Kubota M5640SU Workshop Manual page 128

M5640SU, M5640DT-SU, WSM
Pistons
1. Completely clean carbon (1) in the cylinders.
2. Remove the connecting rad cap (3).
3. Turn the flywheel and bring the piston to top dead center.
4. Draw out the piston upward by lightly tapping it from the bottom
of the crankcase with the grip of a hammer.
5. Draw out the other piston in the same method as above.
(When reassembling)
• Before inserting piston into the cylinder, apply enough engine oil
to the piston.
• When inserting the piston into the cylinder, face the mark on the
connecting rod to the injection pump.
IMPORTANT
• Do not change the combination of cylinder and piston.
Make sure of the position of each piston by marking. For
example, mark "1" on the No. 1 piston.
• Place the piston rings with their gaps at 0.79 rad (45 °) from
the piston pin's direction as shown in the figure.
• Carefully insert the pistons using a piston ring compressor
(6).
• When inserting the piston in place, be careful not to get the
molybdenum disulfide coating torn off its skirt. This
coating is useful in minimizing the clearance with the
cylinder liner. Just after the piston pin has been
press-fitted, in particular, the piston is still hot and the
coating is easy to peel off. Wait until the piston cools down.
Tightening torque Connecting rod screw
(1) Carbon
(2) Connecting Rod Screw
(3) Connecting Rod Cap
(4) Connecting Rod
(5) Molybdenum Disulfide Coating in
Piston Skirt
(6) Piston Ring Compressor
1-S40
ENGINE
45 to 49 N·m
4.5 to 5.0 kgf·m
33 to 36 lbf·ft
(A) Top Ring Gap
(B) Second Ring Gap
(C) Oil Ring Gap
(D) Piston Pin Hole
(a) 0.79 rad (45 °)
9Y1210365ENS0098US0
KiSC issued 07, 2009 A