Home |
Search |
Today's Posts |
#5
posted to rec.boats.building
|
|||
|
|||
Can cooling water be to cold on a Mercruiser
Good answer. I was wondering about the same issues. Not to throw dirt at
anything because I love the motor, I have heard through the grapevine that the Mercruisers "like to be dry" ...rust easily. At this point, that's only a rumor, but the point is that a nice salt-free freshwater system and good ventilation would be good for the motor (any motor, really.) Brian D "David Flew" wrote in message ... Re the difference - it's significant. This is a heat transfer / cooling issue, not one where you can apply the ideal gas laws and use Rankine or absolute temperatures. If the engine block is at say 250F, the rate of cooling for 37 F coolant vs 85 F is (250 - 37) / ( 250 - 85). More importantly, if temperature difference required to remove the developed heat is say 100F, it will run at 185F in the Caribbean and 137 in the colder water ... You can't just restrict the flow or the temperature becomes uneven. So you need a circulating system - might as well consider a fresh water one .. David "derbyrm" wrote in message news:xBuKf.788735$_o.605338@attbi_s71... Just to amplify the following advice a bit, engines run most efficiently when HOT! The only reason your auto engine doesn't run a lot hotter is that it's too hard to keep the pressure reasonable when you go much above 212 F. The other potential problem is "shock cooling." Idle a bit and then turn the engine off. Heat will percolate out from the exhaust and from the combustion chambers. When it's started again, the cold water will cause different parts of the engine to shrink at different rates and you can get piston scuffing at least and possibly other dire actions. That said, there isn't that much difference between the Caribbean's 85 degree water and your 37 degrees. The effects are calculated on the "absolute" temperature scale, so it's 545 to 497 (10%) on the Rankine scale. Roger http://home.insightbb.com/~derbyrm "theMooseisLoose" wrote in message news:8kuKf.34509$6f2.19385@trnddc02... wrote in message ups.com... I am buying a used boat from Stony Point, NY. It has a Mercruiser V8 5.0 with 190 HP with 300 hours on it. I live in Greenland. An island in the arctic region east of Canada where the seawater temperature is around 36-37 F degrees. And thatīs where there might be a problem. I am told that the motor is "use" to be cooled of with warmer water temps around the more southern part of the world. And when I get the boat and the motor is cooled down with seawater that is 36-37 F degrees then it migth not run smooth anymore or develop somekinda problem. Is this story a myth or is there something to it? And if the story is right how can i prevent any problem with the motor. I cannot install fresh water cooling system as it is too late for this motor because it has already 300 hours of seawater cooling I am told. Any help or suggestions will be much appreciated. Sal****er cooling is 'uncontrolled' water circulation drawn from under the boat- with very little control of the engine operating temperature. If you are concerned about 'stabilizing' the engine temperature, the only way to do it is by freshwater cooling. This will allow the engine to run at operating temperature (controlled by the thermostat) and at least run more efficient. And it is NOT too late to do this. |
Thread Tools | Search this Thread |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Forum | |||
rec.boats.paddle sea kayaking FAQ | General | |||
rec.boats.paddle sea kayaking FAQ | General | |||
rec.boats.paddle sea kayaking FAQ | General | |||
rec.boats.paddle sea kayaking FAQ | General | |||
rec.boats.paddle sea kayaking FAQ | General |