Preheating for Crankcase Vent

Porsche 996 Engine Timing Diagram

A preheating line runs for a short distance in the hose for the crankcase vent 24 , between the oil separator 14 and air cleaner lower section. The coolant for preheating is taken from the left cylinder head 23 and enters the cooling system again at the thermostat housing. A bleeder line 25 26 connected to the expansion tank is used to bleed the radiator and engine circuit. The temperature sensor 9 and thermo time switch for the cold start valve 10 are located in the thermostat housing. The...

Hydraulic Valve Lifters

If there is clearance between the cam and lifter, return spring 3 presses the lifter up 1 so that the clearance is eliminated. This movement lowers the pressure in pressure chamber 4 . Because of this low pressure and the engine oil pressure, the check valve 6 opens and oil can flow into the high pressure chamber. As the valve is opened by the cam lobe, the pressure in the pressure chamber 4 increases and closes the check valve 6 . A small amount of oil leaks out through the gap 7 thus...