Engine Overhaul Manual
Jabiru Aircraft
Pty Ltd
Jabiru 2200 & 3300 Aircraft Engines
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Dated : 28/10/2014
Issued By: AS
Page: 116 of 201
L:\files\Manuals_For_Products\Engine_Manuals\Overhaul_Manual\JEM0001-7_Overhaul_Manual_DRAFT_(29_10_14).docx
Figure 142
– Fitting Valves to Head, Fitting Bushes to Rockers
Fit new O rings (2) to the rocker shaft bore of the cylinder head and 2 new O rings to the pushrod tube
bores. Use Nulon L90 to lubricate the O rings for assembly and to prevent damaging them while fitting
the rocker shaft and pushrod tubes. Do not use rubber grease as it will attack these O rings and metal
parts. Note that the large rocker cover O ring is fitted later in the assembly process.
Lubricate the valves and valve guides using oil, then fit the valve springs and collets to the cylinder
head using a spring compressor as shown in Figure 142. Ensure that the lower steel washer (shown at
the lower left of Figure 93
– left) is fitted to the base of each spring.
Note that the rocker shaft and valve rockers are fitted later in the assembly process. However now is
the time to fit new bushes to the rocker arms (if needed). A special tool and a hand press (as shown in
Figure 142) simplifies this job. Orient the new bushes so that the joint in the bush is pointing away from
the crankshaft. Additional details are shown in section 5.11.8.
Fit the induction pipe to the head, again taking care that the correct pipe is fitted to the correct head (the
pipes are stamped with their cylinder number). New gaskets must be used.
If new heads are being fitted to an engine then in most cases some small Welch plugs must be fitted to
the head. For engines using the external oil feed tube for the rocker gear small tubes must also be
fitted to the head. Both of these parts are pressed into the cylinder head (Figure 143).
For engines using the hollow pushrod oil feed the oil ports in the side of the heads are not used. In that
case 2 Welch plugs (Figure 143, right) are fitted to the head
– one on each side – to blank them off.
Fit the outer pushrod cover retaining circlips to the heads as shown in Figure 182. Note the orientation
of these clips: the opening of the clips mus
t point towards the access hole (and 1/8” NPT plug) for the
lower head bolt. In other orientations the clips may interfere with the fit and function of the pushrods.
Figure 143
– Cylinder Head Welch Plug & Lube Tube Installation.
Fitting valve & spring
Using a hand press to
install new rocker bushes
Detail (solid lifter
type rocker shown)
Lube tube ready to be pressed into head
Welch plug ready to be pressed into head