Petrol engine with a working volume of 1.2 liters (VW Polo 4)

the 1.2-litre, 3-cylinder petrol engine is available in two power outputs, namely 40 kW (55 hp) and 47 kW (64 hp). The difference in power is achieved mainly by the different cylinder heads with two and four valves per cylinder. 1.2-litre, 4-valve engine shown here.

The cylinder block and cylinder head are die-cast from aluminum alloy. The cylinder block has a joint with the crankcase along the crankshaft axis, and the seal in the joint plane is provided by liquid sealant. The crankshaft is installed in four main bearings with a joint in the same plane. The engine crankcase contains a balancing mechanism. It is designed to reduce vibrations occurring in the 3-cylinder engine and ensure smooth engine operation. The balancing mechanism is driven by two gears, one of which is located on the crankshaft. The balancing mechanism shaft rotates at the same frequency as the crankshaft, but in the opposite direction. The cylinder head is attached to the cylinder block with bolts.

The engine has two valves per cylinder (40 kW/55 hp) the camshaft is mounted in bearings, one half of which is in the cylinder head cover and the other half in the cylinder head.

The engine has four valves per cylinder (47 kW/64 hp) the intake and exhaust camshafts are located in their own housing. 4 bearing caps are bolted to the camshaft housing.

The valves are driven by camshafts via roller pressure levers, with one end of each lever resting on a hydraulic valve clearance compensator. The camshaft is driven from the crankshaft by a maintenance-free chain.





(The original material is available on the portal www.vwmanual.ru)