Freshwater cooling kit install questions

[billh1963]

I'm days away from closing on a Carolina Classic 25 with the Volvo 7.4 carb'ed engine. Of course, I'm already looking at upgrades and the first thing I want to add is a closed cooling system. It is currently raw water cooled. Is this a DIY project for someone with moderate mechanical aptitude? Does anyone know a reasonable cost online source for these kits? Is there anything I should be wary of or options that I should consider?

Thank you!

 

[Zackman]

Re: Freshwater cooling kit install questions

Bill, is this a new boat (car'b)?

If not, you may want to post the year and number of hours. Has it been used in saltwater. I believe most would advise against adding a closed cooling system on boat more than a few years old, been in saltwater service, or has more than 200 hours.

 

[billh1963]

Re: Freshwater cooling kit install questions

The engine has 600 hours (1997 model) of saltwater use. Looks and runs like new. Mechanical survey very strong. Always flushed after use.

I'd like to get another couple of years out of it before a Crusader 8.1 repower.

From what I have read is the concern that any rust will break loose and plug the heat exchanger?

Bill

 

[Reel Poor]

Re: Freshwater cooling kit install questions

From what I have read is the concern that any rust will break loose and plug the heat exchanger?

Bill

Thats what happens Bill. When the heat exchanger cloggs up there is no way to clean them out.

Since the boat is saltwater cooled be sure you get proof of the last time the exhaust manifolds and risers were changed. They should be changed every four years for preventive maintainance. If the manifolds go bad they usually take out the engine also. If you can't get positive proof I would recommend replacing them, or at least pulling the risers off and inspecting them. Better safe than sorry.

 

[bruceb58]

Re: Freshwater cooling kit install questions

The best price for kits for these is at http://www.oceaneastmarine.com/

I have been doing some research into this myself with your exact engine and am not sure if I want to risk doing it because of my previous salt water usage and I have a lot less than you have...100 hours salt...60 hours fresh.

For the Volvo 7.4L engine, only half systems are available.

If you do decide to go through with it, it is suggested that you run the first year with water only as coolant with a rust inhibitor. After that, only use a silica free coolant. This is because of the salt that will be leeching out of the block.

 

[billh1963]

Re: Freshwater cooling kit install questions

The manifolds and risers were changed last year.

I think I'll stick with the current cooling arrangement and run the engine (with regular flushes) until the engine wears out.

Would you recommend using some of the salt neutralizing additives during the engine flushes?

Thanks!
Bill

 

[LEADLAP]

Re: Freshwater cooling kit install questions

Salt-Away. Available in marine stores.

 

[bijou22]

Re: Freshwater cooling kit install questions

I also looked at this for my VP 4.3 but haven't decided yet what to do. I have however looked at things like saltaway etc and the lab engineer where I work (I work as an engineer for a heat exchange company) reckons fresh water flushing immediately after use will be adequate and that these products are a waste of time / money and he should know with 30 years experience.
Any thoughts?

 

[billh1963]

Re: Freshwater cooling kit install questions

This motor has been flushed regularly its whole life.

I have to wonder if doing something different (like a salt neutralizer) might alter any oxidation or chemistry in the engine.

 

[Zackman]

Re: Freshwater cooling kit install questions

Bill, once the corrosion has started on cast iron, there is no practical way of stopping it. The scale will always be there and a potential problem for a closed cooling system. I believe the only way to stop it is to acid pickle the block, which of course requires a complete disassembly of the engine.

Enjoy your new boat for years and start saving now for that engine swap and the new closed cooling system. 8)

 

[billh1963]

Re: Freshwater cooling kit install questions

Thank you for all the replies. I think I'll leave things as they are!