Figure 13.7 Combustion chamber and piston showing borecooling arrangement
hydraulic tool to allow simultaneous tightening and correct tension of the studs.
Exhaust valve
The valve is similar to earlier types but with hydraulic actuation, a feature originally unique to the K-GF series (Figure 13.8)The valve consists of a cast iron cage and a spindle, with steel seats and the valve mushroom faced with Stellite for hard wearing. Studs secure the valve housing to the cylinder cover.
The hydraulic actuation system is based on a piston pump driven by a cam on the camshaft, and the pressure oil is led to a working cylinder placed on top of the exhaust valve housing. The oil pressure is used to open the valve and closing is accomplished by a ring of helical springs.
Camshaft
The camshaft is divided into sections, one for each cylinder, enclosed and suspended in roller guide housings with replaceable ready-bored