Chrome Moly Rings

Modern engine with moly rings and proper plateau finishes on the bores are for all practical purposes broken in within a.

Chrome moly rings.

The base material and design are the same as used in speed pro plasma moly ring sets only the face coating is changed. There hasn t been a us made engine made since 60 or a bit earlier that did not come from the factory with either chrome or moly rings. Chrome has good resistance to scuff but does not exhibit moly s oil retention capabilities. Most grey cast iron rings specify a 150 to 220 grit with 180.

In addition the second rings are reversed twist taper faced cast iron. Also a reason engines with chrome rings burn more oil than iron moly combos. When rings are discussed it usually concerns the top ring only. Hastings compression rings together with the flex vent oil ring provide the ultimate in piston ring set performance.

This actually requires that during break in the ring come in contact with the cylinder wall. Moly rings have a groove cut in them filled with molybendum a soft metal that does magic stuff while regular cast iron rings are just the cast iron material that the whole ring is made of. Chrome rings neccessitate rough bore finishes to hold enough oil to lube the rings as chrome rings hold zilch for oil unlike moly coated rings. Plain cast iron is a durable wear surface in normal operating conditions and is less costly than the moly or chrome faced ring.

The face of the top rings in these sets are electroplated with chromium to provide a surface that is resistant to abrasive wear. Moly has a very high resistance to scuff. These rings are not lapped round and true at the factory. A steel napier second ring and industry leading cp 20 oil ring round out the package.

And the aterials typically used are cast iron moly chrome or ceramic. They are designed so that the final finishing is in the cylinder. When hastings introduced the revolutionary flex vent oil ring to the world in 1956 a new era in automotive engine technology began. Thus they require a coarser cylinder finish than a modern ring.

The difference betwen a standard cast iron ring and an entry level moly ring is just the moly coating on the edge of the ring where it touches the bore. Chrome file fit ring sets are listed by bore diameter and list available over sizes. 8 cyl moly ring set 4 060 size. American cars made before the mid 50s used plain cast rings 90 of them needed.

But all top rings are cast iron either plain or ductile. The material that s referred to the ring facing or the portion of the ring that runs against the cylinder wall.