Let me down?

Did my poor English make that impression?
On the contarary! This forum is my only internet source for information.
Always some member that is willing to assist with information.
So, I can only blame my less than perfect English if my post came out in a way I did not intend.

 

No problem K.
It has been Africa hot here as well.

 

Oil temperature in these engines comes primarily from the pistons/cylinders. Obviously that transmits to the heads but those temps build from combustion/compression (same goes for pistons). The difference being, about 30-40% of the oil circulation is thrown directly at the cylinder walls (pistons). Oil does remove heat from the bearings/bushings but in the top, it only goes thru the rockers, sprays on the valve springs and returns down thru the cylinders. There's not enough contact surface between the rocker boxes and heads for oil to do much for them.

Air is the only thing that will cool heads and part of what cools the cylinders. So, an oil cooler can help piston/cylinder temps to a degree, but won't affect head temperatures.

So far as oil coolers - generally at highway speeds (55-75) oil will run about 100 degrees over ambient plus or minus about 10% depending on the bike. The best you'll get out of a good, well placed cooler is a 5-8% reduction in oil temps but that can help the engine live longer. One thing you don't want is oil that runs too cool, as it only starts to clean well and dissipate moisture when it's over 150.

 

Not trying to bump this thread/post but wanted to correct a mistake I made - With a good, well placed oil cooler you can expect an 8 -12% reduction.....

 

You are correct on the cylinder and piston temps it's the purpose of the oil and yes running too cool is not good either.. 185 is an awesome temperature for your motor we used to try to maintain the oil temps in the modifieds on dirt at 185*.

Measure your cylinder temp.. 320* is normal on a high comp Evo....

 

thanks for this information, so if I have an oem fan assisted oil cooler then there will be no idea of adding an extra oil cooler ,and you advise going of cylinder cooling fans as jims forceflow fan or others?

 

Sorry, I've never used an auxiliary fan. Cannot say whether they would be much, if any benefit.

 

I get right around those temps using a hand held infrared temp/thermometer gun. After a good ride I pull into the garage, shut down the bike, take off helmet and jacket, grab the hand held and shoot at a few spots on each head.

I will get lower temps on cooler days depending on outside temp. but I think your numbers are good.

 

I read back thru this one and the temps the OP posted in #1 and 3 are actually pretty good, normal even for a near stock bike.

IR thermometer after a ride or during a stop, the front is always cooler than rear but they equalize within a few minutes.

 

It's been my experience that often you are better off not knowing what your oil temps are. As soon as you put any kind of temp gauge on the bike, your eyes will be glued to it. Generally the evo engine doesn't care as long as you have oil pressure and are using a good quality oil. If you are going to add an oil cooler, make sure it's a good one and has a thermostat, as oil has to get up to a fairly high temperature to do its job. My 08 Softail was a very hot bike to ride and I did install an oil cooler on it. Highest oil temps I saw without the cooler was about 270 F and with the oil cooler about 250 F. I didn't like the heat, but the bike didn't seem to care.