Some mixer drivers reported that the engine of the same mixer purchased at the same time with a friend would have problems after using the vehicle for a period of time, but the engine of the friend's vehicle was OK. What is the matter? Let's get to know.

1. 搅拌车的维修数据应用不当

1. improper application of maintenance data of mixer truck

在搅拌车维修中不能科学的选择维修数据是造成机件早期损坏的重要原因。比如气门与气门座接触面的宽度，规定进气门为1-2.2mm，排气门为1.5-2.5mm，但在实际维修当中，很多人认为宽一点比窄一点要好，习惯选用上限或接近上限值，因为刚修好的车气门工作面宽度就已经接近使用极限了。再比如气门脚间隙，一般车辆规定为0.2-0.25mm，但在维护调整中也会认为间隙大一点比小一点好，因此，超上限使用，实际上间隙过大，不但降低发动机功率，还会出现敲击声而早期损坏。

The failure to scientifically select maintenance data in the maintenance of mixer truck is an important reason for the early damage of mechanical parts. For example, the width of the contact surface between the valve and the valve seat is specified as 1-2.2mm for the inlet valve and 1.5-2.5mm for the exhaust valve. However, in the actual maintenance, many people think that it is better to be a little wider than a little narrower. They are used to selecting the upper limit or close to the upper limit, because the width of the valve working surface just repaired is close to the service limit. Another example is the valve foot clearance, which is generally 0.2-0.25mm for vehicles, but it is also considered that a larger clearance is better than a smaller clearance in maintenance and adjustment. Therefore, when the upper limit is exceeded, in fact, the clearance is too large, which not only reduces the engine power, but also causes knocking and early damage.

2. 气门的光磨

2. smooth grinding of valve

在搅拌车的维修中，如果气门出现烧蚀、麻点及凹陷时，均应进行光磨，一般是在光磨机上进行，作业时需要注意四个问题：一是保证气门头与杆部同心，否则应先校直；二是光磨辆在能磨出完整的锥面的前提下是越小越好；三是尽量提高表面光洁度；四是气门杆端部凹陷应予以磨平。

During the maintenance of the mixer truck, if the valve is ablated, pitted or sunken, it should be polished, usually on the grinder. Four problems should be paid attention to during the operation: first, ensure that the valve head is concentric with the rod, 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 shall be ground flat.

3. 气门导管的铰销

3. hinge pin of valve guide

气门杆与气门导管配合间隙是决定气门导管使用寿命的关键，因此当更换新的气门导管时，铰销时应严格掌握好配合间隙，使用各搅拌车车型规定间隙的下限，可有效延长使用寿命。

The fit 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 fit clearance shall be strictly controlled during hinge pin. The lower limit of the clearance shall be specified for each mixer model to effectively extend the service life.

4. 气门的研磨

4. grinding of valve

气门的研磨分为两种情况：一是气门与气门座只有轻微麻点，不需要光磨和铰销时的研磨；二是气门与气门座均经过光磨和铰销后的研磨。前者先用足金钢砂研磨，将麻点研磨掉后，再用细金刚砂研磨，后涂上机油研磨，直至密封符合要求，宽度符合规定为止。后者只有密封性达不到要求时才进行研磨，但操作时一定要注意，不要过分用力，严禁将气门上下敲打，否则将出现凹形砂痕，影响维修质量。

The grinding of valve can be divided into two cases: one is that the valve and valve seat have only slight pitting, and there is no need for smooth grinding and grinding when hinge pin is used; Second, the valve and valve seat are polished and polished after hinge pin. The former shall be ground with full gold steel sand first, and then with fine emery after the pitting is removed, and then coated with engine oil for grinding until the sealing meets the requirements and the width meets the requirements. The latter shall be grinded only when the sealing performance fails to meet the requirements, but 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, affecting the maintenance quality.

混凝土搅拌车发动机出故障不可怕，可怕的是维修不正确，那发动机的性能只会越来越差。搅拌车价格实惠，现在购买正合适。

The engine failure of concrete mixer truck 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. The mixer truck is affordable. Now it's right to buy it.

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The wonderful contents of this article are provided by the knowledge of the automatic feeding mixer. There are many wonderful contents on this website. You can click to enter more contents / We have special customer service to answer your questions