[chris_seven]

Walt,

Interesting set of questions and potential problems.

Kasenit is a relatively simple compound that basically allows carbon to diffuse into the surface of a steel when heated above about 850 degC (Sorry for the funny units). It needs to be this hot as ferritic steels have a phase change around this temperature and the solubility of carbon increases significantly. The amount of carbon that will diffuse into the surface depends on the time at temperature (Fick's 2nd Law of Diffusion if I remember correctly).

The idea of heating locally probably won't work because miniumum time would be around 30 minutes and to gain significant depth can take several hours.

The next issue would be the carbon content of the original part. If the carbon level in this part is greater than around 0.2% there really isn't much of a thermodynamic driving force to cause diffusion and results are likely to be poor.

If you could produce a layer of carbon in the surface you would then have to quench the part in a light oil or preferably a modern polymer material such as HoughtonAquaquench.

Finally would would have to temper and stress relieve.

All of these process would need to fairly well controlled to give successful and repeatable results.

If we consider rockers: I thought most 911 rockers were cast and they are likley to have quite a high carbon content and if this is the case they won't respond very well to case hardening. They are also quite likely to distort when quenched.

I would think that stellite hard facing may be a better option but more difficult to do at home.

As regards cams the problems are similar and it is unlikley that you could have sufficient time at temperature to make this process work.

Some performance billet cams made from steel are gas carburised but they invariably bend during quenching and need to be straightened before final grinding.

A large number of production cams are cast and lobes are hardened using chills placed in the mould. These chills rapidly cool the cast iron in the region of the lobe and cause a 'white iron' structure to be developed. White iron is very hard and wear resistant. The rest of the cam is grey iron and is more ductile and shock resistant.

If you regrind such a cam gas nitriding just won't work successfully. You will produce iron nitirdes on the surface and they are very brittle and likely to spall. I think it may be possible to either plasma nitirde or boronise but this could cost more than new cams.

If I had a reground cast iron cam I would Parkerise the surface which would give a good self lubricating layer with excellent oil film retention.

Race cams I would make from a high grade nitriding steel and gas nitride.

Hope this helps