Subaru XT 1988 Service Manual page 260

1..-
2-4
ENGINE LUBRICATION SYSTEM
MECHANISM AND FUNCTION
General
The engine lubrication system is a fully-pressurized full-flow
filter type. The lubricating oil is pressurized by a trochoid oil
pump with a built-in oil relief valve and oil bypass valve*. This
oil pump is driven by the crankshaft at a speed ratio of 1: 1
through a timing belt.
Lubrication Lines
1800
cc
Engine
Lubrication lines
Crankshaft
front main
bearing
Crankshaft
If the filtering capacity of the oil filter deteriorates, oil is sent
directly to the main gallery through the oil bypass valve_ If the
oil pressure rises in the oil circuit, excess oil is returned to the
oil pump through the oil relief valve.
*: The oil bypass valve is non-disassembling type.
#1
connecting
1-_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ ---,
rod bearing
#2&#3
r-
center main
r---
connecting
bearing rod bearing
Crankshaft
rear main
L......a.
#4
connecting
~-----------------
..
.------ rod bearing
bearing
Cylinder
block main f -
gallery
.------.l~
Oil filter
~
: ' - -_ _ _ ....J
i
-------:
l
I
I
Bypass
j
I
valve
I
Oil strainer
I
I
Oil pan
I
Fig. 1
#1 &#3
camshaft
case
#2&#4
-
4 camshaft
r--
case
#1 &#3
camshaft
. . J
#1 & #3
l
~'___ca_m
_ _
....JI~----------~
H
!~~h!f~
l
r--
,--_be_a_rin-=g,---,I
' - --------' l1
Camshaft
I
~----------~
support
J
4 cylinder head
#1 & #3
#1&#3
H
H LA gallery H LA
Relief
valve
Relief
~
pipe
L . . . - - - - . . . J
#2& #4
camshaft
rl
#2& #4
I
'--_ca_m ____
~J~----------~
-1
~~~h~f~
I
r--
bearing
r
' - - - - - - = - - - '
Camshaft
I~
__________
+-I
support I
#2&#4
-1
#2&#4
4 cylinder head HLA
HLA gallery
Relief
valve
Relief
~
pipe
~
L2-1251
2