Yes the shims could be an alloy steel, but what alloy is anybodys guess. It may just be mild steel that was case hardened, they saved a penny anywhere they could get away with it. I used the O1 and hardened the shim after the machine work. There is a picture of the allow tag and heat treating it in the album also.
I would suspect that there was some wear on the shim, the screw and the sector. Looking at the gear angle and the size of the thrust contact I doubt if there was an appreciable amount of end thrust on the lash adjuster.
My guess is that you could use any number of alloys for the shim and get about the same wear from them.
Denny Graham
Sandwich, IL
