Chrome Moly Rings Break In

Rings and honing procedures have come a long way since the old cast iron ring days.

Chrome moly rings break in.

Moly has a very high resistance to scuff. What s more they didn t handle detonation very well. Moly rings can be steel. But all top rings are cast iron either plain or ductile.

The problem with many chrome facings was that they were extremely hard and difficult to break in properly and often suffered from flaking or cracking when exposed to detonation. Recommended cylinder to piston clearance of 0015 thousandths per inch of bore works out to 0035 to 005 thousands. If the block is honed correctly for the rings being used there is little to no ring break in. In fact molybdenum is quite a soft metal relative to other options like chrome nitrided steel chrome nitride pvd etc.

The material that s referred to the ring facing or the portion of the ring that runs against the cylinder wall. Most grey cast iron rings specify a 150 to 220 grit with 180 being what we recommend. When rings are discussed it usually concerns the top ring only. Molly rings are not as picky and they are easier on the bore than chrome rings.

A great way to take full advantage of the 21st century engineering that goes into piston rings is optimize the break in ring seating procedure. Plain cast iron is a durable wear surface in normal operating conditions and is less costly than the moly or chrome faced ring. As far as moly rings go we use these in most street applications and plasma moly for most street strip race applications. Chrome faced rings were a popular option a few years back but now have also succumbed to progress and are rarely employed in modern performance engines.

This actually requires that during break in the ring come in contact with the cylinder wall. Chrome file fit ring sets are listed by bore diameter and list available over sizes. If you want to go modern than plasma molly rings are the way to go. I have a hastings steel moly ring sitting on my desk in front of me right now.

Prior to plasma molly rings the easiest on the cylinders were cast then molly after that and finally chrome rings that wear real well but are real hard on the cylinder because they are a harder. As we ll see the process is somewhat specific and less than rewarding if you screw it up. It is suggested you not. The base material and design are the same as used in speed pro plasma moly ring sets only the face coating is changed.

The face of the top rings in these sets are electroplated with chromium to provide a surface that is resistant to abrasive wear. The problem with many chrome faced rings was they were extremely hard and difficult to break in due to their hardness. And the aterials typically used are cast iron moly chrome or ceramic.