Analysis on the cause of valve abnormal noise in diesel generator set

When running a diesel generator set, it is often encountered with abnormal valve sound. The following features and solutions of abnormal valve sound are introduced:

(1) air leakage sound of valve
Valve leakage ring in the valve outside, evident in high load, low speed, noise enhanced with the increase of load, the main reason is that in the ream valve seat, due to improper operation or the valve guide hole wear ranks, the valve seat skewed or small valve clearance, lax the valve ablation caused valve is closed and a flat ring.
Treatment: remove the cylinder cover, grind the valve, check the spring spring of the valve, and readjust the valve clearance.

(2) the valve knocks loudly
When the engine is idle, there is continuous knocking sound between the end of the valve stem and its driving parts, which increases with the increase of the rotating speed. When the engine temperature changes or the fire breaks, the sound does not change.
Main reasons:
1. The adjusted valve clearance is changed (the lock is not secure, and the valve rod is worn between the drive parts), and the valve is not well adjusted.
Valve adjusting screw wear, lock nut loose, valve clearance too large or inconsistent.
The spring seat of the valve is worn into the groove, and the valve rod and conduit are badly worn.
Treatment: readjust the valve clearance. If the lock nut on the adjusting screw is loose, it should be locked and replaced with severely worn parts.

(3) the valve spring is broken and should be replaced.

(4) the valve seat rings and the seat ring falls off
The surface of valve seat ring is rough, the processing precision is not qualified, the improper selection and allocation of overfill volume of the seat ring causes loose and open, the improper selection of materials after heat deformation is too large, or the setting technology of valve seat is not up to the requirements.

Treatment: according to the requirements of assembly technology, the valve seat is re-mounted, the upper end face is flush with the body plane, and the upper part should be leveled.