I had a head job (machine surface and fit new valve guides) done on my 244GL with B21E engine but due to some error somewhere one of the valves now has a clearance of 21 thou (cold), but Haynes states valve clearance should be 12 thou to 16 thou (cold). Car runs OK but has a tapping noise due to excessive clearance of this valve even with new hushers. All other valves are hushed silent. I don't care about the tapping noise - I just want to make sure that this excessive clearance won't damage cam lobe or shim, etc etc. Is this OK? If bad I will remove the offending shim and get another machined to get proper clearance, but only if necessary. Please advise.