Automobile Engineering in ME
It is necessary to maintain the valve clearances as they

Make the crankshaft turn smoothly
Increase the speed at which the valves move up and down
Reduce the resistance to sliding that occurs between the cam and the tappet
Allow for lengthening of the valves owing to the heat of combustion

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Automobile Engineering in ME
The function of a first compression ring (top ring) is that it

Creates swirl
Maintains a seal and prevents the fuel leakage
Maintains a seal and prevents escape of burned gases and loss of pressure in the combustion chamber
Increases the combustion temperature

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