8V overcooling project

Pete Roper wrote:

As soon as there's a hint of rain or a wet road the sump temperature plummets. I actually prefer to keep the temperature above 100*C simply to make sure all the moisture sublimes off. With a modern full ester synthetic multigrade there is no concern about the oil degrading as they will function perfectly well at way higher temperatures for way longer than oils of yore.

Really though I don't think the lack of a stat is a tremendous concern unless you live and ride somewhere constantly cold and damp. I've yet to see an 8V that has failed due to oil degradation or water contamination.

It is interesting, I spoke to an engineer at Penrite, keeping the oil temperature around the 100 C mark is the best even with ester based oils as the higher you go the, the shorter the life, plus the additives can be removed from the oil, we found this offshore, born out though testing of the oils for condition, when temperatures were high, I would suggest, it would be more beneficial to try and control the oil temperature being fed to the engine as the oil being fed to the heads are already run though a cooler but from what I understand it would be very difficult to cool the engine circuit. If anyone has an image of the oil circuit on the 8V, can they please post it so I can get my head around it.

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I just removed the oil cooler from the bike to add a temp sensor after the pump.
The CAD designers did an exellent job making it very tight even to add an oil T-piece in it post pump. Try to get one today.

Cooler assy:
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I fitted the temp sender in the banjo bolt on the right head, I am after the main bearing oil schematic as it is not cooled while the hot oil in the sump is going to the mains.

I haven't considered your sensor location yet... I guess due to temp variations when placing the sensor to the engine I'd probably connect sensors to the thermostat or cooler but I'm not sure adding a sensor in the banjo bolt could restrict flow... 1/8npt sensor seems a bit obstructive in the pump banjo.

Still I'm knitpicking on the minor details. Having read on oil temp ranges still it seems best at 103C and max 125C, wondering if a slightly colder stat would be a better choice...
I do understand lane splitting in Europe is legal and exsessive overheating should be rare to even consider more headroom in the bottom range chosing a lowerC stat in change for a less ideal working temp.
I'm not very keen on riding at high outdoor temps as well (experienced a dehydration blackout in my early 20s on a motorcycle and minor surgery) hence the reason to only install a temp sensor now and find out the temp range for my personal riding. I do understand a stat isn't mandatory but recommended.

try to get a 16x1.5mm(2x) stud with 1/8npt side bore installed on the cooler. Those oem adapter and banjo are a weird choice highly not compatible restricting options before getting into a full hose rebuild...

Today I received the: QSP olie T-stuk M16 x 1,5 male - 1/8" NPT female and QSP M16 + 3/8BSP bounded seal. The good news is 1/8 hole is spot on and likely every T-piece, cooler fitting and seal is identical machined thus worth copying.
The downside is it's pretty long and the sensor will block the hole. It needs to be bored to a bigger diameter (I chose 11mm), drilled 7.5mm dia through the 1/8 hole for more depth to fit the sensor AND used a dremel too to mill it oval for max flow.
The pump hose makes a tight fit and bend but I was able to close the cooler case to the engine.
Need to locktite the sensor in now at work before final assembly.
Personally I chose this location to avoid engine case temp measurements.

kr, Erik


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I used a 1/8 NPT brass socket and silver soldered it to the top of the banjo bolt and machined the socket so the tip of the temperature sender is level with the top of the holes in the bolt, there is no restriction. As the engineer said, temperatures over 100C results is quicker degradation of the oil. PS, the temp sensor probe only needs the tip to be in the oil flow to be effective as there is a pocket around the sensor so the oil will swirl around it, while the heat transfer will do the rest.

ErikdeBrabander wrote:

I haven't considered your sensor location yet... I guess due to temp variations when placing the sensor to the engine I'd probably connect sensors to the thermostat or cooler but I'm not sure adding a sensor in the banjo bolt could restrict flow... 1/8npt sensor seems a bit obstructive in the pump banjo.

Still I'm knitpicking on the minor details. Having read on oil temp ranges still it seems best at 103C and max 125C, wondering if a slightly colder stat would be a better choice...
I do understand lane splitting in Europe is legal and exsessive overheating should be rare to even consider more headroom in the bottom range chosing a lowerC stat in change for a less ideal working temp.
I'm not very keen on riding at high outdoor temps as well (experienced a dehydration blackout in my early 20s on a motorcycle and minor surgery) hence the reason to only install a temp sensor now and find out the temp range for my personal riding. I do understand a stat isn't mandatory but recommended.

try to get a 16x1.5mm(2x) stud with 1/8npt side bore installed on the cooler. Those oem adapter and banjo are a weird choice highly not compatible restricting options before getting into a full hose rebuild...

Unfortunately, the thread on the sensor is a bit smaller hence the depth shown here in this lose fit.
Soldering is a nice mod on your banjo!

Temp sensor installed. Closing the cooler assy was a 2hr PITA.
Need a test drive for leakage test when weather permits.
Beeline Moto2 is ordered should be mounted in the centre of the steering bar maintaining a compact cluster.

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What sealant did you use, Loctite 567 is excellent and was used offshore exclusively. It is a good filler if the thread is loose.

I used teflon tape, the same what was on the sensor but a few windings added.

An 1hr drive today showed no leakage. The outdoor temp was 18C and the COOLER IN temp stabilised at 96C@100kmh@5th gear on highway use. In the city, at traffic lights and slow pace (30-50kmh) temp raised to 115C and reduced to 96C@80kmh.

Seems for 18C outdoor the cooling is not bad at all. However, the reduction of oil temp is at a slow pace which makes me wonder if a thermostat with additional extra cooler might be beneficial if I decide a thermostat mod is worth considering but for the time being I'm inconclusive...

And I'm aware an air cooled engine is a compromise anyway.

ErikdeBrabander wrote:

...The outdoor temp was 18C and the COOLER IN temp stabilised at 96C@100kmh@5th gear on highway use. In the city, at traffic lights and slow pace (30-50kmh) temp raised to 115C and reduced to 96C@80kmh.
.

Summer is here now and made a 200km trip. 100km in the morning and 100km back in the afternoon.
26C@100kmh@5th gear showed 103C in the morning
26C@100kmh@5th gear showed 107C in the afternoon, possibly the tarmac warmed up.
In a 20km@30kmh@26C queue showed 129C reducing slowly to 107C@100kmh.

IF one is likely not to use this bike 4 seasons I highly doubt the effort to add the thermostat is worth considering.
And if I'd add a thermostat I'd consider an additional cooler as well this will reduce the lower and higher margins when combined.

But then again, it's not a liquid cooled engine and it is what it is and engeneering did not do a bad job IMO.
I'm very happy I did install the temp gauge for easy of mind. It could be possible the sensor may obstruct the oil flow a bit even after opening the socket around it which might have contributed to a slightly higher temp reading which makes this engine run "not very cold" and I hit a sweet spot per accident.