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 2B describes the operations for removing the engine from the vehicle and all repair procedures that can be performed after that.
Engine description
General information
Six-cylinder engines M52TU and M54 with two camshafts located on top, in-line design. The engine is located longitudinally, the transmission is attached to the rear side of the engine. The difference between the engines is that on the M54 the throttle is fully electronically controlled, which is set to minimize atmospheric pollution.
The exhaust camshaft is driven by a chain from the crankshaft (primary circuit), and the intake - with another chain from the exhaust shaft (secondary circuit). Hydraulic tappets are installed between the cams and valves. Both shafts have seven bearings each, located in a cast housing, which is attached from above to the cylinder head.
The crankshaft also has seven main bearings of a conventional design with liners. The axial play of the crankshaft is limited by thrust bearings located on the 6th support.
Pistons are selected by weight. The upper head of the connecting rod is of a floating type, fixed from axial movements by spring rings.
The oil pump is driven by a chain from the crankshaft.
Valve timing regulators
All models are equipped with an automatic valve timing system known as VANOS. The VANOS system regulates the phases of both the intake and exhaust camshafts independently of each other and is part of the engine management system. The phase control system has a hydraulic actuator. powered by the engine lubrication system. The phases of the shafts are adjusted depending on the speed of the crankshaft, reducing the lead, i.e. opening the valves later, at low and high engine speeds. This improves the controllability of the engine at low speeds and increases power at high speeds. At medium engine speeds, the lead increases (those. valves open earlier), in order to increase torque and reduce exhaust emissions.
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 a head of cylinders.
- 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 of course 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.