RReid

Hi Roger, Hi Per. Thank you both!

Thank you for those photos, Alex. The V-12 was a logical development derived from the V8, and the family resemblance clearly shows in those pictures.

Better the boss than THE BOSS (you). Nice post cussing save.

Hello AVTUR, CNR, and Mike - good to hear from you all, and Thanks!

Hello Peter - The threaded top cap represents the adjusting cap of the full size originals. In my case it is screwed down hard, so rotation is not a concern. The spring cup does ride partly within the valve bore, thereby absorbing the side load as the cam sweeps across.

I started making those notches using a slitting saw, since that was on hand. But it's no longer as sharp as it once was (like me), so I will order some 0.032" end mills to do that job with. I also need to order a fresher 1-72 threading die. So with that I've switched to making up some valves.

Back on page 6 of this thread is a brief discussion of the clever and patented H-S adjustable valve tappet assembly, and whether I could or should try to replicate it in my build. In the end I settled on a good suggestion from Mike (Vixen) that is much simpler to make and more robust at this size, while still retaining a reasonably accurate appearance.

Now, almost exactly two years later (!!) I've gotten around to making a first sample in metal. Happily it turned out pretty well. Only fifteen more sets to go.

Maybe RReid will chime in. Maybe I missed, I dont recall seeing the spark plug size or resultant CR.

Hello Petertha,
You do understand the drawing shown correctly. The coolant space is the profile dimensioned 0.55". The narrow profiles above and below are 0-ring grooves. The hole above, in the fat lip, is for the spark plug, which is a #10 (10-40 threads). The designed CR is 5:1. At this point it all of the completed assemblies fit together correctly, and rotate freely. The valve train has not been competed yet, but the cam drive mechanism has and has been tested with a dummy camshaft.