一些攪拌車司機反映，跟朋友同時購買的同一款攪拌車，自己的車輛在使用一段時間后發動機就會出現問題，可是朋友的車輛發動機卻沒事，這到底是怎么一回事呢？一起來了解一下吧。

Some mixer truck drivers reported that the same mixer truck they bought with their friends would have problems with the engine of their own vehicle after a period of use, but the engine of their friends' vehicle was OK. What is the matter? Let's learn about it.

1、氣門的光磨

1. Smooth grinding of valve

在小型混凝土攪拌車的維修中，如果氣門出現燒蝕、麻點及凹陷時，均應進行光磨，一般是在光磨機上進行，作業時需要注意四個問題：一是保證氣門頭與桿部同心，否則應先校直；二是光磨輛在能磨出完整的錐面的前提下是越小越好；三是盡量提高表面光潔度；四是氣門桿端部凹陷應予以磨平。

In the maintenance of small concrete mixer truck, if the valve is ablated, pitted and dented, it should be polished, generally on the polishing mill. Four problems should be paid attention to during the operation: first, ensure that the valve head and the rod are concentric, otherwise it should be straightened first; Second, on the premise that the smooth grinding vehicle can grind a complete cone, the smaller the better; Third, try to improve the surface finish; Fourth, the depression at the end of the valve stem should be polished.

2、氣門導管的鉸銷

2. Hinge pin of valve guide

氣門桿與氣門導管配合間隙是決定氣門導管使用壽命的關鍵，因此當更換新的氣門導管時，鉸銷時應嚴格掌握好配合間隙，使用各攪拌車車型規定間隙的下限，可有效延長使用壽命。

The fitting clearance between the valve stem and the valve guide is the key to determine the service life of the valve guide. Therefore, when replacing the new valve guide, the fitting clearance shall be strictly controlled during the hinge pin. The lower limit of the clearance specified by each mixer truck model can effectively extend the service life.

3、氣門的研磨

3. Grinding of valves

氣門的研磨分為兩種情況：一是氣門與氣門座只有輕微麻點，不需要光磨和鉸銷時的研磨；二是氣門與氣門座均經過光磨和鉸銷后的研磨。

The grinding of valves can be divided into two situations: first, the valve and valve seat have only slight pockmarks, which do not require polishing and grinding when hinge pins are used; Second, the valve and valve seat are polished after polishing and hinge pin grinding.

前者先用足金鋼砂研磨，將麻點研磨掉后，再用細金剛砂研磨，后涂上機油研磨，直至密封符合要求，寬度符合規定為止。后者只有密封性達不到要求時才進行研磨，但操作時一定要注意，不要過分用力，嚴禁將氣門上下敲打，否則將出現凹形砂痕，影響維修質量。

The former shall be grinded with full gold steel sand first, and then the pockmarks shall be grinded with fine carborundum, and then coated with engine oil until the sealing meets the requirements and the width meets the requirements. The latter can only be grinded when the sealing property fails to meet the requirements. However, attention must be paid during operation to avoid excessive force. It is strictly prohibited to knock the valve up and down, otherwise concave sand marks will appear, which will affect the maintenance quality.

混凝土攪拌車發動機出故障不可怕，可怕的是維修不正確，那發動機的性能只會越來越差。

The failure of the concrete mixer engine is not terrible, but the terrible thing is that the maintenance is not correct, and the performance of the engine will only get worse and worse.