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iTrader: (9)

Has anyone done a full closed cooling including true headers in the mix - fully closed cool loop. A lot of inboards have this but with STOCK exhaust systems. Kind of thinking about this - the good and the bad setting it up this way. I understand the heat exchanger persay will need the ability to produce cooling capacity 3/4 of the engine heat adding the exhaust system in the mix.

class6

For the price of the parts and weight of the parts. plus the amount of water needed to cool the speed loss would not be worth it. buy new headers in 5 years before they go bad.

ICDEDPPL

iTrader: (1)

That`s a lot of heat to cool down.

BUP

iTrader: (9)

Thanks already doing closed cooling anyways no matter what. Also current systems like what Volvo Penta is using for their closed cooled apps is half the weight than past logged heat exchanger systems. They maybe add only 60 to 75 pounds max (wet completely full) compared to past systems. Also will be reducing weight with aluminum engine parts as well. ie heads, alum water circ pump - full alum intake, headers weight is far less than stock Merc cast iron - big weight saving alone with the alum heads and headers compared to stock Merc cast iron stuff. A closed cooled engine adds longevity and is a better set up overall for an custom MPI system, custom intake manifold, heavily worked alum heads and a custom ECM tune set up, well worth its weight in gold and expense to do so. Maintaining Constant same running temps helps as well

Instead of typing all this out - here is the Merc set ups between the 2 for a jist. This is the only info I could find but I am not huge googler to find any indepth more about this.

https://www.perfprotech.com/blog/art...ng-full-system

class6

If your running headers,there is a large surface area seeing inside temps of 1400*. a Manifold system might be a better way if you are going that route. And I don't know if the coolant would start to scale against the inner tube from excessive heat.

ToMorrow44

You're saying you want the closed cooling to also cool the headers? I'm sure it can be done but not sure its worth it. You'd have to do a dry exhaust as you'd have the coolant exiting the jacket and not going into the exhaust stream. As said, the cooling capacity would have to be immense due to the heat of the exhaust. Also, you would need a lot of pressure in the headers to prevent steam pockets, thats why most raw water systems require at least 25psi. Not sure about the marine closed cooling, but automotive cooling systems are usually only 12-14 lbs of pressure.

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iTrader: (9)

Look at the catalyst exhaust set up and they have a by pass valve to keep as much heat in the stock OEM exhaust manifolds at idle speeds and a tad above. It works off of water pressure and that's every engine manu marine side with cats. Not nothing new here just asking if anyone did it whatever set up with headers

Volvo uses cast alum manifolds with cats / O2 sensors with out any issues and its not even on their warranty radar plus all emissions control marine engines have a warranty of 3 years / or 480 hrs which ever comes first. That's even including saltwater use and the same timeframe applies.

Just saying but again I have never seen headers done in closed cooled loop but seen many stock OEM apps that are. I posted a link above about what I am talking about.

Just thinking and asking if anyone did it with true headers

Mbam

We thought about it years ago (in the 80's) but never implemented it. We already had closed cooling for the engines but the headers we had at the time always leaked which presented a problem. Leak stop was one of the ideas. The plan was to run a separate circulating pump for the exhaust. Tomorrow, the 25 psi is usually not seen at the header feed. Also even though you might see 25 psi on the gauge with a seawater system that is aerated water which is not ideal for heat removal. And the pressure is intermittent.

The rule of thumb that I remember for the BTU's represented by the fuel burned for an IC engine is 1/3 at the crank, 1/3 out the cooling system and 1/3 out the exhaust. Yes it would add a good amount of heat to the cooling system but it could be done.

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iTrader: (9)

Thanks Marc and that is correct about the BTU's - I talked to the ex owner of Champ in Florida a couple days ago about this , He was the one that connected me as both of us were going over the idea and the positives and negatives about both set ups and then with the headers.

Brad Zastrow

I would not do it.. With any decent hp it will be difficult to keep the engine cool. What are you trying to gain? Still need a water pickup for the closed cooling heat exchanger and the water needs to dump out of the system. The new engines with catalytic convertors need heat to work. A cool engine will live longer than having to worry about cooking the oil because the heat exchanger can not keep up unless you went to very large exchanger and very large water pickups like Mercury requires for the new 1300's