DIY block heater Lehman 120

[cyfarkas]

I winter in the water in NYC. My setup has the usual loop that heats the hot water tank when running. I plumbed in a small Little Giant 115v magnetic pump at the return (portside under the coolant main coolant tank) to warm the engine while I'm stationary and to also provide ER and salon heat. The engine becomes a big radiator if you will. Yes I bled the air valve.

So far after 2 hours I have the front of the exhaust manifold at 97 degrees. 15 degrees less towards the rear. Less again on the starboard side but it's catching up. I have not removed the thermostat. Too much trouble.

My questions
1. How much fluid am I moving since the thermostat is closed?
2. Any downsides to my madness?

Thanks for your advice.

 

[O C Diver]

Thermostat isn't in the loop. The water heater loop bypasses the thermostat. Only thing the thermostat regulates is coolant going to the raw water heat exchanger.

Ted

 

[psneeld]

What are you using to heat the system? Hot water heater back to the engine?


If so 1500 watts wont do much in the winter up there, especially with a deck between you and the engine....plus...your hot water may be too cool.

 

[O C Diver]

Your heat system is fine to preheat the engine and keep the engine room from freezing. I believe the block heater in my Cummins 6BT in my Doodge pickup is only 600 watts. If the boat is in the water (25 to 30 degrees) it takes very little heat to keep the engine room near 40 degrees. Probably won't make a noticeable difference in the saloon as sound insulation also acts as heat insulation.

 

[psneeld]

True....sorry I didn't differentiate between block heater and saloon warmer.

 

[cyfarkas]

Thank you guys. Yes my my water heater is 20 Gallon, 1500w. Several hours later all is well. Cabin is doing with less heat from portables.

 

[TJM]

I also have twin FL120's in southern Ct.
Currently I have an oil filled radiator between the girls set at 70°.
Engine room is sealed off and insulated very well.

Are you saying that you use the hot water heater element to keep your blocks warm ? Essentially reversing the designed process which is heating your cold shower water with the hot engine coolant. Hmmm

Gets me thinking....
I guess if the heat transfer is efficient enough from your hot water heater to the closed loop cooling system.
You probably keep the pump running all of the time ??

Great idea.

 

[cyfarkas]

Yup. Reversing the process. The pump is a small magnetic type it keeps the block at 100 degrees. Should of done it sooner. the boat is assisted by other portable, electric-oil too, but the nice thing is the temp is very stable and consistent. Plus I have one of my reverse cycle heat on set at 60 when I'm not at the boat. Plus no condensation on the inside of the block, oil is nice and warm without cooking. I visit almost daily, and it's all good.