Possible malfunctions of hydraulic tappets, their causes and methods of elimination
* The following are possible causes of increased noise in idle mode, increasing with increasing crankshaft speed up to 1500 min⁻¹ and not related to the operation of hydraulic tappets:
- increased clearances between valve stems and guide bushings;
- increased to a value exceeding the permissible value, misalignment of the valve and seat;
- non-parallelism of valve spring ends;
- greater than permissible runout of the valve head chamfer.