5. Inspection and servicing of basic engine parts
113
4) Measure spring tension.
5) Assembling valve springs.
The side with the smaller pitch (painted yellow)
should face down (cylinder head).
NOTE:
The pitch of the valve spring is not even. The side with the smaller pitch (yellow) should face down
(cylinder head) when assembled.
6) Spring retainer and spring cotter
Inspect the inside face of the spring retainer, the outside 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.
5.2.5 Assembling the cylinder head
Partially tighten the bolts in the specified order and then
tighten to the specified torque, being careful that the
head does not get distorted.
(1) Clean out the cylinder head bolt holes.
(2) Check for foreign matter on the cylinder
head surface where it comes in contact with
the block.
(3) Coat the head bolt threads and nut seats
with lube oil.
(4) Use the positioning pins to line up the head
gasket with the cylinder block.
(5) Match up the cylinder head with the head
gasket and mount.
Valve spring
Unit
Standard
Limit
Free length A
mm
37.8
36.3
Inclination B
mm
-
1.3
Tension
(1 mm pressure)
(Smaller pitch/
Larger pitch)
N/mm
(kgf/mm)
26.6/35.4
(2.71/3.61)
-
N•m (kgf•m)
First
Second
Cylinder head bolt
tightening torque
27.0-33.0
(2.8-3.4)
53.9-57.9
(5.5-5.9)
Spring tension tester
Up side
Smaller pitch side (yellow)
Down side
(3 cylinder head)
Camshaft side
Disassembly
Assembly
Head bolt disassembly order
Gear case side
Camshaft side
(3 cylinder head)
Head bolt tightening order
Gear case side
1
2
3
5
4
6
10
12
8
13
14
11
9
7
1
2
3
5
4
6
10
12
8
13
14
11
9
7
Summary of Contents for 3YM20
Page 1: ...M9961 03E100 ...
