Technical Oversized valve stem

[paul in manche]

I've got a loose valve stem in the head that I've had cleaned. Someone I know with a larger shed full of machine tools, and importantly the skill to use them is going to make me up a slightly larger diameter one. Is there a specific diameter that they can go up to?
Many thanks in advance for any assistance.

 

[the hobbler]

I've got a loose valve stem in the head that I've had cleaned. Someone I know with a larger shed full of machine tools, and importantly the skill to use them is going to make me up a slightly larger diameter one. Is there a specific diameter that they can go up to?
Many thanks in advance for any assistance.

I don't know what 'over-size' that you can go to with the valve-guides, but if it helps your colleague, the original valve-guide external dimension was:-- 0.5139 to 0.5143in (13.052 to 13.062mm). If he GENTLY reamed out the orifice that the valve-guide fits, just tp ensure that it is round, the new valve-guides will have to be very little larger than the original---chilled, fitted and allowed to naturally expand possibly only a few thou larger.

 

[paul in manche]

Thanks a lot, just the information I needed to know.
The three left in the head seem to have a tiny bit of variation, the loose one was described as being 'a sliding fit with a tiny bit of wobble' but seems to be on the smaller side of your dimensions.