Determining The Operating Cycle of Cylinder 1

Determining the operating cycle of cylinder 1

Information

Compression cycle for cylinder 1 (ignition TDC)

Information
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.





V8 spark plugs

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.





Ignition rod module of cylinder 1

3. Twist the crankshaft in the direction of motion until the ignition rod module comes out again with an audible plop.





Ignition rod module of cylinder 1 pops out

Information
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.





TDC marking of cylinder 1

Intake cycle (overlapping TDC)

Information
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.





V8 spark plugs

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.





Ignition rod module of cylinder 1

3. Twist the crankshaft in the direction of rotation until the ignition rod module comes out again with an audible plop.





Ignition rod module of cylinder 1 pops out

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.





TDC marking of cylinder 1

Information
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.





TDC marking of cylinder 1

Information

Determining the operating cycle of cylinder 1 with the "cylinder pipe" dead center finder.

Information
An alternative method for determining the overlapping TDC is the "cylinder pipe" (dead center finder). This tool is part of the pressure-loss tester.

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.





V8 spark plugs





Loosen spark plugs using spark plug wrench - V6

2. The dead center finder or "cylinder pipe" consists of a glass tube (inspection glass) with a piston -1-, hose and a rubber cone -2-.





Dead center finder - "cylinder pipe"

3. The rubber cone is pressed onto the spark plug hole. The inspection glass is either held by a helper or is secured vertically in a clearly visible position with a magnet.





Tool setup - dead center finder

4. If the engine is now turned in direction of rotation on the crankshaft, the piston in the inspection glass is pressed up in the compression cycle in order to go back down immediately upon reaching the TDC. The piston in the inspection glass stays down in overlapping TDC.





Piston up





Piston down