Troubleshooting engine parts

You will need: a portable lamp, a set of planar probes, ruler, caliper, calipers, micrometer, scraper.

After disassembly carefully clean the parts with kerosene and blow dry them with compressed air (especially oil channels details).

1. Examine the block very carefully bearing crankshaft. Cracks in any field unit is not allowed.

2. Inspect the cylinders on both sides. Scratches, burrs and cracks are not allowed.

3. Determine the actual diameter of the cylinder bore gauge. The cylinder diameter is measured at three zones (Fig. 5.11). Each zone diameter was measured in two mutually perpendicular directions (longitudinal and transverse). In the area above the belt A (at a distance of 5 mm from the parting plane of the head unit) cylinders virtually wear. The difference in size in this zone and in the other zones can be judged on the wear of the cylinders. The nominal size of the cylinder 76,495-76,505 mm roundness and taper should not exceed 0.0065 mm. If the maximum wear of 0.15 mm or greater roundness exceeds the specified value, chisel cylinders to the next oversize pistons (an increase of 0.25 or 0.50 mm), leaving an allowance of 0.03 mm diameter by honing. Then othoninguyte cylinders, maintaining such a diameter that, in installation of the selected repair piston estimated clearance between it and the cylinder was 0.03 mm. Troubleshooting, boring and honing Block spend in the shops, have special equipment.

4. Check the surface flatness connector block with the cylinder head. Attach the caliper (or range) to the plane:

- In the middle of a block;

- In the transverse and longitudinal directions;

- Diagonally plane. Each position feeler gauge define a gap between the caliper and the plane. This will be the flatness. If the deviation exceeds 0.1 mm, replace the unit.

5. Clean carbon deposits from the bottom of the piston scraper (can be made from an old file).

6. Clean the grooves of a deposit under the old piston rings ring by inserting it into the groove of the outer side of the groove and rolling.

7. Inspect the pistons, connecting rods, covers: they must not be cracked.

10. Check flat probe clearance adjustment between the grooves in the piston rings and inserting a ring into the corresponding groove. Nominal (rated) clearance for both compression rings is 0.020 mm. If the ring is large in height and small gap, finish ring height to the desired value, polishing it with emery paper to spread out on a glass plate.

11. Check the feeler gauge backlash in the lock ring setting ring into the cylinder at a depth of about 50 mm.

The gap should be 0.3 mm for both compression rings and 0.4-1.4 mm for the oil scraper ring. If the gap is insufficient, SPIL butt surface of the ring. If the clearance exceeds the allowable, replace the ring.

12. All the pistons and the nominal oversize manufactured with high accuracy and do not require pre-sorting and selecting by mass. If necessary, you can set the individual cylinders previously used pistons, if they are in good condition. Balancing the engine in this case is not disturbed.

13. Measure the inner diameter of the bore gages Dv seat assembly with a rod cap.

14. Measure the caliper thickness T rod inserts.

15. Measure micrometer diameter DH crank pins.

16. Calculate the gap z between the connecting rod bearings and crankshaft journals using the formula z = Dv-2T-DH. Rated current gap of 0,019-0,070 mm. If the actual estimated clearance is less than the limit, it can be used again inserts have been installed. If the clearance is more than the limit, replace the liners on the necks of these new (nominal thickness).

If the crankshaft journals are worn out and reground to repair size, reduced by 0.25 mm, replace the pads repair (increased thickness).

Cervical grind besides having general wear if they have nicks or ovality and the risk of more than 0,004 mm and the taper - more than 0,005 mm.

17. Inspect the upper and lower main bearing shells. Inserts central (third) main bearing different from the rest of the width. In addition, their lateral ends formed wide fillets, playing the role of supporting half rings of the thrust bearing of the crankshaft. If the working surface of the inserts were risks bully, anti-friction layer peeling, replace with new pads.

If the crankshaft journals are worn out and reground to repair size with decreasing diameter of 0.25 mm, replace the pads repair (increased thickness).

Cervical grind besides having wear if they have nicks or ovality and the risk of more than 0,004 mm and the taper - more than 0.005 mm, reducing the diameter to 0.25 mm.

20. Check the parallelism of the thrust collars average radical neck if they are not parallel, the crankshaft is bent and must be replaced.

21. Rinse the channels of the crankshaft, which fill the radial channels petrol, pre-drowning them with one hand wooden plugs. Allow at least 20 minutes and flush the channels with gasoline, injecting him with a rubber bulb. Wooden covers after washing, remove the connecting channels. If necessary, repeat the washing to clean leaking gasoline.

22. Clean the surface of the piston pin from the varnish deposits, previously softened them in a solvent. Look at your fingers. If they found cracks, excessive wear in contact with the bosses of the piston and the traces of turning on the top head of a rod, replace your fingers.

Pairing the piston pin and piston check by inserting a pre-oiled finger into the hole of the piston boss. At an ambient temperature of 20 ?� C finger should enter the hole by pressing a thumb and not fall out of the boss in the upright position of the piston to the piston pin. Drop down from the boss the finger should be replaced by another. If your finger falls again, replace the piston with your finger.