1. Check whether the purchased assembly model matches the engine model.

2. After the product is unpacked, check the appearance of the assembly (cylinder liner, piston, piston ring, piston pin, etc.) to confirm that there is no quality problem, no accidental damage, no mixed or fake products before use.

3. Clean the assembly, test and compare it for trial installation (wet and dry cylinder liners are not suitable for trial installation with the body, and measure with a measuring tool if possible). Piston and cylinder liner, piston ring and cylinder liner and piston, piston pin and piston and connecting rod, cylinder liner and body.

4. It is strictly forbidden to apply oil when installing dry and wet cylinder liners, and install with toner. Clean the seat hole of the machine body to keep the seat hole accuracy without deformation and burrs. If the clearance between the cylinder liner and the body (generally not less than 0.015 mm) is too small, it is recommended to install the cylinder liner with cold shrinkage.

5. When installing the cylinder liner, special tools must be used to smoothly press and install, and no hard knock or rough installation is allowed to avoid deformation of the cylinder liner and damage to related parts.

6. The protruding amount of the cylinder liner and the plane of the body shall not exceed the specified value, and the excessively protruding cylinder liner is easy to be crushed by the cylinder head. If the plane of the cylinder liner and the body is too low, it is easy to cause the cylinder gasket to leak.

7. The deformed body should be repaired or replaced, and the deformed connecting rod or the damaged connecting rod bushing should be replaced.

8. The front and rear ends of the piston are distinguished, the piston ring cannot be installed reversely, and the upper and lower rings are separated. Generally, the piston ring is installed with the marked side facing the top of the piston. The compression clearance of the piston and cylinder head should be kept within the technical requirements of the model (generally kept above 0.30mm, except for micro engines).

9. When the piston and the piston pin hole are in interference or transition fit, to facilitate installation, the piston oil bath or boiling water can be heated, and the oiled piston pin can be pushed in in time after it is heated. Do not heat the piston with an open flame or hot flame.

10. Maintain the amount of free clearance between the piston pin retaining ring and the piston pin to prevent accidents caused by the expansion of the piston pin against the retaining ring.

11. The piston ring should rotate freely and flexibly in the ring groove without jamming, and the outer circular surface is generally not higher than the outer circular surface of the piston ring bank.

12. When installing the piston connecting rod set, clean the assembly first, and then apply clean lubricating oil (no oil is allowed on the top surface of the piston), stagger the piston ring ports (the first ring port should not face the fuel injector side), and set the ring The mouth is on the largest skirt of the piston (except for full skirt pistons). Note that the ring mouth should not be close to the side of the piston pin.

13. When replacing the assembly, pay attention to the inspection of the related parts: the crankshaft moves back and forth (less than 0.30 mm), the seal of the intake pipe, the cleaning of the sediment in the pipeline, the cleaning and replacement of the three filters, the atomization effect of the fuel nozzle, the fuel injection pump Whether the pressure meets the standard, etc.