Nanni N4.40 Workshop Manual page 136

03-M-E3B, 03-M-DI-E3B, 03-M-E3BG, WSM
Pistons
[D1803-M-DI, V2403-M-DI, V2403-M-DI-T]
1. Fully clean the carbon (1) in the cylinders.
2. Remove the connecting rod cap (3).
3. Turn the flywheel and move the piston to top dead center.
4. Lightly tap the piston from the bottom of the crankcase with the
grip of a hammer to pull the piston out.
5. Pull out the other piston in the same procedure as above.
(When reassembling)
• Before you install the piston into the cylinder, apply sufficient
engine oil to the piston.
• When you install the piston into the cylinder, point the mark on
the connecting rod to the injection pump.
IMPORTANT
• Do not change the combination of cylinder and piston.
Align the position of each piston by its mark. For example,
mark "1" on the No. 1 piston.
• Set the top ring with its gap (A) at 1.6 rad (90 °) from the
direction of the piston pin.
Then set the second ring and the oil ring with their gaps (B),
(C) at 2.09 rad (120 °) from the top ring gap (A). (See the
figure.)
• Install the pistons with a piston ring compressor (7)
carefully.
• When you install the piston in position, do not give a
damage to the layer of molybdenum disulfide on the piston
skirt. This layer can decrease the clearance with the
cylinder liner. Immediately after you press-fit the piston
pin, the piston is hot and the layer comes off easily. Only
put in the piston after its temperature decreases.
• When you replace the piston, look at the code number (6)
on top of the piston. Use a replacement piston with the
same code number.
Tightening torque Connecting rod screw
(1) Carbon
(2) Connecting Rod Screw
(3) Connecting Rod Cap
(4) Connecting Rod
(5) Layer of Molybdenum Disulfide
(6) Code Number
(7) Piston Ring Compressor
1-S66
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) 2.09 rad (120 °)
M00000003ENS0096US1
KiSC issued 06, 2009 A