Top dead center of cylinder #1

General information

1. Top Dead Center (TDC) - the highest point in the cylinder, which the piston reaches during its translational movement during the rotation of the crankshaft. Each piston reaches TDC at the end of the compression stroke and at the end of the exhaust stroke. It is generally accepted that TDC corresponds to the position of the piston (usually #1 cylinder) in the compression stroke.
2. When carrying out some procedures, the necessary condition is the position of the engine corresponding to TDC.

3. The piston and cylinder No. 1 are located on the right side of the engine. (Right and left side is usually determined when viewed from the driver's seat). The crankshaft rotates clockwise when viewed from the right side of the vehicle.

Top dead center position

4. Remove all spark plugs (Chapter 1).

5. Disconnect both battery wires (see chapter 5, paragraph 1) until you need to crank the engine over with the starter.

6. Apply the parking brake. Set transmission to neutral. Raise the front right side of the vehicle and place it on stands. Remove the wheel.

7. Remove the cover from under the right wing for access to the crankshaft pulley and timing marks (see fig. 4.7).



8. It is best to turn the crankshaft with a key on its pulley bolt. It can also be turned with a starter (when an assistant turns the ignition key or using the remote starter switch) to a position close to TDC, and then tighten manually with a key. After using the starter, it must be immediately disconnected.


9. On models prior to 05/1988, locate the two pairs of notches on the inner and outer pulley rims. In case of normal rotation of the crankshaft (clockwise) the first pair of marks does not apply to the vehicles shown in this manual. When the second pair of notches is aligned with the rear edge of the protruding mark on the pallet, then this corresponds to TDC. Turn the crankshaft clockwise until the TDC marks are aligned. For greater accuracy, you can use the ruler so that it protrudes from the pallet (see fig. 4.9, a, b).





10. On release models from 05.1988, the TDC mark in the form of a hole is located on the front side of the block (see fig. 4.10, a, b). When combining the second risk on the crankshaft pulley with the mark on the crankcase, unscrew the plug from the TDC mark hole and insert a special pin there (purchased from dealers). It is possible that for this you will have to slightly turn the crankshaft in one direction or another.






11. Cylinders 1 and 4 are now at TDC and one of them has completed its compression stroke. Remove the cap from the engine oil filler neck. If the exhaust camshaft lobe is pointing towards the rear of the vehicle and slightly down, then you have found the correct piston position for cylinder #1. With the cam horizontal and pointing forward, rotate the crankshaft one full turn clockwise so that the pulley notches line up again and the cam points back and slightly down. In this position, the piston of cylinder No. 1 is at TDC on the compression stroke.

12. After setting the piston of cylinder No. 1 to TDC, you can set the TDC in other cylinders by turning the crankshaft 180° (at once) and monitoring the order of operation of the cylinders (see technical data).

13. The TDC position can be determined by another method. To do this, remove the head cover (paragraph 5) and turn the crankshaft (clockwise - see point 8) until the intake valves of the corresponding cylinder open and immediately thereafter close again. Insert wooden rod (about 150 mm long and about 6 mm in diameter) or something like that into the spark plug hole until it stops in the piston crown. Then slowly turn the crankshaft (make sure that the piston does not fall into the cylinder) until the rod stops rising. The piston is near TDC on the compression stroke. After that, remove the rod.

14. TDC is located in the so-called "dead" zone. Passing through it, the piston rises, stops, and then begins to fall. Therefore, it is difficult to accurately determine the position of the TDC in this way. For a more accurate determination of the TDC, you can find the middle point of the dead zone or use the method described in paragraph 9.

15. On models from 05.1998, do not forget to remove the pin.