Engine Overhaul Manual
Jabiru Aircraft
Pty Ltd
Jabiru 2200 & 3300 Aircraft Engines
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Dated : 28/10/2014
Issued By: AS
Page: 189 of 201
L:\files\Manuals_For_Products\Engine_Manuals\Overhaul_Manual\JEM0001-7_Overhaul_Manual_DRAFT_(29_10_14).docx
11 Appendix C - Wear Factors
11.1 Wear Factors
The following table shows typical wear amounts per 1,000 hours of operation, and is intended to all the
reader to assess the possibility of components achieving 1 or more cycles.
Note that these values are given as a guide only. Operation of engines with poor
quality “dirty” oil/and
or corrosion mixed in with oil has elevated wear on contact surfaces. Many other environment-specific
factors will also vary the engine wear rates.
When carrying out a top end inspection, the overhauler must keep these factors in mind
– for example a
cylinder measuring 97.65mm may be within the wear limits for the part but it will not survive another full
cycle. Parts which are unlikely to survive in service for another full cycle must be replaced.
Table 38
– Wear Factors
Part
Typical Wear for 1 Cycle (1000 hours)
Crankshaft end thrust
0.02
Crankshaft Main Bearings
0.005 - 0.010
Crankshaft Mains
0 - 0.005
Crankshaft Big Ends
0.005 - 0.01
Camshaft End Thrust
0.06
Camshaft Bearing Areas (5)
0.01
Camshaft Followers on Stem (Solid)
0.0 - 0.005
Camshaft Fuel Lobe
0.01
Connecting Rod Bearing
0.025 - 0.06
Crankcase Cam Tunnel
0.015
Crankcase Cam Follower Bores
0.02 - 0.03 (Solid Lifter)
Gudgeon Pin Diameter
0.000 - 0.005
Pump Push Rod Length
0.01 - 0.03
Distributor Posts
0.01 Typical
Distributor Shafts
0.00 - 0.01
Valve Rocker Shafts
0.015
Rocker Bushes (Hydraulic)
0.012 - 0.020
Rocker Bushes (Hydraulic
– Pushrod Oil Feed)
Approx ½ of above Hydraulic
Rocker Bushes (Solid)
0.06 - 0.10
Valve Stems Inlet
0.00
Valve Stems Exhaust
0.00 - 0.01
Valve Spring Length
Shortened by 1.60 - 1.80
Cylinder Head Inlet Valve Seat
Visual
Cylinder Head Exhaust Valve Seats
Visual
Cylinder Head Inlet Valve Guides
0.01 - 0.02
Cylinder Head Exhaust Valve Guides
0.01 - 0.02
Oil Pump - Inner to Outer Gear
0.025 - 0.08
Cylinder Bore Wear
0.01 - 0.03 (width and taper)
Piston Diameter
0.0 - 0.01
Piston Ring Sliding Clearances
<0.01
Ring Gaps
1.50 Typical
Ring Gaps - On Oil Additive Engines
3.00 - 4.50