I need your help Phil. See my Feb. 3 posting for the history of this problem. As you suggested, I ordered a new pressure flange and installed it today with the steel gears. The knocking was as bad as ever. I only ran the engine for a few seconds, but when I removed the gears and the new flange I could see a faint groove on its front side corresponding to the hub of the cam gear. There was also an even fainter groove on the backside of the flange, presumably from the front cam journal. Presumably back and forth movement of the cam caused these groove patterns and also likely explains the knocking.

I reread your posting of Feb 3 and I concluded that that the spacer ring should protrude .003” beyond the front face of the flange. In my engine the front of the spacer ring sits about .030” recessed back from the front face of the pressure flange. The Woodruff key keeps the ring from being drawn forward to be even flush with the flange. The only way that I can see for this situation to exist is for the cam itself to be too far back. Not having banged, tapped, or otherwise exerted any backward force on the cam or the gear, I can only conclude this was the situation before I started the gear swap-out. Note that with the original fiber gear set and even when I earlier reinstalled the fiber gear set, there was no knocking. Could one conclude that the fibre gear is more elastic that the steel and therefore less likely to drive the cam back and forth?

As I understand things, I will have to pull the engine and reposition the plug in the rear of the block to bring the cam back to its proper location. Is this the recommended next step?

Thanks as always.
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Barry '67 122S "Betty", '69 122S "Veronica"