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Discussion Starter #1 (Edited)
Hello all!

I have an idea I'd like to run past the knowledgeable folk here.

I've recently had a 3rd stator die in the 2010 848, post here: http://www.ducati.ms/forums/241-tech-forum/553897-diagnosing-alternator-2010-848-a.html

This time around I've replaced the standard VRR with a MOSFET unit at the same time as a new stator, and have my fingers crossed that it will do the job. I'm currently still running it without fairings to try and keep things as cool as possible, as I use the bike as a daily commuter, which includes some stop-start traffic (2-up these days as well), and the weather has been warm here recently (had a few 38-degree-C days).

I'm also suspicious of the amount of heat actually on the stator via the oil - thinking it wouldn't help things.

I had a thought yesterday that it might be possible to fit a small thermo fan to the oil cooler. I reckon you could get a small unit in there, and have it temperature controlled to turn on when the oil reached a certain temperature, similar to the thermo fans on the radiator.

Has anybody done this before?

Even if it doesn't contribute to fixing the stator issue, I can't see trying to keep the oil from overheating being a bad thing.

Any comments or suggestions?

Cheers!
Michael.
 

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Discussion Starter #2
First attempt at cooling the oil. Obtained a late-model R6 cooling fan, and mounted it to the rear of the oil cooler. Brackets made to move the cooler forward for clearance for the fan, and extended oil lines made up to get to the new location.

The plastic shroud around the radiator/oil cooler will remain off for better airflow, as will the lower fairing.

I have the fan operated by a manual switch at the handlebars at the moment. Not sure if I'm going to do any sensor activation at all... I like the idea of turning it on when I want it on.

I found that a lot of the cooling fins behind the tyre were bent from items thrown up from the tyre, and about a third of the fins in total were blocked with dirt, including the bent fins. A couple of hours on the workbench straightening the fins as best I could, and cleaning out each of the fins.

Have to make up a guard for the cooler... something that doesn't restrict the airflow too much.

We'll see how I go through this current summer... hoping I don't have any more stator failures.







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You worry about nothing. Around town, stop start traffic gets the engine quite warm. When the rad can't get rid of any more heat because there's no air movement the fans come on. Your bike will get to about 110 degrees sitting there with the fans going full bore. That's as high as it gets. If it goes higher then there's something wrong with the cooling system.
Dodgy reg/rectifiers kill winding AND heat the oil. That stator and magnet produce a lot of heat and the windings are tight and don't dissipate a lot of heat. This is where the problem lies, not how hot the oil is.
Coolant is the most effective way of keeping the oil cool. That is, the more the rad/pump/airflow cool the bike, the cooler the oil is.
Have a look at where most car makers put the oil coolers, IN THE RADIATOR.
 

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Discussion Starter #4 (Edited)
You worry about nothing. Around town, stop start traffic gets the engine quite warm. When the rad can't get rid of any more heat because there's no air movement the fans come on. Your bike will get to about 110 degrees sitting there with the fans going full bore. That's as high as it gets. If it goes higher then there's something wrong with the cooling system.
Dodgy reg/rectifiers kill winding AND heat the oil. That stator and magnet produce a lot of heat and the windings are tight and don't dissipate a lot of heat. This is where the problem lies, not how hot the oil is.
Coolant is the most effective way of keeping the oil cool. That is, the more the rad/pump/airflow cool the bike, the cooler the oil is.
Have a look at where most car makers put the oil coolers, IN THE RADIATOR.
Thanks for the input, xracer.

I've modified my ECU via TuneECU to have the radiator cooling fans engage at 95 degrees C (did this even before the first stator failure), which is the lowest setting. When it does kick in, the temperature never gets above 97 degrees, the fans always bring it down to 95.

I've had these stator failures on 3 different R/R units - the one that was on the bike when I got it (assumed original), then an OEM replacement, and the last one with a MOSFET aftermarket one (that you'll know runs cooler than the OEM units). And on each failure except the first one, the intermediate connector plug has been removed and the wires soldered together.

I understand that the coolant cooling system will reduce oil temperatures.

Also appreciate that oil coolers are also often cooled by the coolant cooling system (in the radiator).

During my recent research, I've spotted that both the 1098 and 848 Streetfighter bike do their cooling differently. They have 2 coolant radiators, not one, and the engine oil runs through a heat exchanger connected to the coolant system. Both the 1098, 848 and 1198 Superbikes retain the airflow-only oil cooler system for the engine oil.
***EDIT a quick Google search now shows that it looks like the 899/959/1199/1299 might have gone down the dual radiator/heat exchanger route ***

In my mind, this indicates that, whilst the air-only oil cooling is adequate for the Superbikes - that really are designed to be moving quickly all the time and have good airflow to cool them - Ducati themselves thought that the Streetfighters needed a different cooling arrangement - perhaps due to them being designed for more stop-start use than the Superbikes. The radiator/oil cooler arrangement on the Superbikes is a simpler design than the double radiator and heat exchanger system on the Streetfighters, so I can't see Ducati going this route unless they thought it was warranted.

Apologies about posting here and in my other thread about stator failures (http://www.ducati.ms/forums/241-tech-forum/553897-diagnosing-alternator-2010-848-a.html). This thread was only about finding out if anybody had implemented a cooling solution for the oil cooler. Now that I've done this bit, we should probably refer any further discussion to the other thread.

Thanks again for your input.

Cheers!
Michael.
 
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