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Old 11-17-2015, 08:16 AM   #21
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RPR

Why not just bite the bullet and buy a new unit suited for the engine? The current setup has lasted nearly 40 years if I read your posts correctly. Sure sounds like it worked very well.

As discussed, you can make it better by plumbing the manifold for coolant. And you can install a fresh water flush for the cooler. These are sensible upgrades and would be appreciated by the next owner.

But the other stuff you are contemplating are out of the norm and a step backwards IMHO.
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Old 11-17-2015, 10:31 AM   #22
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Originally Posted by R_p_ryan View Post
The part number you quoted, from Mr. Cool says:
"Please note that this part is not intended for salt water. If you're using this part in salt water, please purchase the copper nickel version of the part"
Ok, that's the NA001545CN - another $100.

But you are completely missing the point, which is that a saltwater pool is not the same as the ocean.
"But remember, saltwater swimming pools ARE NOT chlorine-free pools. A salt water system simply means adding pool salt to make pool chlorine by installing a pool chlorine salt water generator."
As with any pool or spa, you need to use acid and Sodium Bicarbonate to keep the pH and total alkalinity in balance within a rather narrow range. Or it will rapidly eat holes in the thin metal.

The pool - saltwater or chlorine - has an aggressive program to kill any growth. It also has a massive filter to keep everything out of the exchanger.

The exchanger you proposing is not serviceable. Heck, it isn't even inspectable. It lacks a drain fitting (though that can be dealt with). It lacks a pencil zinc (maybe there's a place to cut a hole and weld on a nut for a zinc, but what size?).

Hey, but maybe you're on to something. And hundreds of engine manufacturers and tens of millions of boats have completely missed out on shaving a few bucks with this awesome cooling idea. Have at it. After all, you've done your "research" - you asked some random folks on an Internet forum. What could go wrong?

Oh, wait - maybe you want to use your vessel in cold water?
"There is a rough rule of thumb that says a simple fixed tube sheet configuration can only be used for cases where the inlet temperatures of the two streams do not differ by more than 100 'F. Obviously, there must be many qualifications made to such a flat statement, recognizing the differences in materials and their properties, temperature level of operation, start-up and cycling operational procedures, etc."
The Darwin committee has your award on temporary hold pending the outcome of your "upgrade". The good news is, you don't have to be present to win!
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Old 11-17-2015, 11:27 AM   #23
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Since when does ASKING questions, THINKING out of the box or the failure of one engine component line someone up for the Darwin Award? Even jokingly, enough with a quick, first reference to it.

Lots of disgreement from others with the premise without insulting the OP.

I applaud him for bringing up the idea even if proven not likely to succeed.

A few more good points and he may abandon the idea....if after pages of disagreement like some on here will do despite numerous good links to reality... then I will be the first to vote yes for some kind of similar award..
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Old 11-17-2015, 11:51 AM   #24
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Greetings,
Mr. ps. +1
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Old 11-17-2015, 12:49 PM   #25
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Since when does ASKING questions, THINKING out of the box or the failure of one engine component line someone up for the Darwin Award? Even jokingly, enough with a quick, first reference to it.

Lots of disgreement from others with the premise without insulting the OP.

I applaud him for bringing up the idea even if proven not likely to succeed.

A few more good points and he may abandon the idea....if after pages of disagreement like some on here will do despite numerous good links to reality... then I will be the first to vote yes for some kind of similar award..
I'm all for thinking outside the box, but there simply has to be a point where - when it may (will?) cause loss of life - members will step up and say "No". And I feel this is that point, if not for the OP then for anyone else who ends up in this thread after Googling "pool heat exchanger boat".

In my opinion, the raw water side of complex engine plumbing is not a place to look for "innovation". Patio furniture and carpeting on deck? Sure. Household or camping appliances in the galley? Sure. Using a sex object as a toilet paper holder? Um, ok. But replacing an engineered solution for keeping water out of the boat while removing excess heat from an engine just to potentially save some a couple hundred dollars? "Hell No".
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Old 11-17-2015, 12:58 PM   #26
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Greetings,
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Old 11-17-2015, 12:59 PM   #27
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Thinking death in this thread is a stretch.

Advise not condemn. At least that is what I have been reminded of. And some souls tossed for being so direct.

Most boaters will die of many reasons...probably not the direct result of a heat exchanger.
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Old 11-17-2015, 01:55 PM   #28
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Thinking death in this thread is a stretch.

Advise not condemn. At least that is what I have been reminded of. And some souls tossed for being so direct.

Most boaters will die of many reasons...probably not the direct result of a heat exchanger.
A stretch? Maybe, but isn't life safety really the #1 consideration?

Sure, there may not have been many deaths as a direct result of heat exchanger failures. But I would assert that's because marine heat exchangers have evolved over...what, 100 years? They have been designed so that if they fail, the results won't be catastrophic. Think of the alarms boats have. Engine overtemp, coolant overtemp, exhaust overtemp, coolant flow, bilge water level. What is the equivalent in a pool? Microswitches that instantly turn power / heating / circulation off. And that's where the cost of failure is a leakdown, not a boat sinking. And you know that most sinkings are at the dock - this use case seems most likely to happen away from the dock and operating at higher loads.

I think this is one of the most dangerous ideas ever floated on a boating forum and it deserves to be called out as such. But I can understand and accept that you don't agree.
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Old 11-17-2015, 02:01 PM   #29
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Quote:
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RPR

Why not just bite the bullet and buy a new unit suited for the engine? The current setup has lasted nearly 40 years if I read your posts correctly. Sure sounds like it worked very well.

As discussed, you can make it better by plumbing the manifold for coolant. And you can install a fresh water flush for the cooler. These are sensible upgrades and would be appreciated by the next owner.

But the other stuff you are contemplating are out of the norm and a step backwards IMHO.
My concern is adding too much heat to the raw water system by just adding the manifold into the freshwater circuit. If there was a larger sized OEM heat exchanger designed for the extra heat added from the manifold then it would be a simple and appropriate solution. I haven't seen this, so I'm considering alternative ways to increase the cooling capacity, seeing a cheap titanium heat exchanger sounded interesting. (to refugio it sounds so stupid it's worthy of ridicule, but I am actually a reasonably accomplished engineer and I've faced similar criticism for both - ideas that have worked and ideas that have not. So I've learned to notice yet ignore such ridicule).

I have heard of two situations where the manifold was just added, in one case it was perfectly fine, in the other there were issues which led the owner to repower. I think if the cooling circuit is in pristine shape then there is enough cooling capacity, however if there are any issues - from a worn water pump cam to fouling in the air charge cooler, my guess is the system overheats.

As Cappy points notes it about the BTU of the existing system, the addition of the manifold and the capacity of any added exchanger. I don't know those numbers. I haven't seen a "generic" marine-purpose heat exchanger with BTU ratings.

Thanks,
Robert
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Old 11-17-2015, 02:05 PM   #30
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On several different occasions I was involved with designing heat exchangers for industrial use and engine cooling. As one would expect, the playing field is wide open but some basics apply. Two key elements are what are you trying to cool/heat with what medium whether air or solution.

Land based diesel and gas air cooler applications on the incoming side have only to deal with air and at what elevation and temperature. Marine diesels have it a lot tougher as not only is the incoming air a variable but the cooling medium can be fresh, salt or coolant liquid with associated thermal and corrosive issues.

The sizing for the cooler (a radiator if you will) can be easily defined for the un fouled state once air flow, pressure and cooling medium are defined. This is the purpose of proper marinization.

A test for the marine engine builder in this day is the dyno. Not only for emissions compliance but in this case to insure the various coolers and heat exchangers perform at rated fuel burn and expected air and water temperatures.

I do know that the same engine and associated coolers on my vessel were designed for use in the Red Sea, warmer waters than the PNW for sure.

So with all this blather, what is my point? The same as I mentioned in another related thread. Think outside the box and bypass the air cooler completely and see how things behave. Then you have a go forward point of reference for non engineered hit and miss air cooler pursuits. Maybe then some new knowledge can be gained and verified.

On a different note, I do know that a jacket water cooler is a very different unit than a raw water cooler. Using coolant in the same cooler as designed for raw water will effectively de-rate the engine, not necessarily a bad thing. But kind of like bypassing the cooler entirely.
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Old 11-17-2015, 02:51 PM   #31
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Risk is something that has been discussed - here's my perspective.

What is the risk of loss of life from a failed raw water cooled exhaust manifold? It's non-zero and probably significant since failures in the manifold:
- Have actually happened
- Have led to immediate engine failure
- Engine failure could lead to loss of life

What is the risk of loss of life from a failed heat exchanger? It's still non-zero but imo less likely than a failed manifold. A failed heat exchanger is very unlikely to lead to an immediate engine failure, I would say it's at least several minutes, if not hours before an engine failure, and during that time there would be warning signs:
- Bilge pump alarm going off
- Engine temperature rising

I see the risk inherent in the raw water cooled manifold as excessive, since there could be zero warning signs before an engine failure.

In this thread we have one example of the pool heat exchanger working in a marine environment, and likely not the titanium version. I think it's worth further investigation, if I could add this exchanger (iow, in addition to the stock one), to my cooling system, allowing me to bring my manifold into the fresh water circuit. It seems cost effective and safer than the current raw water manifold. I am not saying it *IS* but I'm saying it seems like it is.
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