The pistons and connecting rods

Withdrawal

Remove the cylinder head and oil pan.

Rotate the crankshaft and install the piston of the first cylinder in position of the bottom dead center (BDC).

If the top of the cylinder formed collar, it is necessary to remove scan or scraper, without damaging the cylinder wall. Education bead points to increased wear of the cylinder.

Remove the connecting rod cap bolts of the first cylinder. Remove the cover and remove the lower connecting rod bearings. If the liner is installed again, stick it with adhesive tape to remove the cover.

Hammer handle push the piston in the cylinder and remove it through the top of the cylinder. Remove the upper connecting rod bearing pad and stick it with tape to skim rods.

Put the lid on the rod and fix bolts to keep the old order of the assembly parts.

Repeat the operation, remove the connecting rods with pistons in the other cylinder.

Before checking piston rods to remove the pistons, piston rings and thoroughly clean the pistons.

To remove the piston rings from pistons unclench a ring and insert it evenly around the circumference of two or three old flat probe and slide it to the piston ring. Be careful not to scratch the piston ring ends. Rings are very fragile and can crack if they unclench too. Handle carefully with a sharp leading edge of the piston rings, so as not to cause injury. Hold each set together with the piston rings to re-install them to their seats.

Clean all traces of soot from the top of the piston.

Remove the carbon deposits from the piston ring grooves for using an old piston ring.

After removing the varnish, clean the piston rod solvent and wipe dry.

Carefully examine each plunger for cracks on a skirt and around the piston pin hole.

Check the pistons for wear holes in the skirt and head, as well as the absence of burnouts to the piston head.

Outbreaks pitting piston indicate that the combustion chamber are coolant. It is necessary to determine the cause of any liquid into the combustion chamber and fix it.

Determine clearance of the piston in the cylinder equal to half the difference between the diameters of the cylinder and the piston.

Check each connecting rod for wear, cracks and bending.

Rods do not usually need to be replaced, unless the motor is jammed.

Setting

Before installing the piston pin 2 (Fig. 3.2.48) piston 3 must be heated to a temperature of 60 ?� C.

Note the mounting position of the piston and the cylinder number in which it is installed.

Arrow on piston crown points to pulley belt.

Before installing the piston into the cylinder, piston rings it is necessary to tighten the belt tensioning clamp.

Measure the diameter of the piston.

Piston rings are arranged at an angle of 120 ?�.

Mark ?�TOP?� on the piston ring must be directed to the bottom of the piston.

Measure the end gap of the piston ring.

Check the clearance between the piston ring and the piston groove.

On the connecting rod and the connecting rod cap bear identification labels A, which must be located on one side.

On the connecting rod and connecting rod cap are made identification tides in determining the installation position of the connecting rod. The cylinders 1-3 tides identification must be placed on the part of the pulley, and the cylinders 4-6 - at the flywheel.

When assembling bolts 7 should be replaced with new ones.

Before screwing bolts oil the threads and bearing surface of the bolt heads.

During assembly, observe the correct mounting position of the connecting rod bearings.

Check the clearance in the lock of a piston ring

Insert ring into the corresponding cylinder and push the piston head to a depth of 15 mm, to prevent skewing of the ring as measured, then remove the piston. Measure the clearance probe (Fig. 3.2.49). If the clearance is excessive, replace the ring and repeat the procedure.

If the gap is too small (which is unlikely), it is best to choose a new ring with the regulatory gap in the castle. Otherwise, due to the closing of the rings with the engine there will be serious damage.

In an extreme case, the gap can be increased, neatly sawed ends of the lock ring with a thin needle files. To do this, hold down the needle file in a vice with soft sponges, get a ring so that the ends of the castle appeared on both sides Needle and slowly moving the ring, remove excess material. Keep in mind that the metal rings are very fragile and can easily break.

Check the clearance between the piston rings and the piston grooves

Check the clearance between the piston ring and the piston groove wall. To do this, insert the ring from the outside into the corresponding groove and feeler gauge to measure the gap between the top surface of the ring and the wall of the groove (Fig. 2.3.50). If the clearance exceeds the norm, even when a new ring, replace the piston.

Measure the diameter of the piston

Measure micrometer diameter of the piston in a plane perpendicular to the axis of the piston pin, at a distance of 10 mm from the bottom edge of the skirt of the piston (Fig. 2.3.51).

The value should be different from the nominal value of not more than 0.04 mm. If the wear exceeds the limit of the piston, the piston must be replaced.

Measure the diameter of the cylinder

Bore measured at three levels in the transverse and longitudinal directions. The clearance between the piston and the cylinder is defined as the difference between the measured diameter of the cylinder and the piston.

The deviation from the nominal diameter of the cylinder shall not exceed 0.08 mm.

When installing a new head with established camshafts contact cam surface of a camshaft and pushers of valves should be lubricated with engine oil.

Plastic caps to protect the open valves must not be removed before the installation of the cylinder head.

When replacing the cylinder head must be replaced coolant.

Before removing the cylinder head, ensure that all hoses, pipes and electric sockets are disconnected from it.

Cranks

The connecting rods do not require replacement except jamming of the motor or other serious damage. Check the condition of the connecting rods visually. Cranks, causing doubt, turn to the workshop for repair of engines for inspection and repair experienced specialist.

Replacing the rod is carried out only with the connecting rod cap.

Discontinued connecting rod bearings and connecting rods caps set necessarily in place.

Before removing check that the identification marks on the connecting rod and connecting rod cap. Coat the connecting rod cap numbers of the cylinders in which they are installed.

Radial clearance rod is verified as well as the radial clearance in the main bearing of the crankshaft, using a plastic rod Plastigage.