How to use the information in this chapter
This part of Chapter 2 describes the types of repairs that can be performed without removing the engine from the vehicle. In the event that the engine has already been removed and disassembled as described in part B, all previous disassembly operations can be ignored.
Keep in mind that although repairs to components such as the connecting rod and piston group can be performed without removing the engine from the vehicle, such procedures are usually not performed separately from other operations. Usually, by this time, other components and parts of the engine require replacement and repair (not counting the cleaning of parts and oil channels). Therefore, all such operations are classified as major repairs, and their content is disclosed in Chapter 2B.
Chapter 28 describes the operations for removing the engine from the vehicle and all repair procedures that can be performed after that.
Engine description
On all 4-cylinder engines, the camshaft is located at the top, in the cylinder head. The engine itself is installed longitudinally, a gearbox is bolted to its rear side. An engine of one of two models can be installed on the car. The M43TU 1.9L single camshaft engine was installed from the start of the Series 3 until 1998. Since 2001, the N42 engine with a displacement of 1.8 or 2.0 liters, and with two overhead camshafts, has been installed on all cars.
On the M43TU model, the single camshaft is driven from the crankshaft by a chain. The camshaft cams actuate the valves via hydraulically supported rocker arms. The camshaft is located in bores made directly in the cylinder head.
The N42 model has two camshafts that control 16 valves. The timing mechanism has an automatic valve timing control device, known as Valvetronic, which allows you to adjust the phases of both intake and exhaust valves. Phase change is achieved by hydraulic devices located between the camshafts and sprockets, which can change their relative position during engine operation. The design of the gas distribution mechanism also allows you to change the lift and duration of the open state of the intake valves using an electromechanical device that changes the position of the fulcrum of the lever located between the cam and the valve rocker.
The crankshaft has 5 main bearings with liners. The end play of the crankshaft is regulated by gaskets installed on the 4th or 5th main bearing (depending on the model). Both models of engines are equipped with two balancing shafts rotating in different directions.
Engine pistons are selected by weight. The pistons are connected to the upper heads of the connecting rods by floating fingers, secured against axial movement in the pistons by spring rings.
The oil pump is located in front of the cylinder block and is driven by the crankshaft.
Repair operations that can be performed without removing the engine from the car
The following operations can be performed without removing the engine from the vehicle:
- A) Removal and installation of the block head.
- b) Removal and installation of a timing chain and sprockets.
- V) Removal and installation of camshafts.
- G) Removal and installation of the pallet.
- d) Removal and installation of the lower heads of connecting rods, connecting rods and pistons *
- e) Removal and installation of the oil pump
- and) Replacing the power block supports
- h) Removal and installation of the flywheel / faceplate
* These procedures can be performed without removing the engine from the vehicle. However, for better access and cleanliness, they should be done after the engine has been removed.