Piston head strain

Feature

Longitudinal pull marks on fire shores and ring shores, general ring bonding

Reason

1. Long-term overload operation.
2. Insufficient coolant and poor thermal conductivity.
3. Poor lubrication, such as oil below the standard surface of the oil pool.
4, the oil supply is not allowed, the injector is invalid.
5, the use of inferior fuel oil, the formation of too much carbon, so that the ring is stuck,
Causes the piston to overheat.
6. The air entering the cylinder is unclean and contains more impurities.
7. The piston cooling nozzle has failed.

Piston skirt strain

Feature

The skirt presents a torn longitudinal pull on one or both sides.

Reason

1. The body is deformed, and the connecting rod is bent to appear off-cylinder.
2. The failure of the cooling system causes the temperature to be too high or too low.
3. Improper assembly.
4, the running-in is not good, and directly carry out heavy work.
5. The lubricant is not properly selected or the lubrication system is faulty.
6, "three filters" failure, coarse abrasive particles inhaled into the cylinder resulting in scratches.
7, overload, speeding.
8. The abnormal combustion caused by the failure of the oil supply system causes the engine to overheat.

Piston four-point strain

Feature

Irregular scratches appear near the sides of the pin hole of the piston.

Reason

1. The heat dissipation system is faulty (if the thermostat is not installed, the temperature is too low).
2. Frequent cold start.
3, low temperature overspeed, overload exercise.
4, low temperature, low speed for a long time running.

Hot crack at the top of the piston

Feature

The edge of the combustion chamber is cracked in the radial direction.

Reason

1. Overload operation.
2, the oil supply is not allowed, the injector fails, causing local overheating.
3. Continuous alternating load.
4. Elements such as sulfur and antimony in inferior fuel oil cause high temperature corrosion and accelerate the formation of hot cracks.
5. The boost pressure is too high.

Piston ring melt loss

Feature

The bank is abnormally damaged and is melted

Reason

1. The high temperature and high pressure gas will break the ring, and the well will melt and damage the ring bank at the broken ring; the ring will move up and down in the ring groove, causing damage to the ring bank: in severe cases, the top surface of the ring will be broken, causing the cylinder to be pulled. Cylinder head and other phenomena.
2. The piston is biased to the side, and the other side of the ring is subjected to excessive force to cause breakage.

Top burn through

Feature

A breakdown hole appears in the combustion chamber.

Reason

1. Overload operation.

2. The oil supply is too large.
3. The falling of foreign objects.
4, work rent violence. If the fuel cetane number is too low, the injector fails, and the fuel injection is too early.

Piston pin hole break

Feature

The piston breaks down from the oil ring groove and breaks.

Reason

1, Abnormal impact, causing it to break at the weak oil ring groove.
2, poor lubrication, so that the engine occurs to hold the tile, burn the shaft phenomenon, the connecting rod will break it.
3. After the piston head holds the cylinder, the piston pin pulls it off.
4, the relevant components with large clearance, the impact of the reciprocating inertial force, causing fatigue fracture.
5, overload operation.
6, improper assembly.

Piston ring break

Feature

The fracture is in multiple stages and the fracture is irregular.

Reason

1. The oil supply is not allowed, the injector fails, causing high temperature and high pressure.
2. The components are out of balance or damaged, causing high frequency vibration.
3. Overload operation.
4. Improper assembly.
5. The cylinder sleeve is released or the ring groove is worn out, and the impact is repeated.

Early wear

Reason

1. The air filter fails and the filter element is unqualified.
2. Poor lubrication and poor quality of lubricating oil.
3, the oil supply is not allowed, the cylinder.
4, long-term low temperature operation.
5. Improper assembly.
6, not in accordance with the provisions of running-in, overspeed, overload work.
7. Use inferior fuel.

Engine crash cylinder

Feature

Engine related parts are abnormally damaged or broken.

Piston top surface and fire shore ablation

Feature

The fire shore and top surface are honeycomb or pear-shaped

Reason

1. improper adjustment of fuel supply advance angle
2. The injector failed, secondary injection and oil drop occurred, and the afterburning was severe.
3. The load is running.
4 Insufficient intake air.
5. Supercharger failure.
6. Intercooler is dirty

Circlip release

Feature

The end of the pin hole of the piston is melted,
There are pits of different depths on the inner wall of the cylinder liner.

Reason

1. Improper assembly.
2. The circlip deformation (exceeding the fatigue strength).
3. The quality of the circlip is unqualified.
4. The connecting rod is bent.

Skirt break

Feature

The piston is broken or cracked along the thrust surface.

Reason

1. The clearance between the cylinders is large and the cylinder is severe.
2. The connecting rod is severely bent.
3. Work is rude.
4, poor lubrication (such as oil pool oil and low).

Piston top valve

Feature

The top surface has an impression of a valve collision.

Reason

1. The phase of the valve is not allowed.
2. The valve clearance adjustment is too small.
3. The cylinder head gasket is too thin.
4. The connecting rod and the journal, the camshaft journal and the bearing bush are too large.
5. The valve spring is broken.

Piston top valve

Feature

The inner cavity is black red or red, often accompanied by a sticky ring, a head burning, pulling a cylinder, burning oil and the like.

Reason

1. The fuel supply is not allowed and the injector is invalid.
2. The piston cooling nozzle has failed.
3. Overload operation.

Ring break

Feature

The second ring bank is partially broken along the circumference.

Reason

1, the burning is not normal, the work is rude, leading to fatigue and fracture.
2, overload operation, excessive gas pressure to break the shore.
3, partial cylinder, partial sticky ring.
4. Abrasive wear increases the gap between the ring and the ring groove, the cylinder sleeve is released, and the reciprocating inertial force breaks the ring.

Piston eccentric wear

Feature

The piston wears asymmetrically, often accompanied by burning oil, pulling cylinders, and exhausting.

Reason

1. The body is deformed.
2. The connecting rod is bent or twisted.
3. Improper assembly.

Top color exception

Feature

The combustion chamber and the top surface are grayish white, accompanied by burning oil.

Reason

The fuel is not qualified.