Chrome Moly Rings Break In

Chrome file fit ring sets are listed by bore diameter and list available over sizes.

Chrome moly rings break in.

The face of the top rings in these sets are electroplated with chromium to provide a surface that is resistant to abrasive wear. As far as moly rings go we use these in most street applications and plasma moly for most street strip race applications. But all top rings are cast iron either plain or ductile. 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.

If you want to go modern than plasma molly rings are the way to go. Moly rings do not take 1000 miles to seat. And the aterials typically used are cast iron moly chrome or ceramic. 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.

This goes way beyond just choosing the right break in oil although that s an excellent start. Most grey cast iron rings specify a 150 to 220 grit with 180 being what we recommend. Chrome has good resistance to scuff but does not exhibit moly s oil retention capabilities. Moly rings can be steel.

What s more they didn t handle detonation very well. If the block is honed correctly for the rings being used there is little to no ring break in. Recommended cylinder to piston clearance of 0015 thousandths per inch of bore works out to 0035 to 005 thousands. I have a hastings steel moly ring sitting on my desk in front of me right now.

The problem with many chrome faced rings was they were extremely hard and difficult to break in due to their hardness. The base material and design are the same as used in speed pro plasma moly ring sets only the face coating is changed. Plain cast iron is a durable wear surface in normal operating conditions and is less costly than the moly or chrome faced ring. 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.

As we ll see the process is somewhat specific and less than rewarding if you screw it up. Rings and honing procedures have come a long way since the old cast iron ring days. In fact molybdenum is quite a soft metal relative to other options like chrome nitrided steel chrome nitride pvd etc. Molly rings are not as picky and they are easier on the bore than chrome rings.

Moly has a very high resistance to scuff. When rings are discussed it usually concerns the top ring only. It is suggested you not.