Engine Overhaul Manual
Jabiru Aircraft
Pty Ltd
Jabiru 2200 & 3300 Aircraft Engines
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ISSUE
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6 7
Dated : 28/10/2014
Issued By: AS
Page: 109 of 201
L:\files\Manuals_For_Products\Engine_Manuals\Overhaul_Manual\JEM0001-7_Overhaul_Manual_DRAFT_(29_10_14).docx
Looking at the underside of the piston there is a cast-in lump on one gudgeon pin housing (see Figure
129). This lump must be fitted to the engine on the side of the connecting rod closest to the propeller
flange. Another marking used for the same job is a small arrow or indent cast into the crown. The
arrow must point towards the propeller flange and/or the indent must be on the propeller flange side of
the connecting rod. These markings show the correct orientation of the piston to the thrust loads from
combustion relative to the propeller.
Figure 131
– Fitting Circlip to Piston
Figure 132
– Fitting Wire-Type Piston Circlips
Fit wire-type circlip:
-
Many engines use a wire circlip in place of the part shown in Figure 131. Installation of that type of
clip is shown in Figure 132.
-
The circlip has a lot of tension and as a result installation can be tricky.
-
Overhaulers must
roll
the clip into the groove
– they must never be levered in as this can damage
the piston or the clip.
-
Take care not to scratch or burr the piston or to bend the clip itself.
-
As the clip slips into the groove, listen for a crisp “snap” sound, indicating that it has dropped fully
into place. Always give the installed clip a close inspection after installation. Use a small
screwdriver or pick to check that it is tightly in place
– in the case of the piston, apply an “opening”
load to the ends of the clip, expanding it into the groove. The clip should not move and should not
spin in the piston. If in doubt, fit a replacement.
Fit conventional circlip:
-
Both 25mm and 23mm internal circlips have been used in Jabiru engines, as shown in Figure 131.
-
Visually inspect the clips supplied and identify the “flat” and “round” sides. Figure 133 shows the
two different sides of a typical clip
– note the sharp corners on the top of the left clip while the clip on
the right has a rounded top face and rounded corners. This comes from the clip manufacturing
process and will be apparent in all clips of this type
– one side will be “sharp” and the other “round”.
Note gap between
“eyes” – clip not
fully compressed