Jabiru believe that the Jabiru range of very light engines offers opportunities for light aircraft
designers to develop a new generation of light aircraft.
Jabiru engines are designed to be manufactured in small batch quantities using the very latest
Computer Numerically Controlled (CNC) machine tools. All Jabiru engines are manufactured and
assembled in a very modern factory in Bundaberg where each engine is run in on a Dynometer
and calibrated before delivery. The crankcase halves, cylinder heads, crankshaft, starter motor
housings, gearbox cover (the gearbox powers the distributor rotors) and coil mounts – together
with many smaller components are machined from solid. The sump (oil pan) is the only casting.
The cylinders are machined from bar 4140 chrome molybdenum alloy steel, with the pistons
running directly in the steel bores. The crankshaft is also machined from 4140 chrome
molybdenum alloy steel, the journals of which are precision ground prior to being Magnaflux
inspected. The camshaft is manufactured from 4140 chrome molybdenum alloy steel – with
nitrided journals & cams.
The propeller is direct crankshaft driven and does not use a reduction gearbox. This facilitates its
light-weight design and keeps maintenance costs to a minimum. The crankshaft features a
removable propeller flange which enables the easy replacement of the front crankshaft seal and
provides for a propeller shaft extension to be fitted, should this be required for particular
applications. Cylinder heads are machined from solid aluminium billet, thereby providing a
substantive quality trail to material source. Connecting rods are machined from 4140 alloy steel
and the 45mm big end bearings are of the automotive slipper type.
Many components of the engines are sourced from outside suppliers. These items include
camshaft followers, and the bendix gear in the starter motor. The ignition coils are also sourced
from outside suppliers, and are modified by Jabiru for their own particular application.
An integral alternator using rare earth magnets provides alternating current for battery charging
and electrical accessories. The alternator is attached to the flywheel and is driven directly by the
crankshaft. The ignition system is a transistorised electronic system; two fixed coils mounted
adjacent to the flywheel are energised by rare earth magnets attached to the flywheel. The
passing of the coils by the magnets creates the high voltage current which is then transported by
high tension leads to the centre post of two automotive type distributors (which are simply rotors
and caps) before distribution to automotive spark plugs, two in the top of each cylinder head. The
ignition system is fixed timing and, therefore, removes the need for timing adjustment. The ignition
system is fully redundant, self-generating and does not depend on battery power.
The crankshaft is designed with a double bearing at the propeller flange end and a main bearing
between each big end; it therefore does not have flying webs. 48mm main bearings are also of the
automotive slipper type. Thrust bearings are located fore and aft of the front double bearing
allowing either tractor or pusher installation.
Pistons are manufactured to Jabiru design by a major manufacturer, they are fitted with 3 rings,
the top rings being cast iron to complement the chrome molybdenum cylinder bores. Valves are
7mm (stem dia) which are purpose manufactured for the Jabiru engine.
The valve gear includes pushrods from the hydraulic cam followers to forged steel valve rockers
mounted on a shaft through a Teflon coated bronze-steel bush. Valve guides are manufactured
from aluminium/bronze, as is found in larger aero engines and high performance racing engines.
