Symptoms, causes and elimination of automobile timing gear rattling


Time:

2023-06-16

Gear timing noise is a kind of "cough, cough" rolling noise caused by poor gear fit or flaking, rough tooth surface. The timing gear meshing gap is too large, and the engine makes a slight "click, click" sound at idle speed.

Symptoms, causes and elimination of automobile timing gear rattling

Gear timing noise is a kind of "cough, cough" rolling noise caused by poor gear fit or flaking, rough tooth surface. The timing gear meshing gap is too large, and the engine makes a slight "click, click" sound at idle speed.

The noise is more obvious at medium speed and more chaotic at high speed. If the meshing gap of timing gear is too small, there will be a "whine" metal friction sound, and this sound will increase with the increase of engine speed.

When the timing gear is seriously worn, the above phenomenon will also occur. Touching the valve cover with your hand can obviously feel the body tremor, and your hand has a numb feeling.

[Causes of abnormal noise of timing gear]

The common causes of abnormal noise of timing gear are as follows:

(1) The lubricating oil road is blocked, resulting in poor lubrication of the timing gear, producing dry friction and abnormal noise; improper assembly or the gasket is too thin and the clearance is too small.

(2) During maintenance, the cam timing gear assembly is skewed and uneven, resulting in the tabs rubbing against the flange and making a sharp metallic noise.

(3) When the gear meshing clearance is too large and there is impact load, the tooth surfaces collide with each other to produce a strange sound.

(4) The timing gear processing accuracy is low, there is burr, or the tooth surface is spalling in use, the gear vice contact is poor; the timing gear and flange fixing bolt is loose, the gear axis moves, the shaft and hole center is offset, the gear meshes unevenly and oscillates. It makes irregular noise when running.

(5) The camshaft will be bent, deformed and loosened during use, destroying the parallelism of the timing gear pair and causing early wear and strange noise.