Supplement Airplane Maintenance Manual
Cessna 172 with TAE 125-02-99 / -114
AMM-20-02
Chapter:
Issue:
Issue Date:
Page:
Content:
20-AMM-71-02
3
06.11.2013
2
46
Rev. No:
Rev. Date:
1
25.08.2014
Crankshaft
The stroke is 92 mm (3.62 in), main journal diameter is 55 mm
(2.17 in), rod journal diameter is 50 mm (1.97 in). The original
2-mass flywheel is changed to a modified version.
Connecting Rods
The connecting rods are made of forged steel each including big
end bearing. The big end diameter is 55 mm (2.17 in), the
bushing in the small end has a diameter of 28 mm (1.1 in). In the
case of overload the rod has the tendency to become shorter, it
shows no bending tendency. The rods are forged in one piece,
then the big end is cracked, so that the mating surfaces are
perfectly aligned at assembly. They are equipped with M7 bolts
and are axially guided at the piston. The rod length is 147.85 mm
(5.82 in).
Pistons
The original aluminum pistons have special steel inlays in the
piston ring groove and are a cooling duct design. Special chrome
ceramic rings guarantee good wear resistance.
Cylinder Head
The 4 valve cast aluminum cylinder head has diametrically
opposed valves. There are 2 water jackets which reduce the
temperatures in the critical areas around the exhaust valve seats
and the injector to less than 200 °C.
The hydraulically adjusted roller lifters acting on the nimonic
valves guaranty low friction values benefiting the efficiency and
reliability of the engine. An original three layer steel head gasket
is used. A glow plug is installed for the reason of starting in very
cold conditions.
Camshafts
The forged steel camshafts are gun drilled. A simplex timing
chain is fitted. The cam profiles provide an intake valve lift of
8.5 mm (0.33 in) and an exhaust valve lift of 8 mm (0.31 in).
Valve Train
The intake valves have a shaft diameter of 6 mm (0.24 in) and a
valve head diameter of 28.5 mm (1.12 in), the exhaust valves
have a shaft diameter of 7 mm (0.28 in) and a valve head
diameter of 25.4 mm (1.00 in). The valve springs have an inside
diameter of 15.5 mm (0.61 in), an outside diameter of 21 mm
(0.83 in) and 2.75 mm (0.108 in) wire diameter. The unstressed
height of the spring is 45.5 mm (1.79 in), assembled height is
32.5 mm (1.28 in), it has 8 threads. The valve keys are of type
MK6 to guarantee a good valve rotation.
Содержание Cessna 172
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