There are three areas where leakage can be reduced when it comes to piston rings; the ring end gap, around the groove and between the face and the cylinder wall.
Diamond Finish rings help reduce the path around the groove by sealing much better due to their smooth finish.
The smoother the ring surface, the less areas are available for high cylinder pressures to leak past the rings and into the crankcase. This effect, commonly referred to as blow-by, results in loss of efficiency in each cylinder effectively reducing the power of the engine. Total Seal’s Diamond Finish creates the smoothest finish of any piston ring, but to get a better idea of surface roughness, you need to think smaller. Very small
To really understand the importance of the surface of the ring, as well as that of the groove on the piston, you need to think microscopic. To help visualize the differences in ring surfaces, we’ll get help with Total Seal’s in-house profilometer. This advanced tool measures the peaks and valleys of any surface down to microns providing an up-close look at sealing deficiencies that can occur even on a well-built engine.
If you zoom in on the finish of a typical ductile iron piston ring, the surface looks like a sawtooth which results in leakage areas, albeit, tiny areas. When combustion pressures reach over 1500 psi, you can be sure those gasses are going to find any possible weak point and a standard ductile ring actually has many peaks and valleys forming leakage points. In the tests provided, you can see the results of a ductile iron ring compared to the surface of a Diamond Finish ring. Once you compare these variances next to each other, you really get an idea of how important the surface finish of the ring is for an effective seal.
Total Seal uses an advanced Profilometer to test and verify the surface roughness of our rings. This tool can measure variances in a surface down to 1-microm (one-millionth of a meter).
The peaks and valleys of this graph show the variances of a standard ductile iron ring surface measured in micrometers. Some measure +.1 spanning to -.2
The same test shows the difference of the Diamond Finish surface. The variance is much smoother over the width of the ring which equates to a much more efficient seal to the piston ring land.