Hard Chrome failure on Ducati rocker arms!!

[Ago37]

Hello everyone, I am new to the forum and have literally been captured by the technology behind the systems being used today to harden and coat items.

I have been faced with a problem that plagues all Ducati motorcycle owners, flaking/pitting hard chrome valve rockers.

To those not farmiliar with the Ducati engines they have a desmo valve operation that runs a system with no standard valve return spring and very close valve to rocker clearences. This specification linked to poor hard chroming back in Italy has led to awful components failing on all Ducati's from 1997 to 2001.

The hard chroming sometimes breaks away and in other instances pits or simply wears extremely quickly.

I myself have a set of rockers that are wearing badly and have two that are pitting.

I have scoured the web and have thought to myself with modern technology surely hard chroming again is slightly old fashioned and surely a modern method may be, less labour intensive and provide a superior finish.

The contact patches of the rockers are quite small and are not large items.

I hope to find an alternative solution that potentially could be offered to others in the pursuit of solving a problem that has plagued masses!!

[djewell]

There are lots of candidate materials (such as stellite 6), but they will all need to be ground to achieve the surface finish required for use in an engine. Additionally, pre-machining may be necessary to make room for a thermal spray coating. You may be looking at a situation where there is not enough volume to get a repair/remanufacture cost low enough to be able to sell your solution.

[Stephen Booth]

Hi Ago37,

There many possibilities for coatings, processes, and procedures, but first a few questions:

A) how big is the rocker arm, and what is its mass?
b) where is the wear occuring? is it subject to impact on the valve or tappet? I know these engines have some really high RPM and am concerned about thermal spray in that application.

You might consider a GTAW welding processes. Find a workshop that does repair on tool and dies, let them have a shot the part. It would take some hand profiling afterwards.

Material, I like the idea of Stellite 1 or 12

I mention GTAW against Thermal Spray, since its likely across the globe there are probably 1000x as many GTAW machines, and mold shops as there are Thermal Spray. Mold shops are used to doing hand work, and small job, and would have the skill to avoid deformation.