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Checking the connecting rod and piston assembly
Before checking their condition connecting rod and piston assembly should be thoroughly cleaned and removed from the old piston rings.  | When assembling the engine replacement piston rings is made without fail. |
| - Using a special tool, carefully remove the rings from the piston. Try not to damage in the course of this procedure the surface of the piston.
- Scrape the traces of soot from the bottom of the piston. After removal of the base layer of soot scraper remaining traces can be removed by hand wire brush or fine sandpaper. In no case do not use for this purpose on the electric wire nozzle. The pistons are made of soft material and its surface can be easily damaged.
- Using a special tool for cleaning grooves for installation of piston rings, remove the traces of these coal deposits. In the absence of a special tool available for this purpose is perfect chip of the old piston ring. At the same time, be careful - do not scrape off the material, and do not damage the piston groove walls. Also, keep your finger - the ring has very sharp edges.
 | - The grooves for the installation of the piston rings can be cleaned by a special tool, as shown in this photograph, ..
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 | ... or by using fragments of old piston ring - take care of your fingers.
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- After removing sediment flush connecting rod and piston assembly with solvent and dry them with compressed air (if you have access to its source). Make cross and clean maslovozvratnyh hole in the rear grooves for the piston rings.
- If the pistons and cylinder mirrors do not have serious damage and worn out within acceptable limits, and the engine block is not echoed in the groove, the need to replace the pistons no. Normal wear pistons shown in the form of uniform wiping its abutment surfaces in the vertical direction and light slack fit in its top piston ring groove. However, the replacement piston rings on rebuilt engine should be made mandatory.
- Carefully check each piston for cracks in a skirt in the lugs under the piston pins and rings in the area of installation.
- Make sure there are no scratches and scuffing on the thrust surfaces of skirts, holes in the bottom of the piston and burnouts their edges. The presence of such defects on the skirts of the pistons indicates engine overheating, which may have occurred during the operation of the vehicle and / or improper combustion of the mixture causes excessive temperature rise. These pistons must be replaced. You should carefully check the status of system components lubrication and cooling. Holes in the bottom of the piston can be an indication of improper ignition mixture (too early ignition). Burnouts edges of the piston head is usually talking about a mixture of detonation occurred. In the event that any of the defects of their causes must be eliminated in order to avoid recurrence of the operation of the restored engine. The reasons may include an intake air leak, poor quality fuel mixture setup violation of the ignition timing and the failure of the exhaust gas recirculation (EGR).
- Corrosion of the piston if it appears in the form of small cavities, said contact of the coolant in the combustion chamber and / or the crankcase. The reason again to be eliminated in order to avoid relapse.
- Measure the backlash of piston rings, alternately putting rings in their grooves with blade (s) of the probe. The measurement is performed at several points around the perimeter of the piston and watch over the compliance of the audited ring groove.
 | - Measure the lateral gap of the piston ring in several points of the perimeter of the piston by means of a blade-type probe.
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- Determine the clearance between the piston and cylinder wall by measuring the diameters of the first cylinder (Section Checking the engine block) and then the diameters of the pistons. Make according to the size of its piston cylinders. The diameter of the piston skirt on the measure in the directions perpendicular and parallel to the axis of the piston pin. Subtract the piston diameter of the diameters of the respective cylinders to determine the gap (backlash). If calculation results exceed allowable by the Specification values, the block must be delivered into the bore and the pistons and piston rings are replaced with appropriate repair size.
 | - Measure the diameter of the piston at an angle of 90 ?� to the piston pin and parallel to it.
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- Check the slack fit of the piston on the connecting rod, trying povraschat them relative to each other in opposite directions. Any appreciable gap indicates excessive wear and required to remedy the situation. All work related to the replacement of pistons and rods and installation of new piston pins are the prerogative of specialists Car workshop.
- If you want to make a withdrawal from the piston rods for any reason, this work should produce a specialist workshop. In parallel, there will be checked for signs of rods bending and twisting with the help of special equipment.
| If the product does not require replacement of pistons and connecting rods, disconnect them from each other should not be. |
- Check cranks for cracks and other damage. Temporarily remove the cover of the lower head (rod bearing), remove the pads, wipe the surface of the bearing caps and connecting rods in and inspect for burrs, scuffing and scratching. After inspecting the rods replace the old pads, attach the bearing caps and tighten securing nuts by hand.
| If the recovery engine is because knocking rods, be sure to replace them. |
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