Does scuff mark/discoloration affect the performance of a piston. These were ran on a dynao for several pull trying to get desired hp but was unable to achevie it thus the motor was torn apart after inspection one piston had some slight scuff/discoloration on the side skirt, will the affect the performance, can it be polished , or can it just be left alone? No scratches or scrapes just a mark/scuff about 1/4"X2.5" mark. Thanks for all the help.

 

The scuff mark isn't going to affect the performance of the piston if it's just on the skirt. What I would want to know is what caused the scuff mark. Assuming the mark is bad enough to suggest that it is dragging in the cylinder...is the cylinder true? What is the piston to wall clearance?

Those are what could affect performance because something is causing the piston to drag in the cylinder.

 

I'm buying in that condition will have the wrist pin checked before installing in my motor. Thanks for the quick response .

 

The scuff, is it bad enough to collapse the skirt. You will have to measure.
Overheating, not enough piston to wall clearance. piston pin to piston to tight.
You have measure the skirt compared to the others.

Gene