marinized 240D running hot

Did you connect up the heat exchanger reversed? Engine coolant flows thru the little tubes in the center, the outside is cooled with sea water.

 

It is the opposite. Otherwise it would be almost impossible to clean.

 

Last time I checked a Mercedes diesel is a 4 stroke engine. So consumes its swept volume of atmospheric air in 2 revolutions. Thus 2.4L in 2 revolutions or 1.2L of air in a single revolution. If its turbocharged, then one has to adjust for boost pressure, but its usually not that high if you arent on a race boat...

If you are interested in compression ratio, governed by combustion chamber volume, you have to DIVIDE the displacement by the compression ratio. So a 4 cylinder with 2.4l swept volume = 600cc per cylinder. For simplification, lets say 20:1 compression ratio. Thus combustion chamber volume = 600/20 = 30cc which includes any volume between the top of the piston and the surface of the cylinder head.

You sir have some strange ideas on how things work that aren't based on facts or science or math for that matter. You are suggesting that the air is compressed 16:1 with the piston at BDC ????

 

Since its basically a 50kW engine, if you make the assumption that the heat exchanger system has to move at least the same amount of heat, you should be good. To allow for some system degradation you may need to apply a factor of safety like 1.5-2 when sizing it, so that in future when it has scale or dirt, it is still adequate.

The coolant system on the engine was sized adequately by Mercedes, so its just a matter of having enough heat exchange surface in the heat exchanger itself, as well as adequate water flow on the raw water side. And of course the system has to be capable of getting rid of air on both sides of the heat exchanger so it can run reliably. The way the header tank is tapped into the system can be critical for both feeding coolant into the system as well as purging out air into the header tank naturally.

Usually the inlet and outlet of the raw water connections are made to allow for air purging but one could ask the manufacturer to confirm.

 

Kieth, my bad on adding in the compression ratio, it most certainly won’t consume more air than its displacement x rpm.
I was pointing up the tiny air filter, it wouldn’t take much belt dust or whatever to really make a difference in available airflow. Restricting airflow will drive temps up.

 

Yes you're right, that way it sheds heat from it's outer skin too.