat?

Ocassional weekends; light duty coastal for 2 or 3 weeks at a time;
liveaboard coastal - constant use; extended cruising in the boondocks?

For ocassional or light duty coastal usage I'd leave it as is,
maintain the engine well and flush it with fresh water before any
extended down time. Keep an eye out for cooling system issues, leaks,
etc. It may surprise you with its future longevity if well maintained
in the past.

For constant use or cruising in the boondocks I'd probably consider a
new engine at some point. In my opinion it is already too old to get
much benefit from a FWC conversion. The damage has already been done
and is irreversible.

Wayne.B wrote:
On Wed, 17 May 2006 16:37:31 GMT, Don W
wrote:

What do you think?

It depends.

How are you going to use the boat?

Ocassional weekends; light duty coastal for 2 or 3 weeks at a time;
liveaboard coastal - constant use; extended cruising in the boondocks?

For ocassional or light duty coastal usage I'd leave it as is,
maintain the engine well and flush it with fresh water before any
extended down time. Keep an eye out for cooling system issues, leaks,
etc. It may surprise you with its future longevity if well maintained
in the past.

For constant use or cruising in the boondocks I'd probably consider a
new engine at some point. In my opinion it is already too old to get
much benefit from a FWC conversion. The damage has already been done
and is irreversible.

These Yanmars are not the sort of rubbish you get from dump-truck and
converted auto engines, they are known to last far longer than the
equivalent Volvos, and to assume that in X years you will have Y
deterioration is crazy.

By all means replace the wearing parts, fuel pump, injector pump etc etc,
but keep the engine in good serviceable use until at some future time, the
wear on the block which you seem to fear most, is obvious. This might well
be after you are long finished with sailing, but so what?

Get the 3 injectors serviced annually, this is probably the best money you
will spend, and I always found that this simple service reduces smoking and
gives a fair amount of extra SHP at the start of the season.

Change the engine oil every 100 hrs running, and pay scruculous attention to
winterising the engine if you live in an area where winter means a longish
and frosty lay-up.

I think your engine could well outlast you!


Dennis.

Hi Dennis,

Dennis Pogson wrote:

These Yanmars are not the sort of rubbish you get from dump-truck and
converted auto engines, they are known to last far longer than the
equivalent Volvos, and to assume that in X years you will have Y
deterioration is crazy.

By all means replace the wearing parts, fuel pump, injector pump etc etc,
but keep the engine in good serviceable use until at some future time, the
wear on the block which you seem to fear most, is obvious. This might well
be after you are long finished with sailing, but so what?

Get the 3 injectors serviced annually, this is probably the best money you
will spend, and I always found that this simple service reduces smoking and
gives a fair amount of extra SHP at the start of the season.

Change the engine oil every 100 hrs running, and pay scruculous attention to
winterising the engine if you live in an area where winter means a longish
and frosty lay-up.

I think your engine could well outlast you!

Dennis.

I hope that you are right.

The engine in the boat was put in just a few months ago by the previous
owner, and he purchased it out of Connecticut where it had been traded
in to a dealer and "overhauled". I can always _hope_ that the engine
spent a lot of its life properly flushed out and in a boat that was
sitting on the hard. If I knew that to be the case, I'd feel a lot more
comfortable about the situation when going offshore.

Don W.

In article ,
Don W wrote:

Hi Dennis,

Dennis Pogson wrote:

These Yanmars are not the sort of rubbish you get from dump-truck and
converted auto engines, they are known to last far longer than the
equivalent Volvos, and to assume that in X years you will have Y
deterioration is crazy.

By all means replace the wearing parts, fuel pump, injector pump etc etc,
but keep the engine in good serviceable use until at some future time, the
wear on the block which you seem to fear most, is obvious. This might well
be after you are long finished with sailing, but so what?

Get the 3 injectors serviced annually, this is probably the best money you
will spend, and I always found that this simple service reduces smoking and
gives a fair amount of extra SHP at the start of the season.

Change the engine oil every 100 hrs running, and pay scruculous attention to
winterising the engine if you live in an area where winter means a longish
and frosty lay-up.

I think your engine could well outlast you!

Dennis.

I hope that you are right.

The engine in the boat was put in just a few months ago by the previous
owner, and he purchased it out of Connecticut where it had been traded
in to a dealer and "overhauled". I can always _hope_ that the engine
spent a lot of its life properly flushed out and in a boat that was
sitting on the hard. If I knew that to be the case, I'd feel a lot more
comfortable about the situation when going offshore.

Don W.


Just a note here. Just because the previous owner had new paint and
said the engine was completely rebuilt, doesn't nessesarily mean that it
was. Fresh paint covers a MULTITUDE of problems. I would have asked
for a copy of the Rebuild Invoice and look at what was actually done.
Did in get a Topend? InFrame? or just a new paint job? Who did the work,
and is he experienced on that model and make engine. What was the
criteria used to evaluate Replacment of Worn Parts? What were the main
Bearings and ConRod Bearing Cleareances and Tolerances? I have seen way
to many "Supposed Rebuilds" that weren't, or weren't done right to go by
what a previous owner stated. Diesels can be very good on Engine Time,
but only if they are maintained, and Oil is the cheapest Insurance you
can buy.

Me who has 50K hours on a diesel genset and still going strong...

Wayne.B wrote:

How are you going to use the boat?

Ocassional weekends; light duty coastal for 2 or 3 weeks at a time;
liveaboard coastal - constant use; extended cruising in the boondocks?

We will be using the boat for mostly coastal cruising right now. The
longest run I'm considering for this year is ~28 hours to Port Isabell
which would take us 30 NM offshore.

Next year, however, my wife will be eligible for her sabbatical, and
we're discussing moving the boat to the carribean for a couple of months
of cruising. That would involve passages of four days or so to cross
the gulf from Texas, and living aboard for as much as three months.

For ocassional or light duty coastal usage I'd leave it as is,
maintain the engine well and flush it with fresh water before any
extended down time. Keep an eye out for cooling system issues, leaks,
etc. It may surprise you with its future longevity if well maintained
in the past.

For constant use or cruising in the boondocks I'd probably consider a
new engine at some point. In my opinion it is already too old to get
much benefit from a FWC conversion. The damage has already been done
and is irreversible.

Several knowledgeable people have mentioned that marine engines exposed
to salt water corrode from the inside out, and it makes sense. Right
now, the engine seems to be in fine shape, but my nagging worry is about
how thin the iron around the water passages may be. Since it is cooled
by salt water, it seems that they are probably not only thin already,
but getting thinner--thin being a relative term of course. My thought
on adding FWC would be to run a 75%/25% mixture of antifreeze and fresh
water which would stop the block from getting any thinner.

Your point that the damage has been done is well taken, but at least I
do not have water in the oil, or a leaking water jacket...yet.

Don W.

"Don W" wrote

Several knowledgeable people have mentioned that marine engines exposed
to salt water corrode from the inside out, and it makes sense. Right
now, the engine seems to be in fine shape, but my nagging worry is about
how thin the iron around the water passages may be. Since it is cooled
by salt water, it seems that they are probably not only thin already,
but getting thinner--thin being a relative term of course. My thought
on adding FWC would be to run a 75%/25% mixture of antifreeze and fresh
water which would stop the block from getting any thinner.


Don,

At one time almost all engines were seawater cooled - Those older Yanmars
were much heavier than the later GM series and likely had much thicker wall
thicknesses. They are also equipped with anodes to reduce corrosion - Not
sure how many owners actually change these though - When we bought our boat,
I changed the anodes - they were partly used up, but still serviceable.
Might be worth checking to see if yours were replaced during rebuild. In the
early 80's, there was a drive to get lighter engines for sailboat use, and
the GM series provided that. And, most of the larger GM engines were
equipped with closed circuit cooling.

Our own boat has a 1978 Yanmar 2QM15 direct cooled. It spent most of it's
life in salt water - Never been overhauled and still runs perfectly.

Converting to fresh water cooling can be quite expensive - I would just run
existing engine and gain confidence in it. I would also contact rebuilder,
find out just what was done and get their opinion on expected life of
engine. You always have the sails, if all else fails

On the other hand, if you have $15k to spare, a new engine would be nice
- How much does a new Yanmar cost installed?

One thing a fresh water cooled engine would provide, is an ability to heat
water under way. The raw water cooled engine can't really do that.

GBM

GBM wrote:

"Don W" wrote


Several knowledgeable people have mentioned that marine engines exposed
to salt water corrode from the inside out, and it makes sense. Right
now, the engine seems to be in fine shape, but my nagging worry is about
how thin the iron around the water passages may be. Since it is cooled
by salt water, it seems that they are probably not only thin already,
but getting thinner--thin being a relative term of course. My thought
on adding FWC would be to run a 75%/25% mixture of antifreeze and fresh
water which would stop the block from getting any thinner.



Don,

At one time almost all engines were seawater cooled - Those older Yanmars
were much heavier than the later GM series and likely had much thicker wall
thicknesses. They are also equipped with anodes to reduce corrosion - Not
sure how many owners actually change these though - When we bought our boat,
I changed the anodes - they were partly used up, but still serviceable.
Might be worth checking to see if yours were replaced during rebuild. In the
early 80's, there was a drive to get lighter engines for sailboat use, and
the GM series provided that. And, most of the larger GM engines were
equipped with closed circuit cooling.

Our own boat has a 1978 Yanmar 2QM15 direct cooled. It spent most of it's
life in salt water - Never been overhauled and still runs perfectly.

Hey, that's my exact motor. Maybe we should form a club!


--
Stephen

-------

For any proposition there is always some sufficiently narrow
interpretation of its terms, such that it turns out true, and
some sufficiently wide interpretation such that it turns out
false...concept stretching will refute *any* statement, and will
leave no true statement whatsoever.
-- Imre Lakatos

If it ain't broke don't fix it!
Make sure there is a new anode on the engine and then run it until it
fails - or until you trade the boat off for a new one (which is far
more likely scenario)....

denny

"Stephen Trapani"

Our own boat has a 1978 Yanmar 2QM15 direct cooled. It spent most of
it's
life in salt water - Never been overhauled and still runs perfectly.

Hey, that's my exact motor. Maybe we should form a club!



Stephen,
This group is about as close as we will get - It's a good place to discuss
these things. Then there is also the forum at
http://www.marinedieseldirect.com/ .

I have not looked too closely at converting to fresh water cooling, but I
think someone once said I would need a different exhaust mainfold to do
this. Looking at cooling circuit, I am not so sure. I will start a new
thread about this.

GBM