Yanmar advice needed
 

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.

Yanmar advice needed
 

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.

Yanmar advice needed
 

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.

Yanmar advice needed
 

I'd opt for #2 ... add FWC to extend service life.
there are some fairly inexpensive FWC heat exchangers and add-on pumps
that can work ... (similar to Universal Atomic-4 conversions sucha as
from www.indigoelectronics.com or www.moyermarine.com). Such marine
engines usually dont wear out but corrode through the block ... .

The simple fact of NOT letting the engine 'dry-out' by keeping the
cooling loop as a totally closed system HAS to be one of the greatest
'life-extenders' you can do to a marine engine. With cast Iron, when
you let the engine drain back or dry-out the internal protective
ferrous oxide (black rust) quickly reconverts to destructive ferric
oxide (red rust). Keeping cast iron WET (and HOT) will promote the
good ferrous rust. Corrosion is the ultimate destroyer of marine
engines; stop or lessen the corrosion and you will have the engine for
a LONG time. For a 'real' life extender consider to size the heat
exchanger for the engine AND the exhaust manifold loads; using raw
water only for the heat exchanger, water injection into the water lift
muffler (most system run the exhaust header with raw water --- a
salting issue).

With FWC cooling you can also run the engine much hotter (with a 190
degree T'stat instead of a 135 degree T'stat) for better combustion
efficiency, etc.

hope this helps.

In article , Don W
wrote:

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.

Yanmar advice needed
 

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.

Yanmar advice needed
 

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.

Yanmar advice needed
 

Hi Rich,

Rich Hampel wrote:

I'd opt for #2 ... add FWC to extend service life.
there are some fairly inexpensive FWC heat exchangers and add-on pumps
that can work ... (similar to Universal Atomic-4 conversions sucha as
from www.indigoelectronics.com or www.moyermarine.com). Such marine
engines usually dont wear out but corrode through the block ... .

The simple fact of NOT letting the engine 'dry-out' by keeping the
cooling loop as a totally closed system HAS to be one of the greatest
'life-extenders' you can do to a marine engine. With cast Iron, when
you let the engine drain back or dry-out the internal protective
ferrous oxide (black rust) quickly reconverts to destructive ferric
oxide (red rust). Keeping cast iron WET (and HOT) will promote the
good ferrous rust. Corrosion is the ultimate destroyer of marine
engines; stop or lessen the corrosion and you will have the engine for
a LONG time.

What you wrote fits very well with what my "local experts" have been
telling me.

For a 'real' life extender consider to size the heat
exchanger for the engine AND the exhaust manifold loads; using raw
water only for the heat exchanger, water injection into the water lift
muffler (most system run the exhaust header with raw water --- a
salting issue).

I'm not sure whether the 3HM Yanmar has a wet exhaust manifold or not,
but if it does I'd for sure add it to the FWC loop.

With FWC cooling you can also run the engine much hotter (with a 190
degree T'stat instead of a 135 degree T'stat) for better combustion
efficiency, etc.

Now that you've got me thinking about it, another thought is to run the
FWC loop through a dual engine/electric hot water heater to supply hot
water without electricity. With an electric pump, you could use this in
reverse to preheat the engine block, and the fuel before starting the
engine--probably overkill, but could be done.

I've owned Cummins powered work trucks that had electric engine oil and
fuel preheaters for cold starting.

hope this helps.

Yes it does. All of the discussion helps which is why I value this
newsgroup so much.

Don W.

wrote:


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.

Yanmar advice needed
 

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...

Yanmar advice needed
 

"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

Yanmar advice needed
 

On Wed, 17 May 2006 21:33:35 GMT, Don W
wrote:

I'd opt for #2 ... add FWC to extend service life.
there are some fairly inexpensive FWC heat exchangers and add-on pumps
that can work ... (similar to Universal Atomic-4 conversions sucha as
from www.indigoelectronics.com or www.moyermarine.com). Such marine
engines usually dont wear out but corrode through the block ... .

Compare the cost of a FWC conversion to the cost of a repower. If it
is a lot less and if it will give you greater peace of mind while
cruising, maybe it is worth it. On the other hand if everything is
running fine now, it might pay to use it for awhile and confirm that
it is the right boat for you in all other respects. The engine is
just part of the equation.

There's nothing like a 2 or 3 week cruise on a new boat to highlight
what REALLY needs to be worked on right now.

:-)