2) Valve Guides; 3) Valve Seats - Rotax 912 Series Maintenance Manual

14.5.2)
14.5.3)
Effectivity: 912 Series
AIRCRAFT ENGINES
MAINTENANCE MANUAL II
NOTE: At reassembly coat cylinder sealing face thinly with
LOCTITE
At slight wear, valve and valve seat may be re-lapped, using emery paste.
Because of seat armour, restrict re-lapping to 0,2 mm (.008 in.) max.
Clean cylinder head and single components in gasoline or kerosine.
Check sealing face of cylinder head, and if need be, true up along with
cylinder, but only slight rework is allowed.
Renew valve stem seals. If the engine has been "run hot", check in any
case hardness of cylinder head material, see para 14.5.7.
Valve guides
See fig. 163 and 164.
Check diameter of valve
stem Q and int. dia. of
valve guide W dim. p
and dim. o in para 15.
If wear limit is reached,
renew valve guide.
For this procedure sent
the cylinder head to an
authorized overhaul fa-
cility.
dimensions
(in.)
See Wear Limits in para 15.
Valve seats
See fig. 165.
Ensure sealing surfaces Q of valve
seats are clean. If necessary, re-lap
using emery paste, see para 11.7.16.
Check Imprint width, see dim. [ in
para 15. At presence of burned spots
or deformation, send cylinder head
for overhaul to an authorized overhaul facility.
dimensions
(in.)
See Wear Limits in para 15.
® 221.
o
2
00279
fig. 163
new mm (in.)
1
45°
new mm (in.)
1
Maß /
dim.
p
00281
fig. 164
wear limit mm
00285
fig. 165
[
wear limit mm
page 105
Initial issue, Jan. 01/2002