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Jabiru Aircraft
Pty Ltd
Installation Manual
Jabiru 3300 Aircraft Engine
REVISION
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Dated : 1
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Dec 2016
Page: 48 of 56
Figure 53. Air Dam Installation
12.4
Oil Cooling
The dipstick cap must be screwed fully in before removal for reading oil level.
An oil cooler adapter is supplied with the engine & fits under the oil filter. The cooler can be plumbed either
way to the adaptor
– flow direction is not important. Oil coolers are available from Jabiru Aircraft.
Unless consistently operating in low temperatures, oil coolers are mandatory. Note: if you fly in cold weather
and don’t have an oil cooler you can’t fly if it warms up. You can always block the oil air off in cold conditions.
In continuous operation oil temperatures between 80°C and 90°C (176°F
– 194°F) are desirable. 70°C
(158°F) is the minimum allowable temperature for continuous running and 100°C (212°F) is the maximum
allowable temperature for continuous running.
Over filling with oil is not desirable. It can cause elevated temperatures & excessive oil use & loss.
Hoses should be nominally 10mm (3/8”) bore.
Hoses must be changed every 2 years or if visible degradation (cracking, hardening) is visible at inspection.
A pressure drop of at least 60mm (2.4”) water pressure between the air flowing into the cooler and the air
flowing out of the cowls should provide sufficient oil cooling if using a standard Jabiru oil cooler.
Section 12.1 noted that air leaking through gaps in the cooling system ducts is generally waste air, not
contributing to cooling
– though it noted that there were exceptions to this rule. Oil cooling is the feature of
engine installations
that is most often improved by “leaks” like this. A controlled amount of free air blowing
over the sump, crankcase and underside of the engine can significantly improve oil temperatures (Figure 54
shows a duct of this type fitted to a Jabiru 6-cylinder engine). However, for this to work the cowl installation
must be able to cope with the extra volume of air flowing into the cowl space
– the outlet area or outlet lip
size may need to be increased to suck out the extra volume.
Figure 55 shows an oil cooler installation of a Jabiru 3300. Note Detail C in the lower corner of the drawing,
which shows the cooler being fitted using rubber mounts. This is very important as it insulates the cooler
from engine vibrations
– coolers installed with a soft mount like this are much less likely to fail in service.
Note: If oil cooler hoses are installed with oil on the hose fittings or, with oil on the
inside of the hose in the vicinity of the fittings, hose security may be adversely
affected.