Hino s engine was weak after changing the cylinder head gasket

1. Cylinder wear and failure phenomenon.

There is a noticeable clicking knocking sound during the cold start, and the temperature increases, and the sound is weakened or disappears.

The cylinder pressure is low. Sometimes blue smoke is emitted from the exhaust pipe, and blue smoke is emitted from the oil port.

Reduced engine dynamics.

Increased fuel consumption. Fault diagnosis and elimination of cylinder wear.

Second, the wear law of the cylinder and its causes.

1) Cylinder wear law.

From the longitudinal section of the cylinder (along the axis of the cylinder): irregular "cone" or "cone" with large upper and lower size. Wear the most areas:

When the piston is located at the top dead center, the cylinder wall corresponding to the first piston ring, the upper mouth that the piston ring cannot touch is not worn, forming a "cylinder step". In special cases, the greatest wear of the cylinder is in the middle (waist drum shape). On the same engine, the wear of different cylinders is not the same, and the wear of the front wall of the first cylinder and the rear wall of the last cylinder of the water-cooled engine is more serious.

From the cylinder cross-section: uneven wear, worn into an irregular oval. The maximum wear part of each cylinder along the circumferential direction: generally the most wear of the cylinder wall near the opposite side of the intake valve.

2) Causes of cylinder wear.

Under normal conditions, the wear of the cylinder along the working surface in the piston ring movement area is an irregular cone with a large top and a small bottom along the height direction. The largest part of wear is the cylinder wall corresponding to the first piston ring when the piston is in the top dead center position. However, the upper mouth of the piston ring, which is not in contact with the cylinder wall, is almost not worn, resulting in a noticeable cylinder shoulder.

The reasons why the top is big and the bottom is small:

Mechanical wear: When the piston is located at the top dead center, the high-temperature gas burst pressure is the largest, resulting in the positive pressure of the piston ring on the cylinder wall increases, the friction also increases, the lubricating oil film is destroyed, and the cylinder wall wear corresponding to the first piston ring is the most serious.

Corrosion wear: organic acids and acidic oxides (dissolved in water to form mineral acids) from the combustion of gas mixtures. It has a corrosive effect on the surface of the cylinder, resulting in corrosion and wear. The upper part of the cylinder block cannot be completely covered by the lubricating oil film, and the corrosion effect is more serious.

Abrasive wear: Dust in the air, mechanical impurities in the lubricating oil, and abrasive debris in the engine enter the cylinder walls to cause abrasive wear. The dust in the air is sucked into the upper part of the cylinder, which has sharp edges and corners, so the upper part of the cylinder is also the most worn.

The reason for the waist drum shape: in areas with severe wind and sand, after a large amount of dust enters the cylinder, the abrasive wear is the most serious due to the maximum movement speed of the piston in the middle of the cylinder.

3. Cylinder wear fault diagnosis method.

Detection of faulty cylinder pressure.

Inspect cylinder diameter and cylindricity.

Hello, your question is that the Hino engine often punches the cylinder and dismantles the pad, what should I do? First, if the vehicle often flushes the cylinder head gasket, and the vehicle does not have high temperatures, you need to disassemble the cylinder head, check whether the flatness of the cylinder head and the cylinder block is out of toleranceSecond, if the flatness of the cylinder head or cylinder block is out of tolerance, you need to use special equipment to re-level the cylinder head and cylinder block Third, if the above has been operated, or often close and restart the cylinder gasket, then it is possible that the cylinder head is seriously deformed and the cylinder head needs to be replaced.

Hino engine often pulls cylinders after replacing the four matches, what is the reason?

Engine, cylinder and piston roof are among the more common failures. Engine cylinder pulling and piston roof burning mostly occur at the top of the piston and the first.

At the first and second piston ring grooves, the damage forms mainly include top surface melting, perforation, pitting, keyway-like notches and collapse around the top. The burning of the piston will lead to the blind high-temperature gas channeling into the crankcase, accelerate the oxidation and deterioration of lubrication, the cylinder sealing will deteriorate, the compression ratio will decrease, the fuel combustion process will deteriorate, and the power and economy of the engine will decrease. In severe cases, the piston cracks and breaks, damaging cylinder liners, connecting rods, crankshafts, body and other parts. According to the introduction of various types of engine cylinder pulling cylinder or piston roofing, the reasons for the blowing of the hollow motor cylinder and piston burning the top are roughly as follows:

1. The main factors that cause the engine cylinder and piston to burn out.

1. The cylinder head is deformed, but it does not exceed the maximum deformation and can be smoothed and continued to be used. This shows that this engine has been having high temperatures before.

Then it is possible that the cylinder wall is strained, and there is the following possibility: crankcase gas stringing, insufficient combustion chamber pressure, insufficient combustion and soot (black smoke), and the car will have no strength.

2. As for the high temperature, is the water tank bubbling? Water tank cover? I don't know how the car's electronic fan works?

The mixture is too strong I don't know if it's a gasoline engine or a diesel engine.

1. The camshaft and crankshaft must be calibrated at the same time.

2. There is a timing correction mark on the timing gear of the camshaft, and the marking corresponds to the timing correction mark on the cylinder head.

3. There is a timing calibration mark on the crankshaft timing gear, and the marking corresponds to the timing calibration mark on the cylinder block.

4. After the camshaft and crankshaft are calibrated, the timing transmission device is installed. After completion, the timing mark of the recheck cannot be misplaced.

5. Now the valve clearance of the engine adopts hydraulic valve tappet, which does not need to be adjusted.