SERVICING THE INDIVIDUAL PARTS
D
9
NIKASIL CYLINDER COATING
Nikasil is the brand name for a cylinder coating process
developed by the Mahle piston company. The name is
derived from the two materials used in the process – one
layer of nickel in which the exceptionally hard silicon
carbite is embedded. The major advantages of the
Nikasil coating include its outstanding heat dissipation
and the improved power output, the insignificant wear
and low weight of the cylinder/cylinder liner. It is
inexpensive to repair (replace) a worn coating if the
cylinder barrel is not damaged.
MEASURING THE PISTON AND CYLINDER
LINER, ESTABLISHING THE MOUNTING
CLEARANCE OF THE PISTON
–To establish the wear to the cylinder liner, use a
micrometer to measure the liner in the middle of the
bearing surface.
– Measure the diameter of the cylinder liner in the X and
the Y axis to detect any ovality.
Diameter 450, 550, 650
Cylinder liner size I: 100,000 - 100,012 mm
Cylinder liner size II: 100,013 - 100,025 mm
Diameter 501
Cylinder liner size I: 95,000 - 95,012 mm
Cylinder liner size II: 95,013 - 95,025 mm
NOTE: mark the cylinder liner size (1) on the
side of the cylinder liner, the piston size (2) on
the piston head.
If measured diameter of a size I cylinder liner
falls within the size II tolerance zone, order a
new size II piston.
– The piston is measured at the piston skirt across the
piston pin as shown in the drawing.
– The piston mounting clearance is the difference
between the smallest cylinder liner diameter and the
piston diameter.
Piston mounting clearance 450, 550, 650 uncoated
0,072 - 0,097 mm
Wear limit: 0,12 mm
Piston mounting clearance 450, 550, 650 coated
0,042 - 0,087 mm
Wear limit: 0,12 mm
NOTE: Uncoated pistons have light-colored
metal, coated pistons are dark-colored with
black coating.
Piston mounting clearance 501
Piston size I: 0,040 - 0,080 mm
Piston size II: 0,044 - 0,085 mm
Wear limit: 0,12 mm
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