Cooling system

[Hendo78]

Hi all,

Ive looked around on here and on the www. But can't seem to find the answer so just chucking up a thread.

My question is In relation to raw water (sea water) cooling and coolant engine fluids.

I understand that in a closed system like I have, the raw water is sucked up into a raw water filter via a pump, it then passes through the pump into one oil cooler, up into the heat exchanger, into the exhaust then out the back while the engine coolant is a closed system and cooled in the heat exchanger by the sea water so to the oil coolers.

Now What i want to know is, is there rule of thumb for where the raw water goes first? Is it better to go in to the heat exchanger first then to the oil coolers or into the oil coolers first then to the heat exchanger?

I'm at that point of my boat build where the engine, heat exchangers and oil coolers are all rebuilt and getting ready to install it into the boat so am curious as to what the "best practice" is for this as obviously the first cooler will get colder water than the rest and the more coolers the water goes through the warmer it gets .

The existing setup was through the pump, into the gearbox oil cooler, up to the heat exchanger then into the exhaust but as I had never been in the boat when it was running, I'm not sure if that way worked or not

Should it be a concern or is this something that doesn't really matter and should worry about something else?

What way do you guys/girls have it running?

Thanks in advance for your help.

Cheers
Hendo

 

[Brooksie]

If you have an turbo intercooler (aftercooler) it is usually first to get the seawater (and the coldest water "sees" the hottest air).

Beyond that, I have seen engine oil, transmission oil, and coolant exchangers installed interchangably on different engines for convenience of plumbing. That's not to say you should interchange yours because they could be designed (sized) to follow one another in a specific order as the seawater gets warmer. Again, even reversing the flow of one fluid through an exchanger slightly changes the amount of heat absorbed.

 

[Hendo78]

If you have an turbo intercooler (aftercooler) it is usually first to get the seawater (and the coldest water "sees" the hottest air).

Beyond that, I have seen engine oil, transmission oil, and coolant exchangers installed interchangably on different engines for convenience of plumbing. That's not to say you should interchange yours because they could be designed (sized) to follow one another in a specific order as the seawater gets warmer. Again, even reversing the flow of one fluid through an exchanger slightly changes the amount of heat absorbed.

Hi and thanks for your reply. No she not a turbo mate. Just a naturally aspirated 1991 Perkins TW6.354.4 (non marinized)

The system, as it was when I got it, was a bit haphazard so just seeing what the rule of thumb was.

I have two oil coolers, one for the gearbox, one for the engine oil and a heat exchanger for the engine coolant, but, the engine oil cooler is part of the closed coolant system and doesn't have sea water running through it. I would have thought that running sea water through that cooler as well would have been beneficial??!

 

[jleonard]

, the engine oil cooler is part of the closed coolant system and doesn't have sea water running through it. I would have thought that running sea water through that cooler as well would have been beneficial??!

Not necessarily. The Cummins 6B engines for one use their antifreeze coolant system to cool the oil. That is actually BETTER as there are no maintenance issues.

 

[supertramp]

Without Turbo:
1.) Motorwater-intercooler,
2.) Motoroil-intercooler,
3.) Gearbox-Oil-intercooler,
in my case:
4.) Air-Compressor for Stabilizer,
_____________________________
Norbert

 

[Brooksie]

I have two oil coolers, one for the gearbox, one for the engine oil and a heat exchanger for the engine coolant, but, the engine oil cooler is part of the closed coolant system and doesn't have sea water running through it. I would have thought that running sea water through that cooler as well would have been beneficial??!

Somewhat uncommon but if sized correctly can be better. No corrosion worries and quicker getting oil up to operating temp. Same with gear oil cooler. There is no reason that an exchanger with 180F water can't keep oil below 230F, but it takes a larger exchanger.

If in doubt, you may want to take some temperature readings after a full power run.

 

[psneeld]

most engines I have seen have the oil cooler first...but I'm not convinced it matters unless designed specifically to pretty close tolerances.
the real answer lies in the heat drop across each cooler and if it is sufficient to do it's intended job.

Weak answer but every diesel engine design should have an "arrangement number" that describes what "add-ons" are present and the factory should be able to tell you exactly what pieces and parts go where...

 

[Marin]

As a single point of reference, Hendo, the Ford Lehman 120 is typically set up with the raw water flow from the intake through-hull following this path:

Seacock
Sea strainer
Raw water pump
Oil cooler
Engine heat exchanger
Marine gear (transmission) heat exchanger
Cooled exhaust elbow downstream of the exhaust manifold
Exhaust hose and outlet

 

[LaBomba]

As a single point of reference, Hendo, the Ford Lehman 120 is typically set up with the raw water flow from the intake through-hull following this path:

Seacock
Sea strainer
Raw water pump
Oil cooler
Engine heat exchanger
Marine gear (transmission) heat exchanger
Cooled exhaust elbow downstream of the exhaust manifold
Exhaust hose and outlet

Mine is the same Marin except it goes to the hot water tank as well before going to the exhaust.

 

[Hendo78]

As a single point of reference, Hendo, the Ford Lehman 120 is typically set up with the raw water flow from the intake through-hull following this path:

Seacock
Sea strainer
Raw water pump
Oil cooler
Engine heat exchanger
Marine gear (transmission) heat exchanger
Cooled exhaust elbow downstream of the exhaust manifold
Exhaust hose and outlet

Thank you. Exactly what I wanted. Can always count on you for help! Thanks mate!

 

[Hendo78]

Mine is the same Marin except it goes to the hot water tank as well before going to the exhaust.

Good point to remember when I pipe up the boat

 

[Hendo78]

Thanks everyone or your input. I appreciate your help

 

[Marin]

Mine is the same Marin except it goes to the hot water tank as well before going to the exhaust.

Our starboard engine (FL120) as a hose connection on the port side of the block for the engine coolant (NOT raw water) to go to the hot water heater located in the aft head. The return from this loop re-enters the engine in another location but to be honest I haven't checked exactly where it is.

But our boat does not use the raw (salt) water cooling system to heat the hot water heater. Most of the boats I am familiar with use the same basic setup as ours, using engine coolant to heat the hot water heater.

PS-- I should probably add that the port engine has the same connection on the port side of the block. However this is fitted with a petcock only for draining the engine's coolant. The starboard engine also has the petcock fitting but it's on the end of the hot water heater hose "T" fitting that's screwed into the block.

 

[Codger2]

Most of the boats I am familiar with use the same basic setup as ours, using engine coolant to heat the hot water heater.

 

[LaBomba]

Our starboard engine (FL120) as a hose connection on the port side of the block for the engine coolant (NOT raw water) to go to the hot water heater located in the aft head. The return from this loop re-enters the engine in another location but to be honest I haven't checked exactly where it is.

But our boat does not use the raw (salt) water cooling system to heat the hot water heater. Most of the boats I am familiar with use the same basic setup as ours, using engine coolant to heat the hot water heater.

We are not on salt water but what you are saying makes sense and I am likely mistaken. We just got her in the fall winterized her and put her on the hard. I will check when this snow finally goes away but I'm sure, thinking about it now, that your more than likely right. Thanks

 

[Peter B]

Marin wrote.....
As a single point of reference, Hendo, the Ford Lehman 120 is typically set up with the raw water flow from the intake through-hull following this path:

Seacock
Sea strainer
Raw water pump
Oil cooler
Engine heat exchanger
Marine gear (transmission) heat exchanger
Cooled exhaust elbow downstream of the exhaust manifold
Exhaust hose and outlet

Thank you. Exactly what I wanted. Can always count on you for help! Thanks mate!

Hendo, my Lehman 120 is as Marin describes also. The heat line for the hot water cylinder comes off at separate points either side of the header tank of the main coolant system, and is not part of the raw water flow, which would not really be hot enough to heat anything anyway, I question the poster who said his raw water circulation includes the hot water cylinder. Frankly I doubt that, but if so, I am indeed surprised. I would not want raw seawater going anywhere near my nice new hot water cylinder.

 

[Hendo78]

Marin wrote.....
As a single point of reference, Hendo, the Ford Lehman 120 is typically set up with the raw water flow from the intake through-hull following this path:

Seacock
Sea strainer
Raw water pump
Oil cooler
Engine heat exchanger
Marine gear (transmission) heat exchanger
Cooled exhaust elbow downstream of the exhaust manifold
Exhaust hose and outlet

Hendo, my Lehman 120 is as Marin describes also. The heat line for the hot water cylinder comes off at separate points either side of the header tank of the main coolant system, and is not part of the raw water flow, which would not really be hot enough to heat anything anyway, I question the poster who said his raw water circulation includes the hot water cylinder. Frankly I doubt that, but if so, I am indeed surprised. I would not want raw seawater going anywhere near my nice new hot water cylinder.

Hi Pete,
Yeah good point. I'll Put a 'T' piece somewhere in the engine coolant pipe and run it into and through my water heater then back into the block.

What hot water system are you running?
(Brand model etc)

Is it the dual heating jobs? The one with the electric element as well as the heat exchanger?

All the ones I've been reading about are in the US and postage kills any and all savings.

Cheers for the help Pete

 

[Peter B]

No probs, Hendo - mine was one of these. Isotemp Waterheaters : Isotherm Parts, Marine Refrigeration Parts
I was a bit lucky, in that I saw it advertised in a the paper, and the PO had barely installed it and then sold his boat, so he took it out again, so near new but a made a saving. it is a 42 litre job, and yes, it has the 240v AC element in it as well, and it is the one thing on the boat, apart from the Ctek smart charger, that is ever used from mains power. We connect it to shore power for the time it takes to get ship-shape and ready to leave the dock, and it brings the water up to good hand warm temp in about 20 minutes, then the engine does the rest. In my boat the take off is one side of the header tank, and the other goes into a T junction in the hose, from the head...I think. I'll check tomorrow.

 

[Hendo78]

No probs, Hendo - mine was one of these. Isotemp Waterheaters : Isotherm Parts, Marine Refrigeration Parts
I was a bit lucky, in that I saw it advertised in a the paper, and the PO had barely installed it and then sold his boat, so he took it out again, so near new but a made a saving. it is a 42 litre job, and yes, it has the 240v AC element in it as well, and it is the one thing on the boat, apart from the Ctek smart charger, that is ever used from mains power. We connect it to shore power for the time it takes to get ship-shape and ready to leave the dock, and it brings the water up to good hand warm temp in about 20 minutes, then the engine does the rest. In my boat the take off is one side of the header tank, and the other goes into a T junction in the hose, from the head...I think. I'll check tomorrow.

Cheers old mate! We have the same tastes as I see you have a Ctek charger. You like them? Don't have one but will be putting one in plus solar panels to keep the 16x 100ah batteries at the best.