Engine Overhaul Manual
Jabiru Aircraft
Pty Ltd
Jabiru 2200 & 3300 Aircraft Engines
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Dated : 28/10/2014
Issued By: AS
Page: 41 of 201
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4.4 Special Checks Before Disassembly
4.4.1 In-Situ Propeller Flange & Crankshaft Run-Out Measurement
Figure 45
– Measuring Propeller Flange & Crank Run-Out
This procedure is used to gauge the severity of any potential damage to the crankshaft or propeller
flange before carrying out a bulk strip.
Remove one spark plug from each head.
Carefully sand off paint on crank diameter and prop flange where dial indicator will be located. Applying
a little lubricant (such as greaseless lubricant spray) to the area being measured is also recommended.
Position dial indicator onto crank as shown above and eliminate main bearing clearance by bearing
down on crank when rotating. Rotate crankshaft to measure crankshaft run out. 0.01 - 0.03 mm is
normal, but if run out exceeds of 0.08 mm the crankshaft must be replaced.
Position dial indicator onto prop flange as shown above, eliminate end float by either pulling or pushing
flange when rotating. Rotate prop flange to measure the face run out. 0.02 - 0.06 mm is normal, but if
run out exceeds 0.08 mm then the prop flange must be replaced.
4.4.2 Engine Through-Bolt Check
This procedure is used to check if an engine may have fretting of the crankcase halves before
disassembly. This procedure is not suitable for nuts installed with Loctite 620.
Using a calibrated torque wrench, check the lower engine through bolt nuts. Use a torque setting of
28lb.ft for 3/8” bolts or 32lb.ft for 7/16” bolts.
These nuts were originally installed at 30 & 35lb.ft respectively (Table 9), so if the nuts move at the test
torques above it can indicate that the through bolt tension has reduced, possibly due to fretting of the
crankcase halves. If this is found before a top end inspection the overhauler may have to fully strip the
engine
– it is recommended that they contact Jabiru Aircraft Australia for guidance.
WARNING
Through-bolts & studs are highly loaded. Never torque nuts above the torque setting given in Table
9 or damage to the bolts will result. Accurate wrench calibration & compensation for any adaptors
used is vital when working on these parts.
The results of this test are an indicator only. False negatives and positives are possible. If in
doubt, disassemble the engine and inspect to be sure.
