General information
1. Top Dead Center (TDC) is the highest point in the cylinder that the piston reaches during its forward motion during crankshaft rotation. Each piston reaches the TDC position at the end of the compression stroke and at the end of the exhaust stroke. It is usually considered that TDC corresponds to the position of the piston (usually cylinder #1) in the compression stroke.
2. When performing some procedures, a necessary condition is the engine position corresponding to TDC.
3. Piston and cylinder #1 are located on the right side of the engine. (Right and left sides are usually determined when viewed from the driver's seat.) The crankshaft rotates clockwise when viewed from the right side of the car.
Top dead center position
4. Remove all spark plugs (Chapter 1).
5. Disconnect both battery cables (see Chapter 5, paragraph 1) until you need to crank the engine.
6. Apply the parking brake. Put the transmission in neutral. Raise the front right side of the vehicle and support it on jack stands. Remove the wheel.
7. Remove the cover from under the right wing to access the crankshaft pulley and timing marks (see Fig. 4.7).
8. It is best to turn the crankshaft with a wrench by the bolt of its pulley. It can also be turned with the starter (when an assistant turns the ignition key or with the help of a remote starter switch) to a position close to TDC, and then manually turn it with a wrench. After using the starter, it must be turned off immediately.
9. On models produced before 05.1988, locate the two pairs of marks on the inner and outer rims of the pulley. In the case of normal crankshaft rotation (clockwise), the first pair of marks does not apply to the vehicles presented in this manual. When the second pair of marks is aligned with the rear edge of the protruding mark on the oil pan, this corresponds to TDC. Turn the crankshaft clockwise until the TDC marks are aligned. For greater accuracy, you can use a ruler so that it protrudes from the oil pan (see Fig. 4.9, a, b).
10. On models produced since 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 aligning the second mark on the crankshaft pulley with the mark on the crankcase, unscrew the plug from the TDC mark hole and insert a special pin (purchased from dealers) there. It is possible that you will have to slightly turn the crankshaft in one direction or another to do this.
11. Now cylinders #1 and #4 are at TDC and one of them has completed the compression stroke. Remove the cap from the engine oil filler neck. If the camshaft exhaust cam is directed to the rear of the car and slightly down, then you have found the desired position of the piston of cylinder #1. If the cam is horizontal and directed forward, turn the crankshaft one full turn clockwise so that the pulley marks are aligned again, and the cam is directed back and slightly down. In this position, the piston of cylinder #1 is at TDC in the compression stroke.
12. After setting the piston of cylinder No.1 to TDC, you can set TDC in other cylinders by turning the crankshaft 180° (at one time) and monitoring the firing order of the cylinders (see Technical Data).
13. The TDC position can also be determined by another method. To do this, remove the cylinder head cover (paragraph 5) and turn the crankshaft (clockwise - see paragraph 8) until the inlet valves of the corresponding cylinder open and immediately after that close again. Insert a wooden rod (about 150 mm long and about 6 mm in diameter) or something similar into the spark plug hole until it rests against the piston crown. Then slowly turn the crankshaft (make sure that the piston does not fall into the cylinder) until the rod stops rising. In this case, the piston is close to TDC on the compression stroke. Then 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 TDC position in this way. For a more accurate determination of TDC, you can find the middle point of the dead zone or use the method described in point 9.
15. On models produced from 05.1998, do not forget to remove the pin.