Displacement Parts Reassembly; Hydraulic Valve Tappets; 2) Piston Fitting - Rotax 912 Series Maintenance Manual

14.9) Displacement parts reassembly

14.9.1)
Bolzenachse
pin axis
1 mm
Bolzenmitte
pin centre
04709
fig. 187
Zylinder 1 und 3 /
Cylinder 1 and 3
Effectivity: 912 Series
AIRCRAFT ENGINES
MAINTENANCE MANUAL II

Hydraulic valve tappets

Lubricate bearing bore Q for valve tappets W in crankcase with motor oil.
Anti-Seize to the contact surfaces E of the valve
Apply LOCTITE ®
tappets, lubricate their outside with motor oil and insert them according to
the recorded position into the crankcase. The valve
Kolbenachse
tappets must be able to turn without resistance in the
piston axis
crankcase.

14.9.2) Piston fitting

See fig. 186, 187, 188, 189, 190 and 191.
The piston pin centre is offset from piston centre and the
0,0394 in
piston must be installed with the arrow Q on piston
crown showing towards propeller shaft. This means
that on cylinders 1 and 3 the narrower side W of the
1
pistons must be below the conrod, and on cylinders 2
and 4 the narrower side E of the piston must be above
the conrod.
00303
Install the piston as shown on fig. beside. The offsetting
fig. 186
of piston pin bore is 1 mm (.039 in.).
If the arrow Q on piston crown is no more visible, the
piston must be measured.
Apply MOLYKOTE
the piston pin R , coat bore T in conrod and the bore
in piston Y. Insert piston pin with installation pusher ,
part no. 877 011 (slide fit).
The piston pin may also be inserted with the use of the
Nullhakenring /
circlip piston pin extractor ass'y U, part no. 877 091 . Push
piston pin into the piston, insert puller spindle I from
the opposite side and fit on nut O. By turning the spindle
Kolbenmitte
clockwise, the piston pin can be pulled up to the circlip
piston centre
groove P.
1mm / 0,394 in
auf den Propellerflansch gesehen /
looking at propeller flange
2
®
G-N slide paste over the whole of
Zylinder 2 und 4 /
Cylinder 2 and 4
3
00305
fig. 188
Initial issue, Jan. 01/2002
page 114