Cylinder Head Disassembly - Rotax 912 Series Maintenance Manual

14.5.1)
3
00280
fig. 162
Effectivity: 912 Series
AIRCRAFT ENGINES
MAINTENANCE MANUAL II

Cylinder head disassembly

See fig. 162.
If the cylinder head is not removed and the rocker arms should be
dismantled, turn crankshaft to set the piston of the respective cylinder to
ignition T.D.C. and to have only little pressure on the rocker arm. Depress
rocker arm with test lever 877 690 towards hydraulic valve tappet. Now the
rocker arm is completely released and the rocker arm shaft can be
removed.
NOTE: The hexagon of the cap collar nut may be in an unfavour-
able position as to prevent removal of the rocker arm
shaft. In this case loosen the nut.
2
Withdraw rocker arm shaft and remove both rocker arms.
Compress valve springs utilizing valve spring mounting device
Q, part no. 877 380 and clamp W or similar tool and lift out valve
cotters. Release valve spring. Remove valve spring retainer and
both springs, and withdraw valve.
NOTE: Prior to the removal of valves, clear off burrs which
1
may be present on valve stems to prevent damage
to
coordi
Repeat this procedure for the second valve and clean cylinder
head.
Check oil return tubes W for leaks (visual check). At leaks in the
area E the tubes affected must be renewed. For this procedure,
heat cylinder head to approx. 180
remove any glue residues from bore. Apply LOCTITE
new oil tubes in the area of the two grooves and push tubes into position
in the cold cylinder head.
NOTE: Apply LOCTITE
Prior to removal of the coolant elbow mark or take dimensions of its location
to ensure proper position at re-installation. Heat cylinder head to approx.
80-100°C (180-210°F) and unscrew coolant elbow. Remove residues of
securing agent with a tapping drill M18x1 (part no. 877 570) and check
threads. Apply LOCTITE
and screw elbow into the cold cylinder head. Allow cylinder head to cure
for approx. 10 minutes at 80° C (176° F).
Carbon deposits on the sealing surface to the cylinder, should be removed
carefully with lapping fleece or solvent.
valve stem seal and valve guide. Mark valves
nately.
O C (356
®
only on the cold part!
® 648 on cylinder head and on new coolant elbow
O F). Extract tubes and
®
648 on the
page 104
Initial issue, Jan. 01/2002