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Discussion Starter #1
I saw an Oil Cooler setup at KTMTwins.com. They claim quite a bit of cooling by using one of their Oil Cooler setups. Not sure it will work on the 390 and it is quite Pricey...
Opinions, Ideas, Other oil cooler options(and plumbing)
TX
Kaveman
 

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Hi!

I'm not sure why you would need to add an oil cooler (aside from the obvious answer : TO COOL THE OIL!!) ;-)

I mean, are you having overheating problems? If so, these should be investigated and resolved first.

If the only objective is then to remove heat from the engine, there is already a much easier way, if you haven't done it yet : the SPAL fan. If on top of that you still want an oil cooler (reason for which I'm still unclear) then the only effect is that your rolling temperature would possibly be lower, but your idle/standstill temperature would still be dictated by your cooling system thermo switch ...
 

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To date, I don't think we have seen any 390 equipped with an oil cooler. Perhaps if the bike were fitted with a turbo or a supercharger you might want to think about an oil cooler, but the 390 engine has been raced countless times in very hot weather (eg Texas, Australia, etc) without incident. Don't forget, the oil prescribed - Motorex or Motul 15W-50 - is top drawer and very protective.

Another obstacle to fitting an oil cooler is that the 390 engine is not plumbed for it - there are no out/in spouts to and from a cooler. These would have to be improvised.

As Luc pointed out, the 390's cooling system can effectively shed the necessary calories to keep it running smoothly and safely. A SPAL fan augments the effectiveness of the cooling system significantly. Engine Ice helps as well.

Bottom Line: The 390 engine has sufficient cooling and does not need additional cooling devices, including an oil cooler.
 

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Discussion Starter #4
Thanks for the Insight. No cooling problems, just thinking... As these bikes run very hot.
Kaveman
 

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i think that a small oil cooler from a 400-500 air cooled bike could add some extra overheat safety. For someone that has already spal fan and uses high grade 100% synthetic oil such as motorex, motul 300V, amsoil, red line or torco, etc, yes it wouldn't be a high priority but also it won't harm anything. The only possible problem could be if the oil cooler is quite large (more than 200ml) and there is a serious drop at oil pressure. Like i said the cooler must be from a small displacement air cooled bike.

But if i lived in India, or Florida, etc i would have seriousely considered to add an oil cooler.
 

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Supposing we were in India or Florida and wanted to add an oil cooler for "extra overheat safety", the question would then arise as to just how to do this. The 390 engine has an entirely internal oil circulation system - there are no external oil lines that could easily be tapped. This means that we would have to drill into one of the internal oil galleries and tap it for an oil spigot that could flow oil to the oil cooler. Then we would have to drill another hole into the same gallery, tap in another spigot for the cooler to return - cooled - oil into the same gallery to lubricate (at the same pressure) the engine components fed by that gallery. The engine is not designed to feed oil outside of the engine cases: adapting an oil cooler would be difficult and risky. If it could be made to work, it might have some marginal benefit - it would shed more heat than just the radiator. But such an improvisation would risk fatally compromising the engine's lubrication system if there were a leak or an air bubble which could interrupt the pressurized lubrication of the engine component on the end of the tapped oil gallery. IMO: too risky, too difficult, unnecessary. A better, easier option for increased cooling capacity would be to fit a bigger radiator (eg, from the Duke 690). The Austria-sourced radiators are always combined at the factory with a SPAL fan.
 
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As stated in posts above , the technical difficulty to fit such an oil cooler may prove far more hazardous and potentially damaging by having insufficient oil pressure . Surely fitting a larger coolant fluid radiator with increased flow would be easier and more cost effective with similar results .
 

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now that you said it, yes i figured out there isnt any external oil pipe... That makes the oil cooler think not impossible, but difficult to do. Its not only that you have to drill but also you don't know were to drill in order not to have serious oil pressure drop from spessific spot.


the best spot to take oil for the cooler is the return oil pipe from the cyllinder head. Most bikes have this return oil pipe.
 

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Discussion Starter #9
As for Oil Piping... I think you could tap into the oil filter cover(that's what the KTMTwins one looks like it does). That is an easily replaceable item and there should be good oil pressure there. Make the drain into the oil filler... I was just speculating on this type of mod. Not ready to start it as my 390 still has some warranty and runs perfect. My Buell (air cooled) had a really nice oil cooler setup with a cool looking functional scoop to boot!
Kaveman
 

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Kaveman, If you look at the schematic of the 390 oil circuit (pg. 19) you will see that oil moves under pressure from the Eaton pump directly to the oil filter. After filtration the oil is sent -under pressure - from the filter housing to all the other pressure-lubricated components of the engine. Your oil cooler proposal would release oil pressure from the oil filter housing by routing it out through the oil filter cover, through the cooler and back into the crankcase via the oil filler. This would rob the entire engine of oil pressure and destroy your motor immediately. You need to rethink and devise a scheme that would route oil through a cooler and back into the crankcase WITHOUT disturbing/altering the pressurized oil flow from the Eaton pump to all pressure-lubricated components.

Oil coolers, IMO, are most useful for air-cooled bikes, where they can supplement the heat-shedding capacity of engine finning. Air-cooled engines are often plumbed to accept oil coolers for this reason. In contrast, liquid-cooled engines, such as the 390, are designed with radiators whose size/surface area is calculated to enable the radiator to shed all the calories the motor can generate, even under the most extreme/adverse conditions, with a margin to spare. Oil coolers, in this configuration, are redundant and unnecessary. This is why oil coolers are rarely seen on liquid-cooled bikes.

https://www.evernote.com/shard/s225/sh/dff62ca8-4753-48c2-ba3e-3fd5df0b4a33/3f75ea14ff2d5d8e/res/74658d4e-4cd0-4c94-ad97-54a2ad1b31a3/SSM_902_EN.pdf
 
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I think there's a rather common misconception as to exactly[ how hot (or not) these engines actually operate at. I measured and posted engine temps I recorded pre Spal and EI coolant change and was surprised at my findings. At no time did the engine temps get remotely close to dangerous levels, period. My Yamaha FZ 09 runs much hotter due to later fan actuation (and engine configuration). The increased fan efficiency of the Spal unit coupled with a polypropylene coolant is more than enough in my opinion.
 

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I agree with Pete on this. Just 'coz the gauge says it's hot doesn't mean it's actually hot. It all depends on how the gauge is calibrated & over what temperature range it operates.

Until we know what temperatures = bars on the gauge, we are just guessing
 
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As stated in posts above , the technical difficulty to fit such an oil cooler may prove far more hazardous and potentially damaging by having insufficient oil pressure . Surely fitting a larger coolant fluid radiator with increased flow would be easier and more cost effective with similar results .
This would be my number one concern, the oiling system is a bit of an unknown factor since I don't any one has done an oil cooler. Who knows what the end result would end up being after installing an oil cooler. Some engines rely on oil volume / lower pressure and other engines require high pressure. It would be a gamble for sure.
 

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I think there's a rather common misconception as to exactly[ how hot (or not) these engines actually operate at. I measured and posted engine temps I recorded pre Spal and EI coolant change and was surprised at my findings. At no time did the engine temps get remotely close to dangerous levels, period. My Yamaha FZ 09 runs much hotter due to later fan actuation (and engine configuration). The increased fan efficiency of the Spal unit coupled with a polypropylene coolant is more than enough in my opinion.
Agreed, from the data logging I've done in the past the fan usually cools the bike back down to 194 F and kicks on at 204F, but that is normally when you are just sitting still with no air passing the radiator.
 

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That oil cooler build you posted won't last long lol. All it needs is a tiny piece of metal from that **** weld job to come off and that engine is done for. Also, because he has the nipples facing down to the ground that oil cooler will drain when the engine is off. That is going to delay oil from lubricating the engine, it may not seem like the delay would be a long time, but imagine the constant amount of start ups with out journals and bearings being properly lubricated over a period of time. Not only that but that **** is hanging so low and the pipes don't even have a barb in them.

I mean really, how many hose clamps do you need?
51369


Oh this just keeps getting better!

51371
 
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