Oil Longevity

[skippydiesel]

90 C might just be okay in crusie  - better 95C ++ . Still need to get that elevated temperature, preferably above 100C , usually in Climb Out, to get rid of as much of the volatile fractions as possible.

 

I have seen the inside of car & stationary engines, which for some reason or other, rarely achieved a sustained temperature, during their service life. GUNK!  Back in the days, before high detergent oils, this was common. Pre drain flushing oil/chemicals were often used to try and rid the engines of GUNK

[Thruster88]

23 hours ago, BrendAn said:

Look at this crap my jab spits out.

It doesn't use much oil at all but must make plenty of condensation.

That is a mixture of oil and water. Internal combustion engines always produce water as a by product. Some of this gets past the rings and into the crank case, out the breather and condenses in the catch can. Not in the Jabiru but some installations feed this shite back into the crank case.

[BrendAn]

2 hours ago, skippydiesel said:

90 C might just be okay in crusie  - better 95C ++ . Still need to get that elevated temperature, preferably above 100C , usually in Climb Out, to get rid of as much of the volatile fractions as possible.

 

I have seen the inside of car & stationary engines, which for some reason or other, rarely achieved a sustained temperature, during their service life. GUNK!  Back in the days, before high detergent oils, this was common. Pre drain flushing oil/chemicals were often used to try and rid the engines of GUNK

In cruise, the oil temperature should be above 80°C (ideally between 80° - 100°). This maintains good viscosity, while evaporating most contaminants. If a cooler installation gives cruising temperatures of 80°C in summer but 60°C in winter, the cooler must be partially covered during winter to maintain cruising oil temperatures. Practices such as operating the aircraft with oil temperatures below 80°C and taking off before the oil temperature reaches 50°C substantially increases the risk of oil cooler failure.

from jabiru. 90c is spot on according to this bulletin.      and i did say before my engine is clean. 

 

we used to get hilux diesels  sludging up that bad you could hold the oil filter upside down and hardly any oil would come out.   this was because of running up and down from the pit to the workshop all day without getting hot. the answer was2 lts of diesel mixed with 3 lts of oil and let it idle for 20 minutes then drop the oil.  a lot of people used to do that .

[skippydiesel]

As always - Go with the engine makers advice/recommendation ( 80-90 C still seems very low to me)

 

"i did say before my engine is clean. "

 

I agree that if the drain oil is "clean" it is likly that the engine internals are also clean. Having spent a good portion of my life servicing diesels, I doubt that the look of the oil is an absolute guarantee of the internal condition.