Heat Exchanger Conversion

[clausont]

The engine in our Cal 29 has 169 hours on it. It is raw water cooled and I am considering installing a heat exchanger. It is only in the consideration stage now as I have little knowlege and no experience in doing this. Has anyone done a conversion like this? Any information would be greatly appreciated.

[Alan Wheeler]

It is fairly straight forward. Your big ticket item is the heatexchanger of course. The other main issue is room to place it.
What is the engine???

[Steve Rust]

You will also need a second water pump. Installation will vary depending on your engine.

[clausont]

Ok. I did not think it would be too complicated. Will there need to be any kind of small holding tank or reservoir with it? Also, what about the thermostat temperature. Will there be any benefit from running at a different temperature from what the manual says for raw water? It has nothing for a heat exchanger system.
The engine is a single cylinder Faryman. I think it is the 12 hp model from the documentation that came with the boat. I would not think that it would take mo9uch of a heat exchanger.

[DeepFrz]

Why don't you contact Farymann. They may be able to give you specifics. You should be able to run the engine at a higher temperature, but you really should get the information from Farymann.
Good luck.

Farymann Diesel GmbH

[never monday]

I don't know of anyone FWCing the F12. I don't know of a higher deg thermostat available for it either. It's such a simple engine, why complicate it?

[clausont]

Never Monday - Your point is probably the main one that I was curious about but did not ask. So now I will ask it: Is it worth installing a heat exchanger on this engine. My thought on this is to keep the block in good shape internally so it does not rust through a water jacket or something along those lines. It is a simple engine, but still expensive if I had to replace it sometime down the road. Will the heat exchanger protect the block to the point of being worth it.
Will the extra water pump on such a low hp engine use enough energy to cause a problem (ie: overload the engine).
Hmmm - perhaps there is more to consider here than I first thought.

[Chief Engineer]

A heat Exchanger, a reservoir with radiator type cap, overflow bottle, hose and another pump mounted on the pulley on the fly wheel.

You will also need to fabricate a bracket for the pump and all the associated hardware.

You are talking a "few" Dollars or Euros there. Off the top of my head, the pump hose and heat exhanger is going to set you back around $300.00 alone.

My suggestion is to either get a manual on the engine and trace the water flow circuit...or do it yourself....you may be surprised.

Generally speaking, it is not a good idea to try to re-engineer an engine from the original installation. This is especially true for exhaust systems.

Contact Faryman and see if they ever offered the engine with fresh water cooling as an option.

I can appreciate your concerns about engine deterioration....but if you are concerned about "rusting out" keep in mind that the area that faces the biggest problem on any engine is the interface (mixing) of hot water and exhaust gases. (exhaust elbows)

[Steve Rust]

An RWC diesel engine usually runs a cooler thermostat to prevent the formation of salt water scale in the coolent passages that would occur at the higher temps that a FWC engine runs at. A diesel runs more efficiantly at these higher temps so a RWC diesel is a compromise between simplicity and efficancy. If converting to a FWC system it would be best to use a hotter thermostat. Whether this is worth the effort and cost is debatable. One of the modern lightweight diesels probably would not last long using RWC cooling but these old engines were designed and built for it. My 1982 Vovo MD7B is RWC and I have thought about it. There were/are kits available to convert my engine so maybe Farymann also had something avalable.

[sildene]

I am adding fresh water cooling to my 3-cyl diesel because, when removing the existing exhaust manifold, I was dismayed by the amount of hard baked crud and rust flakes in it's water jacket. And in my case I could not physically access all the water channels in the engine block, so unseen accumulation is going on. I know you can use a laser thermometer to try to track down hot spots, but this can be a hit and miss affair.

(An engine reconditioner had a go at the exhaust manifold with his special chemical bath, but all the hardened stuff would not budge. Only a chisel seemed to do anything.)

You can't use anti-rust coolant with raw water cooling and a periodic flush does not make a big difference, in my opinion. Still, as pointed out above, it's a cost-benefit equation for the owner.

To keep installation simple, you may consider:

1) A heat exchanger with built-in header tank, rather than separate. Both formats are available.
2) An electric circulation pump, instead of an engine driven pump.

To ensure the heat exchanger is of adequate capacity (and not over sized), I contacted the heat exchanger manufacturer (Bowman, in my case) and his computerised simulation calculated the right size (note there is also variation in capacity between 1-way, 2-way and 3-way flows inside the same size exchanger). I had to supply the raw water pump capacity and some engine specs.

Johnson Pumps manufacture an electric circulation pump specific for engine coolant circulation - no seals (no maintenance) and magnetic drive. Johnson series CM10 and CM30, for which they claim MTBF of 2500 hours. Key point is the low current draw - depending on model, max 2.5A - so even if the alternator breaks down, your battery bank could get you home. In some ways, this is similar to using an electric fuel pump instead of an engine driven lift pump.


By the way, I am still working on installing my setup, so if anyone here has any experience, suggestions or opinions regarding the good or bad of electric engine circulation pumps, I'd love to hear them.

[Alan Wheeler]

Work done is work done. It doesn't matter if the work is electrical or mechanical. Just because the electric pump draws 2.5A, that 2.5A's of energy has to be made and that is by the Alternator/Generator which is driven by the Engine. So in the end, the Engine still has to do the work.
The Farymen was built to be a RWC engine. Complicating it with a heat exchanger will probably not extend it's life by much. Running it hotter will not improve it either. It is not a high perfromance engine that you will notice any efficiency improvement by running it hotter.
The crud build up in the engines can be removed using a boiling Caustic Soda solution. You heat up the engine and then drain it of water. You then pour in the hot solution and leave it for an half hr.
A proper way of doing it, but difficult to do, is to pump the solution in a closed cycle and heating the solution. After this, you empty it all out and flush it with water.
NEVER do this to an engine with an Aluminium Head or Block.

[clausont]

Alot of excellent points here. The general concensus here (and I agree) is that the single cylinder Faryman is a tough old engine designed and engineered to be run as a rwc engine and that installing a heat exchanger will not likely add much benefit.
I will contact Farymen for further information as has been suggested here to see what they say also.
Thanks for all of your input on this matter. I will let everyone here know the answer that Faryman gives.

[never monday]

The vulnerable parts to the Farymann are the cylinder and head. These are also the only internal parts that see sea water. Both can be had for replacement cheaply if needed. The first thing to rust out and IS YOUR WARNING SIGN. Is a small 3/8-1/2 freeze plug under the back lower horizontal surface of the head. This plug is zinc steel and will go away. All RWC engines are thermostatted at 140 deg F. This minimizes the risk of salt coming out of solution. Notice I said MINIMIZES. You can still get hot spots, plug an intake, loose an impeller...etc. Then the internal temps go up, could be way up. It's these small over heats that cause the salt to settle in the cylinder and degrade the steel.
Personally, If I had that engine as propulsion or gen power (FP4000 & 4200) I wouldn't go thru the hassle and expense of converting it.

Just my $.02USD

[clausont]

Pat, That is better information about this little engine than I could have hoped to find out. I appreciate your $.02USD worth - it is worth alot more to me than that.
Thanks again all.

[Boko~maru]

Well, it would appear that the information I have gotten is contrary to the direction in this thread. I purchased a Westerbeke 4.2 KW Peanut Generator on ebay. This unit is based on the single cyinder Farryman diesel engine. Actually, I have learned that this unit is really made in Italy, and just relabeled by Westerbeke to their name. After the purchase, I started surfing the net for Information and parts sources. I spoke with a small company owner about this setup and what I was trying to accomplish. While this person was in competition with this unit, his tone was complementry toward it. His unit is also based on the Farryman engine. The one thing he did warn me about: " If you want that engine to last, you need to convert it to fresh water cooled." "If you don't, the salt water in the raw water cooling, will eat it up" Makes sense to me, I have aquired all the parts to make the conversion from Ebay, The Generator has been installed, so has all the conversion parts. I need to plumb it all together. In that plumbing, I need to figure out how & where to add a Zink on the Seawater side. the final installation is still down the list, but should be finished this Fall. If you want, I can keep this board advised. By the way, thanks for the info on the thermostat; one more bit of knowlege I needed.