Piston ring coatings and uses.

Chrome moly again, I keep hearing this word brought up.
Just to clear this myth up there are piston rings with no coatings referred to as cast rings, most of the various ring materials including cast and ductile can be used with out coatings to perform well.
For light duty engines that will see light to moderate use and little high speed and or heavy load use and which aren't subject to heavy dust or high heat these rings work just fine.
In fact these rings are used more than any other for low end crate engines and low cost rebuilds.

The second type is a Chrome ring.
It has a cast ductile or steel base and a chrome plated face.
The chrome is very hard and resist scuffing and scoring.
In addition the hard face will not easily pick up grit like a plain face ring and is recommended for use in very dusty conditions such as gravel pits, dirt roads and dirt tracks.
Instead of trapping dirt and debris that can scratch up the cylinder it is scrapped off and returned to the oil where it can be filtered out.
Once very popular before the perfection of better coatings there are some disadvantages in terms of engine life,sealing characteristics and temperature resistance that can come up.
Finally there is the moly ring, not chrome moly there is no such thing it is either moly or chrome not both.
A moly ring has a groove cut into the face of the ring that is filled with molybdenum.
One way that this is done is to insert a moly wire into the groove with a flame spray process.
The other is plasma moly these are use in high performance race engines.
This involves spraying a durable moly compound using a plasma arc process into the ring groove to fill it and permanently bond it with the ring base material.  
Engine builder,self taught auto body guy.
Horsepower sells engines and torque wins races

Very good post, thanks for putting it up.

 
When The Flag Drops,,,



The Bull Chit Stops,,,


P. Engineer, Engine Builder

Thanks tuff.
No problem.  
Engine builder,self taught auto body guy.
Horsepower sells engines and torque wins races