Orca system closed cooling operation

[rowlex]

I have a 2000 bayliner 2150 5.0 with the orca heat exchanger. I am wondering how the system works, is it a constant flow? As much water as the impeller can circulate it circulates? It seems as though there would not be any thermostat type of device so flow would not be limited anywhere.

Thanks!

 

[GA_Boater]

Re: Orca system closed cooling operation

Think of it as your car/truck except the air cooled radiator is replaced with the lake/sea water cooled exchanger. So just like your car the coolant is thermostatically controlled internal to the motor and the external cooling medium, air or water flow speed and volume is controlled by the speed of the vehicle. The faster you go, more air/water flows through the radiator/exchanger.

Make sense?

 

[rowlex]

Re: Orca system closed cooling operation

Makes sense, so the rate of flow is not controlled by a thermostat correct? Only engine speed?

The reason I ask is that winterizing a motor with the orca system and the antifreeze kit should be pretty fail proof if I do not have to wait for a thermostat to open.

 

[tpenfield]

Re: Orca system closed cooling operation

Yes, the flow of raw water (sea/lake water) is not regulated, and is based on what the intake pump can do at any given engine speed. The heat control is on the engine side of the system where the thermostat resides.

It may be advisable to drain the raw water side of the heat exchanger, just in case you do not run enough antifreeze through the system, particularly if it is a 'half' system and the exhaust manifolds are raw water cooled. You would want to drain the heat exchanger and the exhaust manifolds.

Additionally, you will want to make sure that you have a sufficient concentration of regular automotive antifreeze in the 'closed' side of the system to be sure that the engine itself is protected from freezing. Same issues as a car in winter.

 

[GA_Boater]

Re: Orca system closed cooling operation

Makes sense, so the rate of flow is not controlled by a thermostat correct? Only engine speed?

The reason I ask is that winterizing a motor with the orca system and the antifreeze kit should be pretty fail proof if I do not have to wait for a thermostat to open.

If you have antifreeze in the system, which is normal for a pressurized system, again like your car - No need to wait for the thermostat to open. It's because the Orca system is isolated from the water coming from the impeller. Many of the folks here advocate draining the fresh water side instead of using an antifreeze kit.

 

[rowlex]

Re: Orca system closed cooling operation

thank you gentlemen, I have the 5 gallon antifreeze kit and im going to use the pink RV stuff. I'll drain the risers before switching to the antifreeze.

Thats also why I asked about the orca system as many here advise against antifreeze but I think it may be more fool proof with the closed cooling.

 

[Lou C]

Re: Orca system closed cooling operation

While its true that you don't have to worry about the thermostat opening on a closed cooling engine, the issue with using antifreeze that way is if the impeller can suck it in fast enough so that the impeller does not get burned up and the engine does not overheat. Sometimes with an engine mounted impeller unless you pressurize the AF flow with a bilge pump or similar the impeller can't get primed because of the distance from the lower unit intakes and the impeller. If it were me I'd flush the engine, change the motor oil and filter, run it again to make sure the filter does not leak, fog it and then drain the heat exchanger and manifolds. I'd then manually fill the raw water side of the exchanger with -100 AF and the manifolds as well. Simple, fool proof, no burned impeller no overheated engine.

If you have an Alpha drive it may work as long as the muffs fit really tightly since the Alpha impeller is right in the lower unit. But the manual drain and back fill method is the best way.

I honestly do not understand the fascination people have with these winterizing kits, they are a short cut that can wind up being a real headache if you wind up with a burned impeller, an overheated engine and still have to get the boat winterized. Just drain it. You really don't have to even add AF for freeze protection if you drain it right, its really for corrosion protection because it keeps air out and adds corrosion inhibitors.