Date:  03/10/2010   Bulletin Number: 50.3.3.341 

Subject:  Supersession of Ring Set S41846 to S41890 with HVOF Coating                                                                                     

Product Line Part Number(s) Engine Manufacturer Engine Size 

Rings-HV S41846; S41890 CATERPILLAR 3400 SERIES

 Action: 

The S41846 ring set has been superseded to the improved S41890 ring set. 

The S41890 ring set incorporates the advanced process of High Velocity Oxygen Fuel (HVOF) Thermal 

Spray coating PCF380™. 

The HVOF PCF380 coating was originally developed to operate in the harsh environment of the EGR engines and in 

those applications it offers much improved wear characteristics over ring sets using chrome or any of the 

thermal coatings currently available. 

When used in a non-EGR engine the benefits are even more pronounced.

 Tests demonstrate liner and ring wear is reduced by up to 75% when used in conjunction with a hardened liner. 

This is running change and these rings sets can be mixed in an engine without adversely effecting performance.