|
1. Before to begin survey, it is necessary to clear assemblages of pistons/rods and to remove from them piston rings.
|
|
2. Accurately unclench rings and remove them from the piston bottom. Use two-three old probeа not to allow to rings to drop in in already empty flutes (address to an accompanying illustration). Pay attention, маслосъемное the ring consists of two parts. |
3. Clean off from the bottom of the piston the basic deposit. Then smooth out its wire brush or small наждачной a skin.
4. Remove a deposit from flutes under piston rings, using a fragment of an old ring (break an old ring half-and-half, working cautiously not to cut fingers). Be attentive, do not remove together with a deposit metal and do not scratch a wall of flutes.
5. After deposit removal clear assemblage of the piston/rod by kerosene or suitable solvent and carefully dry up it. Be convinced that returnable lubricant apertures in ring flutes are not hammered.
6. If pistons and walls of cylinders are not damaged and not worn out and if the block of cylinders does not require a repoint, it is possible to establish old pistons. Normal deterioration of the piston is shown in uniform vertically deterioration of surfaces of its axial pressure and small люфте the top ring in a flute. At engine assemblage piston rings should be necessarily replaced.
7. Attentively examine each piston on presence of cracks on a skirt, round apertures under a piston finger and between flutes under rings.
8. Examine a piston skirt on presence of damages, and the piston bottom - on formation of apertures and an edge burn-out. If the skirt has scratches or notches, or on the piston bottom deepenings or the burnt sites, the engine, probably were formed, overheated and-or there was a wrong combustion (the proportion of a fuel mix or the moment of injection/moment of ignition have been incorrectly adjusted). Carefully check up cooling and greasing systems. The burnt through places on the parties of pistons show that there was a break of gases. If any of the damages set forth above was found out, will establish the reasons and eliminate them, differently damages will occur again. On petrol engines leak of entrance air, wrong adjustment fuel / an air mix or a wrong corner of an advancing of ignition can be the reason. On diesel engines - the wrong moment of injection of the fuel pump or a defective atomizer.
9. Piston corrosion specifies that the cooling liquid has filtered into the chamber of combustion and-or картер. Will establish the reason of leak and eliminate it.
10. If new rings on old pistons are established, measure a backlash between a ring and a flute wall, having inserted a new ring into a flute and measuring a backlash probeом. Check up a backlash in three-four places round each flute. Any concrete given by the manufacturer it is not defined, but if the measured backlash is more than 0.10 mm, be required new pistons. If the new ring enters into a flute too hardly, it most likely because of the dirt which has remained in a flute.
|
|
11a. Check up a backlash between pistons and walls of cylinders/sleeves, measuring internal diameter of a sleeve or the cylinder (address to Section Removal and installation of an intermediate shaft) and diameter of the piston. Measure diameter of the piston on a skirt to perpendicularly piston finger (address to illustrations). Subtract diameter of the piston from diameter of the cylinder/sleeve and receive a backlash. If it is more than the data resulted in Specifications, the block of cylinders it is necessary to chisel and establish new pistons and rings. On engines E7J, new pistons and sleeves are delivered by co-ordinated steams. |
|
|
11b. The label of diameter is noted on the piston bottom. |
|
|
12a. Check up installation of a piston finger, twisting the piston and a rod in counter directions. If is available люфт, it specifies in excessive deterioration and pistons and rods it is necessary to divide (engines K7M and E7J). It it is necessary to charge HUNDRED Renault or to the expert in an engine partition. |
|
|
12b. Notice that on diesel engines and petrol engines F3R and F7R piston fingers are fixed by blocking rings. Notice an arrangement of the piston concerning a rod (address to illustrations). |
|
|
13a. Before ring installation on the piston check up backlashes of cuts (address to illustrations). |
|
|
13b. Any given by the manufacturer it is not defined, but it is roughly possible to use following values: 0.50 mm for компрессионных rings and hardly are more - for маслосъемных than rings. In rings Renault to regulate a backlash it is impossible. |
|
