MG Car Repair: Engine Miss, valve seat recession, valve adjustment

Question
I just read your procedure on how to diagnose a engine miss on a '66 MGB.  One of the steps you describe adjusting the valves if there is low compression in the cylinder and you said to adjust to .012 and not what the book says.
I have a 1973 engine in a '75 car, does the same gap apply to the 1973 engine?

Answer
Hi Ross,
Yes, while working in MG dealerships we noted that many times we had customer complaints of valve noise, even just after a valve adjustment. We found that the transition ramp of the cam was not right for the valve clearance that MG had quoted and that valve clearance would not be maintained with the valve being knocked off the seat and then dropped on the seat in the head. By trial and error we came to .012" as an alternative clearance that was much quieter and required mush less readjustments. We noted much less valve seat recession and no increase in valve burning. Also NO customer complaints of valve noise after a valve adjustment. On later MGs BLM finally noted that somewhat by decreasing clearance cold down to .013" but still said .015" hot. I tried many MGs hot and cold and only found about .001" difference between hot and cold. Since the early MGs had a head torque on every other inspection we did the valve adjustment cold since the engine had to be cold to torque the head.

For your own information, set the clearance at .012" then heat the engine up and check the clearance for a hot setting.
Howard