4.2.3. Reduction of the piston of the first cylinder in the provision of the top dead point (TDP)

The description of the procedure given below is made on the basis of the assumption of correctness of the VV installation of candle wires and the distributor of ignition. If there is a need of reduction of the engine for VMT for the purpose of updating of the provision of the distributor, position of the piston in the first cylinder of the engine can be qualitatively defined by tracking of change of compression pressure through a candle opening. Further it is necessary to achieve combination of the corresponding adjusting tags (see paragraph 9).


The Top Dead Point (TDP) is called the highest point of a piston stroke in the cylinder. Strictly speaking, in 4-stroke engines in the course of rotation of a bent shaft this situation is reached by each of pistons twice: once at the end of a step of compression and the second – at the end of a final step. During the performing of settings of phases of gas distribution and installation of a corner of an advancing of ignition VMT of the end of a step of compression of the piston is in most cases used (usually the first cylinder).

Need for reduction of the piston (it) in the provision of VMT arises when holding many procedures, in particular such as removal/installation of the camshaft, components of the GRM drive and distributor of ignition.

 PERFORMANCE ORDER

1. Make sure that transmission is transferred to neutral situation, then strongly cock the parking brake, or prop up back wheels of the car antiretractable boots.
2. Immobilize system of ignition, having disunited electric sockets of the distributor (see the Head Elektrooborudovaniye of the engine).
3. Temporarily put out of action a power supply system (see the Head of the Power supply system and release).
4. Remove spark plugs (see the Head Routine maintenance).
5. Reduction of any of pistons in the provision of VMT is made by a provorachivaniye of a bent shaft of the engine by one of the ways described below. If to look at the engine in front (from a driving belt), the direction counterclockwise will be the normal direction of rotation of a bent shaft. Remember that the attempt of a provorachivaniye of a shaft clockwise can lead to violation of adjustments of a gas-distributing belt.
   a) The most effective method is the shaft provorachivaniye in the normal direction for the bolt screwed in an end face of a forward pin by means of a face key with the ratchet drive;
   b) Use of the remote switch of a starter will allow to save time (follow instructions of manufacturers). As soon as the piston appears rather close from VMT of the end of a step of compression, the starter stops and further adjustment is carried out by the method described in point (a);
   c) In the presence of the assistant, the preliminary provorachivaniye of the engine can be carried out by short breakthroughs from the driver's place under the leadership of the operator. The same principle, as stated in point (b). Final adjustment, besides, is made manually, by means of a face key (see point and).
6. Remember position of the plug of connection of a candle wire of the first cylinder on a distributor cover. If the plug is not marked, walk on a wire from a candle to a cover and put the corresponding tag independently.
7. Uncover the distributor and put it aside (see the Head Routine maintenance).

8. Mark the case in a point directly under the plug of the first cylinder of a cover (see an accompanying illustration).

9. Find adjusting tags on a pulley of a bent shaft. The tag illuminated white corresponds to the provision of VMT. Now, turning a bent shaft in the normal direction (see paragraph 5), achieve exact combination of this tag with the index on the lower cover of a gas-distributing belt (see an accompanying illustration).

10. Now check position of the runner of the distributor – it has to be the developed nose precisely on a tag on the case. If the runner is deployed concerning a tag on 180 °, therefore, the piston of the first cylinder is in the provision of VMT of the end of a final step.
11. To bring the piston into VMT of the end of a step of compression, it is necessary to turn a bent shaft on one whole revolution (360 °) counterclockwise. Now the runner has to be deployed by a nose to a tag.
12. If all listed above conditions about combination of tags are met, the task can be considered executed, – the piston of the first cylinder is given to the provision of VMT of the end of a step of compression.
13. Now, that serially, as ignition to bring the remained pistons into VMT, it is necessary to put the corresponding tags on a distributor case rim (as it was done higher for the plug of connection of the first candle wire). Provorachivaniye of a bent shaft will be inevitably followed by rotation of the runner which combination of a nose with the corresponding tag and will be confirmation on reduction of the corresponding piston in VMT of the end of a step of compression.