After the removal of a cylinder and piston the connecting rod must be supported to prevent damage to the rod and crankcase. This is done by supporting each connecting rod with torque hold down plate ST-222, rubber band (discard-ed cylinder base on seal rings) looped around the cylinder base studs as shown in figure 5-3.
5-12. Removal of the other cylinders and pistons may be done in any desired order, but less turning of the crankshaft is involved if the cylinders are removed suc-cessively in the engine's firing order 1-3-2-4. Left hand rotation firing order 1-4-2-3.
5-13. Hydraulic Lifters. Remove the hydraulic lifter from the crankcase. Place each lifter as removed from crankcase in its proper location in the cleaning basket. The hydraulic lifters must be replaced in the same loca-tion in crankcase from which they were removed.
DISASSEMBLY
5-14. Cylinders. Place cylinder over the cylinder holding block (64526-2), assemble valve spring compressor (ST-419) on cylinder, and compress valve springs far enough to remove the valve retaining keys.
NOTE
If keys are stuck tight in spring seat, a light blow with a leather mallet on top of compressor will release keys.
5-15. Remove all valve spring seats and springs from
rocker box, keeping parts for each valve separate. Hold valves by the stem to keep them from dropping out of the cylinder, and remove cylinder from holding block. Now reach inside of cylinder and remove valves. If difficulty is experienced in pulling the tops of the valve stems through the valve guides, push the valves back in position and clean the carbon from the stems.
Section5 OVERHAUL MANUAL LYCOMING 76 SERIES AIRCRAFT ENGINES Cylinder,Piston and Valve Train
OVERHAUL MANUAL LYCOMING 76 SERIES AIRCRAFT ENGINES Section 5 Cylinder,Piston and ValveTrain
4
6
-7
4. Connecting Rod Bolt
1. Nut 5. Connecting Rod 8. Oil Regulating Ring2. Connecting Rod Cap 6. Piston 9. Compression Ring3. Bearing Insert 7. Piston Pin Plug 10. Piston Pin
Figure 5-2. Piston and Connecting Rod Assembly
CA UTION
Do not drive the valves through the guides.
5-16. Place each valve, with its springs, seats and keys in its proper compartment of the cleaning and inspection basket (64553). No further disassembly of the cylinder is necessary unless inspection warrants the replacement of valve guides, valve seat, or primer nipple.
5-17. Pistons. Using the piston ring expander (64713), remove the rings from all pistons. Remove the rings in order, starting with the top ring and working down. Be careful not to scratch or score piston when removing rings.
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