Timing Case
The following components are attached to the timing case of the X 20 DTL engine (see illustration G 1026):
- Front view of timing case
- Rear side of timing case cover
- Coolant pump
- Assembly aperture cover for injection pump sprocket
- TDC mark on timing case and torsional vibration damper
- Oil pump cover
- Oil pressure regulating valve
- Closure bolts (x 2) - required for manufacture
- Oil safety valve
- Duplex chain tensioner
Each individual component is described in detail in the following sections.
6.2.2 Timing Case
Timing Chains
The camshaft is driven by a two-stage chain drive system. The crankshaft drives the sprockets on the injection pump shaft via a duplex timing chain. A simplex timing chain leads from here to the camshaft. Correct chain tension is ensured by two hydraulic chain tensioners (maintenance-free). The timing chains are guided through two centrally supported tension rails and also through guide rails fastened on the tensioned side of the timing case.
| Number of teeth and links: | |
|---|---|
| Reinforced duplex sleeve-type chain | 78 links |
| Duplex crankshaft sprocket | 19 teeth |
| Duplex injection pump sprocket | 38 teeth |
| Strengthened simplex sleeve-type chain | 80 links |
| Simplex injection pump sprocket | 27 teeth |
| Simplex camshaft sprocket | 27 teeth |
Legend for illustration G 1027:
- Simplex chain tensioner
- Guide rails
- Duplex chain tensioner
- Tension rails
6.2.3 Timing Chains
6.2.3 Timing Chains
TDC Reference Points of the Individual Sprockets: (illustration G 1028):
- Duplex crankshaft sprocket connected to crankshaft by lock washer
- Duplex injection pump sprocket by hole pattern
- Simplex injection pump sprocket by arrow mark
- Simplex camshaft sprocket has a floating fastening
6.2.3 Timing Chains
Chain Tensioners
The two hydraulic chain tensioners are located in the cylinder head (for the simplex chain) and in the timing case (for the duplex chain). The chain tensioners share an identical design and function but have different dampening characteristics. The chain tensioners have different outer contours and diameters to ensure that they do not get confused on installation.
| I | Simplex chain tensioner | Diameter: | 17.95 mm |
|---|---|---|---|
| II | Duplex chain tensioner | Diameter: | 19.00 mm |
6.2.4 Chain Tensioner
- Simplex chain tensioner
- Duplex chain tensioner
6.2.4 Chain Tensioner
Design of Chain Tensioners (illustration G 1030):
- Simplex chain tensioner
- Duplex chain tensioner
- Closure bolt with seal ring
- Release pin
- Plunger with retaining ring
- Spring
- Casing
- High pressure ball valve
