Piston ring problems
 

I have a brand new Mahle P/C set.
During the preassembly of the engine for checking valve to piston clearense I discovered some bad marks at the barrels.
After some investigation we found out the middle ring made those black stripes.
The edge of the ring have some roughness who you can feel with the fingers.
Have been in touch with Mahle and they don't of this problem.
The have never heard of those problems before.
All the six rings are the same.
The ring gap is 0,35mm.
Has anyone had such problems?

http://forums.pelicanparts.com/uploa...1475332303.jpg


http://forums.pelicanparts.com/uploa...1475332342.jpg

Macro picture of the rings? Just curious what they look like where the roughness is.

I will try to take some macro pictures

Did you file the ring gaps? I recently found that the 2nd ring on a set of JE rings developed a noticeable burr when I used my piston ring grinder and I had to dress each one with a small file to remove the sharp edges. The 2nd ring was much worse than the top rings.

No, I haven´t file the gap.
I will order a new set first to compare.
Have some thoughts about to try to use 1200 sandpaper

Are these nikasil /6 cylinders?
I seen these marks when new, but nikasil is hard as hell so as long as it's not deep (as in you can't feel them) it's OK and normal.
Nikasil is way harder than the rings.

Of course check to be sure.

ok il ask the question as i just don't know ..
when they sold you the p/c set did they provide the rings also or are they from a different provider. ? were they shipped to you assembled or did you do all that yourself ?

Those marks came after the pre assembly.

I guess the ring comes from another provider.
The rings came beside the piston in a plastic bag.
I did the ring assembly.
But I have bought Mahle P/C earlier where the ring where assembled.
I have a dialog with Mahle to figure out what we do next.

Just fyi my Mahle P&C came with rings assembled on pistons allready.....

My Mahle's were pistons only and they came with the rings installed.