I am just making a cam ring for a model three cylinder radial aero engine. This is a new experience for me – first cam I've made! There are just two cams, an exhaust and an inlet, mounted closely together on a cam ring, diameter a tad over 2.5" diameter. The ring is a snug fit on a support piece. As it was a first attempt I made it out of EN1A, not ideal material maybe but given my record of making scrap parts and the likelihood of having to make it again probably a wise move.

In an ideal world the cam would be case hardened, and I would like to do that out of completeness, but again that would be a first for me, so a number of questions arise:

1. If the engine is not going to be used other than once or twice to prove it runs then is it worth it?

2. Will there be any growth in the cam rings as a result of case hardening, and is so, by how much?

3. Will the ring as a whole grow – I want it to still fit on it's support ring after?

4. Is there a way to case harden only the cams and not the rest of the ring? I did read somewhere recently about using fireclay or similar to protect tapped holes, would applying that to the whole of the area to be protected work?

5. Is it normal to case harden cam rings for model IC engines? That should have probably been the first question.

All things for me to ponder over the festive season, but if anyone has been there, done that and can offer thoughts and/or advice then it would be gratefully received.

In the meantime, Merry Christmas to one and all, keep safe

Chris

PS – a final question, how easy is the case hardeneing process?

Edited By ChrisH on 24/12/2020 12:42:23

Thanks Dave – sound advice from you as always

Chris