Crazy? Converting Fresh to Raw water cooled

[Dsanduril]

Witzgall,

we have a 2003 installed new in 1985. Raw water cooled. In the intervening years it has collected about 5000 hours. Have had to replace the exhaust elbow once because it got crudded up enough that we started losing water flow. When we have worked on the engine we haven't seen any significant buildup other than at the elbow (guess that makes sense, since the water is getting introduced to some very hot gases at that elbow). I've always thought the next engine would be FW cooled (mostly because of all the things I've read) but the reality is that this RW cooled engine (and the MD2B before it) have not had any major problems with the cooling system.

[Vasco]

I'm quite familiar with the Volvo 2000 series engines having had a 2002 and a 2003. I am not a fan of Volvo after those experiences. If you switch to raw water cooled make sure you can get at the starboard side easily. You will have to re-new pencil zincs frequently. If you can't get at that, your exhaust manifold will develop holes very quickly.

[Paul L]

Chris
I think for this particular engine swapping to RW cooled makes sense. It really simplifies the engine and removes many of the headaches of tbe 2003. I' m sure you'll need to do some cooling system flushes over the years, but the FW system needs it every 2 or 3 years too. I'm sure this conversion sounds silly to those that havn't owned a 2002/2003. It seems that the 2003 RW owners that I've met are a lot happier with the engine than the FW owners.

[charliehows]

Originally Posted by witzgall

Charlie - the local Beta rep told me that the 2000 series from Volvo was originally designed as a raw water cooled engine. The kludge they call a freshwater cooling system was bolted on after the fact. Changing over is simple - I need to remove all of the fresh waster stuff - water pump, pipes and heat exchanger. Change out the thermostat. Replace the pipes from the thermostat and manafold with a single part to connect the two through my hot water heater. Then one or two plug on the engine.
We would also need to change the belt, as it drives the fresh water pump, and would no longer, so it would need to be shorter.

Jim,
We currently have about 2900 hours on the engine. If I could get another 3000, or even 1500 that would be fine. How often did you have salt water plugging problems? I surely don't want to exchange one headache for another.

Chris

Well if its designed to take raw water, there are definitely advantages to having a much simpler cooling system - ive come to prefer raw water cooling...

[hellosailor]

If you convert to raw water cooling, you lower the eventual resale value of the boat. Not just by the equipment, but because 20-25 years in salt water can literally eat out the engine cooling passages.

And you also will depower the engine, as salts crystalize out around 140F versus the 170-180F that a fresh or isolated engine runs at. Will burn more fuel and supply less power, since you WILL have to run the engine 30-40 degrees colder.

Yes, you will have 'less stuff' and conform more to KISS, but I'd really say you're throwing out something that's more valuable than you realize. If the system suffers from gasket leaks, the odds are the mating surfaces need to be cleaned or aligned, or perhaps it simply needs different gaskets. Sometimes PermaTex Form-A-Gasket is a better way to seal things. It works perfectly well, if you follow the instructions wrt clean surfaces, proper curing times, etc.

[Pacificcatalyst]

The raw water cooling system on our boat was replaced about 10 years ago, after the head was so compromised with corrosion that it would no longer hold its seals. Of course that was after 70 years of almost continuous use.....
The heads were re-cast and replaced at the same time the cooling was switched over.
So, if you're just looking for another few thousand hours, I don't see a problem with changing, provided you follow the advice already given; a lower temp thermostat and checking/changing your freeze plugs.
Now the other side, there are undesirable side effects from running your engine cooler than it's designed to run, carbon build up in the combustion chamber along with smoking and blowing soot around come to mind.
The salts will penetrate the cast iron in your engine, and no flushing treatment that I know of will get them out. There they will continue to slowly degrade your engines cast iron parts.
Even thought I might make the change if I were you, I would never buy a boat with raw water cooling unless the price reflected the cost of replacing the engine.

[olaf hart]

Just bought a boat with a salt water cooled 2003, about 1300 hrs.
The surveyor ran two of these engines as generators in his charter boats, over 5000 hours on each, was a real fund of information.
He changes out the elbows every 4 years. Said to check the cooling pipes.
There was a LOT of scale around the connections, which are also the flat washer type, but little or none in the chambers I could probe.
The thermostat was also the wrong type, 170 not 140 degrees, which I changed to the salt water one.
I recall a thread somewhere where someone made a better sort of C clamp for the joints, said they sorted our the seal problems. I have had none yet.
The surveyor said the 2003 was based on a Perkins engine, someone else said they were Peugeot. Anyone know the real story?
I also noticed it was a real problem to bleed the fuel system, took a lot of work to clear air from the lines. Anyone had this experience?

[Pete7]

Originally Posted by olaf hart

The surveyor said the 2003 was based on a Perkins engine, someone else said they were Peugeot. Anyone know the real story?
I also noticed it was a real problem to bleed the fuel system, took a lot of work to clear air from the lines. Anyone had this experience?

The 2000 series are the last of the engines designed by Volvo for marine use, later models were bought in and marinised.

The fuel pump will only work with the cam in certain positions, sometimes you have to turn the engine over a bit. Also worth thinking about the fuel lift pump, they don't last for ever but the core engine does which is why things like exhaust elbows eventually block up or corrode out.

Pete

[Pete7]

Someone looking for a heat exchanger:

http://www.cruisersforum.com/forums/...ger-90922.html