Rick--- With all the talk that occurrs on this and other boating forums about the proper operating temperature range for a diesel I have been pondering a failry basic question for a bit now.
The short version of the question is this: is the relationship between coolant temperature and combustion chamber temperature such that if the coolant temperature is indicating properly on the gauge per the manual, does this always mean that the combustion chamber temperature is also in its correct range?
The background is this---- People often talk about their engine temperature in terms of what they see on the coolant gauge. They talk about the horrors that will occur if you run a diesel at less than it's optimal temperature range. The typical comment, which I myself have made from time to time is, "If you run your engine at too low an rpm it will run too cool and over time this could be detrimental to the engine."
When I have said this, I have meant the engine's combustion temperature being too cool.
Now I assume the engine manufacturers design the cooling systems of their engines, from coolant circulation volume and flow to thermostat characteristics to coolant temperature sensor and gauge, so that when the engine is operating in its proper temperature range (combustion) the temperature gauge on the panel will indicate the proper temperature (coolant).
So.....if on the typical diesel engine installed in the typical recreational boat the coolant temperature gauge is indicating the correct operating temperature per the manufacturer's manual, does that always mean that the combustion chamber temperature is also in the correct range?
The application of my question is this: At a cruising rpm of 1650 the coolant temperature gauges of the two FL120s in our boat indicate the proper temperature per the manual. If I pull the power back so the engines are operating at 1500 rpm (or even less) and the coolant temperatures remain at the same place on the gauges (kept there by the thermostats) can I assume that the combustion chamber temperatures are also remaining in the correct range?
So I would not have to worry about "too-cool" combustion chamber temperatures as long as the coolant temperature was at the right figure on the gauge per the operating manual.
The short version of the question is this: is the relationship between coolant temperature and combustion chamber temperature such that if the coolant temperature is indicating properly on the gauge per the manual, does this always mean that the combustion chamber temperature is also in its correct range?
The background is this---- People often talk about their engine temperature in terms of what they see on the coolant gauge. They talk about the horrors that will occur if you run a diesel at less than it's optimal temperature range. The typical comment, which I myself have made from time to time is, "If you run your engine at too low an rpm it will run too cool and over time this could be detrimental to the engine."
When I have said this, I have meant the engine's combustion temperature being too cool.
Now I assume the engine manufacturers design the cooling systems of their engines, from coolant circulation volume and flow to thermostat characteristics to coolant temperature sensor and gauge, so that when the engine is operating in its proper temperature range (combustion) the temperature gauge on the panel will indicate the proper temperature (coolant).
So.....if on the typical diesel engine installed in the typical recreational boat the coolant temperature gauge is indicating the correct operating temperature per the manufacturer's manual, does that always mean that the combustion chamber temperature is also in the correct range?
The application of my question is this: At a cruising rpm of 1650 the coolant temperature gauges of the two FL120s in our boat indicate the proper temperature per the manual. If I pull the power back so the engines are operating at 1500 rpm (or even less) and the coolant temperatures remain at the same place on the gauges (kept there by the thermostats) can I assume that the combustion chamber temperatures are also remaining in the correct range?
So I would not have to worry about "too-cool" combustion chamber temperatures as long as the coolant temperature was at the right figure on the gauge per the operating manual.