When fitting new piston rings it's worth,"Honing" the cylinder.I use a tool the same as in this video,
http://www.youtube.com/watch?v=oUwC019Ll1A
This is to de-glaze the cylinder walls and make a controlled rough surface for the new rings to,"Bite" into the metal and form a better seal on,"Running-in".
As per the video you should not have too high or slow RPM on the drill and try and time the in-out movements evenly and NEVER stop at one point inside the cylinder.
We are aiming for a 45 Deg cross pattern.You only need to ream in and out between 10 and 15 times max on a cylinder that has no deep scores.
If the cylinder has deep scores then only a re-bore or liners re-bored will fix it.
Fitting new rings:
You will need a Piston ring compressor like this,
http://www.machinemart.co.uk/shop/produ ... compressor
Available on eBay etc as well.
The Piston rings will have a very tiny,"N" on the topside surface.You may need to use a magnifying glass to see it.This tells the installer to fit ,"This Side Up" towards the top of the piston crown.
Looking at the top of the piston as a,"Clock Face" with the two wrist pin(little end)holes at 9'o'clock and 3'o'clock the two piston rings should be fitted with their gaps at 8'Oclock and 4'o'clock opposite about 120 Deg from each other.The scraper ring can be fitted so it's gap is at 6'o'clock.
This configuration is important to allow the best possible gas and oil seal from the rings.
