The maintenance of the valve conduit of the diesel engine is as follows:
Valve seal is not tight enough to cause lubricating oil to penetrate into the cylinder, causing combustion chamber to burn oil.
Common causes of "tight seal" of diesel engine valve guide:
1 the reasons for the tight sealing of the valve guide are usually the failure of the hole of the catheter and the seat of the catheter, or the rough surface and the concave groove of the casting.
2 in addition, if the valve is hard knocking with a hand hammer in the installation of a valve guide, when the diesel engine works, the cylinder head is quickly heated by the expansion of the cylinder head, which is easy to cause the valve tube seat hole to be greatly heated, and the seal is not strictly sealed.
The maintenance methods of the valve conduit of the diesel engine are as follows:
Check the sealing method of the valve tube, first confirm that the cylinder does not move oil. At this time, remove the valve rocker arm and the rocker seat. In the concave hole of the valve spring seat, the clean gasoline is poured into the hole of the valve spring seat of the cylinder. The gasoline is temporarily condensed. Then the cylinder head is turned over. If there is a marked wet shape in the valve hole, it means that the seal is not strict. It should be overhauled or replaced.
The gap between the valve rod and the valve tube should not be too large. When the gap is more than 0.2mm, the valve tube should be replaced. The common method of checking the gap between the valve rod and the valve tube is to check the gap between the valve rod and the valve tube. It is about 15mm about the valve head off the plane of the cylinder head. The valve is close to the edge of the valve large head with the dial and then the valve is pushed back and forth with the hand direction. The reading of the meter is the gap between the valve stem and the valve guide.
The replacement of the valve guide should be carried out before the grinding valve seat. This is because the valve seat is processed according to the center line of the valve guide.
The valve tube of a diesel engine usually has two forms of inlet and exhaust valve. The difference is that the exhaust valve tube is extended to the inner wall of the exhaust pipe part and turning into a step. The purpose is to avoid the exhaust valve to be stuck in the tube after heat expansion.
The valve tube is in interference with the tube seat hole on the cylinder head. The interference amount is generally 0.009~0.046mm., so when replacing the catheter, it is necessary to use special tools and press. But many people often use the hammer hard knocking when installing the valve tube. In this way, when the diesel engine worker makes the cylinder cover because of the heat expansion, it is easy to make the valve tube. In the end, the valve tube will appear to move up and down in the catheter Kong Zhong. When the valve tube is displaced to the bottom, the valve head may crack the valve head when the valve closes quickly.
After pressing into the new valve tube, a simple method of checking the fit gap between the valve rod and the valve tube is to insert the valve rod into the valve tube, and the valve should be able to drop slowly under the effect of its own quality. When the valve is moved around the valve rod, there should be only a very small amount of sloshing, that is, the clearance is appropriate. If it is too tight, reamers can be reamed with reamers. The adjustable valve tube reamer can be selected according to the diameter of the valve rod to reaming the inner diameter of the valve tube. When reaming, the amount of reamer should not be too large, and the reamer should be vertical, and the side reaming should be matched until it meets the required clearance requirements. 495 diesel engine, for example, the standard value of the gap between the inlet and exhaust door and the conduit is 0.05~0.l Omm, the limit value must not be greater than 0.20mm.
