ok. i have installed a double radiator. it works great almost to good. i rode it around for about 15 min and it never got up to 150 degrees. i have a temp gauge on my sporsman 400 2 stroke. i was thinking the 150 was the operating temp. i have never hurd of messing one up for being to cool, but i just want to make sure. i have some picts up at my site. http://photos.yahoo.com/bigrych9

 

How did you purge the air out of that? Looks impossible. Were you having a problem with it overheating? If you didn't get all of the air out, then you probably have a large air pocket or multiple air pockets and coolant may not be flowing properly giving you the low temp reading.

 

i made the hose long enough where i could raise the radiator straight up then i filled it. i cracked the screw on the head and poured fluid untill it came out the top. this will get all the air out. i then let radiator down and zip tied the hoses where i wanted them.

 

Most engines were designed to operate around 190-200 degrees. The clearances and specs were designed for that type of thermal expansion. Running the motor cooler does have its benefits, but one of the drawbacks is that it will wear out quicker.

 

Rockey,

Please go into more detail on wearing the motor out quicker.

 

I am no expert on the subject, but it is a known fact. Having raced a Mustang for several years one of the tricks to getting more power was to run a lower temp thermostat. Going too low would cause the engine to run a bit erratic because the computer would operate in "open loop" whereas, once it reached a certain temp, it would operate in closed loop using feedback from the 02 sensors. Of course that doesn't apply here (except maybe on a Cannondale), but what does apply is the fact that the engine will wear out quicker due to more friction. The engine was designed and spec'd to operate at a cetain temperature. All the bearing clearances and ring gaps are based on that. If you run it cooler, it will have more friction and therefore wear out a bit quicker. How much quicker? I don't know

 

I still have a hard time believing that the engine will wear out quicker at all due to operating at lower temps. Heat is the number 1 enemy of any mechanical device. The higher temp an engine can operate at without wearing prematurely has a main advantage of producing more power from the amount of fuel and air entering the cylinder. As long as the piston and rings are lubed well, I don't see how the engine could wear quicker unless the cylinder is at a much lower temperature than the piston and rings. If you have substantial research to prove your belief, I'm open to understanding your point better......otherwise, I don't buy it. I'm not trying to start a flame war.......as I don't know everything........I just want more proof.

 

A higher temperature engine will produce more power as long as the air being delivered to the combustion chanber is not heat saturated by the motor. Colder air produces more power because it is more dense.

I understand your doubts, I have been there before. A quick example would be to put a ratchet on the crankshaft of a cold motor and turn it over by hand. Then do the same with the same exact motor only at operating temperature. Guess which one is easier to turn over? I've done it before many times on my 302. There is a reason engineers put 190 degree thermostats on engines rather than 150 degree thermostats.

 

Rockey is correct, running at a temperature lower than what an engine is designed for can be damaging. Not only as Rockey said is increased friction a problem but your engine needs to reach optimal temps(around 200ºF) in order to evaporate unwanted contaminants.

 

This could affect car engines much more than the 2-stroke engine maximus and myself have. The car engine (as well as most 4-strokers) have journal bearings, which rely on a film of oil between the crank and the actual bearing to prevent wear. Our 2-stroke engines have needle bearings, and have constant lubrication from the fuel charge, especially with premix. If you measured the amount of torque required to turn over a cold versus 190 degree Polaris 400 (without spark plug in to negate compression effects), I highly doubt there would be a difference. Anyway, I don't believe with his particular situation that he will be shortening the lift of his 2-stroke any at all.......and could possibly achieve longer engine life.