Mandrel for piston pin pressing-in

In VAZ automobile engines, the piston pin must be pressed into the heated head of the connecting rod. The piston pin is pressed with interference of 0.04 mm. The design clearance of 0.01 mm shall be observed. At a temperature of 20 degrees Celsius, the finger should walk easily inside the piston. However, the piston pin should not fall out of the piston in the vertical position in the lubricated state. When pressing the piston pin, make sure that the piston is pressed tightly against the upper head of the connecting rod. The work must be carried out very quickly, because the connecting rod head is cooled very quickly, which, in the end, leads to the finger taking the wrong position and it will not be possible to change it. The operation should be carried out very quickly, since a rapidly cooling connecting rod can "grasp" the finger until it is fully pressed, and in a cooled connecting rod the position of the finger can no longer be changed. The accessory is designed to press the piston pin directly into the piston and into the upper head of the connecting rod. Technology of pin pressing (installation) with short mandrels. We put the piston on a wooden lining. We insert the heated head of the connecting rod between the piston bosses, holding it by the lower part with our hand in the sleeve. With the other hand, install the finger in the hole of the piston bosses and in the upper head of the connecting rod (insignificant force) so that the finger protrudes from the piston by 5... 7 mm. With a mandrel with an adjusted size A, we insert the finger completely. Sometimes you have to knock a little on the mandrel with a hammer. If the finger simply falls to the wooden lining, this in the vast majority of cases means that the connecting rod is unsuitable for finger represses. The calculated tension in the connection pin - the upper head of the connecting rod at the Zhiguli should be within 0,010... 0,042 mm. Do not forget about checking the connection of the pin - boss of the piston (design clearance 0,008... 0,016 mm).