4.3.25. Installation of conrod and piston assemblies and check of size of working gaps in conrod bearings of a bent shaft

Try not to touch surfaces of new inserts barehanded in order to avoid undesirable contact of bearings with always with the traces of oil and chemically aggressive substances which are present at fingers.


 PERFORMANCE ORDER

1. Before installation of conrod and piston assemblies of a wall of cylinders have to be carefully wiped, from their upper edges traces of step wear are completely removed and it is chamfered. It is meant that the bent shaft is already installed on the regular place in the block.
2. Uncover the lower head of a rod of the piston of the first cylinder (be verified with the factory or put in the course of dismantle tags). Take inserts of the old bearing from a head of a rod and its cover and carefully wipe their beds pure неворсящейся with rags.
3. Wipe a back of a new top insert and put it to bed the bearing in a rod head. Track that the directing uvula of an insert got to a reciprocal flute in a rod. At all not to a zastukivayta an insert in a bed the hammer. Grease with nothing the bearing at this stage.
4. Wipe a back of the second insert and lay it in a cover of the lower head of a rod. Again track that the uvula got to a reciprocal groove. Do not apply any lubricant – extremely important that the interfaced surfaces of the bearing and a rod remained absolutely pure and dry.

5. Arrange piston rings locks as it is shown on an accompanying illustration.


Have no locks of rings to coaxially piston finger AT ALL, or perpendicular to its axis.


6. Pull on bolts of fastening of a cover of the lower head of a rod pieces of an old fuel hose for protection of a mirror of the cylinder and a neck of a bent shaft against casual damages to process of installation of conrod and piston assembly.
7. Grease the piston and piston rings with pure motive oil and put on the piston a tool mandrel for a staving of rings. Leave a skirt of the piston acting from a tool mandrel approximately on 6.4 mm for free gas station it in the cylinder. Rings have to be pressed out aflush with the forming surface of the piston.
8. Turn a bent shaft so that the neck of the first crank fell into NMT state. Oil motive a mirror of the first cylinder.

9. Having developed assembly by a tag in the form of deepening or an arrow on the piston bottom on the engine forward (see an accompanying illustration), accurately fill a rod in the first cylinder of the block. Bring a piston skirt to the cylinder, having densely pressed to the surface of the block bottom edge of a mandrel of the tool for a staving of rings.

10. Tap the upper edge of a mandrel for a guarantee of dense pressing it to the block on all perimeter of bottom edge.

11. Accurately tapping on the piston bottom with the wooden handle of the hammer (see an accompanying illustration), enter the piston in the cylinder, at the same time directing the lower head of a rod to a neck of a crank of a bent shaft. Piston rings can unexpectedly jump out from under a tool mandrel therefore constantly you watch density of its pressing to the block. Act without hurrying, at emergence of the slightest resistance immediately stop a piston zastukivaniye. Find out the reason of jamming and eliminate it. Do not make at all attempts to push the piston in the cylinder by force, – it can lead to its mechanical damage or destruction of piston rings.

Check of a working gap of the conrod bearing

 PERFORMANCE ORDER

1. After introduction of conrod and piston assembly to the engine, before final installation of a cover of the lower head of a rod, it is necessary to check a working gap of the conrod bearing of a bent shaft.

2. Cut off a piece of the calibrated plastic wire from the measuring Plastigage set, length width of an insert of the conrod bearing are slightly shorter, and lay it along the first conrod neck of a bent shaft, parallel to an axis of the last (see an accompanying illustration).

3. Wipe the surface of the bearing in a cover of the lower head of a rod, remove protective hoses from fixing bolts and establish a cover on a rod. Track that the tag on a cover was turned in the same party, as a tag on a rod.
4. Previously having oiled, screw nuts of fastening of a cover and tighten them with the required effort. In order to avoid jamming of a key, use a thin-walled face head. At emergence of signs of jamming of a key between a nut and a rod, slightly raise a head and continue tightening. Do not allow a provorachivaniye of a bent shaft in the course of tightening of fixture of a cover of the conrod bearing.

Do not allow a provorachivaniye of a bent shaft in the course of implementation of all procedure.


5. Turn off nuts and carefully uncover a rod. Try not to damage the flattened-out piece of the calibrated wire.

6. On width of the flattened-out wire measured on the scale printed on packing to the Plastigage set (see an accompanying illustration), determine the size of a working gap in the bearing. Compare result of measurement to requirements of Specifications.

7. If the size of a gap exceeds the limit of admissible range before looking for inserts of other standard size, check whether got under backs enclosed in beds in a rod and a cover of inserts dirt/oil. Once again measure diameter of a neck of a shaft. The wire flattening since one end more than from another speaks about existence of conicity of a neck.

Final installation of conrod and piston group

 PERFORMANCE ORDER

1. Carefully scratch out a nail or edge of an old credit card all traces of the calibrated wire from the surface of a neck and/or the bearing.
2. Make sure of absoluteness of purity of both bearing surfaces, then evenly grease them with a thin layer of molibdensoderzhashchy assembly motive lubricant. For ensuring access to a surface of the top insert it is necessary to push a little the piston in the cylinder, – do not forget to put on rod cover bolts protective hoses in order to avoid damage of a surface of a neck of a shaft. Try not to allow vyskakivaniye from the cylinder of piston rings.
3. Return a rod into place, having carefully put on it the lower head a neck of the crank, remove protective hoses from bolts, establish a cover and in two stages tighten fixing nuts with the required effort.
4. Repeat all procedure for the remained conrod and piston assemblies.
5. Do not miss the next important points from attention:
   a) You watch that on backs of inserts and their bed in rods and covers dirt did not get;
   b) You watch that each assembly was established in the cylinder (even in case of installation of new components as gaps of piston rings were adjusted to concrete cylinders);
   c) Pistons have to settle down a tag/arrow on the bottom on the engine forward (towards the GRM drive);
   d) Do not forget to oil before installation of assemblies motive mirrors of cylinders;
   e) Before final installation of covers of bearings after check of working gaps in the last do not forget to grease bearings.
6. Having finished installation of conrod and piston assemblies, check freedom of rotation of a bent shaft, having turned it several times manually.
7. In conclusion it is necessary to double-check an axial side play of a bent shaft (see Removal of conrod and piston assemblies).
8. Compare results of measurement of an axial side play to requirements of Specifications. If the side play was normal before dismantling of the engine and old conrod and piston assemblies are used, no surprises should be. In case of a side play size exit out of admissible limits after replacement of rods, the last need to be removed from the engine and to give to a workshop of car service for the corresponding machining.