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Oil temp
Jabiru engines are now used almost in every type of climate. Oil coolers are
necessary to ensure warranty, however in some climates and certain installations
they may possibly not be required in. Oil needs to be around 75-100ºC to be in
the right zone. Oil which never gets above 73ºC (165ºF) is deemed too cool
because it never gets hot enough whilst circulating in the engine to evaporate
moisture which will lead to corrosion of engine components and breakdown of the
oil. If oil does not get sufficiently hot therefore, it is necessary to
partially cover the element in order to raise the temperature to the correct
level. In some later (above serial no 711) 2200 installations, folks have
removed the oil cooler totally which has enabled operation at more realistic
temperatures. Maximum oil temp is 118ºC. The maximum observed on a 4 cylinder
engine without oil cooler has been 114ºC which was observed in a Jabiru UL at La
Rochelle where the ambient temp was 44ºC.
Note that the use of a heavy monograde oil in cold temperatures can place
stresses upon components such as oil coolers due to the hydraulic pulsations
from the oil pump.It is therefore essential to warm up your oil to 50ºC prior to
take off to ensure sufficient fluidity.
You must ensure oil temp is at least 50ºC before take-off. You can always run a
fast idle once the oil gets to 35-40ºC to speed up warm up time.
Oil Types
Only aviation types are approved for our engines. Running in period needs a
non-compound (straight) 80 or 100 in summer, Mobil Red Band, Shell or BP be left
in for 25-30 Hours. After running in the use of Multigrade Aero Shell 15W50,
Total Aero DM 15W-50 or BP Multigrade Aero Oil certainly is more suitable for
cooler climates to aid starting, & corrosion resistance and is the preferred
lubricant for Jabiru engines. Do not use any additives in your oil, whatever the
manufacturer claims. Also, do not use automotive (car or motorcycle) oils.
Most of us change the filter every oil change. If you don’t then a quantity of
old oil stays in the filter which doesn’t drain out. Yes, infrequent changes or
poor quality oils show up on components when overhauled. It’s well worth
inspecting the contents of the oil filter from time to time.
Oil Coolers:
When doing an oil change, the oil lines must be left on the cooler. The oil in
the cooler and inside the engine after draining the oil only make up a small
percentage of residual oil. Some oil can be drained by allowing the adaptor and
hoses to hang lower. Re-attaching an oil line, (oil moistened) is not a good
idea, this line can detach later on as some owners have found due to wet
attachment and poor clamp pressure. During servicing check for oil leaks cooler
hoses, clamps and the oil cooler element itself. It’s a good idea to use lock
wire between jubilee clips holding the oil cooler pipes on and adjacent
metalwork to avoid the pipes popping off. This is a recent mod to Rotax engines
after oil pipes blew off.
Service bulletin JSP004 pertains primarily to six cylinder engines and concerns
possible cracking of the oil coolers due to pulsations from the oil pumps, and
thermal expansion cracking of the cooler if it is rigidly attached to the sump
of the aircraft. It also provides guidelines with respect to oil types and the
necessity to warm up the engine correctly prior to take-off. It states a minimum
of 50ºC is required. The oil pump mod also carries the benefit of less
cavitation and improved oil pressures, particularly at low RPM's. Note that as
the engine warms up, there's no reason why you cannot warm up at a higher rpm,
eg at 40ºC you could run it at 2000RPM.
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