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Unformatted text preview: ‘piston slap’ while it is cold
and this tendency increases with wear. The less clearance between the piston and the cylinder wall
will lead to siezing of piston.
2. Since the aluminium alloys used for pistons have high **heat conductivity (nearly four
times that of cast iron), therefore, these pistons ensure high rate of heat transfer and thus keeps
down the maximum temperature difference between the centre and edges of the piston head or
Notes: (a) For a cast iron piston, the temperature at the centre of the piston head (TC) is about 425°C to 450°C
under full load conditions and the temperature at the edges of the piston head (TE) is about 200°C to 225°C.
(b) For aluminium alloy pistons, TC is about 260°C to 290°C and TE is about 185°C to 215°C. 3. Since the aluminium alloys are about ***three times lighter than cast iron, therfore, its
mechanical strength is good at low tempreatures, but they lose their strength (about 50%) at temperatures
above 325°C. Sometimes, the...
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- Spring '11