Determining the Operating Cycle of Cylinder 1
Determining the operating cycle of cylinder 1Information
Determining the operating cycle of cylinder 1 with the "cylinder pipe" dead center finder.
ATTENTION Risk of damage to timing drive mechanism!
^ Never twist the crankshaft against the direction of rotation.
^ Remove and install the chain tensioner only in overlapping TDC.
^ Never twist the crankshaft when the chain tensioner is removed.
^ Never twist the camshafts when the chain tensioner is removed.
^ Never apply forces across the camshafts in the timing drive mechanism.
^ Always counter the sprocket wheels when performing assembly work on them.
^ Forces from the valve drive can cause the timing chain to jump over or tilt.
Note: An alternative method for determining the overlapping TDC is the "cylinder pipe" (dead center finder). This tool is part of the pressure-loss tester WE 1066, Workshop Installation Manual 3.1.4.
For some tasks, it is necessary to be familiar with the position of the piston in the cylinder (ignition TDC, overlapping TDC).
Ignition is off, ignition key is removed.
1. Remove spark plugs for the relevant cylinder 3.
2. The dead center finder or "cylinder pipe" consists of glass tubes (inspection glass) with pistons -1-, a hose and a rubber taper -2-.
3. The rubber taper is pressed onto the spark plug hole. The inspection glass is either held by an assistant Tool setup - dead center finder or secured vertically using a magnet so that it is clearly visible.
4. If the engine is then turned in the direction of rotation on the crankshaft, the piston in the inspection glass is pressed upward in the compression cycle Top piston, and moves back down again immediately once the TDC has been reached. The piston remains down in the inspection glass in the overlapping TDC Bottom piston.
Compression cycle for cylinder 1 (ignition TDC)
Note: This method only works in ignition rod modules that have rubber seals facing the spark-plug recess.
1. Remove spark plugs for the relevant cylinder 3.
2. Find ignition TDC of cylinder 1. To do this, insert the ignition rod module of the first cylinder into the corresponding opening in the valve cover and press in firmly.
3. Twist the crankshaft in the direction of motion until the ignition rod module comes out again with an audible plop.
Note: If the crankshaft is then turned through 180°, the piston in cylinder 1 will be located in the bottom dead center (BDC). The emission cycle then follows.
4. Then twist the crankshaft until the fixing bore on the crankshaft belt pulley is aligned with the bore in the timing case cover. The engine is now located in the ignition TDC of cylinder 1.
Intake cycle (overlapping TDC)
Note: This method only works in ignition rod modules that have rubber seals facing the spark-plug recess.
1. Remove spark plugs for the relevant cylinder 3.
2. Find overlapping TDC of cylinder 1. To do this, insert the ignition rod module of the first cylinder into the corresponding opening in the valve cover and press in firmly.
3. Twist the crankshaft in the direction of rotation until the ignition rod module comes out again with an audible plop.
4. Then twist the crankshaft until the fixing bore on the crankshaft belt pulley is aligned with the bore in the timing case cover. The engine is now located in the ignition TDC of cylinder 1.
Note: If the crankshaft is then turned through 180°, the piston in cylinder 1 will be located in the bottom dead center (BDC). The compression cycle then follows.
5. Remove the marking mandrel if necessary and twist the crankshaft through 360° in the direction of motion. The engine is now located in the overlapping TDC of cylinder 1.