The Overhaul To Abnormal Sound Of Automotive Engine Valve

1. The percussion sound

When the engine is idling, there are continuous knocking sound between the end of valve stem and drive parts, enhanced with the speed increases, and when the engine temperature change or off the fire, the sound did not change.

Main reasons:

(1) adjusted valve clearance changes (the lock is not strong, the wear between the valve stem and the drive parts), the valve is not adjusted.

(2) The wear to valve screw; lock nut loose and valve clearance is too large or inconsistent.

(3) valve spring seat wear to the tank, the wear between valve stem and catheter is too larger.

Approach: re-adjust the valve clearance. The loose adjustment screw locknut should be securely locked, and replace the badly worn parts.

2. The leak sound

It is more obvious in the high-load and low-speed situation that valve outdoor sound enhanced with the load increases. The main reason are the improper operation and the over wear to bore of the valve guide when when reaming valve seat, which make the valve seat skewed or a small clearance, resulting in valve ablation to cause the valve lax and then leak sound.

Approach: Remove the cylinder head, grind valve, check valve spring stretch, re-adjust valve clearance.

3. The valve spring is broken and should be replaced.

4. Valve seat sound, seat retainer off

The rough surface of valve seat, substandard machining accuracy and the improper option to amount of interference make the valve seat loose. Improper selection in case of hot deformation make it too large, or the assembly craft of valve seat are undesirable.

Approach: In accordance with the requirements of the assembly craft, inlay the valve seat again, and make the above face and body plane flush.

At last, if you want to find some car diagnostic tools like Launch X431 Tool and nissan consult iii, you can go to visit www.vtoolshop.com.