BB temps and cooling?

[Rexone]

Problem is pressure comes way down at idle so if you were in the 210 - 220 range it would just start boiling as the pressure dropped idling around. Not good. Have to plan the system around the lowest pressure which to be safe would be zero IMO. I said 200 max above because I don't enjoy running on the edge and there could be inconsistancies within the engine with spots hotter than at the sender. I maintain that 160-180 is a safe range. We have sold thousands of the bypass thermostats since we started building them 2 decades ago, without problems.
Like I said first, ask 10 people get 10 answers. This is just my answer based on what we've experienced and seen over the years. It should not be interpreted as gospel. If you've had a different experience you should follow that. Engines will run fine cold as mentioned above. I just don't feel it's maximising their power potential or oiling protection.

[LakesOnly]

Originally posted by Rexone
...pressure comes way down at idle, so if you were in the 210 - 220 range it would just start boiling as the pressure dropped idling around.
Been there, done that....
LO

[fourspeednup]

Wow, this thread really exploded with info. Thanks for all the input. As I said, my boat needs a total replumb and when I get around to it might as well do it right I think I'll just be messin with the gate valve for a while and run th emotor as close to 160 as I can get (the average temp discussed in here )

[cyclone]

Originally posted by fourspeednup
An car engine is designed to run between 180-200 degrees. In my boat it runs 120-130. At the lower temp it will make less power because....well shit I don't really know why but I know it losses efficiency at colder temps. New cars/trucks run much hotter. Fuel distribution sucks when a motor is cold...that's why carbs have choke's, to richen the air:fuel ratio.
I run a valve between the pump and block to control water flow but it doesn't do much good. I can have the thing almost completely shut and it still runs 130 at the river. Pressure regulators are used on some jets to prevent too much water from entering the block and seeping past gaskets. There was a thread on here not too long ago on that topic...may have been in the v-drive forum. do a search
New cars and trucks running hotter is simply a tactic to reduce emissions. In a boat you dont have to worry about emissions (not yet anyway).
Dyno testing has convinced me that running the engine colder does in fact help it make more power vs running it hot (180 degrees and up)
Subsequent tear downs of my last 3 engines has also shown to me that i'm not doing any damage by running the engine at 130-160 temps.
I'm by no means an expert on the subject this is based purely upon my own experiences with my engines and others that i'm familiar with.

[cyclone]

forgot to add one little thing. since most of our boats do not have closed cooling systems the temp gauge isn't showing the actual temperature of the engine, rather you are seeing the temperature of the water running into the engine from the jet which circulates through the engine quickly and is dumped overboard. When i overheated my engine last summer the temp gauge only read 220 degrees yet the oil was boiling in the pan. The engine was obviously hotter than 220 degrees. something to think about.