This is a great article and it highlights the issues faced when determining just how well a given muti grade will flow when cool.

http://books.google.com/books?id=chx...ed=0CC8Q6AEwCQ

Another option would be to run a oil warmer if using an oil like a 20w-50. This above article highlights the issue with oils that have high VII(viscosity index improvers) and how that relates to cold flow. Remember that cold flow is in effect when a motor oil is cooled to ambient temperature and expected to crank at said temp. A lot different situation vs what is the case at freezing, so there isn't as much data.

In essence not all 10-40'/15-50's etc are created equally.

My buddy is a crew chief for an American lemans team Ls powered Vette. He said they will not start the car until the oil temp is 210. If its started b4 it reaches 210 it will not make it through the race motor will blow 210 is what they keep the temp at all the time. Oh yeah the run 5w30 Mobil 1. Nothing special right out of the jug you buy at Walmart. 650hp 24hrs. Then the motor gets pulled and put on the dyno for 24hrs...

Yup because quite a bit of the total wear happens during the warm up phase. Obviously changing tolerances with temperature, activation of chemical additives like ZDDP, and viscosity are the main reasons why.

I'm not surprised they use a OTC oil in that class. NASCAR, Top fuel and countless others actually have a on site team from the oil company that perform testing and actually specially blend one off oils. Especially for NASCAR teams that have been experimenting with lower viscosity oils. In the end it all to some degree benefits you and I, the end user.

Personally I think a pan heater would be a no brainer in a boat. Maybe even better than a pre oiler...

And at some point in time and for X amount of time, the motor oil needs to reach 212 degrees to burn off condensation. The internal combustion process produces tiny water droplets. (condensation)

Exactly the reason I chose the 215 degree oil thernostat

I would imagine if you ran 210 degree oil through the motor by the time it makes its way back to the sump/ oil tank it's gonna be hotter and therefore boiled. What they was is 210 into the motor. That's the magic number so I've been told.

Water doesn't need to boil to remove itself from the oil and become airborn.

Evaporation can happen at (mostly) all temperatures , but greatly increases as the temperature goes up.

212°F (steam) will obviously rid water faster, but I feel a minimum of 180°F + is all good and I'm comfortable with that.

Everyone's miles may vary.

Love the oil threads. I have run Amsiol marine and Brad penn in my motors. Other than that, Im just here to read the bantering

Straight from the factory mercruiser high performance / Merc Racing training classes. Also there is a Service Bulletin on this as well 95-3 to all dealers plus other related info running to low internal oil temps. Anyways here is the info taught in class years ago..

Oil thermostat and the filter adaptor. In the housing is an oil by pass valve if the oil filter should become plugged to bypass. The most important to the design is to control oil temperature in which improves engine lubrication and greatly reduces moisture in the engine.

The oil t -stat closed, the oil from the engine flows directly to the oil filter and then back to the engine, when the oil t-stat opens ie: when the oil t-stat is fully open, oil is directed first to the cooler, then back thru the oil filter and then returned to the engine. The oil t-stat starts to open at 194 degrees and is fully open at 284 degrees.

Internally a stock Mercury racing engine the oil reaches 194 degrees min at all times regardless unless a problem ie: cooling problem or a oil cooling problem of sort like for example, improper oil t-stat not working correctly or bypass problem of some sort..

My point Mercruiser does not want oil temps too low. Also they go into this great lengths in their dealer support literature about this for big blocks. This info and the Service Bulletin also includes the Bulldog engines and the 525SC, 600 SC and the 800 SC among others.

BUP, obviously oil thermostats are beneficial to an engines health to cold is no good as is too hot. My question is how beneficial would it be to pre-heat the oil before start up? I have a ginormous aluminum pan and really wouldn't be difficult to install a heater. Just have to make sure it's properly secured. Don't want anything floating around in the oil pan. Also, I bet it would be easy to rig up a circulating system to run warm oil through out b4 start up. But, how beneficial would it be? Lets say $500 in parts and some labor. Would it be worth it?