Engine Overhaul Manual
Jabiru Aircraft
Pty Ltd
Jabiru 2200 & 3300 Aircraft Engines
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Dated : 28/10/2014
Issued By: AS
Page: 81 of 201
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5.11.6 Cylinder Head
– Cylinder Seal
Figure 93
– Valves Assembly, Cylinder Head / Cylinder Lapping
5.11.6.1 Inspection and repair
If second-hand cylinder heads are being used they must be lapped to seal onto the cylinder spigot. The
process is similar to grinding a galve
– valve grinding paste is applied to the cylinder spigot and the
head rotated against it. An old, unservicable cylinder, held in a vice, should be used for this task. This
step is not necessary with new heads. Figure 93 refers.
A visual check will show when the surfaces are mated / lapped properly. As per the valves, care should
be taken to remove the minimum amount of material.
After lapping the valves or head must be cleaned thoroughly to make sure all the grinding paste has
been removed.
5.11.7 Valve Springs, Spring Washers & Pushrods
Complete Overhaul:
mandatory replacement of valve springs
5.11.7.1 Mandatory updates
The valve springs used for hydraulic lifter engines are different to those used in solid lifter engines.
Note that the spring designed for the hydraulic lifter engine can also be used on solid lifter engines.
Pushrods are different lengths for hydraulic and solid lifter engines.
Acceptable pushrod lengths are given in Table 10.
5.11.7.2 Inspection and repair
Top End Overhaul:
Measure the valve spring lengths as shown in Figure 94
– each spring must
measure within the limits set in Table 10 to be returned to service. If any springs are shorter than this
then order a complete new set of valve springs
– if a few are short then tension will be down for all
springs.
Check both ends of the springs for sharp edges or burrs which could damage the valve spring washers.
Sharp edges and burrs should be polished off.
Inspect valve spring washers (top and bottom) for wear. Worn parts must be replaced. Measure top
spring washer thickness
– minimum thickness 1.3mm.
