Valve Clearance Adjustment - Westerbeke 20B TWO Tehnical Manual

VALVE CLEARANCE ADJUSTMENT
Valve Clearance Adjustment
Cylinder head bolts lIl.USt. be retightened before adjust-
ing the valve clearance. When retightening the cylinder
head bolts, draw out coolant, loosen the bolts slightly,
and then retighten the bolts to the specified torque in the
numerical order illustrated at right.
Tightening torque: M 10 bolt 54.2 - 61.5 Ib-ft
(7.5 - 8.5 kg-m)
M8 bolt 10.8 - 15.9 Ib-ft
(2.0 - 3.0 kg-m)
The rocker assembly (the rocker arms, shaft, and stays)
is to be kept removed when the cylinder head bolts are
retightened.
Rocker stay tightening torque: M8 bolt 10.8 - 15.9 Ib-ft
(1.5 - 2.2 kg-m)
1. Set the cylinder to be adjusted to the top dead center
of the compression stroke.
Valve clearance: 0.0098 in. (0.25 mm) (cold) for
both intake and exhaust valves.
2. The top dead center of the compression stroke can
be obtained by aligning the T.O.C. (Top Oead Center)
mark (notch) on the crankshaft pulley with the mark
on the gear case.
3. First align the T.O.C. mark for the No. 1 cylinder.
Confirm that the valves do not move up and down
when the crankshaft is turned about 20° in the normal
direction of rotation and in the reverse direction.
4. When setting the top dead center for the 3 cylinder
engine, perform as follows:
a. Two Cylinder Engine From T.O.C. for the NO.1
cylinder, turn the crankshaft 180° clockwise and the
NO.2 cylinder is set to T.O.C.
b. Three Cylinder Engine From the T.O.C. for the No.
1 cylinder, turn the crankshaft 240° clockwise to set
the No.3 cylinder T.O.C. Further, turn the
crankshaft 240° clockwise, and the No. 2 cylinder
is set to T.O.C.
33
4
o
0
2
0
1
Cylinder Head Bolt Tightening Sequence
Cylinder Head Bolt Tightening Sequence
ADJUST EXH.\USl' V.UVES TO 0.012 INCH&'!
(11.:111
~
.. )
ADJUST INTAKE VALVES TO 0.010 I:SCHES
(0.2~
MM)
Injection Timing Mark
208
308
Westerbeke Engines