LYCOMING OPERATOR’S MANUAL SECTION 5
O-360 AND ASSOCIATED MODELS MAINTENANCE PROCEDURES
(c) Tighten the inch hold-down nuts to 300 in.-lbs. (25 ft.-lbs.) torque. Sequence of tightening
is optional.
(d) As a final check, hold the torque wrench on each nut for about five seconds. If the nut does
not turn, it may be presumed to be tightened to correct torque.
CAUTION
AFTER ALL CYLINDER BASE NUTS HAVE BEEN TIGHTENED, REMOVE ANY NICKS IN
THE CYLINDER FINS BY FILING OR BURRING.
(6) Install new shroud tube oil seals on both ends of shroud tube. Install shroud tube and lock in
place as required for type of cylinder.
(7) Assemble each push rod in its respective shroud tube, and assemble each rocker in its respective
position by placing rocker between bosses and sliding valve rocker shaft in place to retain rocker.
Before installing exhaust valve rocker, place rotator cap over end of exhaust valve stem.
(8) Be sure that the piston is at top center of compression stroke and that both valves are closed.
Checkclearance between the valve stem tip and the valve rocker. In order to checkthis clearance,
place the thumb of one hand on the valve rocker directly over the end of the push rod and push
down so as to compress the hydraulic tappet spring. While holding the spring compressed, the
valve clearance should be between .028and .080 inch. If clearance does not come within these
limits, remove the push rod and insert a longer or shorter push rod, as required, to correct
clearance.
NOTE
Inserting a longer push rod will decrease the valve clearance.
(9) Install intercylinder baffles, rocker boxcovers, intake pipes, rocker boxdrain tubes and exhaust
manifold.
5. GENERATOR OR ALTERNATOR DRIVE BELT TENSION.
Checkthe tension of a new belt 25 hours after installation. Refer to latest revision of Service Instruction
No. 1129 and latest revision of Service Letter No. L160 for methods of checking generator or alternator
drive belt tension.
6. TURBOCHARGER CONTROLS.
a. Density Controller – The density controller is adjusted at the factory to maintain a predetermined
constant for desired horsepower.
The density controller is set to the curve, see Figure 5-4, under the following conditions: Engine
stabilized at operating conditions, full throttle with oil pressure at 80 psi ±5 psi.
If it is suspected that the manifold pressure is not within limits, it may be checked to the curve.
EXAMPLE
Operating at the stated conditions with a compressor discharge temperature of 120°F, the
manifold pressure should be 34.8 in. Hg. ± .3 in. Hg.
5-9
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