Setting the piston of the first cylinder to TDC in the compression stroke is an essential part of the process of replacing pulleys and timing belt, as well as adjusting the valve clearance.
To set the piston to TDC, it is necessary to turn the crankshaft clockwise when looking at the engine from the toothed belt side. Turn the crankshaft with a wrench using the central bolt securing the pulley to the crankshaft.
Caution! Before setting the piston of the first cylinder to TDC, turn off the ignition and move the gearshift lever to the neutral position.
To set the piston of the first cylinder to TDC, follow the following order:
- disable the ignition system by disconnecting the electrical connector from the ignition unit;
- remove the spark plugs and install the compression tester tip into the spark plug hole of the first cylinder;
- 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. Continue turning the crankshaft until the mark on the vibration damper aligns with the TDC mark on the front cover (figure 3.1).
Figure 3.1. Aligning the mark on the vibration damper with the TDC mark on the front cover
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.