CD25D with Yanmar cooling exchanger

[n5ama]

I purchased a CD25D from the fresh water Lake Superior. I moved the boat to it's new home in Clear Lake, TX. I changed the cathodic protection anode to zinc but I'm interested in what it would take to convert the Yanmar from raw water cooling to a antifreeze cooling system (obviously not because of the extreme winter temps down here
- mostly 40s-50s at night ) but because of the salt water.

Is there a recommended way to do this? Maybe a provider that offers a kit that includes pump, exchanger etc?

Any help greatly appreciated.
Tom

[sgbernd]

You don't mention the age or hours of the engine.

It may or may not be worth it depending on the age and hours of the engine. Heat exchangers, driving a second water pump, etc. are a significant expense and engineering challenge. For a 30+yr old engine, likely it is nearing the end of life. So the goal is trying to extend its life as long as possible while minimizing expense and effort.

A poor-man's approach is to plumb a T valve and hose into the engine raw water inlet between the seacock and engine. At the end of your sail, while the engine is still hot so the thermostat is open, close the seacock, open the valve, insert the hose into a bucket of fresh water, start the engine, and run a bucket or three of fresh water thru the engine which will wash out much of the salt. Thus the engine runs in salt but sleeps in fresh. This is not as good as a heat exchanger, and tap water is not so benign as ethylene glycol, but may be a reasonable solution at modest cost.

Steve Bernd

[n5ama]

You don't mention the age or hours of the engine.

It may or may not be worth it depending on the age and hours of the engine. Heat exchangers, driving a second water pump, etc. are a significant expense and engineering challenge. For a 30+yr old engine, likely it is nearing the end of life. So the goal is trying to extend its life as long as possible while minimizing expense and effort.

A poor-man's approach is to plumb a T valve and hose into the engine raw water inlet between the seacock and engine. At the end of your sail, while the engine is still hot so the thermostat is open, close the seacock, open the valve, insert the hose into a bucket of fresh water, start the engine, and run a bucket or three of fresh water thru the engine which will wash out much of the salt. Thus the engine runs in salt but sleeps in fresh. This is not as good as a heat exchanger, and tap water is not so benign as ethylene glycol, but may be a reasonable solution at modest cost.

Steve Bernd

Now Steve, that is thinking outside the box!!

My little engine is real strong and I don’t anticipate any end-of-life issues. It spent its entire life in fresh water, it and the boat looks very close to new. Tojo appears to be running strong (as strong as a single cylinder can run - LOL) and I’ll do what I can to continue its good health.

The T valve sounds like a great idea. I guess it just depends on how long the thermostat will hold open with that cold water running through it. I guess if I was really anal I could heat the water up to 200 degrees and keep the thermostat open.

Thanks again

[sgbernd]

As my Dad used to say, there are more ways than one to skin a cat. Not sure how many cats need skinning, but you get the idea.

Anyway, I did this with my MD7B for many years before I finally gave up on it and repowered. As an added benefit, I installed a strainer on the end of the hose. In event of a major leak, (God forbid!) where the electric bilge pump is over powered and the manual pump is wearing out my arm, the idea was to make the hose long enough such that it extended below the floorboards. I could use the engine water pump to help de-water the boat. If you push the throttle up to the red line, it moves some serious water. I never had a chance to test it which is fine by me. The strainer is needed as if you are flooding, there will be all sorts of debris in the bilge which will clog the water pump leaving neither pump nor power.

Steve Bernd

[n5ama]

As my Dad used to say, there are more ways than one to skin a cat. Not sure how many cats need skinning, but you get the idea.

Anyway, I did this with my MD7B for many years before I finally gave up on it and repowered. As an added benefit, I installed a strainer on the end of the hose. In event of a major leak, (God forbid!) where the electric bilge pump is over powered and the manual pump is wearing out my arm, the idea was to make the hose long enough such that it extended below the floorboards. I could use the engine water pump to help de-water the boat. If you push the throttle up to the red line, it moves some serious water. I never had a chance to test it which is fine by me. The strainer is needed as if you are flooding, there will be all sorts of debris in the bilge which will clog the water pump leaving neither pump nor power.

Steve Bernd

I’ve heard of using the engine water pump before. Great idea and in the event the batteries are dead from flooding or otherwise used up would provide a high volume bilge pump as long as you had fuel for your engine.

I’m thinking of a hose with a female hose connector that can be connected to the slip water supply. A screen could be attached to a male connector to make it work in either the bilge or a bucket of fresh water.

It would require a robust “T” fitting and valve for reliability.

[sgbernd]

I'd advise caution with that approach, as you don't want to pressurize the inlet. The water pump is designed to suck, not resist. I am not sure what might happen if you put 45psi on the inlet. Maybe nothing, maybe something, maybe something bad. However, a quick disconnect is a good idea to neaten the installation.

I wrapped mine around the inside of the engine compartment entrance secured by hooks so it is neat and easily stowed.

Steve Bernd

[Dick Kobayashi]

I am not trying to be offensive, but rather offer sound advice: Forget this idea.

I recently sold my 1983 25D with the original engine. These are Japanese tractor engines adapted by Yanmar for marine commercial use. (Japan is an island) Salt water is not a problem. What is a problem is NO WATER. Make sure the high temp alarm works, make sure you have a filter basket on the intake side, check to see you have water coming out of the exhaust before getting underway and service the little pump at least annually to YANMAR specs. Do these things and the engine will be ok from a cooling standpoint.

IMHO there are many improvement projects on a 25D or anyboat. Like putting in an electric bilge pump, creating storage where there is none, and putting that self-cleaning stuff on the topsides.