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4.2.11. Check and adjustment of valvate gaps


Example of calculation of thickness of an adjusting washer

I \Inlet valve
Е — the Final valve
1 — the Measured gap
2 — the Difference between 1 and 3
3 — the Nominal gap
4 — Thickness of an original adjusting washer
5 — Thickness of the required new adjusting washer

Check

Importance of correctness of installation of valvate gaps cannot be overestimated in view of that impact which it exerts on efficiency of return and service life of the engine. Nevertheless, this check is not among procedures of routine maintenance of the car and has to be made only at emergence of excessive level of the noise published by the valvate mechanism and also in case of falling of the power developed by the engine. An inspection is carried out on the cold engine.

 PERFORMANCE ORDER

1. Cock the parking brake, then a front of the car and establish to a poddomkratta it on props. Remove the right forward wheel.
2. Working in front under the car, release clamps, turn out fixing bolts and remove a plastic cover from a wing cornice for the purpose of ensuring access to a bolt of a cogwheel of a bent shaft.
3. Now the engine can be turned for a bolt of a pulley of a bent shaft by means of a suitable face key with a collar.

It is much simpler to turn the engine at the turned-out nozzles or glow plugs.

4. Uncover a head of cylinders (see Removal and installation of a cover of a head of cylinders).
5. On the sheet of paper outline the scheme of an arrangement of cylinders, having numbered them in the appropriate order (including the first that which is located from the party of the engine turned to a flywheel). Specify locations of each of valves with reduction of the required value of size of a working gap. Over designation of each of valves draw two line for the purpose of drawing on them the gap (1) which is really taking place and sizes of necessary adjustment (2) (see the illustration Example of Calculation of Thickness of an Adjusting Washer).
6. Turn a bent shaft so that the inlet valve of the first cylinder was completely closed. The corresponding cam of the camshaft at the same time has to be developed by a working ledge from a pusher.

7. The probe of lezviyny type measure the size of the gap taking place between the basis of a cam and a face surface of a pusher (see an illustration 11.8 in Part A). Write down result of measurement over line (1) over designation of the corresponding valve on the scheme.

8. Repeat measurement for the remained seven valves, consistently turning a bent shaft for the purpose of reduction them in a closed position (see item 6). Apply results of measurements on the scheme.
9. Now define a difference between result of measurement and nominal rate of a working gap for each of valves. Apply results of calculations on the scheme over line (2) over designation of the corresponding valves. As nominal rates of working gaps for inlet and final valves are various, try not to allow confusions. The sequence of an arrangement of valves on both sides of the engine is identical and has the following order:
Inlet - Final - Final - Inlet - Inlet - Final - Final - Inlet
10. If all gaps lie within admissible ranges, establish into place a cover of a head of cylinders (see Removal and installation of a cover of a head of cylinders) and a plastic cover of a cornice of a wing. Establish the right forward wheel, then lower the car on the earth and tighten bolts of fastening of a wheel with the required effort.
11. In case of identification of inadmissible deviations it is necessary to make correction of valvate gaps (see further)

Adjustment

 PERFORMANCE ORDER

1. Remove the camshaft (see Removal, check of a state and installation of the camshaft and pushers of valves).
2. Take from the nest in a head the first pusher and remove an adjusting washer from a valve core end face. Remember that the washer can podlipnut to a pusher, - try not to drop it in the course of extraction of the last. Dry wipe a washer, having completely removed from it oil traces, then a micrometer measure thickness. Usually thickness of a washer is applied on its surface, however marking can not be true owing to wear of metal.
3. If the gap measured for this valve exceeds admissible value, it is necessary to pick up a washer of bigger thickness at a size applied on the scheme for this valve over line (2). If gap size, on the contrary, is excessively small, thickness of a washer has to be respectively reduced.
4. Carry out under designation of each of valves on the scheme three more lines (see the illustration Example of Calculation of Thickness of an Adjusting Washer). Over the line (4) inscribe result of measurement of thickness of the removed washer. Add to it (or subtract from it) the size inscribed over line (2) and write down result of calculation over line (5).
5. Washers are issued with thickness in the range from 2.225 mm to 3.550 mm with a step to 0.025 mm. Before installation the new washer should be wiped carefully.
6. Repeat the procedure described in subitem 2 — 4 for the remained valves. Try not to mix pushers.
7. Before installation oil adjusting washers pure motive and establish them on end faces of cores of the corresponding valves by marking down. After each of washers establish a pusher which also should be greased previously. After installation the pusher should not be taken any more from a head as it can lead to loss of a washer.
8. Having finished installation of components, return into place the camshaft (see Removal, check of a state and installation of the camshaft and pushers of valves). Before installation of a cover of a head of cylinders double-check valvate gaps.