Yanmar 3JH3E - 2-4 Valve springs

Chapter 2 Basic Engine
_2_._C..;.y_J1_·n_d_er_R_e_a_d
__________________________
3,4JH3(B)(C)E
(4)
Valve stem seals
The valve stern seals in the
intake/exhaust
valve
guides cannot
be
re-used once they are removed -
be
sure to replace them.
When assembling the intake/exhaust valves, apply
an
adequate quantity of engine oil on the valve stem
before inserting them.
Valve
stem
seal
,
Valve
guide
f---+--+
2-4 Valve springs
!
Cylinder
head
'
t.
'
'
.
'
2-4.1 Checking valve springs
(1)
Check the spring for scratches or corrosion.
(2)
Measure
the
free length of the spring.
(3)
Measure inclination.
Square
gaude
A
2-8
(4) Measure spring tension.
Spring
tension
tester
(Inside)
mm
Valve
spring
Standard
Wear
limit
Free
length
44.4
43.0
Distortion
-
1.1
Tension
(1mm
pressure)
2.36/3.101
-
<Remarks>
Tension
is
shown for the smaller pitch.
Assembling valve springs.
The side with the smaller pitch (painted yellow} should
face down (cylinder head).
Up
side
t
~
Down
side
f
11
j }
Smalle, pitch
side
(yellow)
NOTE :
The
pitch
of
the valve spring is not even.
The
side
with the smaller pitch (yellow) should face down
(cylinder head) when assembled.
(5) Spring retainer
and
spring
cotter
Inspect the inside face of the spring retainer, the out-
side surface of the spring cotter, the contact area of the
spring cotter inside surface and the notch
in
the head
of the valve stem. Replace the spring retainer and
spring cotter when the contact area
is
less than
70%,
or when the spring cotter has been recessed because
of
wear.
Printed in Japan
HINSHI-H8009