Subaru EX13 Service Manual page 12

4-5 PISTON RINGS
The piston rings are made of special cast iron. The profile of the top ring is a barrel face or tapered face, and
that of the second ring is a tapered face. There are 2 types of oil ring depending on the engine specification.
As those are interchangeable, the cutter ring with coil expander type can be selected as the spare part.
4-6 CAMSHAFT
The camshaft and the sprocket are made of special
sintered alloy. They are constructed as a single piece.
The camshaft is provided with intake and exhaust cam,
and the decompression release lever is mounted on
the sprocket shaft end side.
4-7 VALVE ARRANGEMENT
This engine has a chain-driven overhead cam and
overhead valve construction, with a single cam
performing both intake and exhaust operations.
4-8 CYLINDER HEAD
The cylinder head is an aluminum die-casting with a
pent roof combustion chamber construction. The intake
and exhaust ports are arranged in a cross direction to
improve combustion efficiency.
1
TOP
1
RING
2
SECOND
3
2
RING
OIL
3
RING
Fig. 4-5
EXHAUST VALVE
- 9 -
BARREL
(EX13/27)
TAPER
(EX17/21)
TAPER
CUTTER RING
WITH COIL
EXPANDER
THREE-PIECE
CONSTRUCTION
Fig. 4-6
INTAKE VALVE
Fig. 4-7
Fig. 4-8