How to Confirm The Piston Crown Clearance of Diesel Generator?

Many diesel generator set manufacturers have clear regulations on piston crown clearance. Excessive or insufficient clearance between the piston tips can cause abnormal operation of the diesel engine. Excessive top clearance can reduce the compression ratio, and diesel generators may experience insufficient power; If the top clearance is too small, there may be faults such as piston top valve. Therefore, the piston crown clearance cannot be changed arbitrarily.

Improper clearance between the piston tips of diesel generators. When assembling a diesel engine, if the clearance is not adjusted properly, it can affect the compression ratio of the diesel generator set, leading to piston cylinder pulling or piston burning. This requires that the diesel generator set be strictly adjusted according to the requirements during assembly.

(1) The meaning of piston crown clearance (also known as compression clearance). The cylinder head, cylinder liner, and piston together form the combustion chamber of a diesel engine. The size of the combustion chamber space determines the compression ratio of the diesel engine, which in turn directly affects the power and economic performance of the diesel engine. The so-called piston top clearance or compression clearance refers to the distance from the top of the piston to the bottom of the cylinder head.

Many diesel engine manufacturers have clear regulations on piston crown clearance. Excessive or insufficient clearance between the piston tips can cause abnormal operation of the diesel engine. Excessive top clearance can reduce the compression ratio, and diesel engines may experience issues such as insufficient power; If the top clearance is too small, there may be faults such as piston top valve. Therefore, the piston crown clearance cannot be changed arbitrarily. In actual use, if there is an incorrect gap between the piston crown, different cylinder gasket thicknesses can be selected for fine adjustment.

(2) Determination of piston crown clearance. The thickness of the cylinder gasket directly affects the size of the piston crown clearance (also known as compression clearance), which in turn affects the compression ratio. Therefore, before installing the cylinder head, it is necessary to accurately determine the thickness of the cylinder gasket according to technical requirements.

General testing methods. The general inspection method and steps for piston crown clearance are as follows:

1. Remove the cylinder head; 2. Take a few pieces of fuse with a diameter of about 3mm, evenly lay them (stick them with lubricating grease) on the piston crown, but avoid the valve position; 3. Install the cylinder head; 4. Tighten the cylinder head bolts in two or three times according to the specified sequence and torque; 5. Shake the crankshaft to rotate the piston past the top dead center: 6. Remove the cylinder head, take out the pressed fuse, measure its thickness, and calculate the average value, which is the piston top clearance of the cylinder.

Compare this value with the standard piston crown clearance of the diesel engine. If it does not meet the requirements, it can be adjusted by replacing the cylinder gasket with a different thickness.

Dingbo Power was founded in 1974 and is one of the earliest manufacturers of generators and diesel generator sets in China. If you want get more information, please feel free to send email to sales@dieselgeneratortech.com we will pay highly attention on your question.