Setting the piston of the first cylinder to TDC in the compression stroke is an essential part of the process of replacing the pulleys and timing chain, as well as adjusting the valve clearance.
To set the piston of the first cylinder to TDC, follow the following order:
- before setting the piston of the first cylinder to TDC, turn off the ignition and set the gear shift lever to neutral position;
- disable the ignition system by disconnecting the electrical connectors from the ignition coils;
- to set the piston to TDC, turn the crankshaft clockwise when looking at the engine from the side of the timing chain. Turn the crankshaft with a wrench using the central bolt securing the pulley to the crankshaft;
- remove the spark plugs and install the compression tester tip into the spark plug hole of the first cylinder. The compression tester tip must be screwed into the spark plug hole and have a length of at least 150 mm;
- turn the crankshaft clockwise and as the piston of the first cylinder approaches TDC, the compression gauge will begin to show an increase in pressure in the cylinder;
Figure 3.52. Aligning the mark on the vibration damper with the TDC or 0 mark on the front chain cover
- continue turning the crankshaft until the mark on the vibration damper aligns with the TDC or 0 mark on the front chain cover (figure 3.52).
If a compression gauge is not available, you can cover the spark plug hole with your finger and determine when compression begins in the first cylinder by the increase in pressure when turning the crankshaft. Continue turning the crankshaft until the mark on the vibration damper aligns with the TDC or 0 mark on the front chain cover (see Figure 3.52).
After setting the piston of the first cylinder to TDC in the compression stroke, by turning the crankshaft 180°, you can set the remaining pistons to TDC in the sequence corresponding to the order of cylinder operation.