Engine - Subaru XT 1988 Service Manual

ENGINE 2-3
Fig. 3
VALVE AND VALVE SPRING
1) The valve has a small valve stem diameter [7 mm (0.28 in)
dia_l to reduce the valve weight. The variable pitch valve
spring is adopted to improve valve follow-up performance at
high engine speeds_
2) The valve has a large valve head diameter to increase
engine output.
TIMING BELT, TENSIONER AND SPROCKET
1) Two timing belts drive the left and right-hand camshafts.
The timing belt is composed of a core featuring great strength
and less elongation, canvas (tooth face portion) having superior
wear resistance, and highly heat-resistant rubber.
2) The timing belt has special round teeth featuring positive
engagement with sprocket teeth and smooth and low-noise
operation. The crankshaft sprockets, oil pump sprocket and
idler are made of sintered alloy_
3) The camshaft sprockets are made of sheet metal, and are
common between right and left.
4) A grease-sealed type ball bearing is used in the tensioner.
The tensioner spring gives the timing belt an initial tension
which is adjustable by loosening the tensioner mounting bolt.
5
Lash adjuster
1 Timing belt RH
2 Timing belt LH
3 Crankshaft sprocket
4 Camshaft sprocket
Fig. 4
Sintered alloy chip
5 Tensioner RH
6 Tensioner LH
7 Oil pump sprocket
8 Idler
TIMING BELT COVER
L2-789
L2-996
1) The resin-mold timing belt cover, consisting of six pieces,
is used to protect the timing belt against dust and water.
2) Each of the left-hand and right-hand side covers has an
access hole for belt tensioner adjustment.