b.
Using the same sequence, tighten the 1/2 inch nuts to 600 inch pounds (50 foot pounds).
Section5 OVERHAUL MANUAL LYCOMING Cylinder,Piston and Valve Train
c.
Tighten the 3/8 inch hold down nuts to 300 inch
pounds (25 foot pounds) torque. Sequence is optional.
d.
As a final check hold the wrench at the correct torque,
on each nut for about five seconds. If the nut does not
turn, it may be presumed to be tightened to correct tor-
que.
5-84. After all cylinder base nuts have been tightened, remove any nicks in the cylinder fins by filing or burring.
5-85. Install some type of vented plug in each spark plug hole after assembly of cylinder to prevent entrance of foreign matter and at the same time to permit the engine to be turned easily by hand.
5-86. Install hydraulic lifter (1) in crankcase. (Figure 5-1).
5-87. Assemble new shroud tube seal (3) on both ends of shroud tubes. (Figure 5-1.)
5-88. Parallel Cylinder. (Figure 5-1.) Install each shroud tube through its hole in the rocker box and press to firmly seat the seals in their respective position in the cylinder head and crankcase. Install shroud tube spring (5), lockplate (6), and 1/4-20 plain nut (7) over stud provided in the rocker box. Tighten nut to proper torque and secure by bending the lockplate up around the nut.
5-89. Dip the push rod in the oil mixture as described in paragraph 3-39 and insert the full length into the shroud tube. Press tightly against the outer end of push rod to check spring tension and free travel of the dry hydraulic lifter assembly.
NOTE
Before installing the exhaust rocker arm be certain that the exhaust valve rotator cap is on the valve stem.
76 SERIES AIRCRAFT ENGINES
5-90. Install two square washers (9), rocker arm (8) and rocker arm fulcrum (10) seat on stud. Install 5/16-24self-locking nut (11) and tighten to the proper torque, see Table of Limits figure reference (877). Check the dry tap-pet clearance by pressing the thumb on the push rod end of the rocker arm. Record the clearance between the rocker arm and the top of valve stem. Use valve clearance gage ST-23. Valve clearance is .028-.080 inch. The adjust-ment of the dry tappet clearance is obtained by increasing or decreasing the number of square washers (9) placed under the rocker arm fulcrum. Increased number of washers will increase the clearance.
NOTE
When adjusting the dry tappet clearance it is best to use a plain 5/16-24 nut. Then after the proper clearance is obtain-ed install the 5/16-24 self-locking nut.
5-91. At completion of valve clearance check on each cylinder, recheck clearance on all cylinders and make necessary corrections. Coat all mechanism parts within rocker boxes as described in paragraph 3-37 and 3-39. Assemble rocker box cover gaskets and covers on each rocker box and tighten to specified torque.
5-92. Intercylinder Baffles. All intercylinder baffles must be attached with an "S" type retaining hook and a slotted retainer. Hook the baffle retaining hook through the hole in the baffle. Place the baffle in position beneath and bet-ween the cylinders, running the hook up between the cylinder barrels. Place a baffle retainer in place between the cylinders and using a baffle installation tool (64885), bring the retainer hook through the slot in the retainer. During the operation the retainer is forced down until the hook comes above the surface of the retainer far enough to be hooked over the bridge between the slots in the re-tainer.
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