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Thread: Closed Cooling Question

  1. #1
    I Am Going To Be Putting A Fresh 454 Gen Vi In My 77 Omega (the 455 It Came With Had A Hole Through The Side Of One Cylinder). I Have Been Thinking About Putting In Closed Cooling. Does Anyone Have Any Opinions On It?? Lake Texoma Has A High Salt Content, And Pretty Much Ate The Insides Out Of The 305's I Had In My 1979 Formula. Of Course They Were Pretty Old Engines. I'd Hate To See That Happen To My New 454. Also, Limited Winterizing Needed Would Be Nice.

  2. #2
    Aluminum Squirt
    I have a closed cooling system in my prop boat (don't tell anybody I own one), and I like it. Pros are: consistent running temperatures, no winterizing (at least here in CA, some closed systems need to have the exchanger drained of raw water to avoid freezing in cold climates), less salt/sand/silt/debris in the motor. Cons are: need a second water pump of some type either to circulate raw water or coolant, weight will be higher from the added components, increased cost, and the system will be a little more complicated and add a few more things that can go wrong in a day of boating (that's not to say that a closed system is not reliable, just that if you add parts, those parts can fail).
    I see it on a lot of the bigger, non race aluminum boats. It's a nice system and if you are boating where you need it, then by all means go for it. It will look a little out of place on a low freeboard California style jetboat, but whose to say you can't make some cool billet brackets, add some braided lines and chrome the exchanger! There are quite a few small things that can be done to a standard motor/cooling package to increase its ability to live in a hostile environment, ie coatings, paint, flushing, routine maintenance etc. I know its not very specific, but I hope this helps a little-Aluminum Squirt

  3. #3
    If you have the room, a few extra dollars, and don't care about another 40 pounds then get it.
    No corrosion in the block or heads.
    Correct cylinder head temps = more horsepower.
    No dirt, sand or crap in the engine means no hot spots on the cylinders.
    I think the positives outway the neg especially in my case where I live around salt water.
    Here is my boat - I fabricated the closed loop system myself.

  4. #4
    Got any more pics of your ride? Thats realy nice. How did you make your heat exchanger?

  5. #5
    Oh now that's what I'm talking about! Somebody knows how to fabricate and think for themself! Very nice! Can we please have some more info on that whole buildup? Hows the startup and low speed drivability factor with the draw through setup?

  6. #6
    Thanks For The Input. I Was Thinking In Terms Of Some Kind Of Fabricated System. I Hope Mine Turns Out Like The Pics. I May Just Buy An Exchanger An Fab The Mounting And Plumbing.
    Thanks Again,

  7. #7
    Aluminum Squirt
    You know, I think I remember this exact same discussion with similar posts. It was a year or two ago. Somebody posted asking about closed cooling systems, and a few knuckleheads like myself answered up, and then ttmott posted a picture of not only a fabricated closed system but one of the best looking boats on the boards. I think upon seeing his outrageous boat, we all shut the hell up and the post died. Is this dejavu, did I drink too many margaritas tonight, or did this really happen?-Aluminum Squirt

  8. #8
    The pictures are the build I did back in the RJB days; that's probably where you remember it. It has changed quite a bit from a induction point due to a problematic lean condition that gernaded the intercooler - but that is for another post..... The cooling system is the same.
    The Cooling system is nothing fancy. The heat exchanger is a simple return loop type that is made from 6-inch schedule 5 stainless pipe. The tubing is 3/8" and 1/4" stainless steel bent in a "U" shape (hence return heat exchanger) and welded to a plate. The end cap has a divider inside it so the antifreeze will flow in one end of the tubing and out the other. There is about 300 feet of tubing in the thing. It will probably cool an equivalent of a 12 liter engine. There is also an expansion tank mounted high which is made from 4" stainless pipe. I have a 160 degree thermostat in the engine and the thing will run all day between 170 and 180 degrees. The intercooler and exhaust manifolds still are on raw water because if they should leak I didn't want the cylinders to fill up when sitting around. Due to the need to feed raw water to the heat exchanger, intercooler, and exhaust manifolds I enlarged the jet pump tap to .650 ID and welded a 3/4" aluminum pipe nipple on. I sized the heat exchanger based upon a percentage of heat to be removed from the engine at a given KW rating then multiplied it by two. The tubing was estimated based upon the heat transfer capability of the tubing I had available then I muliplied it by two.
    Commertial heat exchangers are smaller and work just as good; you can pick a new one up for around 300 bones. Ones with Inconel tubes are more.

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