How to identify the pros and cons of motorcycle pistons

In the absence of precision measuring instruments, only through observation and simple measurement to identify and judge. To this end, it is recommended that you from the following "seven" aspects to identify the pros and cons of motorcycle piston quality and authenticity.

First, the regular manufacturers of pistons generally used eutectic Al-Si alloy casting

Its aluminum piston hardness greater than 100HB (Brinell hardness), the tensile strength of 2450MPa or more. High-quality piston in the eutectic aluminum-silicon alloy composition of silicon content up to 13%, due to the thermal deformation of silicon is small, it has excellent thermal stability at high temperatures, but the high silicon content in the piston material, the piston processing Manufacturing process requires a relative increase.

Second, the formal requirements of the piston precision factory production is high

The top of the piston generally has group marks, usually groups A, B, C, and D, which are dimensional group marks of the skirt of the piston. In addition, the piston skirt also has a number of very fine groove, mainly used to store lubricating oil, to enhance the piston skirt lubrication. Defective pistons due to rough processing, it is impossible to go through such a sophisticated processing technology.

Quality goods piston skirt wall processing is very thin, the wall thickness. Support the caliper to measure the skirt skirt unilateral size, if the use of digital vernier caliper measurement, because of its high accuracy, the measurement results more accurate.

Third, the regular factory piston skirt cross section non-circular

The lower part of the piston ring groove (referring to the oil ring groove) to the bottom of the cylinder piston piston skirt, its role is when the piston reciprocating motion in the cylinder as a guide and bear the lateral pressure. Piston in the non-working state with its work in the force, under the heat is not the same. This is because the piston work will be subject to varying degrees of heat stress deformation.

Piston in working condition, due to stress and heat, along the direction of the piston pin piston deformation increases, while the deformation along the direction perpendicular to the piston pin is small.

Fourth, the formal factory head size slightly smaller than the skirt size

Regular manufacturers generally will piston head size (above the first piston ring position) intentional car small 0.25 ~ 0.35mm (such as: CB125T motorcycle piston diameter of 44mm, while the piston head is 43.5mm), mainly to To prevent the combustion chamber temperature increases, the piston head thermal expansion is too large, resulting in pull cylinder or cylinder. Therefore, the available vernier caliper or digital caliper to measure the first piston ring above the piston head size, if there is no margin of 0.40 ~ 0.60mm, is unqualified.

Fifth, the regular manufacturer of thick piston head

The piston head is generally thicker in order to increase the strength and rigidity of the piston and to reduce the thermal resistance of heat flow from the top of the piston to the piston ring so that heat passes from the top of the piston through the piston ring and the cylinder wall to the heat sink or cooling Liquid, which can effectively prevent the top of the piston temperature is too high.

Sixth, the regular manufacturer of piston ring groove width size more accurate

Generally matched with the matching piston ring thickness size to ensure that the piston ring in the piston ring groove with the appropriate fit clearance, the gap is called the ring backlash; and the depth of the ring groove and the piston ring is the piston ring back Gap, if the backlash is too small, will make the piston ring sluggish in the piston ring groove, backlash is too large, it is easy to channeling oil. Therefore, the piston ring groove manufacturing brought great difficulty.

Quality piston is a regular manufacturer of precision CNC lathe system, the depth and width of the piston ring groove control are more accurate.

Seven, pay attention to check the piston compression height

As each type of engine has a different compression ratio than the loaded heat load, the pistons with the same diameter differ in relevant dimensions. Among them, the piston compression height is an important part of the piston parts, it will affect the engine's compression ratio and ignition advance. Therefore, the replacement of the piston must be measured when the piston compression height.

    Qufu Golden Emperor Piston Co., Ltd. is located in the hometown of Confucius, the great thinker and educator in our country - Qufu, Shandong Province. It is a manufacturer with more than 40 years of experience in piston manufacturing, a key high-tech enterprise under the National Torch Plan and a national auto parts export base enterprise. Leading products for cars, diesel engines, motorcycles and general-purpose gasoline engine piston, the product variety of more than 1,000 species.