Theory ... water flow
#21
Pressure is needed to raise the boiling point of water so you don’t get the steam/ hot spots. But if you let the coolant run through the system unrestricted there is no heat transfer. Like running over the hot coals. Run over them and it will not hurt as bad as walking. The negative point I was trying to make was the over pressure we get in boats. With out a closed system we need to regulate the max pressure.
#22
Well, maybe not. Heat transfer of any kind is done when 2 molecules touch. There is no "cold transfer" just a loss of heat from one molecule to the other. Now stay with me here. If you turn on your stove burner and let it heat up, you can touch it for a very short period and not get burned(cell damage from heat transfer), why? Because enough heat didn't transfer from the burner to your skin. Now inside the engine you have water molecules pushing by some parts of the engine at a high rate of speed. If that speed is too high then there is no time for that particular spot to transfer heat to the water molecules and it will run hotter in that spot. As you slow down the flow less and less spots experience this phenomenon and the engine will run cooler. This will not show up on every engine but on some that are marginal on cooling , some restriction to flow velocity is necessary to maintain proper cooling.
#24
Registered

Joined: Nov 2004
Posts: 14,108
Likes: 3,694
From: On A Dirt Floor
Good topic. I understand both sides to the argument.
In our early spring/late fall cold waters, if we run without t-stats our oil temp takes forever to come up to a decent temp and backs down to a cold temp quick when throttles are let off.
During this cold water times of year, using a t-stat to bring engine water temps up we get more acceptable oil temps and duration of oil temps.
Since oil is on the other side of the metal than water, I would think that oil temp may be a good indicator of how well the water is removing heat from the engine.
I def agree that water psi as read in block should be looked at. Too low of psi may create cooling issues and of course too high of a psi may will create unwanted / unwelcomed leaks.
In our early spring/late fall cold waters, if we run without t-stats our oil temp takes forever to come up to a decent temp and backs down to a cold temp quick when throttles are let off.
During this cold water times of year, using a t-stat to bring engine water temps up we get more acceptable oil temps and duration of oil temps.
Since oil is on the other side of the metal than water, I would think that oil temp may be a good indicator of how well the water is removing heat from the engine.
I def agree that water psi as read in block should be looked at. Too low of psi may create cooling issues and of course too high of a psi may will create unwanted / unwelcomed leaks.
#25
#27
Yes, it's Old School 1, an 89? Bullet.
#28
Nope, I like my 160 thermostats and no milky oil
Merc did a fine job on my stock 502 cooling systems
Merc did a fine job on my stock 502 cooling systems
#29
Good topic. I understand both sides to the argument.
In our early spring/late fall cold waters, if we run without t-stats our oil temp takes forever to come up to a decent temp and backs down to a cold temp quick when throttles are let off.
During this cold water times of year, using a t-stat to bring engine water temps up we get more acceptable oil temps and duration of oil temps.
Since oil is on the other side of the metal than water, I would think that oil temp may be a good indicator of how well the water is removing heat from the engine.
I def agree that water psi as read in block should be looked at. Too low of psi may create cooling issues and of course too high of a psi may will create unwanted / unwelcomed leaks.
In our early spring/late fall cold waters, if we run without t-stats our oil temp takes forever to come up to a decent temp and backs down to a cold temp quick when throttles are let off.
During this cold water times of year, using a t-stat to bring engine water temps up we get more acceptable oil temps and duration of oil temps.
Since oil is on the other side of the metal than water, I would think that oil temp may be a good indicator of how well the water is removing heat from the engine.
I def agree that water psi as read in block should be looked at. Too low of psi may create cooling issues and of course too high of a psi may will create unwanted / unwelcomed leaks.
#30
I run a set-up with no by-pass and no t-stat. Cold water never got motor up to temperature and I had severe condensation issues (milky oil). Installed an oil t-stat in lines between filter housing and oil cooler and problem solved. Used a simple model purchased from Summit Racing. Now oil stays free of moisture and temp gauge on motor creeps up into low range occasionally.


