Valve clearances - significant difference?

[SimonH450P]

Car and engine new to me… So, just checked all valve clearances and cylinders 2-6 are all within spec, nearly all .012, a few .013, only the valves on cylinder 1, both are .016 exhaust /.017 inlet.

Should I be worried, does this imply anything serious with that cylinder? Why is it so far out compared to the others? Is it significant in any way?

Or should I just make adjustments to these two shims and crack on?

[mike020150]

As you are finding out, adjusting tappet clearances isn't a five minute task. Consequently, if you make a mistake and only find out later, or you don't have the correct sized shims to hand whilst doing the job, it's very tempting just to leave things as they are and put up with the extra tapping noise. These days, it's more common for clearances to reduce in use, due to unleaded fuel and valve seat recession, than it is for them to increase. Thus, purely from what you've written, I'd speculate the cause isn't likely to be a fundamental problem. Mike.