Setting the piston of the first cylinder to TDC on the compression stroke is an essential part of the process of replacing the pulleys and the timing chain, as well as adjusting the valve clearance.
Install the piston of the first cylinder at TDC in the following order:
- before setting the piston of the first cylinder to TDC, turn off the ignition and set the gear lever to the 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 as you look at the engine from the timing chain side. Turn the crankshaft with a key for the central bolt securing the pulley to the crankshaft;
- unscrew the spark plugs and install the tip of the compression tester in the hole for the spark plug of the first cylinder. The tip of the compression tester must be screwed into the hole for the candle and have a length of at least 150 mm;
- turn the crankshaft clockwise and when the piston of the first cylinder approaches TDC, the compression gauge will begin to show an increase in pressure in the cylinder;
Pic. 3.52. Alignment of the mark on the vibration damper with the TDC or 0 sign on the front cover of the chain
- continue turning the crankshaft until the mark on the vibration damper aligns with the TDC or 0 sign on the chain front cover (pic. 3.52).
If a compression gauge is not available, you can close the spark plug hole with your finger and, by increasing pressure when turning the crankshaft, determine when compression begins in the first cylinder. Next, continue to turn the crankshaft until the mark on the vibration damper aligns with the TDC or 0 sign on the chain front cover (see fig. 3.52).
After setting the piston of the first cylinder to TDC in the compression stroke, turning the crankshaft by 180°, you can set the remaining pistons to TDC in the sequence corresponding to the order of operation of the cylinders.