Chrome Moly Rings Break In

Molly rings are not as picky and they are easier on the bore than chrome rings.

Chrome moly rings break in.

In wot dyno testing likely the rings are seated by the end of the first few runs. 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. Break0in time is longer and the ends cannot be filled to increase the end gap. Chrome used today primarily by overseas oems and in industrial engines is a much harder non porous material.

The problem with many chrome faced rings was they were extremely hard and difficult. If you want to go modern than plasma molly rings are the way to go. Also chrome rings should not be used on engine s that run on propane or natural gas. With today s rings especially moly faced versions this can be achieved in a very short period of time and certainly within 20 to 30 miles of street driving.

Recommended cylinder to piston clearance of 0015 thousandths per inch of bore works out to 0035 to 005 thousands. Resistance to abrasive wear is considerably better than moly rings but the bores must be perfectly straight and round. Chrome s extreme density and hardness resists the impingement of dirt into the face of the ring which accelerates cylinder wear and actually contributes to the exhaust gases carrying some of the airborne contaminant out through the exhaust system. Chrome faced rings were popular at one time but have lost favor and aren t used much anymore by engine builders.

Many use them just because of the chrome and they take longer to break in because of this. Some feel that special honeing is required for chrome. The plain non chrome rings are softer and break in right away. Plasma moly is a relatively soft and porous ring facing with excellent oil carrying capacity and comparatively fast conformability break in to the cylinder bore surface.

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. Chrome has more resistance to scuffing and scoring than cast iron but somewhat less than moly. This actually requires that during break in the ring come in contact with the cylinder wall. Most grey cast iron rings specify a 150 to 220 grit with 180 being what we recommend.

The chrome are considered stronger and used in most high perfornance high compression engines and those runing nos.