Talk:Piston ring

message: This was in the article.  Without more informatuion it isn't very useful so I moved it here RJFJR 17:22, 7 August 2007 (UTC)
thread_title: types

message: Text from the website of BECO, a piston ring manufacturer:
Piston Rings are subject to wear as they rub up and down the cylinder bore.  To minimize this, BECO Piston Rings are made of wear resistant materials (cast irons and steels) and coated or treated to enhance the wear resistance.  Typically top and oil control rings are coated with Chromium or Nitrided, possibly Plasma Sprayed or have a PVD (physical vapour deposit) Ceramic coating.  For enhanced scuff resistance and further improved wear most modern diesel engines will have top rings coated with a modified chromium coating.  The lower oil control ring is designed to leave a film of lubricating oil a few micrometres thick on the bore, as the piston descends.  Three piece oil ring, i.e. with two rails and one spacer, is used for gasoline engines.
Text from the section "Wear due to piston side-load"
Piston rings are subject to wear as they move up and down the cylinder bore. To minimize this, they are made of wear resistant materials such as cast iron and steel and coated or treated to enhance the wear resistance. Two-stroke port design is critical to ring life. Newer modern motorcycle manufacturer's have many single function but sererated port's to retain the ring. Typically, top ring and oil control rings will be coated with Chromium, or Nitrided-possibly plasma sprayed or have a PVD (physical vapour deposit) ceramic coating. For enhanced scuff resistance and further improved wear, most modern diesel engines have top rings coated with a modified chromium coating known as CKS, a patent coating from Goetze. The lower oil control ring is designed to leave a lubricating oil film, a few micrometres thick on the bore, as the piston descends. Three piece oil rings, i.e. with two rails and one spacer, are used for four-stroke gasoline engines.
A case of can you spot the difference? Also, there are parts of the secton that have horrible grammar, I'll try and fix it when I have some time to spare! :) Silica-gel (talk) 10:16, 5 February 2008 (UTC)
thread_title:  Copied text 

message: As I’m a newbie I’d rather not publish directly but instead put it here for more experienced editors to see if it is publish worthy.
From the article: 
"(Radial wear on ring face reduces thickness of used/worn ring (face wear in bore) essentially increasing face circumference of ring and thereby increasing size of ring end gap.)"
Isn’t it supposed to be 'decreasing face circumference of ring'? The gap is a result of the ring circumference being *shorter* then the bore circumference and as the ring wears out it gets shorter, i think.
Also IMHO, the explanation is lacking:
Since the circumference of the ring is a proportional to the square of the radius (i.e. the distance from the edge of the ring to the center of the cylinder), even a millimeter is wear will have a significant result. For example if the radius is 5 cm, 1 millimeter of wear will result in more then 3 centimeters of extra gap.  (5.0cm x 5.0cm x 3.1416 = 78.54cm, compared to 4.9cm x 4.9cm x 3.1416 = 75.43 cm).  —Preceding unsigned comment added by Hrneo (talk • contribs) 16:37, 14 November 2008 (UTC)
thread_title:  A mistake?