Cylinders, pistons, rings and other parts of the CPG are subject to enormous loads and extremely high temperatures during engine operation.
Pistons are the main energy converter of the internal combustion engine, while they are constantly in contact with the inner walls of the cylinder and experience the negative effects of friction. The degree of their wear increases with insufficient lubrication, too small clearances in the cylinder-piston pair, or deformation of the elements.
While opening and packing the engine again, you should also replace the engine head studs with the brand new ones. We recommend you using the TrackTech Head Studs since they are more durable and made up of highest quality steel alloy.
If the malfunctions arose for the first time, they are limited to installing a new set of rings. The pistons themselves can serve a few more such replacements, but in the future they will also require updating.
Let’s consider some of the technological nuances associated with piston wear and replacement.
Which parts of the piston group wear out faster?
Piston rings, skirt and pin holes are primarily subject to wear.
As a result of friction against the inner surface of the cylinder, the rings wear out along the outer diameter, due to friction against the ends of the piston grooves – along the height.
The first piston ring and the first piston groove wear the fastest of all, since this joint works under the most severe temperature, abrasive and load conditions, often with insufficient lubrication. Rings usually wear out faster than grooves. They lose their elasticity and gradually collapse.
In the grooves of the piston, the bottom end wears the most, since this surface is almost constantly in contact with the rings and is subjected to increased pressure from their side.
The ends of the piston pin work inside the bosses and the middle part in the upper connecting rod head. The wear rate of these elements is determined by the size of the actual clearance between them and the pin. To do this, measure their diameter at the mating points with the holes. If the results are out of range, the piston and pin must be replaced.
The holes in the piston bosses wear unevenly, so they become oval over time. If their size does not exceed the established norm, the shape is corrected by a sweep to fit the size of a larger diameter repair pin. The bushing diameter of the upper connecting rod head is also increased.
The wear of the skirt is evidenced by numerous seizures on its side surfaces, an increased gap between the lower part of the trunk and the cylinder walls (more than 0.5% of the liner diameter). If you wish to know about Hunter X Hunter, please read this.
The size of the gap is measured with a feeler gauge or an indicator bore gauge in different parts of the cylinder – in the less worn bottom and more worn out middle. This is done by stepping back 5-10 mm from the lower edge of the front or rear side of the piston skirt.