Changing to a closed cooling system..??

[Jbird]

I want to use my old Larsen tri hull for some winter fishing. I was wondering if anyone here had switched from an open to a closed cooling system. My thinking is, with a closed system I could plumb in an automotive style heater and winterizing for outside storage would be a cinch. My sterndive is OMC mated to a GM four banger. Would I still be able to run river water through the exhaust/intake manifold? I'm in the process of replacing the engine mount stringers so the engine compartment is exposed and begging for modification. This old newbie from North California thanks you in advance. Jbird

[gonzo]

You can plumb a heater with an open system. Tap into the circulation pump.

[Jbird]

I may not know enough about marine cooling systems yet, I have a book coming in the next few days. My thought was to convert to an automotive style cooling system, radiator, thermostat, temperature controlled electric cooling fan, the whole enchilada. Am I missing something? Jbird

[longliner45]

fortunatly one of the best has responded ,,I had a skiff ,,with a inboard 292 chaevy,,it was keel cooled and had a wet exaust ,,so some water was going out to cool the exaust,,cant speak for gonzo ,,he is a busy man ,but if you give him some more info ,,he probably knows what to do.....longliner

[Jbird]

Well I got the book, what a disappointment. Glenn Ls Inboard Installations has a bunch of good information but not what I was looking for. I'll probably leave well enough alone and tap into the circulation pump for a heater. Jbird

[mongo75]

Jbird- you also should take into consideration that if you use some sort of heating element (I'm guessing like a block heater for a diesel??) what about failure, as in if it burns out, or the cord gets unplugged by accident? You might have a day before it freezes (does it freeze in NorCal?- I don't worry about that in San Diego). OR am I missing the boat here? Most closed cooling systems have a heat exchanger and expansion tank, but no actual radiator and cooling fan. However if you're trying to totally rid the boat's dependance on raw water intake, and you had the room, and means to move enough air to keep the radiator cool, I guess it could work.

[Jango]

Jbird
I assume you,re also looking for Freeze protection. Yes, the closed cooling system will do what you want - water with coolent circulating through the motor and heater (just like a car).

You will however have Sea water in your Exhaust. Manifolds should be Drained when not in use during freezing Temps.

[Jbird]

Thanks Mongo and Jango. Are you guys related??? I'm just gonna leave things alone for now. I've almost got the floorboards finished up, everything else seems to have gotten in the way. I aquired an injected 4.3 V6 that will bolt right to my outdrive.....maybe next year.... Thanks again Jbird

[wooky]

I am also considering adding a closed cooling system and realize that the raw water will exit through the exhaust after going through the heat exchanger. Does anyone have a diagram or picture of the inside of the exchanger, I have a friend who might probably build one for me, possibly from scrap stainless. Also, what capacity for an inline 6?

Thanks

[hmattos]

We - see www.explorermarine.co.uk - have installed the excellent STEYR 164 hp diesel which is entirely water cooled but has heat exchangers to keep the coolant in and the sea water cools that and then passes out through the exhaust manifold and down the exhaust. They also have smaller heat exchangers to cool the turbo air, the fuel and the gearbox oil!

A heat exchanger consists of a bunch of bronze tubes which carry engine coolant - antifreeze - inside a bigger tube - up to about 4 inches - which carries sea water. It is much smaller and much quieter than the car type water to air radiator.

Type " boat heat exchangers " into Google and plenty will be learned....

Good luck

[Jango]

Wooky,

Here is a schematic on closed cooling.

http://www.depcopump.com/catalog107/81.pdf

Sea water surrounding tubes carrying water and antifreeze, connected to an Expansion Tank feeding the Engine Block, Head and Intake Manifold.
Sea Water exits thru Exhaust Manifolds which inturn cools them.

[wooky]

Thanks Jango and hmattos, sometimes you just have to "know the code" on google to find what you are looking for. Anyway, I'm figuring that once I get past the initial extra cost of the exchanger I'll save in the long run by not having corrosion and freeze-up problems with the engine, even though here in Georgia we don't have many hard freezes.