[GerhardH]

To measure the gap of the valve guides is not so easy for beginners. In my opinion you need a couple of hours to get a feeling what can be true and what not.
First cleaning of the guides. I used two measurement tools. First digital inside calipper. You have 5 digits thats could be a litte bit confusing because even if you make the identically measurement twice, you dont get the same last digit.
But on the end is easier than expected.
Let say a new valve has 0.341" shaft diameter (and this is over the complete shaft lenght. Than the maximum stem clearance can be inlet 0.0027" + 0.001" and exhaust 0.0027" +0.002". So that means the guide must be less than 0.3447" inlet and 0.3457" outlet. In practice I was measure all inlets and exhausts and was looking that I have no 0.35" at all. I get all guides below the limit. Than I asked an expert, he don't measured the system, only moved a new valve in the guides and told me: "Good for go"! Guide job will only burn additional money and is not necessary yet.

Second I used an inside feeler and micro, was also very suitable and delivered the same results.

Further I measured a brand new bronze insert: 0.342, ok bether than my existing with 0.344 but will do without guide job.