Hello,
I wonder if you have ever tried to use one of these on an a/c cylinder head?
Frankly useless, unless you use spacers and so on rendering the whole thing unstable and DANGEROUS.
For many years I've used a home made cut open piece of box section, with a washer welded on, together with a suitable G clamp.
Tips: put 13 mm nuts on the rocker shafts, this will allow you to put the cyl head in a vice and work comfortably.
beware when you are winding down the valve spring, as the collets will be stuck, and so the whole thing lets go with a bit of a bang.
When you are putting the collets back, use a dab of grease on the inside, and a magnetised thin screwdriver to place them, believe me it makes life easier,
I can take photo of tool if you want, v easy to make, costs nowt, lasts forever, etc,etc,
Cordialement
