The stellite foot contacts the camshaft. Part is a 7/16" diameter shaft 3" long that is internally threaded on one end to adjust clearance at the valve and the other end is 1/2" x 3/4" where the stellite is soldered on. Think of a tall skinny top hat shape. I am trying to copy exactly how the factory did it in 1929. The valves, springs and half the lifter all run out in the air so are rusty and worn out. What steel they used for this is unknown but it is file hard. The problem I see is heating the part up to melt the solder will take it over 1000 degrees and anneal the steel. I was thinking of using 8620 as I have been making other parts for the engine out of it and pack carburizing with no problems. Perhaps another steel would be better? Another option is to weld hard face in place of the stellite, but can you quench a part from high temp with hard face or will it crack?
In case you think I don't know what I am doing, you are 100% correct. Machining the parts is a piece of cake but the stellite??????????????
How did they do this 89 years ago?
I could perhaps crawl up in the attic and look it up. My oldest metallurgy texts were Dad's, Marshall College, 1926-1929, and bought used at that.
"Ordnance steel" - your 8620 - did, in fact, yield to Stellite here and there. Longer-lives for key parts of crew-served machine guns, IIRC.
Denis friction-welding technique is serious OLD. I've used it. One welds FIRST, then heat-treats the steel. The Stellite just ignores all that - its own critical temperatures "on a higher plane", so to speak.
But I'd not bother, here.
I'd just case-harden the living piss out of 8620, then Parkerize and oil it it to deal with that "exposed" challenge, same as battlefield use has proven to work well, a hundred million weapons or three..
Armaments works were also able to get serious-deep hard-surface penetration in 8620 when they NEEDED that. Other times, thinner "gas carburizing" at high production rates was used where that was good enough.
And.. one CAN weld 8620.. with "some" care.. but waay less trouble than welding 4XXX.
Check the elements in the alloy. They are actually VERY close cousins in most other respects.
Nitriding has been a pragmatic and affordable IC-engine go-to for ages by now, as well. hard Chrome or even electroless Cobalt can deal with a good deal of "scuffing", too.
So long as.. you don't go OCD about "period correct" LUBRICANTS? Modern lubes would let even ignorant 4XXX "pre-hard" live longer in this service than you might expect. Just keep your valve lash religiously adjusted so you are dealing more with sliding than hammer-blows. DAMHIKT.
Whomever specified Stellite, 1929, was attempting to over-Engineer so as to "bubba proof" and/or brag. The material was not yet well-understood, still sort of an "exotic".
It wasn't otherwise common, nor needed, any more than tubular titanium con rods for an otherwise rather marginally engineered and "ephemeral" Ferrari V-12.
Medical professional I once knew pulled the V-12 out of his Ferrari, re-purposed it into a ski boat he ran about five power-on hours in a whole year, if that.
The lovely to look at Ferrari was a much more reliable and docile in traffic daily-driver with a small block Chevy V8 mill. The girls he was always adding to his collection never knew enough about V12/V8 exhaust sound to detect the difference.
They eyeball your ass? Only checking how thick the wallet is!
